UltimateZoneBuilder/Source/Plugins/BuilderModes/VisualModes/BaseVisualMode.cs

#region ================== Copyright (c) 2007 Pascal vd Heiden

/*
 * Copyright (c) 2007 Pascal vd Heiden, www.codeimp.com
 * This program is released under GNU General Public License
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 */

#endregion

#region ================== Namespaces

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Windows.Forms;
using CodeImp.DoomBuilder.BuilderModes.Interface;
using CodeImp.DoomBuilder.Windows;
using CodeImp.DoomBuilder.Map;
using CodeImp.DoomBuilder.Rendering;
using CodeImp.DoomBuilder.Geometry;
using CodeImp.DoomBuilder.Editing;
using CodeImp.DoomBuilder.Actions;
using CodeImp.DoomBuilder.VisualModes;
using CodeImp.DoomBuilder.Config;
using CodeImp.DoomBuilder.GZBuilder.Data;
using CodeImp.DoomBuilder.Types;
using CodeImp.DoomBuilder.Data;

#endregion

namespace CodeImp.DoomBuilder.BuilderModes
{
	[EditMode(DisplayName = "Visual Mode",
			  SwitchAction = "gzdbvisualmode", // Action name used to switch to this mode
			  ButtonImage = "VisualMode.png",	// Image resource name for the button
			  ButtonOrder = 1,					// Position of the button (lower is more to the left)
			  ButtonGroup = "001_visual",
			  UseByDefault = true)]

	public class BaseVisualMode : VisualMode
	{
		#region ================== Constants
		// Object picking
		private const long PICK_INTERVAL = 80;
		private const long PICK_INTERVAL_PAINT_SELECT = 10; // biwa

		// Gravity
		private const float GRAVITY = -0.06f;
		
		#endregion
		
		#region ================== Variables

		// Gravity
		private Vector3D gravity;
		private double cameraflooroffset = 41.0;		// same as in doom
		private double cameraceilingoffset = 10.0;
		
		// Object picking
		private VisualPickResult target;
		private long lastpicktime;
		private bool locktarget;
		private bool useSelectionFromClassicMode;//mxd
		private readonly Timer selectioninfoupdatetimer; //mxd

		// This keeps extra element info
		private Dictionary<Sector, SectorData> sectordata;
		private Dictionary<Thing, ThingData> thingdata;
		private Dictionary<Vertex, VertexData> vertexdata; //mxd
		//private Dictionary<Thing, EffectDynamicLight> lightdata; //mxd
		
		// This is true when a selection was made because the action is performed
		// on an object that was not selected. In this case the previous selection
		// is cleared and the targeted object is temporarely selected to perform
		// the action on. After the action is completed, the object is deselected.
		private bool singleselection;
		
		// We keep these to determine if we need to make a new undo level
		private bool selectionchanged;
		private int lastundogroup;
		private VisualActionResult actionresult;
		private bool undocreated;

		// List of selected objects when an action is performed
		private List<IVisualEventReceiver> selectedobjects;
		
		//mxd. Used in Cut/PasteSelection actions
		private readonly List<ThingCopyData> copybuffer;
		private Type lasthighlighttype;

		// biwa. Info for paint selection
		protected bool paintselectpressed;
		protected Type paintselecttype = null;
		protected IVisualPickable highlighted; // biwa

		//mxd. Moved here from Tools
		private struct SidedefAlignJob
		{
			public Sidedef sidedef;

			public double offsetx;
			public double scaleX; //mxd
			public double scaleY; //mxd

			private Sidedef controlside; //mxd
			public Sidedef controlSide
			{
				get
				{
					return controlside;
				}
				set
				{
					controlside = value;
					ceilingheight = (controlside.Index != sidedef.Index && controlside.Line.Args[1] == 0 ? controlside.Sector.FloorHeight : controlside.Sector.CeilHeight);
				}
			}

			private int ceilingheight; //mxd
			public int ceilingHeight { get { return ceilingheight; } } //mxd

			// When this is true, the previous sidedef was on the left of
			// this one and the texture X offset of this sidedef can be set
			// directly. When this is false, the length of this sidedef
			// must be subtracted from the X offset first.
			public bool forward;
		}
		
		#endregion
		
		#region ================== Properties

		public override object HighlightedObject
		{
			get
			{
				// Geometry picked?
				VisualGeometry vg = target.picked as VisualGeometry;
				if(vg != null)
				{
					if(vg.Sidedef != null) return vg.Sidedef;
					if(vg.Sector != null) return vg.Sector;
					return null;
				}
				// Thing picked?
				VisualThing vt = target.picked as VisualThing;
				if(vt != null) return vt.Thing;

				return null;
			}
		}

		public object HighlightedTarget { get { return target.picked; } } //mxd
		public bool UseSelectionFromClassicMode { get { return useSelectionFromClassicMode; } } //mxd

		new public IRenderer3D Renderer { get { return renderer; } }
		
		public bool IsSingleSelection { get { return singleselection; } }
		public bool SelectionChanged { get { return selectionchanged; } set { selectionchanged |= value; } }

		public bool PaintSelectPressed { get { return paintselectpressed; } } // biwa
		public Type PaintSelectType { get { return paintselecttype; } set { paintselecttype = value; } } // biwa
		public IVisualPickable Highlighted { get { return highlighted; } } // biwa

		#endregion
		
		#region ================== Constructor / Disposer

		// Constructor
		public BaseVisualMode()
		{
			// Initialize
			this.gravity = new Vector3D(0.0f, 0.0f, 0.0f);
			this.selectedobjects = new List<IVisualEventReceiver>();
			
			//mxd
			this.copybuffer = new List<ThingCopyData>();
			this.selectioninfoupdatetimer = new Timer();
			selectioninfoupdatetimer.Interval = 100;
			selectioninfoupdatetimer.Tick += SelectioninfoupdatetimerOnTick;
			
			// We have no destructor
			GC.SuppressFinalize(this);
		}

		// Disposer
		public override void Dispose()
		{
			// Not already disposed?
			if(!isdisposed)
			{
				// Clean up
				selectioninfoupdatetimer.Dispose(); //mxd
				
				// Done
				base.Dispose();
			}
		}

		#endregion
		
		#region ================== Methods

		// This calculates brightness level
		internal int CalculateBrightness(int level)
		{
			return renderer.CalculateBrightness(level);
		}

		//mxd. This calculates brightness level with doom-style shading
		internal int CalculateBrightness(int level, Sidedef sd) 
		{
			return renderer.CalculateBrightness(level, sd);
		}
		
		// This adds a selected object
		internal void AddSelectedObject(IVisualEventReceiver obj)
		{
			selectedobjects.Add(obj);
			selectionchanged = true;
			selectioninfoupdatetimer.Start(); //mxd
		}
		
		// This removes a selected object
		internal void RemoveSelectedObject(IVisualEventReceiver obj)
		{
			selectedobjects.Remove(obj);
			selectionchanged = true;
			selectioninfoupdatetimer.Start(); //mxd
		}
		
		// This is called before an action is performed
		public void PreAction(int multiselectionundogroup)
		{
			actionresult = new VisualActionResult();

			PickTargetUnlocked();

			// If the action is not performed on a selected object, clear the
			// current selection and make a temporary selection for the target.
			if ((target.picked != null) && !target.picked.Selected && (BuilderPlug.Me.VisualModeClearSelection || (selectedobjects.Count == 0)))
			{
				// Single object, no selection
				singleselection = true;

				// Only clear the selection if anything is selected, since it can be very time consuming on huge maps
				if(BuilderPlug.Me.VisualModeClearSelection && selectedobjects.Count > 0)
					ClearSelection();

				undocreated = false;
			}
			else
			{
				singleselection = false;
				
				// Check if we should make a new undo level
				// We don't want to do this if this is the same action with the same
				// selection and the action wants to group the undo levels
				if((lastundogroup != multiselectionundogroup) || (lastundogroup == UndoGroup.None) ||
				   (multiselectionundogroup == UndoGroup.None) || selectionchanged)
				{
					// We want to create a new undo level, but not just yet
					lastundogroup = multiselectionundogroup;
					undocreated = false;
				}
				else
				{
					// We don't want to make a new undo level (changes will be combined)
					undocreated = true;
				}
			}
		}

		// Called before an action is performed. This does not make an undo level
		private void PreActionNoChange()
		{
			actionresult = new VisualActionResult();
			singleselection = false;
			undocreated = false;
		}
		
		// This is called after an action is performed
		private void PostAction()
		{
			if(!string.IsNullOrEmpty(actionresult.displaystatus))
				General.Interface.DisplayStatus(StatusType.Action, actionresult.displaystatus);

			// Reset changed flags
			foreach(KeyValuePair<Sector, VisualSector> vs in allsectors)
			{
				BaseVisualSector bvs = (BaseVisualSector)vs.Value;
				foreach(VisualFloor vf in bvs.ExtraFloors) vf.Changed = false;
				foreach(VisualCeiling vc in bvs.ExtraCeilings) vc.Changed = false;
				foreach(VisualFloor vf in bvs.ExtraBackFloors) vf.Changed = false; //mxd
				foreach(VisualCeiling vc in bvs.ExtraBackCeilings) vc.Changed = false; //mxd
				bvs.Floor.Changed = false;
				bvs.Ceiling.Changed = false;
			}
			
			selectionchanged = false;

			// Only clear the selection if anything is selected, since it can be very time consuming on huge maps
			if (singleselection && selectedobjects.Count > 0) ClearSelection();
			
			UpdateChangedObjects();
			ShowTargetInfo();
		}
		
		// This sets the result for an action
		public void SetActionResult(VisualActionResult result)
		{
			actionresult = result;
		}

		// This sets the result for an action
		public void SetActionResult(string displaystatus)
		{
			actionresult = new VisualActionResult {displaystatus = displaystatus};
		}
		
		// This creates an undo, when only a single selection is made
		// When a multi-selection is made, the undo is created by the PreAction function
		public int CreateUndo(string description, int group, int grouptag)
		{
			if(!undocreated)
			{
				undocreated = true;

				if(singleselection)
					return General.Map.UndoRedo.CreateUndo(description, this, group, grouptag);
				return General.Map.UndoRedo.CreateUndo(description, this, UndoGroup.None, 0);
			}

			return 0;
		}

		// This creates an undo, when only a single selection is made
		// When a multi-selection is made, the undo is created by the PreAction function
		public int CreateUndo(string description)
		{
			return CreateUndo(description, UndoGroup.None, 0);
		}

		// This makes a list of the selected object
		private void RebuildSelectedObjectsList()
		{
			// Make list of selected objects
			selectedobjects = new List<IVisualEventReceiver>();
			foreach(KeyValuePair<Sector, VisualSector> vs in allsectors)
			{
				if(vs.Value != null)
				{
					BaseVisualSector bvs = (BaseVisualSector)vs.Value;
					if((bvs.Floor != null) && bvs.Floor.Selected) selectedobjects.Add(bvs.Floor);
					if((bvs.Ceiling != null) && bvs.Ceiling.Selected) selectedobjects.Add(bvs.Ceiling);
					
					// Also check extra floors
					if (bvs.ExtraFloors.Count > 0)
						foreach (VisualFloor vf in bvs.ExtraFloors)
							if (vf.Selected) selectedobjects.Add(vf);

					if (bvs.ExtraBackFloors.Count > 0)
						foreach (VisualFloor vf in bvs.ExtraBackFloors)
							if (vf.Selected) selectedobjects.Add(vf);

					// Also check extra ceilings
					if (bvs.ExtraCeilings.Count > 0)
						foreach (VisualCeiling vc in bvs.ExtraCeilings)
							if (vc.Selected) selectedobjects.Add(vc);

					if (bvs.ExtraBackCeilings.Count > 0)
						foreach (VisualCeiling vc in bvs.ExtraBackCeilings)
							if (vc.Selected) selectedobjects.Add(vc);

					foreach (Sidedef sd in vs.Key.Sidedefs)
					{
						List<VisualGeometry> sidedefgeos = bvs.GetSidedefGeometry(sd);
						foreach(VisualGeometry sdg in sidedefgeos)
						{
							if(sdg.Selected) selectedobjects.Add((IVisualEventReceiver)sdg);
						}
					}
				}
			}

			foreach(KeyValuePair<Thing, VisualThing> vt in allthings)
			{
				if(vt.Value != null)
				{
					BaseVisualThing bvt = (BaseVisualThing)vt.Value;
					if(bvt.Selected) selectedobjects.Add(bvt);
				}
			}

			//mxd
			if(General.Map.UDMF && General.Settings.GZShowVisualVertices) 
			{
				foreach(KeyValuePair<Vertex, VisualVertexPair> pair in vertices) 
				{
					if(pair.Value.CeilingVertex.Selected)
						selectedobjects.Add((BaseVisualVertex)pair.Value.CeilingVertex);
					if(pair.Value.FloorVertex.Selected)
						selectedobjects.Add((BaseVisualVertex)pair.Value.FloorVertex);
				}
			}

			if (General.Map.UDMF)
			{
				foreach (KeyValuePair<Sector, List<VisualSlope>> kvp in allslopehandles)
				{
					foreach (BaseVisualSlope handle in kvp.Value)
						if (handle.Selected) selectedobjects.Add(handle);
				}
			}

			//mxd
			UpdateSelectionInfo();
		}

		//mxd. Need this to apply changes to 3d-floor even if control sector doesn't exist as BaseVisualSector
		internal BaseVisualSector CreateBaseVisualSector(Sector s) 
		{
			BaseVisualSector vs = new BaseVisualSector(this, s);
			allsectors.Add(s, vs);
			return vs;
		}

		// This creates a visual sector
		protected override VisualSector CreateVisualSector(Sector s)
		{
			BaseVisualSector vs = new BaseVisualSector(this, s);
			allsectors.Add(s, vs); //mxd
			return vs;
		}

		internal VisualSlope CreateVisualSlopeHandle(SectorLevel level, Sidedef sd, bool up)
		{
			VisualSidedefSlope handle = new VisualSidedefSlope(this, level, sd, up);

			if (!allslopehandles.ContainsKey(sd.Sector))
				allslopehandles.Add(sd.Sector, new List<VisualSlope>());

			if (!sidedefslopehandles.ContainsKey(sd.Sector))
				sidedefslopehandles.Add(sd.Sector, new List<VisualSlope>());

			allslopehandles[sd.Sector].Add(handle);
			sidedefslopehandles[sd.Sector].Add(handle);

			return handle;
		}

		internal VisualSlope CreateVisualSlopeHandle(SectorLevel level, Vertex v, Sector s, bool up)
		{
			VisualVertexSlope handle = new VisualVertexSlope(this, level, v, s, up);

			/*
			if (!allslopehandles.ContainsKey(level.sector))
				allslopehandles.Add(level.sector, new List<VisualSlope>());

			if (!vertexslopehandles.ContainsKey(level.sector))
				vertexslopehandles.Add(level.sector, new List<VisualSlope>());

			allslopehandles[level.sector].Add(handle);
			vertexslopehandles[level.sector].Add(handle);
			*/

			if (!allslopehandles.ContainsKey(s))
				allslopehandles.Add(s, new List<VisualSlope>());

			if (!vertexslopehandles.ContainsKey(s))
				vertexslopehandles.Add(s, new List<VisualSlope>());

			allslopehandles[s].Add(handle);
			vertexslopehandles[s].Add(handle);

			return handle;
		}

		// This creates a visual thing
		protected override VisualThing CreateVisualThing(Thing t)
		{
			BaseVisualThing vt = new BaseVisualThing(this, t);
			return vt.Setup() ? vt : null;
		}

		// This locks the target so that it isn't changed until unlocked
		public void LockTarget()
		{
			locktarget = true;
		}
		
		// This unlocks the target so that is changes to the aimed geometry again
		public void UnlockTarget()
		{
			locktarget = false;
		}
		
		// This picks a new target, if not locked
		private void PickTargetUnlocked()
		{
			if(!locktarget) PickTarget();
		}
		
		// This picks a new target
		private void PickTarget()
		{
			// Find the object we are aiming at
			Vector3D start = General.Map.VisualCamera.Position;
			Vector3D delta = General.Map.VisualCamera.Target - General.Map.VisualCamera.Position;
			delta = delta.GetFixedLength(General.Settings.ViewDistance * PICK_RANGE);
			VisualPickResult newtarget = PickObject(start, start + delta);
			VisualSlope pickedhandle = null;
			
			// Should we update the info on panels?
			bool updateinfo = (newtarget.picked != target.picked);

			// Operating on slope handles is potentially expensive, so only do it it absolutely necessary (i.e. when a new slope handle was selected)
			if (updateinfo)
			{
				if (target.picked is VisualSlope) // Old target
				{
					// Remove all smart pivot handles from being processed. There should only be exactly one, but better save than sorry
					List<VisualSlope> sph = new List<VisualSlope>();

					foreach (VisualSlope vs in usedslopehandles)
					{
						if(vs.SmartPivot && !(vs.Selected || vs.Pivot))
							sph.Add(vs);

						vs.SmartPivot = false;
					}

					foreach (VisualSlope vs in sph)
						usedslopehandles.Remove(vs);

					// Don't render old slope handle anymore
					if (!((VisualSlope)target.picked).Selected && !((VisualSlope)target.picked).Pivot)
						usedslopehandles.Remove((VisualSlope)target.picked);
				}

				if(newtarget.picked is VisualSlope)
				{
					usedslopehandles.Add((VisualSlope)newtarget.picked);

					pickedhandle = ((VisualSlope)newtarget.picked);
				}
			}

			// Apply new target
			target = newtarget;

			// Get the smart pivot handle for the targeted slope handle, so that it can be drawn. We have to do it after the current
			// target is set because otherwise it might get wrong results if the old target was a floor/ceiling
			if (pickedhandle != null)
			{
				VisualSlope handle = pickedhandle.GetSmartPivotHandle();
				if (handle != null)
				{
					handle.SmartPivot = true;
					usedslopehandles.Add(handle);
				}
			}

			// Show target info
			if (updateinfo)
				ShowTargetInfo();
		}

		// This shows the picked target information
		public void ShowTargetInfo()
		{
			// Any result?
			if(target.picked != null)
			{
				// Geometry picked?
				if(target.picked is VisualGeometry)
				{
					VisualGeometry pickedgeo = (VisualGeometry)target.picked;
					
					// Sidedef?
					if(pickedgeo is BaseVisualGeometrySidedef)
					{
						BaseVisualGeometrySidedef pickedsidedef = (BaseVisualGeometrySidedef)pickedgeo;
						General.Interface.ShowLinedefInfo(pickedsidedef.GetControlLinedef(), pickedsidedef.Sidedef); //mxd
					}
					// Sector?
					else if(pickedgeo is BaseVisualGeometrySector)
					{
						BaseVisualGeometrySector pickedsector = (BaseVisualGeometrySector)pickedgeo;
						bool isceiling = (pickedsector is VisualCeiling); //mxd
						General.Interface.ShowSectorInfo(pickedsector.Level.sector, isceiling, !isceiling);
					}
					else
					{
						General.Interface.HideInfo();
					}
				} 
				// Thing picked?
				else if(target.picked is VisualThing) 
				{ 
					VisualThing pickedthing = (VisualThing)target.picked;
					General.Interface.ShowThingInfo(pickedthing.Thing);
				} 
				//mxd. Vertex picked?
				else if(target.picked is VisualVertex)
				{
					VisualVertex pickedvert = (VisualVertex)target.picked;
					General.Interface.ShowVertexInfo(pickedvert.Vertex);
				}
			}
			else
			{
				General.Interface.HideInfo();
			}
		}
		
		// This updates the VisualSectors and VisualThings that have their Changed property set
		private void UpdateChangedObjects()
		{
			foreach(KeyValuePair<Sector, VisualSector> vs in allsectors)
			{
				if(vs.Value != null)
				{
					BaseVisualSector bvs = (BaseVisualSector)vs.Value;
					if(bvs.Changed)
					{
						bvs.Rebuild();

						// Also update slope handles
						if (allslopehandles.ContainsKey(vs.Key))
							foreach (VisualSlope handle in allslopehandles[vs.Key])
								handle.Update();
					}
				}
			}

			foreach(KeyValuePair<Thing, VisualThing> vt in allthings)
			{
				if(vt.Value != null)
				{
					BaseVisualThing bvt = (BaseVisualThing)vt.Value;
					if(bvt.Changed) bvt.Rebuild();
				}
			}

			//mxd
			if(General.Map.UDMF) 
			{
				foreach(KeyValuePair<Vertex, VisualVertexPair> pair in vertices)
					pair.Value.Update();
			}

			//mxd. Update event lines (still better than updating them on every frame redraw)
			renderer.SetEventLines(LinksCollector.GetHelperShapes(General.Map.ThingsFilter.VisibleThings, blockmap));
		}

		//mxd
		protected override void MoveSelectedThings(Vector2D direction, bool absoluteposition) 
		{
			List<VisualThing> visualthings = GetSelectedVisualThings(true);
			if(visualthings.Count == 0) return;

			PreAction(UndoGroup.ThingMove);

			Vector3D[] coords = new Vector3D[visualthings.Count];
			for(int i = 0; i < visualthings.Count; i++)
				coords[i] = visualthings[i].Thing.Position;

			//move things...
			Vector3D[] translatedcoords = TranslateCoordinates(coords, direction, absoluteposition);
			for(int i = 0; i < visualthings.Count; i++) 
			{
				BaseVisualThing t = (BaseVisualThing)visualthings[i];
				t.OnMove(translatedcoords[i]);
			}

			// Things may've changed sectors...
			FillBlockMap();

			PostAction();
		}

		//mxd
		private static Vector3D[] TranslateCoordinates(Vector3D[] coordinates, Vector2D direction, bool absolutePosition) 
		{
			if(coordinates.Length == 0) return null;

			direction.x = Math.Round(direction.x);
			direction.y = Math.Round(direction.y);

			Vector3D[] translatedCoords = new Vector3D[coordinates.Length];

			//move things...
			if(!absolutePosition) //...relatively (that's easy)
			{ 
				int camAngle = (int)Math.Round(Angle2D.RadToDeg(General.Map.VisualCamera.AngleXY));
				int sector = General.ClampAngle(camAngle - 45) / 90;
				direction = direction.GetRotated(sector * Angle2D.PIHALF);

				for(int i = 0; i < coordinates.Length; i++)
					translatedCoords[i] = coordinates[i] + new Vector3D(direction);

				return translatedCoords;
			}

			//...to specified location preserving relative positioning (that's harder)
			if(coordinates.Length == 1) //just move it there
			{
				translatedCoords[0] = new Vector3D(direction.x, direction.y, coordinates[0].z);
				return translatedCoords;
			}

			//we need some reference
			double minX = coordinates[0].x;
			double maxX = minX;
			double minY = coordinates[0].y;
			double maxY = minY;

			//get bounding coordinates for selected things
			for(int i = 1; i < coordinates.Length; i++) 
			{
				if(coordinates[i].x < minX)
					minX = coordinates[i].x;
				else if(coordinates[i].x > maxX)
					maxX = coordinates[i].x;

				if(coordinates[i].y < minY)
					minY = coordinates[i].y;
				else if(coordinates[i].y > maxY)
					maxY = coordinates[i].y;
			}

			Vector2D selectionCenter = new Vector2D(minX + (maxX - minX) / 2, minY + (maxY - minY) / 2);

			//move them
			for(int i = 0; i < coordinates.Length; i++)
				translatedCoords[i] = new Vector3D(Math.Round(direction.x - (selectionCenter.x - coordinates[i].x)), Math.Round(direction.y - (selectionCenter.y - coordinates[i].y)), Math.Round(coordinates[i].z));

			return translatedCoords;
		}

		//mxd
		public override void UpdateSelectionInfo() 
		{
			// Collect info
			int numWalls = 0;
			int numFloors = 0;
			int numCeilings = 0;
			int numThings = 0;
			int numVerts = 0;

			foreach(IVisualEventReceiver obj in selectedobjects) 
			{
				if(!obj.Selected) continue;

				if(obj is BaseVisualThing) numThings++;
				else if(obj is BaseVisualVertex) numVerts++;
				else if(obj is VisualCeiling) numCeilings++;
				else if(obj is VisualFloor)	numFloors++;
				else if(obj is VisualMiddleSingle || obj is VisualMiddleDouble || obj is VisualLower || obj is VisualUpper || obj is VisualMiddle3D || obj is VisualMiddleBack)
					numWalls++;
			}

			List<string> results = new List<string>();
			if(numWalls > 0) results.Add(numWalls + (numWalls > 1 ? " sidedefs" : " sidedef"));
			if(numFloors > 0) results.Add(numFloors + (numFloors > 1 ? " floors" : " floor"));
			if(numCeilings > 0) results.Add(numCeilings + (numCeilings > 1 ? " ceilings" : " ceiling"));
			if(numThings > 0) results.Add(numThings + (numThings > 1 ? " things" : " thing"));
			if(numVerts > 0) results.Add(numVerts + (numVerts > 1 ? " vertices" : " vertex"));

			// Display results
			string result = string.Empty;
			if(results.Count > 0) 
			{
				result = string.Join(", ", results.ToArray());
				int pos = result.LastIndexOf(",", StringComparison.Ordinal);
				if(pos != -1) result = result.Remove(pos, 1).Insert(pos, " and");
				result += " selected.";
			}

			General.Interface.DisplayStatus(StatusType.Selection, result);
		}

		//mxd
		internal void StartRealtimeInterfaceUpdate(SelectionType selectiontype)
		{
			switch(selectiontype)
			{
				case SelectionType.All:
				case SelectionType.Linedefs:
				case SelectionType.Sectors:
					General.Interface.OnEditFormValuesChanged += Interface_OnSectorEditFormValuesChanged;
					break;
				case SelectionType.Things:
					General.Interface.OnEditFormValuesChanged += Interface_OnThingEditFormValuesChanged;
					break;
				default:
					General.Interface.OnEditFormValuesChanged += Interface_OnEditFormValuesChanged;
					break;
			}
		}

		//mxd
		internal void StopRealtimeInterfaceUpdate(SelectionType selectiontype)
		{
			switch(selectiontype)
			{
				case SelectionType.All:
				case SelectionType.Linedefs:
				case SelectionType.Sectors:
					General.Interface.OnEditFormValuesChanged -= Interface_OnSectorEditFormValuesChanged;
					break;
				case SelectionType.Things:
					General.Interface.OnEditFormValuesChanged -= Interface_OnThingEditFormValuesChanged;
					break;
				default:
					General.Interface.OnEditFormValuesChanged -= Interface_OnEditFormValuesChanged;
					break;
			}
		}

		private List<VisualSidedefSlope> GetSlopeHandlePair()
		{
			List<VisualSidedefSlope> handles = GetSelectedSlopeHandles();

			// No handles selected, try to slope between highlighted handle and it smart pivot
			if (handles.Count == 0 && HighlightedTarget is VisualSidedefSlope)
			{
				//VisualSidedefSlope handle = VisualSidedefSlope.GetSmartPivotHandle((VisualSidedefSlope)HighlightedTarget, this);
				VisualSidedefSlope handle = (VisualSidedefSlope)((VisualSidedefSlope)HighlightedTarget).GetSmartPivotHandle();
				if (handle == null)
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Couldn't find a smart pivot handle.");
					return handles;
				}

				handles.Add((VisualSidedefSlope)HighlightedTarget);
				handles.Add(handle);
			}
			// One handle selected, try to slope between it and the highlighted handle or the selected one's smart pivot
			else if (handles.Count == 1)
			{
				if (HighlightedTarget == handles[0] || !(HighlightedTarget is VisualSidedefSlope))
				{
					VisualSidedefSlope handle;

					if (HighlightedTarget is VisualSidedefSlope)
						handle = (VisualSidedefSlope)((VisualSidedefSlope)HighlightedTarget).GetSmartPivotHandle();
					else
						handle = (VisualSidedefSlope)(handles[0].GetSmartPivotHandle());

					if (handle == null)
					{
						General.Interface.DisplayStatus(StatusType.Warning, "Couldn't find a smart pivot handle.");
						return handles;
					}

					handles.Add(handle);
				}
				else
				{
					handles.Add((VisualSidedefSlope)HighlightedTarget);
				}
			}
			// Return if more than two handles are selected
			else if (handles.Count > 2)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Too many slope handles selected.");
				return handles;
			}
			// Everything else
			else if (handles.Count != 2)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "No slope handles selected or highlighted.");
				return handles;
			}

			return handles;
		}
		
		#endregion

		#region ================== Extended Methods

		// This requests a sector's extra data
		internal SectorData GetSectorData(Sector s)
		{
			// Make fresh sector data when it doesn't exist yet
			if(!sectordata.ContainsKey(s))
				sectordata[s] = new SectorData(this, s);
			
			return sectordata[s];
		}

		//mxd. This requests a sector's extra data or null if given sector doesn't have it
		internal SectorData GetSectorDataEx(Sector s)
		{
			return (sectordata.ContainsKey(s) ? sectordata[s] : null);
		}

		// This requests a things's extra data
		internal ThingData GetThingData(Thing t)
		{
			// Make fresh sector data when it doesn't exist yet
			if(!thingdata.ContainsKey(t))
				thingdata[t] = new ThingData(this, t);
			
			return thingdata[t];
		}

		//mxd
		internal VertexData GetVertexData(Vertex v) 
		{
			if(!vertexdata.ContainsKey(v))
				vertexdata[v] = new VertexData(this, v);
			return vertexdata[v];
		}

		internal BaseVisualVertex GetVisualVertex(Vertex v, bool floor) 
		{
			if(!vertices.ContainsKey(v))
				vertices.Add(v, new VisualVertexPair(new BaseVisualVertex(this, v, false), new BaseVisualVertex(this, v, true)));

			return (floor ? (BaseVisualVertex)vertices[v].FloorVertex : (BaseVisualVertex)vertices[v].CeilingVertex);
		}

		//mxd
		internal void UpdateVertexHandle(Vertex v) 
		{
			if(!vertices.ContainsKey(v))
				vertices.Add(v, new VisualVertexPair(new BaseVisualVertex(this, v, false), new BaseVisualVertex(this, v, true)));
			else
				vertices[v].Changed = true;
		}
		
		// This rebuilds the sector data
		// This requires that the blockmap is up-to-date!
		internal void RebuildElementData()
		{
			HashSet<Sector> effectsectors = null; //mxd
			List<Linedef>[] slopelinedefpass = new List<Linedef>[] { new List<Linedef>(), new List<Linedef>() };
			List<Thing>[] slopethingpass = new List<Thing>[] { new List<Thing>(), new List<Thing>() };

			if (!General.Settings.EnhancedRenderingEffects) //mxd
			{
				// Store all sectors with effects
				if(sectordata != null && sectordata.Count > 0) 
					effectsectors = new HashSet<Sector>(sectordata.Keys);

				// Remove all vertex handles from selection
				if(vertices != null && vertices.Count > 0) 
				{
                    for (int i = 0; i < selectedobjects.Count; i++)
                    {
                        if (selectedobjects[i] is BaseVisualVertex)
                        {
                            RemoveSelectedObject(selectedobjects[i]);
                            i--;
                        }
                    }
				}
			}

			Dictionary<int, List<Sector>> sectortags = new Dictionary<int, List<Sector>>();
			Dictionary<int, List<Thing>> thingtags = new Dictionary<int, List<Thing>>();
			Dictionary<int, List<Linedef>> linetags = new Dictionary<int, List<Linedef>>();
			sectordata = new Dictionary<Sector, SectorData>(General.Map.Map.Sectors.Count);
			thingdata = new Dictionary<Thing, ThingData>(General.Map.Map.Things.Count);

			//mxd. Rebuild all sectors with effects
			if(effectsectors != null) 
			{
				foreach(Sector s in effectsectors)
				{
					if(!VisualSectorExists(s)) continue;

					// The visual sector associated is now outdated
					BaseVisualSector vs = (BaseVisualSector)GetVisualSector(s);
					vs.UpdateSectorGeometry(true);
				}
			}

			if(General.Map.UDMF) 
			{
				vertexdata = new Dictionary<Vertex, VertexData>(General.Map.Map.Vertices.Count); //mxd
				vertices.Clear();
			}

			if(!General.Settings.EnhancedRenderingEffects) return; //mxd
			
			// Find all sector who's tag is not 0 and hash them so that we can find them quickly
			foreach(Sector s in General.Map.Map.Sectors)
			{
				foreach(int tag in s.Tags)
				{
					if(tag == 0) continue;
					if(!sectortags.ContainsKey(tag)) sectortags[tag] = new List<Sector>();
					sectortags[tag].Add(s);
				}

				// ========== Thing vertex slope, vertices with UDMF vertex offsets ==========
				if (s.Sidedefs.Count == 3)
				{
					if (General.Map.UDMF) GetSectorData(s).AddEffectVertexOffset(); //mxd
					List<Thing> slopeceilingthings = new List<Thing>(3);
					List<Thing> slopefloorthings = new List<Thing>(3);

					foreach (Sidedef sd in s.Sidedefs)
					{
						Vertex v = sd.IsFront ? sd.Line.End : sd.Line.Start;

						// Check if a thing is at this vertex
						foreach (VisualBlockEntry block in blockmap.GetBlocks(v.Position))
						{
							foreach (Thing t in block.Things)
							{
								if ((Vector2D)t.Position == v.Position)
								{
									switch (t.Type)
									{
										case 1504: slopefloorthings.Add(t); break;
										case 1505: slopeceilingthings.Add(t); break;
									}
								}
							}
						}
					}

					// Slope any floor vertices?
					if (slopefloorthings.Count > 0)
					{
						SectorData sd = GetSectorData(s);
						sd.AddEffectThingVertexSlope(slopefloorthings, true);
					}

					// Slope any ceiling vertices?
					if (slopeceilingthings.Count > 0)
					{
						SectorData sd = GetSectorData(s);
						sd.AddEffectThingVertexSlope(slopeceilingthings, false);
					}
				}
			}

			// Find interesting things (such as sector slopes)
			// Pass one of slope things, and determine which one are for pass two
			//TODO: rewrite using classnames instead of numbers
			foreach (Thing t in General.Map.Map.Things)
			{
				// SRB2
				if (t.Type == 750)
				{
					if (!thingtags.ContainsKey(t.Tag)) thingtags[t.Tag] = new List<Thing>();
					thingtags[t.Tag].Add(t);
				}
				continue;

				switch (t.Type)
				{
					// ========== Copy slope ==========
					case 9511:
					case 9510:
						slopethingpass[1].Add(t);
						break;

					// ========== Thing line slope ==========
					case 9501:
					case 9500:
						if (linetags.ContainsKey(t.Args[0]))
						{
							// Only slope each sector once, even when multiple lines of the same sector are tagged. See https://github.com/jewalky/UltimateDoomBuilder/issues/491
							List<Sector> slopedsectors = new List<Sector>();

							foreach (Linedef ld in linetags[t.Args[0]])
							{
								if (ld.Line.GetSideOfLine(t.Position) < 0.0f)
								{
									if (ld.Front != null && !slopedsectors.Contains(ld.Front.Sector))
									{
										GetSectorData(ld.Front.Sector).AddEffectThingLineSlope(t, ld.Front);
										slopedsectors.Add(ld.Front.Sector);
									}
								}
								else if (ld.Back != null && !slopedsectors.Contains(ld.Back.Sector))
								{
									GetSectorData(ld.Back.Sector).AddEffectThingLineSlope(t, ld.Back);
									slopedsectors.Add(ld.Back.Sector);
								}
							}
						}
						break;

					// ========== Thing slope ==========
					case 9503:
					case 9502:
						t.DetermineSector(blockmap);
						if (t.Sector != null)
						{
							SectorData sd = GetSectorData(t.Sector);
							sd.AddEffectThingSlope(t);
						}
						break;
				}
			}

			// Find interesting linedefs (such as line slopes)
			// This also determines which slope lines belong to pass one and pass two. See https://zdoom.org/wiki/Slope
			foreach (Linedef l in General.Map.Map.Linedefs)
			{
				// Builds a cache of linedef ids/tags. Used for slope things. Use linedef tags in UDMF
				if(General.Map.UDMF)
				{
					foreach(int tag in l.Tags)
					{
						if (!linetags.ContainsKey(tag)) linetags[tag] = new List<Linedef>();
						linetags[tag].Add(l);
					}
				}

				//mxd. Rewritten to use action ID instead of number
				if (l.Action == 0 || !General.Map.Config.LinedefActions.ContainsKey(l.Action)) continue;

				switch(General.Map.Config.LinedefActions[l.Action].Id.ToLowerInvariant())
				{
					// ========== Line Set Identification (121) (see https://zdoom.org/wiki/Line_SetIdentification) ==========
					// Builds a cache of linedef ids/tags. Used for slope things. Only used for Hexen format
					case "line_setidentification":
						int tag = l.Args[0] + l.Args[4] * 256;
						if (!linetags.ContainsKey(tag)) linetags[tag] = new List<Linedef>();
						linetags[tag].Add(l);
						break;

					// ========== Plane Align (181) (see http://zdoom.org/wiki/Plane_Align) ==========
					case "plane_align":
						slopelinedefpass[0].Add(l);
						break;

					// ========== Plane Copy (118) (mxd) (see http://zdoom.org/wiki/Plane_Copy) ==========
					case "plane_copy":
						slopelinedefpass[1].Add(l);
						break;

					case "srb2_vertexslope":
					{
						List<Thing> sourcethings = new List<Thing>();
						if (!thingtags.ContainsKey(l.Args[1]) || thingtags[l.Args[1]].Count == 0)
							break;
						foreach (Thing thing in thingtags[l.Args[1]])
						{
							if (sourcethings.Contains(thing))
								continue;
							sourcethings.Add(thing);
							break;
						}
						if (!thingtags.ContainsKey(l.Args[2]) || thingtags[l.Args[2]].Count == 0)
							break;
						foreach (Thing thing in thingtags[l.Args[2]])
						{
							if (sourcethings.Contains(thing))
								continue;
							sourcethings.Add(thing);
							break;
						}
						if (!thingtags.ContainsKey(l.Args[3]) || thingtags[l.Args[3]].Count == 0)
							break;
						foreach (Thing thing in thingtags[l.Args[3]])
						{
							if (sourcethings.Contains(thing))
								continue;
							sourcethings.Add(thing);
							break;
						}
						SectorData sd = GetSectorData((l.Args[0] < 2) ? l.Front.Sector : l.Back.Sector);
						sd.AddEffectSRB2ThingVertexSlope(sourcethings, (l.Args[0] & 1) != 1);
						break;
					}

					// ========== Sector 3D floor (160) (see http://zdoom.org/wiki/Sector_Set3dFloor) ==========
					case "sector_set3dfloor":
						if(l.Front != null)
						{
							//mxd. Added hi-tag/line ID check 
							int sectortag = (General.Map.UDMF || (l.Args[1] & (int)Effect3DFloor.FloorTypes.HiTagIsLineID) != 0) ? l.Args[0] : l.Args[0] + (l.Args[4] << 8);
							if(sectortags.ContainsKey(sectortag)) 
							{
								List<Sector> sectors = sectortags[sectortag];
								foreach(Sector s in sectors) 
								{
									SectorData sd = GetSectorData(s);
									sd.AddEffect3DFloor(l);
								}
							}
						}
						break;

					case "srb2_fofsolid":
					case "srb2_fofwater":
					case "srb2_fofsolidopaque":
					case "srb2_fofcrumbling":
					case "srb2_fofintangible":
					case "srb2_fofbustable":
					case "srb2_foflaser":
					case "srb2_fofcustom":
						if (l.Front != null && sectortags.ContainsKey(l.Args[0]))
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach (Sector s in sectors)
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffect3DFloor(l);
							}
						}
						break;

					case "srb2_foflight":
					case "srb2_foffog":
					case "srb2_fofintangibleinvisible":
						if (l.Front != null && sectortags.ContainsKey(l.Args[0]))
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach (Sector s in sectors)
							{
								SectorData sd = GetSectorData(s);
								//sd.AddEffectBrightnessLevel(l);
								sd.AddEffect3DFloor(l);
							}
						}
						break;

					// ========== Transfer Brightness (50) (see http://zdoom.org/wiki/ExtraFloor_LightOnly) =========
					case "extrafloor_lightonly":
						if(l.Front != null && sectortags.ContainsKey(l.Args[0]))
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach(Sector s in sectors) 
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectBrightnessLevel(l);
							}
						}
						break;

					// ========== mxd. Transfer Floor Brightness (210) (see http://www.zdoom.org/w/index.php?title=Transfer_FloorLight) =========
					case "transfer_floorlight":
						if(l.Front != null && sectortags.ContainsKey(l.Args[0])) 
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach(Sector s in sectors) 
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectTransferFloorBrightness(l);
							}
						}
						break;

					// ========== mxd. Transfer Ceiling Brightness (211) (see http://www.zdoom.org/w/index.php?title=Transfer_CeilingLight) =========
					case "transfer_ceilinglight":
						if(l.Front != null && sectortags.ContainsKey(l.Args[0])) 
						{
							List<Sector> sectors = sectortags[l.Args[0]];
							foreach(Sector s in sectors) 
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectTransferCeilingBrightness(l);
							}
						}
						break;

					// ========== mxd. BOOM: Set Tagged Floor Lighting to Lighting on 1st Sidedef's Sector (213) =========
					case "boom_transfer_floorlight":
						if(l.Front != null && sectortags.ContainsKey(l.Tag))
						{
							List<Sector> sectors = sectortags[l.Tag];
							foreach(Sector s in sectors)
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectTransferFloorBrightness(l);
							}
						}
						break;

					// ========== mxd. BOOM: Set Tagged Ceiling Lighting to Lighting on 1st Sidedef's Sector (261) =========
					case "boom_transfer_ceilinglight":
						if(l.Front != null && sectortags.ContainsKey(l.Tag))
						{
							List<Sector> sectors = sectortags[l.Tag];
							foreach(Sector s in sectors)
							{
								SectorData sd = GetSectorData(s);
								sd.AddEffectTransferCeilingBrightness(l);
							}
						}
						break;
				}
			}

			// Pass one for linedefs
			foreach (Linedef l in slopelinedefpass[0])
			{
				//mxd. Rewritten to use action ID instead of number
				if (l.Action == 0 || !General.Map.Config.LinedefActions.ContainsKey(l.Action)) continue;

				switch (General.Map.Config.LinedefActions[l.Action].Id.ToLowerInvariant())
				{
					// ========== Plane Align (181) (see http://zdoom.org/wiki/Plane_Align) ==========
					case "plane_align":
						if (((l.Args[0] == 1) || (l.Args[1] == 1)) && (l.Front != null))
						{
							SectorData sd = GetSectorData(l.Front.Sector);
							sd.AddEffectLineSlope(l);
						}
						if (((l.Args[0] == 2) || (l.Args[1] == 2)) && (l.Back != null))
						{
							SectorData sd = GetSectorData(l.Back.Sector);
							sd.AddEffectLineSlope(l);
						}
						break;
				}
			}

			// Pass two of slope things
			//TODO: rewrite using classnames instead of numbers
			foreach (Thing t in slopethingpass[1])
			{
				switch (t.Type)
				{
					// ========== Copy slope ==========
					case 9511:
					case 9510:
						t.DetermineSector(blockmap);
						if (t.Sector != null)
						{
							SectorData sd = GetSectorData(t.Sector);
							sd.AddEffectCopySlope(t);
						}
						break;
				}
			}
			

			// Pass two for linedefs
			foreach (Linedef l in slopelinedefpass[1])
			{
				if (l.Action == 0 || !General.Map.Config.LinedefActions.ContainsKey(l.Action)) continue;

				switch (General.Map.Config.LinedefActions[l.Action].Id.ToLowerInvariant())
				{
					// ========== Plane Copy (118) (mxd) (see http://zdoom.org/wiki/Plane_Copy) ==========
					case "plane_copy":
						{
							//check the flags...
							bool floorCopyToBack = false;
							bool floorCopyToFront = false;
							bool ceilingCopyToBack = false;
							bool ceilingCopyToFront = false;

							if (l.Args[4] > 0 && l.Args[4] != 3 && l.Args[4] != 12)
							{
								floorCopyToBack = (l.Args[4] & 1) == 1;
								floorCopyToFront = (l.Args[4] & 2) == 2;
								ceilingCopyToBack = (l.Args[4] & 4) == 4;
								ceilingCopyToFront = (l.Args[4] & 8) == 8;
							}

							// Copy slope to front sector
							if (l.Front != null)
							{
								if ((l.Args[0] > 0 || l.Args[1] > 0) || (l.Back != null && (floorCopyToFront || ceilingCopyToFront)))
								{
									SectorData sd = GetSectorData(l.Front.Sector);
									sd.AddEffectPlaneClopySlope(l, true);
								}
							}

							// Copy slope to back sector
							if (l.Back != null)
							{
								if ((l.Args[2] > 0 || l.Args[3] > 0) || (l.Front != null && (floorCopyToBack || ceilingCopyToBack)))
								{
									SectorData sd = GetSectorData(l.Back.Sector);
									sd.AddEffectPlaneClopySlope(l, false);
								}
							}
						}
						break;
				}
			}

			// Visual slope handles
			foreach (KeyValuePair<Sector, List<VisualSlope>> kvp in allslopehandles)
			{
				foreach (VisualSlope handle in kvp.Value)
					if (handle != null && handle.Selected)
						if (handle is BaseVisualSlope)
							RemoveSelectedObject((BaseVisualSlope)handle);

				kvp.Value.Clear();
			}
			usedslopehandles.Clear();
			allslopehandles.Clear();
			sidedefslopehandles.Clear();
			vertexslopehandles.Clear();

			BuildSlopeHandles(General.Map.Map.Sectors.ToList());
		}

		private void BuildSlopeHandles(List<Sector> sectors)
		{
			if (!General.Map.UDMF)
				return;

			foreach (Sector s in sectors)
			{
				if (s.IsDisposed)
					continue;

				SectorData sectordata = GetSectorData(s);
				sectordata.Update();

				// Clear old data
				if (allslopehandles.ContainsKey(s)) allslopehandles.Remove(s);
				if (sidedefslopehandles.ContainsKey(s))	sidedefslopehandles.Remove(s);
				if (vertexslopehandles.ContainsKey(s)) vertexslopehandles.Remove(s);


				// Create visual sidedef slope handles
				foreach (Sidedef sidedef in s.Sidedefs)
				{
					// Create handles for the regular floor and ceiling
					CreateVisualSlopeHandle(sectordata.Floor, sidedef, true);
					CreateVisualSlopeHandle(sectordata.Ceiling, sidedef, false);

					// Create handles for 3D floors
					if (sectordata.ExtraFloors.Count > 0)
					{
						foreach (Effect3DFloor floor in sectordata.ExtraFloors)
						{
							CreateVisualSlopeHandle(floor.Floor, sidedef, false);
							CreateVisualSlopeHandle(floor.Ceiling, sidedef, true);
						}
					}
				}
			}

			// Create visual vertex slope handles
			foreach(Vertex v in General.Map.Map.Vertices)
			{
				if (v.IsDisposed || v.Linedefs.Count == 0)
					continue;

				HashSet<Sector> vertexsectors = new HashSet<Sector>();

				// Find all sectors that have lines connected to this vertex
				foreach(Linedef ld in v.Linedefs)
				{
					if (ld.IsDisposed)
						continue;

					if (ld.Front != null && ld.Front.Sector != null && !ld.Front.Sector.IsDisposed) vertexsectors.Add(ld.Front.Sector);
					if (ld.Back != null && ld.Back.Sector != null && !ld.Back.Sector.IsDisposed) vertexsectors.Add(ld.Back.Sector);
				}

				foreach(Sector s in vertexsectors)
				{
					SectorData sectordata = GetSectorData(s);
					sectordata.Update();

					// Create handles for the regular floor and ceiling
					CreateVisualSlopeHandle(sectordata.Floor, v, s, true);
					CreateVisualSlopeHandle(sectordata.Ceiling, v, s, false);

					// Create handles for 3D floors
					if (sectordata.ExtraFloors.Count > 0)
					{
						foreach (Effect3DFloor floor in sectordata.ExtraFloors)
						{
							CreateVisualSlopeHandle(floor.Floor, v, s, false);
							CreateVisualSlopeHandle(floor.Ceiling, v, s, true);
						}
					}
				}
			}
		}
		
		#endregion

		#region ================== Events

		// Help!
		public override void OnHelp()
		{
			General.ShowHelp("e_visual.html");
		}

		// When entering this mode
		public override void OnEngage()
		{
			//mxd
			useSelectionFromClassicMode = BuilderPlug.Me.SyncSelection ? !General.Interface.ShiftState : General.Interface.ShiftState;
			if(useSelectionFromClassicMode)	UpdateSelectionInfo();

			// Read settings
			cameraflooroffset = General.Map.Config.ReadSetting("cameraflooroffset", cameraflooroffset);
			cameraceilingoffset = General.Map.Config.ReadSetting("cameraceilingoffset", cameraceilingoffset);

            //mxd. Update fog color (otherwise FogBoundaries won't be setup correctly)
            foreach (Sector s in General.Map.Map.Sectors)
                s.UpdateFogColor();

			// biwa. We need a blockmap for the slope things. Can't wait until it's built in base.OnEngage
			// This was the root cause for issue #160
			FillBlockMap();

            // (Re)create special effects
            RebuildElementData();

			// Objects are only selected when they are created, so for objects that are selected we have to make sure
			// that they are created immediately. Otherwise the selection order will not be correct, or the objects
			// will not be selected at all if they are out of the user's camera range when entering visual mode
			// See https://github.com/jewalky/UltimateDoomBuilder/issues/938
			if (useSelectionFromClassicMode)
			{
				foreach (Sector s in General.Map.Map.GetSelectedSectors(true))
				{
					BaseVisualSector bvs = CreateBaseVisualSector(s);
					bvs.Ceiling.PerformAutoSelection();
					bvs.Floor.PerformAutoSelection();
				}

				// Things are automatically selected on creation
				foreach (Thing t in General.Map.Map.GetSelectedThings(true))
					allthings[t] = CreateVisualThing(t);

				// For linedefs it's a bit more complicated...
				foreach (Linedef ld in General.Map.Map.GetSelectedLinedefs(true))
				{
					foreach (Sidedef sd in new Sidedef[] { ld.Front, ld.Back })
					{
						if (sd != null)
						{
							if (!allsectors.ContainsKey(sd.Sector))
								CreateBaseVisualSector(sd.Sector).Rebuild(); // We have to rebuild the sector so that potential 3D floors get created

							VisualSidedefParts vsp = ((BaseVisualSector)allsectors[sd.Sector]).Sides[sd];
							vsp.upper?.PerformAutoSelection();
							vsp.middlesingle?.PerformAutoSelection();
							vsp.middledouble?.PerformAutoSelection();
							vsp.lower?.PerformAutoSelection();

							if (vsp.middle3d != null)
								foreach (VisualMiddle3D vm in vsp.middle3d)
									vm.PerformAutoSelection();

							if (vsp.middleback != null)
								foreach (VisualMiddleBack vm in vsp.middleback)
									vm.PerformAutoSelection();
						}
					}
				}
			}

			//mxd. Update event lines
			renderer.SetEventLines(LinksCollector.GetHelperShapes(General.Map.ThingsFilter.VisibleThings, blockmap));

            // [ZZ] this enables calling of this object from the outside world. Only after properly initialized pls.
            base.OnEngage();
        }

		// When returning to another mode
		public override void OnDisengage()
		{
			base.OnDisengage();

			//mxd
			if(BuilderPlug.Me.SyncSelection ? !General.Interface.ShiftState : General.Interface.ShiftState)
			{
				//clear previously selected stuff
				General.Map.Map.ClearAllSelected();
				
				//refill selection
				List<int> selectedsectorindices = new List<int>();
				List<int> selectedlineindices = new List<int>();
				List<int> selectedvertexindices = new List<int>();

				foreach(IVisualEventReceiver obj in selectedobjects)
				{
					if(obj is BaseVisualThing) 
					{
						((BaseVisualThing)obj).Thing.Selected = true;
					}
					else if(obj is VisualFloor || obj is VisualCeiling) 
					{
						VisualGeometry vg = (VisualGeometry)obj;
						if(vg.Sector != null && vg.Sector.Sector != null && !selectedsectorindices.Contains(vg.Sector.Sector.Index))
						{
							selectedsectorindices.Add(vg.Sector.Sector.Index);
							vg.Sector.Sector.Selected = true;
						}
					}
					else if(obj is VisualLower || obj is VisualUpper || obj is VisualMiddleDouble 
						|| obj is VisualMiddleSingle || obj is VisualMiddle3D) 
					{
						VisualGeometry vg = (VisualGeometry)obj;
						if(vg.Sidedef != null && !selectedlineindices.Contains(vg.Sidedef.Line.Index))
						{
							selectedlineindices.Add(vg.Sidedef.Line.Index);
							vg.Sidedef.Line.Selected = true;
						}
					}
					else if(obj is VisualVertex)
					{
						VisualVertex v = (VisualVertex)obj;
						if(!selectedvertexindices.Contains(v.Vertex.Index))
						{
							selectedvertexindices.Add(v.Vertex.Index);
							v.Vertex.Selected = true;
						}
					}
				}
			}

			General.Map.Map.Update();
		}
		
		// Processing
		public override void OnProcess(long deltatime)
		{
			long pickinterval = PICK_INTERVAL; // biwa
			// Process things?
			base.ProcessThings = (BuilderPlug.Me.ShowVisualThings != 0);
			
			// Setup the move multiplier depending on gravity
			Vector3D movemultiplier = new Vector3D(1.0, 1.0, 1.0);
			if(BuilderPlug.Me.UseGravity) movemultiplier.z = 0.0;
			General.Map.VisualCamera.MoveMultiplier = movemultiplier;
			
			// Apply gravity?
			if(BuilderPlug.Me.UseGravity && (General.Map.VisualCamera.Sector != null))
			{
				SectorData sd = GetSectorData(General.Map.VisualCamera.Sector);
				if(!sd.Updated) sd.Update();

				// Camera below floor level?
				Vector3D feetposition = General.Map.VisualCamera.Position;
				SectorLevel floorlevel = sd.GetFloorBelow(feetposition) ?? sd.Floor;
				double floorheight = floorlevel.plane.GetZ(General.Map.VisualCamera.Position);
				if(General.Map.VisualCamera.Position.z < (floorheight + cameraflooroffset + 0.1))
				{
					// Stay above floor
					gravity = new Vector3D(0.0, 0.0, 0.0);
					General.Map.VisualCamera.Position = new Vector3D(General.Map.VisualCamera.Position.x,
																	 General.Map.VisualCamera.Position.y,
																	 floorheight + cameraflooroffset);
				}
				else
				{
					// Fall down
					gravity.z += GRAVITY * General.Map.VisualCamera.Gravity * deltatime;
					if(gravity.z > 3.0) gravity.z = 3.0;

					// Test if we don't go through a floor
					if((General.Map.VisualCamera.Position.z + gravity.z) < (floorheight + cameraflooroffset + 0.1))
					{
						// Stay above floor
						gravity = new Vector3D(0.0, 0.0, 0.0);
						General.Map.VisualCamera.Position = new Vector3D(General.Map.VisualCamera.Position.x,
																		 General.Map.VisualCamera.Position.y,
																		 floorheight + cameraflooroffset);
					}
					else
					{
						// Apply gravity vector
						General.Map.VisualCamera.Position += gravity;
					}
				}

				// Camera above ceiling?
				feetposition = General.Map.VisualCamera.Position - new Vector3D(0, 0, cameraflooroffset - 7.0);
				SectorLevel ceillevel = sd.GetCeilingAbove(feetposition) ?? sd.Ceiling;
				double ceilheight = ceillevel.plane.GetZ(General.Map.VisualCamera.Position);
				if(General.Map.VisualCamera.Position.z > (ceilheight - cameraceilingoffset - 0.01))
				{
					// Stay below ceiling
					General.Map.VisualCamera.Position = new Vector3D(General.Map.VisualCamera.Position.x,
																	 General.Map.VisualCamera.Position.y,
																	 ceilheight - cameraceilingoffset);
				}
			}
			else
			{
				gravity = new Vector3D(0.0, 0.0, 0.0);
			}
			
			// Do processing
			base.OnProcess(deltatime);

			// Process visible geometry
			foreach(IVisualEventReceiver g in visiblegeometry)
			{
				g.OnProcess(deltatime);
			}

			// biwa. Use a lower pick interval for paint selection, to make it more reliable
			if (paintselectpressed)
				pickinterval = PICK_INTERVAL_PAINT_SELECT;
			
			// Time to pick a new target?
			if(Clock.CurrentTime > (lastpicktime + pickinterval))
			{
				PickTargetUnlocked();
				lastpicktime = Clock.CurrentTime;
			}
			
			// The mouse is always in motion
			MouseEventArgs args = new MouseEventArgs(General.Interface.MouseButtons, 0, 0, 0, 0);
			OnMouseMove(args);
		}

		//mxd
		public override void OnClockReset()
		{
			base.OnClockReset();
			lastpicktime = 0;
		}

		// This draws a frame
		public override void OnRedrawDisplay()
		{
			renderer.SetClassicLightingColorMap(General.Map.Data.MainColorMap);

			// Start drawing
			if(renderer.Start())
			{
				// Use fog!
				renderer.SetFogMode(true);

				// Set target for highlighting
				renderer.ShowSelection = General.Settings.GZOldHighlightMode || General.Settings.UseHighlight; //mxd

				if(General.Settings.UseHighlight)
					renderer.SetHighlightedObject(target.picked);
				
				// Begin with geometry
				renderer.StartGeometry();

				// Render all visible sectors
				foreach(VisualGeometry g in visiblegeometry)
					renderer.AddSectorGeometry(g);

				if(BuilderPlug.Me.ShowVisualThings != 0)
				{
					// Render things in cages?
					renderer.DrawThingCages = ((BuilderPlug.Me.ShowVisualThings & 2) != 0);
					
					// Render all visible things
					foreach(VisualThing t in visiblethings)
						renderer.AddThingGeometry(t);
				}

				//mxd
				if(General.Map.UDMF && General.Settings.GZShowVisualVertices && vertices.Count > 0) 
				{
					List<VisualVertex> verts = new List<VisualVertex>();

					foreach(KeyValuePair<Vertex, VisualVertexPair> pair in vertices)
						verts.AddRange(pair.Value.Vertices);

					renderer.SetVisualVertices(verts);
				}

				renderer.SetVisualSlopeHandles(usedslopehandles);

				// Done rendering geometry
				renderer.FinishGeometry();
				
				// Render crosshair
				renderer.RenderCrosshair();
				
				// Present!
				renderer.Finish();
			}
		}
		
		// After resources were reloaded
		protected override void ResourcesReloaded()
		{
			base.ResourcesReloaded();
			RebuildElementData();
			UpdateChangedObjects(); //mxd
			PickTarget();
		}
		
		// This usually happens when geometry is changed by undo, redo, cut or paste actions
		// and uses the marks to check what needs to be reloaded.
		protected override void ResourcesReloadedPartial()
		{
			// Let the core do this (it will just dispose the sectors that were changed)
			base.ResourcesReloadedPartial();

			if (General.Map.UndoRedo.GeometryChanged)
			{
				// The base doesn't know anything about slobe handles, so we have to clear them up ourself
				if (General.Map.UDMF)
				{
					List<Sector> removedsectors = new List<Sector>();

					// Get the sectors that were disposed...
					foreach(Sector s in allslopehandles.Keys)
					{
						if (s.IsDisposed)
							removedsectors.Add(s);
					}

					// ... so that we can remove their slope handles
					foreach(Sector s in removedsectors)
					{
						allslopehandles[s].Clear();
						allslopehandles.Remove(s);

						sidedefslopehandles[s].Clear();
						sidedefslopehandles.Remove(s);

						vertexslopehandles[s].Clear();
						vertexslopehandles.Remove(s);
					}

					// Rebuild slope handles for the changed sectors
					BuildSlopeHandles(General.Map.Map.GetMarkedSectors(true));
				}
			}
			else
			{
				bool sectorsmarked = false;

				// Neighbour sectors must be updated as well
				foreach (Sector s in General.Map.Map.Sectors)
				{
					if(s.Marked)
					{
						sectorsmarked = true;
						foreach(Sidedef sd in s.Sidedefs)
						{
							sd.Marked = true;
							if(sd.Other != null) sd.Other.Marked = true;
						}
					}
				}
				
				// Go for all sidedefs to update
				foreach(Sidedef sd in General.Map.Map.Sidedefs)
				{
					if(sd.Marked && VisualSectorExists(sd.Sector))
					{
						BaseVisualSector vs = (BaseVisualSector)GetVisualSector(sd.Sector);
						VisualSidedefParts parts = vs.GetSidedefParts(sd);
						parts.SetupAllParts();
					}
				}
				
				// Go for all sectors to update
				foreach(Sector s in General.Map.Map.Sectors)
				{
					if(s.Marked)
					{
						SectorData sd = GetSectorDataEx(s);
						if(sd != null)
						{
							sd.Reset(false); //mxd (changed Reset implementation)

							// UpdateSectorGeometry for associated sectors (sd.UpdateAlso) as well!
							foreach(KeyValuePair<Sector, bool> us in sd.UpdateAlso)
							{
								if(VisualSectorExists(us.Key))
								{
									BaseVisualSector vs = (BaseVisualSector)GetVisualSector(us.Key);
									vs.UpdateSectorGeometry(us.Value);
								}
							}
						}
						
						// And update for this sector ofcourse
						if(VisualSectorExists(s))
						{
							BaseVisualSector vs = (BaseVisualSector)GetVisualSector(s);
							vs.UpdateSectorGeometry(false);
						}
					}
				}
				
				if(!sectorsmarked)
				{
					// No sectors or geometry changed. So we only have
					// to update things when they have changed.
					HashSet<Thing> toremove = new HashSet<Thing>(); //mxd
					foreach(KeyValuePair<Thing, VisualThing> vt in allthings)
					{
						if((vt.Value != null) && vt.Key.Marked)
						{
							if(vt.Key.IsDisposed) toremove.Add(vt.Key); //mxd. Disposed things will cause problems
							else ((BaseVisualThing)vt.Value).Rebuild();
						}
					}

					//mxd. Remove disposed things
					foreach(Thing t in toremove)
					{
						if(allthings[t] != null) allthings[t].Dispose();
						allthings.Remove(t);
					}
				}
				else
				{
					// Things depend on the sector they are in and because we can't
					// easily determine which ones changed, we dispose all things
					foreach(KeyValuePair<Thing, VisualThing> vt in allthings)
						if(vt.Value != null) vt.Value.Dispose();
					
					// Apply new lists
					allthings = new Dictionary<Thing, VisualThing>(allthings.Count);
				}
				
				// Clear visibility collections
				visiblesectors.Clear();
				visibleblocks.Clear();
				visiblegeometry.Clear();
				visiblethings.Clear();
				
				// Make new blockmap
				if(sectorsmarked || General.Map.UndoRedo.PopulationChanged || General.Map.IsChanged)
					FillBlockMap();
				
				RebuildElementData();
				UpdateChangedObjects();
				
				// Visibility culling (this re-creates the needed resources)
				DoCulling();
			}
			
			// Determine what we're aiming at now
			PickTarget();
		}
		
		// Mouse moves
		public override void OnMouseMove(MouseEventArgs e)
		{
			base.OnMouseMove(e);
			IVisualEventReceiver o = GetTargetEventReceiver(true);
			o.OnMouseMove(e);

			//mxd. Show hints!
			if(o.GetType() != lasthighlighttype) 
			{
				if(General.Interface.ActiveDockerTabName == "Help") 
				{
					if(o is BaseVisualGeometrySidedef) 
					{
						General.Hints.ShowHints(this.GetType(), "sidedefs");
					}
					else if(o is BaseVisualGeometrySector) 
					{
						General.Hints.ShowHints(this.GetType(), "sectors");
					}
					else if(o is BaseVisualThing) 
					{
						General.Hints.ShowHints(this.GetType(), "things");
					}
					else if(o is BaseVisualVertex) 
					{
						General.Hints.ShowHints(this.GetType(), "vertices");
					}
					else 
					{
						General.Hints.ShowHints(this.GetType(), HintsManager.GENERAL);
					}
				}

				lasthighlighttype = o.GetType();
			}

			// biwa
			if (o is NullVisualEventReceiver)
				highlighted = null;
			else if (o is VisualGeometry)
				highlighted = (VisualGeometry)o;
			else if (o is VisualThing)
				highlighted = (VisualThing)o;
		}
		
		// Undo performed
		public override void OnUndoEnd()
		{
			base.OnUndoEnd();

			//mxd. Effects may've become invalid
			if(sectordata != null && sectordata.Count > 0) RebuildElementData();

			//mxd. As well as geometry...
			foreach(VisualSector sector in visiblesectors)
			{
				BaseVisualSector vs = (BaseVisualSector)sector;
				if(vs != null) vs.Rebuild();
			}

			RebuildSelectedObjectsList();
			
			// We can't group with this undo level anymore
			lastundogroup = UndoGroup.None;
		}
		
		// Redo performed
		public override void OnRedoEnd()
		{
			base.OnRedoEnd();

			//mxd. Effects may've become invalid
			if(sectordata != null && sectordata.Count > 0) RebuildElementData();

			//mxd. As well as geometry...
			foreach(VisualSector sector in visiblesectors) 
			{
				BaseVisualSector vs = (BaseVisualSector)sector;
				if(vs != null) vs.Rebuild();
			}

			RebuildSelectedObjectsList();
		}

		public override void OnScriptRunEnd()
		{
			base.OnScriptRunEnd();

			FillBlockMap();

			// Effects may've become invalid
			if (sectordata != null && sectordata.Count > 0) RebuildElementData();

			// As well as geometry...
			foreach (VisualSector sector in visiblesectors)
			{
				BaseVisualSector vs = (BaseVisualSector)sector;
				if (vs != null) vs.Rebuild();
			}

			RebuildSelectedObjectsList();
		}

		//mxd
		private void Interface_OnSectorEditFormValuesChanged(object sender, EventArgs e) 
		{
			if(allsectors == null) return;

			// Reset changed flags
			foreach(KeyValuePair<Sector, VisualSector> vs in allsectors) 
			{
				BaseVisualSector bvs = (BaseVisualSector)vs.Value;
				foreach(VisualFloor vf in bvs.ExtraFloors) vf.Changed = false;
				foreach(VisualCeiling vc in bvs.ExtraCeilings) vc.Changed = false;
				foreach(VisualFloor vf in bvs.ExtraBackFloors) vf.Changed = false;
				foreach(VisualCeiling vc in bvs.ExtraBackCeilings) vc.Changed = false;
				bvs.Floor.Changed = false;
				bvs.Ceiling.Changed = false;
			}

			UpdateChangedObjects();
			ShowTargetInfo();
		}

		//mxd
		private void Interface_OnThingEditFormValuesChanged(object sender, EventArgs e) 
		{
			//update visual sectors, which are affected by certain things
			List<Thing> things = GetSelectedThings();
			foreach(Thing t in things) 
			{
				if(thingdata.ContainsKey(t)) 
				{
					// Update what must be updated
					ThingData td = GetThingData(t);
					foreach(KeyValuePair<Sector, bool> s in td.UpdateAlso) 
					{
						if(VisualSectorExists(s.Key)) 
						{
							BaseVisualSector vs = (BaseVisualSector)GetVisualSector(s.Key);
							vs.UpdateSectorGeometry(s.Value);
						}
					}
				}
			}
			
			UpdateChangedObjects();
			ShowTargetInfo();
		}

		//mxd
		private void Interface_OnEditFormValuesChanged(object sender, EventArgs e) 
		{
			UpdateChangedObjects();
			ShowTargetInfo();
		}

		private void Interface_OnUpdateChangedObjects(object sender, EventArgs e)
		{
			UpdateChangedObjects();
		}

		//mxd
		private void SelectioninfoupdatetimerOnTick(object sender, EventArgs eventArgs) 
		{
			selectioninfoupdatetimer.Stop();
			UpdateSelectionInfo();
		}
		
		#endregion

		#region ================== Action Assist

		// Because some actions can only be called on a single (the targeted) object because
		// they show a dialog window or something, these functions help applying the result
		// to all compatible selected objects.
		
		// Apply texture offsets
		public void ApplyTextureOffsetChange(int dx, int dy)
		{
			List<IVisualEventReceiver> objs = GetSelectedObjects(false, true, false, false, false);
			
			//mxd. Because Upper/Middle/Lower textures offsets should be threated separately in UDMF
			//MaxW. But they're not for Eternity, so this needs its own config setting
			if(General.Map.UDMF && General.Map.Config.UseLocalSidedefTextureOffsets)
			{
				HashSet<BaseVisualGeometrySidedef> donesides = new HashSet<BaseVisualGeometrySidedef>();
				foreach(IVisualEventReceiver i in objs) 
				{
					BaseVisualGeometrySidedef vs = (BaseVisualGeometrySidedef)i; //mxd
					if(!donesides.Contains(vs)) 
					{
						//mxd. added scaling by texture scale
						if(vs.Texture.UsedInMap) //mxd. Otherwise it's MissingTexture3D and we probably don't want to drag that
							vs.OnChangeTextureOffset((int)(dx / vs.Texture.Scale.x), (int)(dy / vs.Texture.Scale.y), false);

						donesides.Add(vs);
					}
				}
			}
			else
			{
				HashSet<Sidedef> donesides = new HashSet<Sidedef>();
				foreach(IVisualEventReceiver i in objs) 
				{
					BaseVisualGeometrySidedef vs = (BaseVisualGeometrySidedef)i; //mxd
					if(!donesides.Contains(vs.Sidedef)) 
					{
						//mxd. added scaling by texture scale
						if(vs.Texture.UsedInMap) //mxd. Otherwise it's MissingTexture3D and we probably don't want to drag that
							vs.OnChangeTextureOffset((int)(dx / vs.Texture.Scale.x), (int)(dy / vs.Texture.Scale.y), false);

						donesides.Add(vs.Sidedef);
					}
				}
			}
		}

		// Apply flat offsets
		public void ApplyFlatOffsetChange(int dx, int dy)
		{
			HashSet<int> donesectors = new HashSet<int>();
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, false, false, false, false);
			foreach(IVisualEventReceiver i in objs)
			{
				BaseVisualGeometrySector bvs = (BaseVisualGeometrySector)i;
				if(bvs != null && !donesectors.Contains(bvs.Sector.Sector.Index))
				{
					//mxd. Sector surface belongs to 3d-floor?
					if(bvs.Level.sector.Index != bvs.Sector.Sector.Index)
					{
						// Don't update control sector several times
						if(!donesectors.Contains(bvs.Level.sector.Index))
						{
							// Update the offsets
							bvs.OnChangeTextureOffset(dx, dy, false);

							// Update control sector
							SectorData sd = GetSectorData(bvs.Level.sector);
							sd.Update();
							BaseVisualSector vs = (BaseVisualSector)GetVisualSector(bvs.Level.sector);
							vs.Rebuild();

							// Add to collection
							donesectors.Add(bvs.Level.sector.Index);

							// Update 3d-floors
							List<Sector> updatealso = new List<Sector>(sd.UpdateAlso.Keys);
							foreach(Sector other in updatealso)
							{
								if(!donesectors.Contains(other.Index))
								{
									BaseVisualSector vsother = (BaseVisualSector)GetVisualSector(other);
									vsother.Rebuild();

									// Add to collection
									donesectors.Add(other.Index);
								}
							}
						}
					}
					else
					{
						//mxd. Regular sector surface. Just update the offsets
						bvs.OnChangeTextureOffset(dx, dy, false);

						//mxd. Add to collection
						donesectors.Add(bvs.Sector.Sector.Index);
					}

					//mxd. Update sector geometry
					bvs.Sector.Rebuild();
				}
			}
		}

		// Apply upper unpegged flag
		public void ApplyUpperUnpegged(bool set)
		{
			List<IVisualEventReceiver> objs = GetSelectedObjects(false, true, false, false, false);
			foreach(IVisualEventReceiver i in objs)
			{
				i.ApplyUpperUnpegged(set);
			}
		}

		// Apply lower unpegged flag
		public void ApplyLowerUnpegged(bool set)
		{
			List<IVisualEventReceiver> objs = GetSelectedObjects(false, true, false, false, false);
			foreach(IVisualEventReceiver i in objs)
			{
				i.ApplyLowerUnpegged(set);
			}
		}

		// Apply texture change
		public void ApplySelectTexture(string texture, bool flat)
		{
			List<IVisualEventReceiver> objs;
			
			if(General.Map.Config.MixTexturesFlats)
			{
				// Apply on all compatible types
				objs = GetSelectedObjects(true, true, false, false, false);
			}
			else
			{
				// We don't want to mix textures and flats, so apply only on the appropriate type
				objs = GetSelectedObjects(flat, !flat, false, false, false);
			}
			
			foreach(IVisualEventReceiver i in objs)
			{
				i.ApplyTexture(texture);
			}
		}

        // This returns all selected objects
        internal List<IVisualEventReceiver> GetSelectedObjects(bool includesectors, bool includesidedefs, bool includethings, bool includevertices, bool includeslopehandles)
		{
			List<IVisualEventReceiver> objs = new List<IVisualEventReceiver>();
			foreach(IVisualEventReceiver i in selectedobjects)
			{
				if(includesectors && (i is BaseVisualGeometrySector)) objs.Add(i);
				else if(includesidedefs && (i is BaseVisualGeometrySidedef)) objs.Add(i);
				else if(includethings && (i is BaseVisualThing)) objs.Add(i);
				else if(includevertices && (i is BaseVisualVertex)) objs.Add(i); //mxd
				else if (includeslopehandles && (i is VisualSlope)) objs.Add(i); // biwa
			}

			// Add highlight?
			if(selectedobjects.Count == 0)
			{
				IVisualEventReceiver i = (target.picked as IVisualEventReceiver);
				if(includesectors && (i is BaseVisualGeometrySector)) objs.Add(i);
				else if(includesidedefs && (i is BaseVisualGeometrySidedef)) objs.Add(i);
				else if(includethings && (i is BaseVisualThing)) objs.Add(i);
				else if(includevertices && (i is BaseVisualVertex)) objs.Add(i); //mxd
				else if (includeslopehandles && (i is VisualSlope)) objs.Add(i); // biwa
			}

			return objs;
		}

		//mxd
		private static IEnumerable<IVisualEventReceiver> RemoveDuplicateSidedefs(IEnumerable<IVisualEventReceiver> objs) 
		{
			HashSet<Sidedef> processed = new HashSet<Sidedef>();
			List<IVisualEventReceiver> result = new List<IVisualEventReceiver>();

			if(General.Map.UDMF)
			{
				// For UDMF maps, we only need to remove duplicate extrafloor sidedefs
				foreach(IVisualEventReceiver i in objs)
				{
					if(i is VisualMiddle3D)
					{
						VisualMiddle3D vm = i as VisualMiddle3D;
						if(!processed.Contains(vm.Sidedef))
						{
							processed.Add(vm.Sidedef);
							result.Add(i);
						}
					}
					else
					{
						result.Add(i);
					}
				}
			}
			else
			{
				// For Doom/Hexen maps, we need to remove all duplicates
				foreach(IVisualEventReceiver i in objs)
				{
					BaseVisualGeometrySidedef sidedef = i as BaseVisualGeometrySidedef;
					if(sidedef != null)
					{
						if(!processed.Contains(sidedef.Sidedef))
						{
							processed.Add(sidedef.Sidedef);
							result.Add(i);
						}
					}
					else
					{
						result.Add(i);
					}
				}
			}

			return result;
		}

		// This returns all selected sectors, no doubles
		public List<Sector> GetSelectedSectors()
		{
			HashSet<Sector> added = new HashSet<Sector>();
			List<Sector> sectors = new List<Sector>();
			foreach(IVisualEventReceiver i in selectedobjects)
			{
				BaseVisualGeometrySector sector = i as BaseVisualGeometrySector;
				if(sector != null && !added.Contains(sector.Level.sector))
				{
					sectors.Add(sector.Level.sector);
					added.Add(sector.Level.sector);
				}
			}

			// Add highlight?
			if((selectedobjects.Count == 0) && (target.picked is BaseVisualGeometrySector))
			{
				Sector s = ((BaseVisualGeometrySector)target.picked).Level.sector;
				if(!added.Contains(s)) sectors.Add(s);
			}
			
			return sectors;
		}

		/// <summary>
		/// Determines if the floor and/or ceiling of a sector is selected.
		/// </summary>
		/// <param name="sector">The sector to check</param>
		/// <param name="floor">If floor is selected or not</param>
		/// <param name="ceiling">If ceiling is selected or not</param>
		public void GetSelectedSurfaceTypesBySector(Sector sector, out bool floor, out bool ceiling)
		{
			floor = ceiling = false;

			foreach(IVisualEventReceiver i in selectedobjects)
			{
				if (i is VisualFloor && ((VisualFloor)i).Level.sector == sector)
					floor = true;
				else if (i is VisualCeiling && ((VisualCeiling)i).Level.sector == sector)
					ceiling = true;
			}
		}

		// This returns all selected linedefs, no doubles
		public List<Linedef> GetSelectedLinedefs()
		{
			HashSet<Linedef> added = new HashSet<Linedef>();
			List<Linedef> linedefs = new List<Linedef>();
			foreach(IVisualEventReceiver i in selectedobjects)
			{
				BaseVisualGeometrySidedef sidedef = i as BaseVisualGeometrySidedef;
				if(sidedef != null)
				{
					Linedef l = sidedef.GetControlLinedef(); //mxd
					if(!added.Contains(l))
					{
						linedefs.Add(l);
						added.Add(l);
					}
				}
			}

			// Add highlight?
			if((selectedobjects.Count == 0) && (target.picked is BaseVisualGeometrySidedef))
			{
				Linedef l = ((BaseVisualGeometrySidedef)target.picked).GetControlLinedef(); //mxd
				if(!added.Contains(l)) linedefs.Add(l);
			}

			return linedefs;
		}

		/// <summary>
		/// Determines if the upper/middle/lower parts of a sidedef are selected.
		/// </summary>
		/// <param name="sidedef">The sidedef tzo check</param>
		/// <param name="upper">If the upper part is selected</param>
		/// <param name="middle">If the middle part is selected</param>
		/// <param name="lower">If the lower part is selected</param>
		public void GetSelectedSurfaceTypesBySidedef(Sidedef sidedef, out bool upper, out bool middle, out bool lower)
		{
			upper = middle = lower = false;

			foreach(IVisualEventReceiver i in selectedobjects)
			{
				if (i is VisualUpper && ((VisualUpper)i).Sidedef == sidedef)
					upper = true;
				else if ((i is VisualMiddleSingle || i is VisualMiddleDouble || i is VisualMiddleBack) && ((BaseVisualGeometrySidedef)i).Sidedef == sidedef)
					middle = true;
				else if (i is VisualLower && ((VisualLower)i).Sidedef == sidedef)
					lower = true;
			}
		}

		// This returns all selected sidedefs, no doubles
		public List<Sidedef> GetSelectedSidedefs()
		{
			HashSet<Sidedef> added = new HashSet<Sidedef>();
			List<Sidedef> sidedefs = new List<Sidedef>();
			foreach(IVisualEventReceiver i in selectedobjects)
			{
				BaseVisualGeometrySidedef sidedef = i as BaseVisualGeometrySidedef;
				if(sidedef != null && !added.Contains(sidedef.Sidedef))
				{
					sidedefs.Add(sidedef.Sidedef);
					added.Add(sidedef.Sidedef);
				}
			}

			// Add highlight?
			/*
			if((selectedobjects.Count == 0) && (target.picked is BaseVisualGeometrySidedef))
			{
				Sidedef sd = ((BaseVisualGeometrySidedef)target.picked).Sidedef;
				if(!added.Contains(sd)) sidedefs.Add(sd);
			}
			*/

			return sidedefs;
		}

		// This returns all selected things, no doubles
		public List<Thing> GetSelectedThings()
		{
			HashSet<Thing> added = new HashSet<Thing>();
			List<Thing> things = new List<Thing>();
			foreach(IVisualEventReceiver i in selectedobjects)
			{
				BaseVisualThing thing = i as BaseVisualThing;
				if(thing != null && !added.Contains(thing.Thing))
				{
					things.Add(thing.Thing);
					added.Add(thing.Thing);
				}
			}

			// Add highlight?
			if((selectedobjects.Count == 0) && (target.picked is BaseVisualThing))
			{
				Thing t = ((BaseVisualThing)target.picked).Thing;
				if(!added.Contains(t)) things.Add(t);
			}

			return things;
		}

		//mxd. This returns all selected vertices, no doubles
		public List<Vertex> GetSelectedVertices() 
		{
			HashSet<Vertex> added = new HashSet<Vertex>();
			List<Vertex> verts = new List<Vertex>();

			foreach(IVisualEventReceiver i in selectedobjects)
			{
				BaseVisualVertex vertex = i as BaseVisualVertex;
				if(vertex != null && !added.Contains(vertex.Vertex)) 
				{
					verts.Add(vertex.Vertex);
					added.Add(vertex.Vertex);
				}
			}

			// Add highlight?
			if((selectedobjects.Count == 0) && (target.picked is BaseVisualVertex)) 
			{
				Vertex v = ((BaseVisualVertex)target.picked).Vertex;
				if(!added.Contains(v)) verts.Add(v);
			}

			return verts;
		}

		// This returns all selected slope handles, no doubles
		private List<VisualSidedefSlope> GetSelectedSlopeHandles()
		{
			HashSet<VisualSidedefSlope> added = new HashSet<VisualSidedefSlope>();
			List<VisualSidedefSlope> handles = new List<VisualSidedefSlope>();

			foreach(IVisualEventReceiver i in selectedobjects)
			{
				VisualSidedefSlope handle = i as VisualSidedefSlope;
				if(handle != null && !added.Contains(handle))
				{
					handles.Add(handle);
					added.Add(handle);
				}
			}

			// Add highlight?
			if((selectedobjects.Count == 0) && (target.picked is VisualSidedefSlope))
			{
				VisualSidedefSlope handle = (VisualSidedefSlope)target.picked;
				if (!added.Contains(handle)) handles.Add(handle);
			}

			return handles;
		}
		
		// This returns the IVisualEventReceiver on which the action must be performed
		private IVisualEventReceiver GetTargetEventReceiver(bool targetonly)
		{
			if(target.picked != null)
			{
				if(singleselection || target.picked.Selected || targetonly || target.picked is VisualSlope)
				{
					return (IVisualEventReceiver)target.picked;
				}

				if(selectedobjects.Count > 0)
				{
					return selectedobjects[0];
				}

				return (IVisualEventReceiver)target.picked;
			}

			return new NullVisualEventReceiver();
		}

		//mxd. Copied from BuilderModes.ThingsMode
		// This creates a new thing
		private static Thing CreateThing(Vector2D pos) 
		{
			if(pos.x < General.Map.Config.LeftBoundary || pos.x > General.Map.Config.RightBoundary ||
				pos.y > General.Map.Config.TopBoundary || pos.y < General.Map.Config.BottomBoundary) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Failed to insert thing: outside of map boundaries.");
				return null;
			}

			// Create thing
			Thing t = General.Map.Map.CreateThing();
			if(t != null) 
			{
				General.Settings.ApplyDefaultThingSettings(t);
				t.Move(pos);
				t.UpdateConfiguration();
				General.Map.IsChanged = true;
				
				// Update things filter so that it includes this thing
				General.Map.ThingsFilter.Update();

				// Snap to grid enabled?
				if(General.Interface.SnapToGrid) 
				{
					// Snap to grid
					t.SnapToGrid();
				} 
				else 
				{
					// Snap to map format accuracy
					t.SnapToAccuracy();
				}
			}

			return t;
        }
		
		#endregion

		#region ================== Actions

        // [ZZ] I moved this out of ClearSelection because "cut selection" action needs this to only affect things.
        private void ClearSelection(bool clearsectors, bool clearsidedefs, bool clearthings, bool clearvertices, bool clearslopehandles, bool displaystatus)
        {
            selectedobjects.RemoveAll(obj =>
            {
                return ((obj is BaseVisualGeometrySector && clearsectors) ||
                        (obj is BaseVisualGeometrySidedef && clearsidedefs) ||
                        (obj is BaseVisualThing && clearthings) ||
                        (obj is BaseVisualVertex && clearvertices) ||
						(obj is VisualSlope && clearslopehandles));
            });

            //
            foreach (KeyValuePair<Sector, VisualSector> vs in allsectors)
            {
                if (vs.Value != null)
                {
                    BaseVisualSector bvs = (BaseVisualSector)vs.Value;
                    if (clearsectors)
                    {
                        if (bvs.Floor != null) bvs.Floor.Selected = false;
                        if (bvs.Ceiling != null) bvs.Ceiling.Selected = false;
                        foreach (VisualFloor vf in bvs.ExtraFloors) vf.Selected = false;
                        foreach (VisualCeiling vc in bvs.ExtraCeilings) vc.Selected = false;
                        foreach (VisualFloor vf in bvs.ExtraBackFloors) vf.Selected = false; //mxd
                        foreach (VisualCeiling vc in bvs.ExtraBackCeilings) vc.Selected = false; //mxd
                    }

                    if (clearsidedefs)
                    {
                        foreach (Sidedef sd in vs.Key.Sidedefs)
                        {
                            //mxd. VisualSidedefParts can contain references to visual geometry, which is not present in VisualSector.sidedefgeometry
                            bvs.GetSidedefParts(sd).DeselectAllParts();
                        }
                    }
                }
            }

            if (clearthings)
            {
                foreach (KeyValuePair<Thing, VisualThing> vt in allthings)
                {
                    if (vt.Value != null)
                    {
                        BaseVisualThing bvt = (BaseVisualThing)vt.Value;
                        bvt.Selected = false;
                    }
                }
            }

            //mxd
            if (clearvertices)
            {
                if (General.Map.UDMF)
                {
                    foreach (KeyValuePair<Vertex, VisualVertexPair> pair in vertices) pair.Value.Deselect();
                }
            }

			// biwa
			if (clearslopehandles)
			{
				if (General.Map.UDMF)
				{
					VisualSlope oldsmartpivot = null;

					foreach (KeyValuePair<Sector, List<VisualSlope>> kvp in allslopehandles)
					{
						foreach (VisualSlope handle in kvp.Value)
						{
							// We want to keep the old smart pivot handle
							if (handle.SmartPivot)
								oldsmartpivot = handle;

							handle.Selected = false;
							handle.Pivot = false;
							handle.SmartPivot = false;
						}
					}

					usedslopehandles.Clear();

					// Clearing the used slopes also clears the currently highlighted handle and the smart pivot handle. For
					// performance reasons PickTarget() will not do its slope handle stuff if the current and new pick are
					// the same, so we need to re-add the currently picked slope handle and its smart pivot handle
					if (target.picked is VisualSlope)
					{
						usedslopehandles.Add((VisualSlope)target.picked);

						if (oldsmartpivot != null)
						{
							oldsmartpivot.SmartPivot = true;
							usedslopehandles.Add(oldsmartpivot);
						}
					}
				}
			}

			//mxd
			if (displaystatus)
            {
               General.Interface.DisplayStatus(StatusType.Selection, string.Empty);
            }
        }

        [BeginAction("clearselection", BaseAction = true)]
		public void ClearSelection()
		{
            ClearSelection(true, true, true, true, true, true);
		}

		[BeginAction("visualselect", BaseAction = true)]
		public void BeginSelect()
		{
			PreActionNoChange();
			PickTargetUnlocked();
			GetTargetEventReceiver(true).OnSelectBegin();
			PostAction();
		}

		[EndAction("visualselect", BaseAction = true)]
		public void EndSelect()
		{
			IVisualEventReceiver target = GetTargetEventReceiver(true);
			target.OnSelectEnd();

			//mxd
			if((General.Interface.ShiftState || General.Interface.CtrlState) && selectedobjects.Count > 0) 
			{
				if(General.Interface.AltState)
				{
					target.SelectNeighbours(target.Selected, General.Interface.ShiftState, General.Interface.CtrlState);
				}
				else
				{
					IVisualEventReceiver[] selection = new IVisualEventReceiver[selectedobjects.Count];
					selectedobjects.CopyTo(selection);
					
					foreach(IVisualEventReceiver obj in selection)
						obj.SelectNeighbours(target.Selected, General.Interface.ShiftState, General.Interface.CtrlState);
				}
			}

			Renderer.ShowSelection = true;
			Renderer.ShowHighlight = true;
			PostAction();
		}

		[BeginAction("visualedit", BaseAction = true)]
		public void BeginEdit()
		{
			PreAction(UndoGroup.None);
			GetTargetEventReceiver(false).OnEditBegin();
			PostAction();
		}

		[EndAction("visualedit", BaseAction = true)]
		public void EndEdit()
		{
			PreActionNoChange();
			GetTargetEventReceiver(false).OnEditEnd();
			PostAction();
		}

		[BeginAction("raisesector8")]
		public void RaiseSector8()
		{
			PreAction(UndoGroup.SectorHeightChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, true);
			bool hasvisualslopehandles = objs.Any(o => o is VisualSlope);
			foreach (IVisualEventReceiver i in objs) // If slope handles are selected only apply the action to them
				if (!hasvisualslopehandles || (hasvisualslopehandles && i is VisualSlope))
					i.OnChangeTargetHeight(8);
			PostAction();
		}

		[BeginAction("lowersector8")]
		public void LowerSector8()
		{
			PreAction(UndoGroup.SectorHeightChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, true);
			bool hasvisualslopehandles = objs.Any(o => o is VisualSlope);
			foreach (IVisualEventReceiver i in objs) // If slope handles are selected only apply the action to them
				if (!hasvisualslopehandles || (hasvisualslopehandles && i is VisualSlope))
					i.OnChangeTargetHeight(-8);
			PostAction();
		}

	    [BeginAction("raisesector1")]
	    public void RaiseSector1() {
	        PreAction(UndoGroup.SectorHeightChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, true);
			bool hasvisualslopehandles = objs.Any(o => o is VisualSlope);
			foreach (IVisualEventReceiver i in objs) // If slope handles are selected only apply the action to them
				if (!hasvisualslopehandles || (hasvisualslopehandles && i is VisualSlope))
					i.OnChangeTargetHeight(1);
			PostAction();
	    }

	    [BeginAction("lowersector1")]
	    public void LowerSector1() {
	        PreAction(UndoGroup.SectorHeightChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, true);
			bool hasvisualslopehandles = objs.Any(o => o is VisualSlope);
			foreach (IVisualEventReceiver i in objs) // If slope handles are selected only apply the action to them
				if (!hasvisualslopehandles || (hasvisualslopehandles && i is VisualSlope))
					i.OnChangeTargetHeight(-1);
			PostAction();
	    }

	    [BeginAction("raisesector128")]
	    public void RaiseSector128() {
	        PreAction(UndoGroup.SectorHeightChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, true);
			bool hasvisualslopehandles = objs.Any(o => o is VisualSlope);
			foreach (IVisualEventReceiver i in objs) // If slope handles are selected only apply the action to them
				if (!hasvisualslopehandles || (hasvisualslopehandles && i is VisualSlope))
					i.OnChangeTargetHeight(128);
			PostAction();
	    }

	    [BeginAction("lowersector128")]
	    public void LowerSector128() {
	        PreAction(UndoGroup.SectorHeightChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, true);
			bool hasvisualslopehandles = objs.Any(o => o is VisualSlope);
			foreach (IVisualEventReceiver i in objs) // If slope handles are selected only apply the action to them
				if (!hasvisualslopehandles || (hasvisualslopehandles && i is VisualSlope))
					i.OnChangeTargetHeight(-128);
			PostAction();
	    }

		[BeginAction("raisemapelementbygridsize")]
		public void RaiseMapElementByGridSize()
		{
			PreAction(UndoGroup.SectorHeightChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, true);
			bool hasvisualslopehandles = objs.Any(o => o is VisualSlope);
			foreach (IVisualEventReceiver i in objs) // If slope handles are selected only apply the action to them
				if (!hasvisualslopehandles || (hasvisualslopehandles && i is VisualSlope))
					i.OnChangeTargetHeight(General.Map.Grid.GridSize);
			PostAction();
		}

		[BeginAction("lowermapelementbygridsize")]
		public void LowerMapElementByGridSize()
		{
			PreAction(UndoGroup.SectorHeightChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, true);
			bool hasvisualslopehandles = objs.Any(o => o is VisualSlope);
			foreach (IVisualEventReceiver i in objs) // If slope handles are selected only apply the action to them
				if (!hasvisualslopehandles || (hasvisualslopehandles && i is VisualSlope))
					i.OnChangeTargetHeight(-General.Map.Grid.GridSize);
			PostAction();
		}


		//mxd
		[BeginAction("raisesectortonearest")]
		public void RaiseSectorToNearest() 
		{
			List<VisualSidedefSlope> selectedhandles = GetSelectedSlopeHandles();

			if (selectedhandles.Count > 0)
			{
				if (selectedhandles.Count > 1)
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Can only raise to nearest when one visual slope handle is selected");
					return;
				}

				int startheight = (int)Math.Round(selectedhandles[0].GetCenterPoint().z);
				int targetheight = int.MaxValue;

				foreach (KeyValuePair<Sector, List<VisualSlope>> kvp in sidedefslopehandles)
				{
					foreach (VisualSidedefSlope handle in kvp.Value)
					{
						if (handle != selectedhandles[0] && handle.Sidedef.Line == selectedhandles[0].Sidedef.Line)
						{
							int z = (int)Math.Round(handle.GetCenterPoint().z);

							if (z > startheight && z < targetheight)
								targetheight = z;
						}
					}
				}

				if (targetheight != int.MaxValue)
				{
					PreAction(UndoGroup.SectorHeightChange);
					selectedhandles[0].OnChangeTargetHeight(targetheight - startheight);
					PostAction();
				}
				else
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Can't raise: already at the highest level");
				}
			}
			else
			{
				Dictionary<Sector, VisualFloor> floors = new Dictionary<Sector, VisualFloor>();
				Dictionary<Sector, VisualCeiling> ceilings = new Dictionary<Sector, VisualCeiling>();
				List<BaseVisualThing> things = new List<BaseVisualThing>();
				bool withinSelection = General.Interface.CtrlState;

				// Get selection
				if (selectedobjects.Count == 0)
				{
					if (target.picked is VisualFloor)
					{
						VisualFloor vf = (VisualFloor)target.picked;
						floors[vf.Level.sector] = vf;
					}
					else if (target.picked is VisualCeiling)
					{
						VisualCeiling vc = (VisualCeiling)target.picked;
						ceilings[vc.Level.sector] = vc;
					}
					else if (target.picked is BaseVisualThing)
					{
						things.Add((BaseVisualThing)target.picked);
					}
				}
				else
				{
					foreach (IVisualEventReceiver i in selectedobjects)
					{
						if (i is VisualFloor)
						{
							VisualFloor vf = (VisualFloor)i;
							floors[vf.Level.sector] = vf;
						}
						else if (i is VisualCeiling)
						{
							VisualCeiling vc = (VisualCeiling)i;
							ceilings[vc.Level.sector] = vc;
						}
						else if (i is BaseVisualThing)
						{
							things.Add((BaseVisualThing)i);
						}
					}
				}

				// Check what we have
				if (floors.Count + ceilings.Count == 0 && (things.Count == 0 || !General.Map.FormatInterface.HasThingHeight))
				{
					General.Interface.DisplayStatus(StatusType.Warning, "No suitable objects found!");
					return;
				}

				if (withinSelection)
				{
					string s = string.Empty;

					if (floors.Count == 1) s = "floors";

					if (ceilings.Count == 1)
					{
						if (!string.IsNullOrEmpty(s)) s += " and ";
						s += "ceilings";
					}

					if (!string.IsNullOrEmpty(s))
					{
						General.Interface.DisplayStatus(StatusType.Warning, "Can't do: at least 2 selected " + s + " are required!");
						return;
					}
				}

				// Process floors...
				int maxSelectedHeight = int.MinValue;
				int minSelectedCeilingHeight = int.MaxValue;
				int targetCeilingHeight = int.MaxValue;

				// Get highest ceiling height from selection
				foreach (KeyValuePair<Sector, VisualCeiling> group in ceilings)
				{
					if (group.Key.CeilHeight > maxSelectedHeight) maxSelectedHeight = group.Key.CeilHeight;
				}

				if (withinSelection)
				{
					// We are raising, so we don't need to check anything
					targetCeilingHeight = maxSelectedHeight;
				}
				else
				{
					// Get next higher floor or ceiling from surrounding unselected sectors
					foreach (Sector s in BuilderModesTools.GetSectorsAround(this, ceilings.Keys))
					{
						if (s.FloorHeight < targetCeilingHeight && s.FloorHeight > maxSelectedHeight)
							targetCeilingHeight = s.FloorHeight;
						else if (s.CeilHeight < targetCeilingHeight && s.CeilHeight > maxSelectedHeight)
							targetCeilingHeight = s.CeilHeight;
					}
				}

				// Ceilings...
				maxSelectedHeight = int.MinValue;
				int targetFloorHeight = int.MaxValue;

				// Get maximum floor and minimum ceiling heights from selection
				foreach (KeyValuePair<Sector, VisualFloor> group in floors)
				{
					if (group.Key.FloorHeight > maxSelectedHeight) maxSelectedHeight = group.Key.FloorHeight;
					if (group.Key.CeilHeight < minSelectedCeilingHeight) minSelectedCeilingHeight = group.Key.CeilHeight;
				}

				if (withinSelection)
				{
					// Check heights
					if (minSelectedCeilingHeight < maxSelectedHeight)
					{
						General.Interface.DisplayStatus(StatusType.Warning, "Can't do: lowest ceiling is lower than highest floor!");
						return;
					}
					targetFloorHeight = maxSelectedHeight;
				}
				else
				{
					// Get next higher floor or ceiling from surrounding unselected sectors
					foreach (Sector s in BuilderModesTools.GetSectorsAround(this, floors.Keys))
					{
						if (s.FloorHeight > maxSelectedHeight && s.FloorHeight < targetFloorHeight && s.FloorHeight <= minSelectedCeilingHeight)
							targetFloorHeight = s.FloorHeight;
						else if (s.CeilHeight > maxSelectedHeight && s.CeilHeight < targetFloorHeight && s.CeilHeight <= minSelectedCeilingHeight)
							targetFloorHeight = s.CeilHeight;
					}
				}

				//CHECK VALUES
				string alignFailDescription = string.Empty;

				if (floors.Count > 0 && targetFloorHeight == int.MaxValue)
				{
					// Raise to lowest ceiling?
					if (!withinSelection && minSelectedCeilingHeight > maxSelectedHeight)
					{
						targetFloorHeight = minSelectedCeilingHeight;
					}
					else
					{
						alignFailDescription = floors.Count > 1 ? "floors" : "floor";
					}
				}

				if (ceilings.Count > 0 && targetCeilingHeight == int.MaxValue)
				{
					if (!string.IsNullOrEmpty(alignFailDescription)) alignFailDescription += " and ";
					alignFailDescription += ceilings.Count > 1 ? "ceilings" : "ceiling";
				}

				if (!string.IsNullOrEmpty(alignFailDescription))
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Unable to align selected " + alignFailDescription + "!");
					return;
				}

				//APPLY VALUES
				PreAction(UndoGroup.SectorHeightChange);

				// Change floors heights
				if (floors.Count > 0)
				{
					foreach (KeyValuePair<Sector, VisualFloor> group in floors)
					{
						if (targetFloorHeight != group.Key.FloorHeight)
							group.Value.OnChangeTargetHeight(targetFloorHeight - group.Key.FloorHeight);
					}
				}

				// Change ceilings heights
				if (ceilings.Count > 0)
				{
					foreach (KeyValuePair<Sector, VisualCeiling> group in ceilings)
					{
						if (targetCeilingHeight != group.Key.CeilHeight)
							group.Value.OnChangeTargetHeight(targetCeilingHeight - group.Key.CeilHeight);
					}
				}

				// Change things heights. Align to higher 3d floor or actual ceiling.
				if (General.Map.FormatInterface.HasThingHeight)
				{
					foreach (BaseVisualThing vt in things)
					{
						if (vt.Thing.Sector == null) continue;
						SectorData sd = GetSectorData(vt.Thing.Sector);
						vt.OnMove(new Vector3D(vt.Thing.Position, BuilderModesTools.GetHigherThingZ(this, sd, vt)));
					}
				}

				PostAction();
			}
		}

		//mxd
		[BeginAction("lowersectortonearest")]
		public void LowerSectorToNearest() 
		{
			List<VisualSidedefSlope> selectedhandles = GetSelectedSlopeHandles();

			if (selectedhandles.Count > 0)
			{
				if (selectedhandles.Count > 1)
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Can only lower to nearest when one visual slope handle is selected");
					return;
				}

				int startheight = (int)Math.Round(selectedhandles[0].GetCenterPoint().z);
				int targetheight = int.MinValue;

				foreach (KeyValuePair<Sector, List<VisualSlope>> kvp in sidedefslopehandles)
				{
					foreach (VisualSidedefSlope handle in kvp.Value)
					{
						if (handle != selectedhandles[0] && handle.Sidedef.Line == selectedhandles[0].Sidedef.Line)
						{
							int z = (int)Math.Round(handle.GetCenterPoint().z);

							if (z < startheight && z > targetheight)
								targetheight = z;
						}
					}
				}

				if (targetheight != int.MinValue)
				{
					PreAction(UndoGroup.SectorHeightChange);
					selectedhandles[0].OnChangeTargetHeight(-(startheight - targetheight));
					PostAction();
				}
				else
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Can't lower: already at the lowest level");
				}
			}
			else
			{
				Dictionary<Sector, VisualFloor> floors = new Dictionary<Sector, VisualFloor>();
				Dictionary<Sector, VisualCeiling> ceilings = new Dictionary<Sector, VisualCeiling>();
				List<BaseVisualThing> things = new List<BaseVisualThing>();
				bool withinSelection = General.Interface.CtrlState;

				// Get selection
				if (selectedobjects.Count == 0)
				{
					if (target.picked is VisualFloor)
					{
						VisualFloor vf = (VisualFloor)target.picked;
						floors[vf.Level.sector] = vf;
					}
					else if (target.picked is VisualCeiling)
					{
						VisualCeiling vc = (VisualCeiling)target.picked;
						ceilings[vc.Level.sector] = vc;
					}
					else if (target.picked is BaseVisualThing)
					{
						things.Add((BaseVisualThing)target.picked);
					}
				}
				else
				{
					foreach (IVisualEventReceiver i in selectedobjects)
					{
						if (i is VisualFloor)
						{
							VisualFloor vf = (VisualFloor)i;
							floors[vf.Level.sector] = vf;
						}
						else if (i is VisualCeiling)
						{
							VisualCeiling vc = (VisualCeiling)i;
							ceilings[vc.Level.sector] = vc;
						}
						else if (i is BaseVisualThing)
						{
							things.Add((BaseVisualThing)i);
						}
					}
				}

				// Check what we have
				if (floors.Count + ceilings.Count == 0 && (things.Count == 0 || !General.Map.FormatInterface.HasThingHeight))
				{
					General.Interface.DisplayStatus(StatusType.Warning, "No suitable objects found!");
					return;
				}

				if (withinSelection)
				{
					string s = string.Empty;

					if (floors.Count == 1) s = "floors";

					if (ceilings.Count == 1)
					{
						if (!string.IsNullOrEmpty(s)) s += " and ";
						s += "ceilings";
					}

					if (!string.IsNullOrEmpty(s))
					{
						General.Interface.DisplayStatus(StatusType.Warning, "Can't do: at least 2 selected " + s + " are required!");
						return;
					}
				}

				// Process floors...
				int minSelectedHeight = int.MaxValue;
				int targetFloorHeight = int.MinValue;

				// Get minimum floor height from selection
				foreach (KeyValuePair<Sector, VisualFloor> group in floors)
				{
					if (group.Key.FloorHeight < minSelectedHeight) minSelectedHeight = group.Key.FloorHeight;
				}

				if (withinSelection)
				{
					// We are lowering, so we don't need to check anything
					targetFloorHeight = minSelectedHeight;
				}
				else
				{
					// Get next lower ceiling or floor from surrounding unselected sectors
					foreach (Sector s in BuilderModesTools.GetSectorsAround(this, floors.Keys))
					{
						if (s.CeilHeight > targetFloorHeight && s.CeilHeight < minSelectedHeight)
							targetFloorHeight = s.CeilHeight;
						else if (s.FloorHeight > targetFloorHeight && s.FloorHeight < minSelectedHeight)
							targetFloorHeight = s.FloorHeight;
					}
				}

				// Ceilings...
				minSelectedHeight = int.MaxValue;
				int maxSelectedFloorHeight = int.MinValue;
				int targetCeilingHeight = int.MinValue;

				// Get minimum ceiling and maximum floor heights from selection
				foreach (KeyValuePair<Sector, VisualCeiling> group in ceilings)
				{
					if (group.Key.CeilHeight < minSelectedHeight) minSelectedHeight = group.Key.CeilHeight;
					if (group.Key.FloorHeight > maxSelectedFloorHeight) maxSelectedFloorHeight = group.Key.FloorHeight;
				}

				if (withinSelection)
				{
					if (minSelectedHeight < maxSelectedFloorHeight)
					{
						General.Interface.DisplayStatus(StatusType.Warning, "Can't do: lowest ceiling is lower than highest floor!");
						return;
					}
					targetCeilingHeight = minSelectedHeight;
				}
				else
				{
					// Get next lower ceiling or floor from surrounding unselected sectors
					foreach (Sector s in BuilderModesTools.GetSectorsAround(this, ceilings.Keys))
					{
						if (s.CeilHeight > targetCeilingHeight && s.CeilHeight < minSelectedHeight && s.CeilHeight >= maxSelectedFloorHeight)
							targetCeilingHeight = s.CeilHeight;
						else if (s.FloorHeight > targetCeilingHeight && s.FloorHeight < minSelectedHeight && s.FloorHeight >= maxSelectedFloorHeight)
							targetCeilingHeight = s.FloorHeight;
					}
				}

				//CHECK VALUES:
				string alignFailDescription = string.Empty;

				if (floors.Count > 0 && targetFloorHeight == int.MinValue)
					alignFailDescription = floors.Count > 1 ? "floors" : "floor";

				if (ceilings.Count > 0 && targetCeilingHeight == int.MinValue)
				{
					// Drop to highest floor?
					if (!withinSelection && maxSelectedFloorHeight < minSelectedHeight)
					{
						targetCeilingHeight = maxSelectedFloorHeight;
					}
					else
					{
						if (!string.IsNullOrEmpty(alignFailDescription)) alignFailDescription += " and ";
						alignFailDescription += ceilings.Count > 1 ? "ceilings" : "ceiling";
					}
				}

				if (!string.IsNullOrEmpty(alignFailDescription))
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Unable to align selected " + alignFailDescription + "!");
					return;
				}

				//APPLY VALUES:
				PreAction(UndoGroup.SectorHeightChange);

				// Change floor height
				if (floors.Count > 0)
				{
					foreach (KeyValuePair<Sector, VisualFloor> group in floors)
					{
						if (targetFloorHeight != group.Key.FloorHeight)
							group.Value.OnChangeTargetHeight(targetFloorHeight - group.Key.FloorHeight);
					}
				}

				// Change ceiling height
				if (ceilings.Count > 0)
				{
					foreach (KeyValuePair<Sector, VisualCeiling> group in ceilings)
					{
						if (targetCeilingHeight != group.Key.CeilHeight)
							group.Value.OnChangeTargetHeight(targetCeilingHeight - group.Key.CeilHeight);
					}
				}

				// Change things height. Drop to lower 3d floor or to actual sector's floor.
				if (General.Map.FormatInterface.HasThingHeight)
				{
					foreach (BaseVisualThing vt in things)
					{
						if (vt.Thing.Sector == null) continue;
						SectorData sd = GetSectorData(vt.Thing.Sector);
						vt.OnMove(new Vector3D(vt.Thing.Position, BuilderModesTools.GetLowerThingZ(this, sd, vt)));
					}
				}

				PostAction();
			}
		}

		//mxd
		[BeginAction("matchbrightness")]
		public void MatchBrightness() 
		{
			//check input
			if(!General.Map.UDMF) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "'Match Brightness' action works only in UDMF map format!");
				return;
			}

			if(selectedobjects.Count == 0) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "'Match Brightness' action requires a selection!");
				return;
			}

			IVisualEventReceiver highlighted = (IVisualEventReceiver)target.picked;

			if(highlighted is BaseVisualThing) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Highlight a surface, to which you want to match the brightness.");
				return;
			}

			//get target brightness
			int targetbrightness;
			if(highlighted is VisualFloor) 
			{
				VisualFloor v = (VisualFloor)highlighted;
				targetbrightness = v.Level.sector.Fields.GetValue("lightfloor", 0);
				if(!v.Level.sector.Fields.GetValue("lightfloorabsolute", false)) 
				{
					targetbrightness += v.Level.sector.Brightness;
				}
			} 
			else if(highlighted is VisualCeiling) 
			{
				VisualCeiling v = (VisualCeiling)highlighted;
				targetbrightness = v.Level.sector.Fields.GetValue("lightceiling", 0);
				if(!v.Level.sector.Fields.GetValue("lightceilingabsolute", false)) 
				{
					targetbrightness += v.Level.sector.Brightness;
				}
			} 
			else if(highlighted is VisualUpper || highlighted is VisualMiddleSingle || highlighted is VisualMiddleDouble || highlighted is VisualLower) 
			{
				BaseVisualGeometrySidedef v = (BaseVisualGeometrySidedef)highlighted;
				targetbrightness = v.Sidedef.Fields.GetValue("light", 0);
				if(!v.Sidedef.Fields.GetValue("lightabsolute", false)) 
				{
					targetbrightness += v.Sidedef.Sector.Brightness;
				}
			} 
			else if(highlighted is VisualMiddle3D) 
			{
				VisualMiddle3D v = (VisualMiddle3D)highlighted;
				Sidedef sd = v.GetControlLinedef().Front;
				if(sd == null) 
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Highlight a surface, to which you want to match the brightness.");
					return;
				}
				targetbrightness = sd.Fields.GetValue("light", 0);
				if(!sd.Fields.GetValue("lightabsolute", false)) 
				{
					targetbrightness += sd.Sector.Brightness;
				}

			} 
			else 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Highlight a surface, to which you want to match the brightness.");
				return;
			}

			//make undo
			CreateUndo("Match Brightness");
			targetbrightness = General.Clamp(targetbrightness, 0, 255);

			//apply new brightness
			foreach(IVisualEventReceiver obj in selectedobjects) 
			{
				if(obj == highlighted) continue;

				if(obj is VisualFloor) 
				{
					VisualFloor v = (VisualFloor)obj;
					v.Level.sector.Fields.BeforeFieldsChange();
					v.Sector.Changed = true;

					if(v.Level.sector.Fields.GetValue("lightfloorabsolute", false)) 
					{
						v.Level.sector.Fields["lightfloor"] = new UniValue(UniversalType.Integer, targetbrightness);
					} 
					else 
					{
						UniFields.SetInteger(v.Level.sector.Fields, "lightfloor", targetbrightness - v.Level.sector.Brightness, 0);
					}

					v.Sector.UpdateSectorGeometry(false);
				} 
				else if(obj is VisualCeiling) 
				{
					VisualCeiling v = (VisualCeiling)obj;
					v.Level.sector.Fields.BeforeFieldsChange();
					v.Sector.Changed = true;
					v.Sector.Sector.UpdateNeeded = true;

					if(v.Level.sector.Fields.GetValue("lightceilingabsolute", false)) 
					{
						v.Level.sector.Fields["lightceiling"] = new UniValue(UniversalType.Integer, targetbrightness);
					} 
					else 
					{
						UniFields.SetInteger(v.Level.sector.Fields, "lightceiling", targetbrightness - v.Level.sector.Brightness, 0);
					}

					v.Sector.UpdateSectorGeometry(false);
				} 
				else if(obj is VisualUpper || obj is VisualMiddleSingle || obj is VisualMiddleDouble || obj is VisualLower) 
				{
					BaseVisualGeometrySidedef v = (BaseVisualGeometrySidedef)obj;
					v.Sidedef.Fields.BeforeFieldsChange();
					v.Sector.Changed = true;

					if(v.Sidedef.Fields.GetValue("lightabsolute", false)) 
					{
						v.Sidedef.Fields["light"] = new UniValue(UniversalType.Integer, targetbrightness);
					} 
					else 
					{
						UniFields.SetInteger(v.Sidedef.Fields, "light", targetbrightness - v.Sidedef.Sector.Brightness, 0);
					}

					//Update 'lightfog' flag
					Tools.UpdateLightFogFlag(v.Sidedef);
				}
			}

			//Done
			General.Interface.DisplayStatus(StatusType.Action, "Matched brightness for " + selectedobjects.Count + " surfaces.");
			Interface_OnSectorEditFormValuesChanged(this, EventArgs.Empty);
		}

		[BeginAction("showvisualthings")]
		public void ShowVisualThings()
		{
			BuilderPlug.Me.ShowVisualThings++;
			if(BuilderPlug.Me.ShowVisualThings > 2) BuilderPlug.Me.ShowVisualThings = 0;

			string shortmessage = "Thing visibility is now " + (BuilderPlug.Me.ShowVisualThings > 0 ? (BuilderPlug.Me.ShowVisualThings > 1 ? "ON" : "SPRITE ONLY") : "OFF") + ".";
			string message = shortmessage;
			string key = Actions.Action.GetShortcutKeyDesc(General.Actions.Current.ShortcutKey);

			if (!string.IsNullOrEmpty(key))
				message += $" Press '{key}' to change.";

			General.ToastManager.ShowToast("showvisualthings", ToastType.INFO, "Changed thing visibility", message, new StatusInfo(StatusType.Action, shortmessage));
		}

		[BeginAction("raisebrightness8")]
		public void RaiseBrightness8()
		{
			PreAction(UndoGroup.SectorBrightnessChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, false, false, false);
			foreach(IVisualEventReceiver i in objs) i.OnChangeTargetBrightness(true);
			PostAction();
		}

		[BeginAction("lowerbrightness8")]
		public void LowerBrightness8()
		{
			PreAction(UndoGroup.SectorBrightnessChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, false, false, false);
			foreach(IVisualEventReceiver i in objs) i.OnChangeTargetBrightness(false);
			PostAction();
		}

		[BeginAction("movetextureleft")]	public void MoveTextureLeft1() { MoveTextureByOffset(-1, 0); }
		[BeginAction("movetextureright")]	public void MoveTextureRight1() { MoveTextureByOffset(1, 0); }
		[BeginAction("movetextureup")]		public void MoveTextureUp1() { MoveTextureByOffset(0, -1); }
		[BeginAction("movetexturedown")]	public void MoveTextureDown1() { MoveTextureByOffset(0, 1); }
		[BeginAction("movetextureleft8")]	public void MoveTextureLeft8() { MoveTextureByOffset(-8, 0); }
		[BeginAction("movetextureright8")]	public void MoveTextureRight8() { MoveTextureByOffset(8, 0); }
		[BeginAction("movetextureup8")]		public void MoveTextureUp8() { MoveTextureByOffset(0, -8); }
		[BeginAction("movetexturedown8")]	public void MoveTextureDown8() { MoveTextureByOffset(0, 8); }
		[BeginAction("movetextureleftgs")]	public void MoveTextureLeftGrid() { MoveTextureByOffset(-General.Map.Grid.GridSize, 0); }  //mxd
		[BeginAction("movetexturerightgs")]	public void MoveTextureRightGrid() { MoveTextureByOffset(General.Map.Grid.GridSize, 0); }  //mxd
		[BeginAction("movetextureupgs")]	public void MoveTextureUpGrid() { MoveTextureByOffset(0, -General.Map.Grid.GridSize); } //mxd
		[BeginAction("movetexturedowngs")]	public void MoveTextureDownGrid() { MoveTextureByOffset(0, General.Map.Grid.GridSize); } //mxd

		//mxd
		private void MoveTextureByOffset(int ox, int oy)
		{
			PreAction(UndoGroup.TextureOffsetChange);
			IEnumerable<IVisualEventReceiver> objs = RemoveDuplicateSidedefs(GetSelectedObjects(true, true, false, false, false));
			foreach(IVisualEventReceiver i in objs) i.OnChangeTextureOffset(ox, oy, true);
			PostAction();
		}

		//mxd
		[BeginAction("scaleup")]	public void ScaleTextureUp() { ScaleTexture(1, 1); }
		[BeginAction("scaledown")]  public void ScaleTextureDown() { ScaleTexture(-1, -1); }
		[BeginAction("scaleupx")]   public void ScaleTextureUpX() { ScaleTexture(1, 0); }
		[BeginAction("scaledownx")] public void ScaleTextureDownX() { ScaleTexture(-1, 0); }
		[BeginAction("scaleupy")]   public void ScaleTextureUpY() { ScaleTexture(0, 1); } 
		[BeginAction("scaledowny")] public void ScaleTextureDownY() { ScaleTexture(0, -1); }

		//mxd
		private void ScaleTexture(int incrementx, int incrementy)
		{
			PreAction(UndoGroup.TextureScaleChange);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, false, false);
			foreach(IVisualEventReceiver i in objs) i.OnChangeScale(incrementx, incrementy);
			PostAction();
		}

		[BeginAction("textureselect")]
		public void TextureSelect()
		{
			PreAction(UndoGroup.None);
			renderer.SetCrosshairBusy(true);
			General.Interface.RedrawDisplay();
			GetTargetEventReceiver(false).OnSelectTexture();
			renderer.SetCrosshairBusy(false);
			PostAction();
		}

		[BeginAction("texturecopy")]
		public void TextureCopy()
		{
			PreActionNoChange();
			IVisualEventReceiver i = GetTargetEventReceiver(true);
			i.OnCopyTexture(); //mxd
			if(!(i is VisualThing)) copybuffer.Clear(); //mxd. Not copying things any more...
			PostAction();
		}

		[BeginAction("texturepaste")]
		public void TexturePaste()
		{
			PreAction(UndoGroup.None);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, false, false, false);
			foreach(IVisualEventReceiver i in objs) i.OnPasteTexture();
			PostAction();
		}

		//mxd
		[BeginAction("visualautoalign")]
		public void TextureAutoAlign() 
		{
			PreAction(UndoGroup.None);
			renderer.SetCrosshairBusy(true);
			General.Interface.RedrawDisplay();
			GetTargetEventReceiver(false).OnTextureAlign(true, true);
			UpdateChangedObjects();
			renderer.SetCrosshairBusy(false);
			PostAction();
		}

		[BeginAction("visualautoalignx")]
		public void TextureAutoAlignX()
		{
			PreAction(UndoGroup.None);
			renderer.SetCrosshairBusy(true);
			General.Interface.RedrawDisplay();
			GetTargetEventReceiver(false).OnTextureAlign(true, false);
			UpdateChangedObjects();
			renderer.SetCrosshairBusy(false);
			PostAction();
		}

		[BeginAction("visualautoaligny")]
		public void TextureAutoAlignY()
		{
			PreAction(UndoGroup.None);
			renderer.SetCrosshairBusy(true);
			General.Interface.RedrawDisplay();
			GetTargetEventReceiver(false).OnTextureAlign(false, true);
			UpdateChangedObjects();
			renderer.SetCrosshairBusy(false);
			PostAction();
		}

		//mxd
		[BeginAction("visualautoaligntoselection")]
		public void TextureAlignToSelected() 
		{
			PreAction(UndoGroup.None);
			renderer.SetCrosshairBusy(true);
			General.Interface.RedrawDisplay();

			AutoAlignTexturesToSelected(true, true);

			UpdateChangedObjects();
			renderer.SetCrosshairBusy(false);
			PostAction();
		}

		//mxd
		[BeginAction("visualautoaligntoselectionx")]
		public void TextureAlignToSelectedX() 
		{
			PreAction(UndoGroup.None);
			renderer.SetCrosshairBusy(true);
			General.Interface.RedrawDisplay();

			AutoAlignTexturesToSelected(true, false);

			UpdateChangedObjects();
			renderer.SetCrosshairBusy(false);
			PostAction();
		}

		//mxd
		[BeginAction("visualautoaligntoselectiony")]
		public void TextureAlignToSelectedY() 
		{
			PreAction(UndoGroup.None);
			renderer.SetCrosshairBusy(true);
			General.Interface.RedrawDisplay();

			AutoAlignTexturesToSelected(false, true);

			UpdateChangedObjects();
			renderer.SetCrosshairBusy(false);
			PostAction();
		}

		//mxd
		private void AutoAlignTexturesToSelected(bool alignX, bool alignY) 
		{
			string rest;
			if(alignX && alignY) rest = "(X and Y)";
			else if(alignX) rest = "(X)";
			else rest = "(Y)";

			CreateUndo("Auto-align textures to selected sidedefs " + rest);
			SetActionResult("Auto-aligned textures to selected sidedefs " + rest + ".");

			// Clear all marks, this will align everything it can
			General.Map.Map.ClearMarkedSidedefs(false);
			
			//get selection
			List<IVisualEventReceiver> objs = GetSelectedObjects(false, true, false, false, false);

			//align
			foreach(IVisualEventReceiver i in objs) 
			{
				BaseVisualGeometrySidedef side = (BaseVisualGeometrySidedef)i;
				
				// Make sure the texture is loaded (we need the texture size)
				if(!side.Texture.IsImageLoaded) side.Texture.LoadImageNow();

				//Align textures
				AutoAlignTextures(side, side.Texture, alignX, alignY, false, false);

				// Get the changed sidedefs
				List<Sidedef> changes = General.Map.Map.GetMarkedSidedefs(true);

				foreach(Sidedef sd in changes) 
				{
					// Update the parts for this sidedef!
					if(VisualSectorExists(sd.Sector)) 
					{
						BaseVisualSector vs = (BaseVisualSector)GetVisualSector(sd.Sector);
						VisualSidedefParts parts = vs.GetSidedefParts(sd);
						parts.SetupAllParts();
					}
				}
			}
		}

		//mxd
		[BeginAction("visualfittextures")]
		private void FitTextures() 
		{
			PreAction(UndoGroup.None);
			
			// Get selection
			List<IVisualEventReceiver> objs = GetSelectedObjects(false, true, false, false, false);
			List<BaseVisualGeometrySidedef> sides = new List<BaseVisualGeometrySidedef>();
			foreach(IVisualEventReceiver i in objs)
			{
				BaseVisualGeometrySidedef side = (BaseVisualGeometrySidedef)i;
				if(side != null) sides.Add(side);
			}

			if(sides.Count == 0)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Fit Textures action requires selected sidedefs.");
				return;
			}

			// Show form
			FitTexturesForm form = new FitTexturesForm();

			// Undo changes?
			if(form.Setup(sides) && form.ShowDialog((Form)General.Interface) == DialogResult.Cancel)
				General.Map.UndoRedo.WithdrawUndo();

			PostAction();
		}

		[BeginAction("toggleupperunpegged")]
		public void ToggleUpperUnpegged()
		{
			PreAction(UndoGroup.None);
			GetTargetEventReceiver(false).OnToggleUpperUnpegged();
			PostAction();
		}

		[BeginAction("togglelowerunpegged")]
		public void ToggleLowerUnpegged()
		{
			PreAction(UndoGroup.None);
			GetTargetEventReceiver(false).OnToggleLowerUnpegged();
			PostAction();
		}

		[BeginAction("togglegravity")]
		public void ToggleGravity()
		{
			BuilderPlug.Me.UseGravity = !BuilderPlug.Me.UseGravity;

			string shortmessage = "Gravity is now " + (BuilderPlug.Me.UseGravity ? "ON" : "OFF") + ".";
			string message = shortmessage;
			string key = Actions.Action.GetShortcutKeyDesc(General.Actions.Current.ShortcutKey);

			if (!string.IsNullOrEmpty(key))
				message += $" Press '{key}' to toggle.";

			General.ToastManager.ShowToast("togglegravity", ToastType.INFO, "Changed gravity", message, new StatusInfo(StatusType.Action, shortmessage));
		}

		[BeginAction("resettexture")]
		public void ResetTexture()
		{
			PreAction(UndoGroup.None);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, false, false);
			foreach(IVisualEventReceiver i in objs) i.OnResetTextureOffset();
			PostAction();
		}

		[BeginAction("resettextureudmf")]
		public void ResetLocalOffsets() 
		{
			PreAction(UndoGroup.None);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, false, false);
			foreach(IVisualEventReceiver i in objs) i.OnResetLocalTextureOffset();
			PostAction();
		}

		[BeginAction("floodfilltextures")]
		public void FloodfillTextures()
		{
			PreAction(UndoGroup.None);
			GetTargetEventReceiver(false).OnTextureFloodfill();
			PostAction();
		}

		[BeginAction("texturecopyoffsets")]
		public void TextureCopyOffsets()
		{
			PreActionNoChange();
			GetTargetEventReceiver(true).OnCopyTextureOffsets(); //mxd
			PostAction();
		}

		[BeginAction("texturepasteoffsets")]
		public void TexturePasteOffsets()
		{
			PreAction(UndoGroup.None);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, false, false, false);
			foreach(IVisualEventReceiver i in objs) i.OnPasteTextureOffsets();
			PostAction();
		}

		[BeginAction("copyproperties")]
		public void CopyProperties()
		{
			PreActionNoChange();
			GetTargetEventReceiver(true).OnCopyProperties(); //mxd
			PostAction();
		}

		[BeginAction("pasteproperties")]
		public void PasteProperties()
		{
			PreAction(UndoGroup.None);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, false);
			foreach(IVisualEventReceiver i in objs) i.OnPasteProperties(false);
			PostAction();
		}

		//mxd
		[BeginAction("pastepropertieswithoptions")]
		public void PastePropertiesWithOptions()
		{
			// Which options to show?
			HashSet<int> added;
			var targettypes = new List<MapElementType>();
			var selection = new List<IVisualEventReceiver>();

			// Sectors selected?
			var obj = GetSelectedObjects(true, false, false, false, false);
			if(obj.Count > 0)
			{
				targettypes.Add(MapElementType.SECTOR);

				// Don't add duplicates
				added = new HashSet<int>();
				foreach(IVisualEventReceiver receiver in obj)
				{
					VisualGeometry vg = (VisualGeometry)receiver;
					if(vg != null && !added.Contains(vg.Sector.GetHashCode()))
					{
						selection.Add(receiver);
						added.Add(vg.Sector.GetHashCode());
					}
				}
			}

			// Sidedefs selected?
			obj = GetSelectedObjects(false, true, false, false, false);
			if(obj.Count > 0)
			{
				targettypes.Add(MapElementType.SIDEDEF);

				// Don't add duplicates
				added = new HashSet<int>();
				foreach(IVisualEventReceiver receiver in obj)
				{
					VisualGeometry vg = (VisualGeometry)receiver;
					if(vg != null && !added.Contains(vg.Sidedef.Line.GetHashCode()))
					{
						selection.Add(receiver);
						added.Add(vg.Sidedef.Line.GetHashCode());
					}
				}
			}

			// Things selected?
			obj = GetSelectedObjects(false, false, true, false, false);
			if(obj.Count > 0)
			{
				targettypes.Add(MapElementType.THING);

				// Don't add duplicates
				added = new HashSet<int>();
				foreach(IVisualEventReceiver receiver in obj)
				{
					VisualThing vt = (VisualThing)receiver;
					if(vt != null && !added.Contains(vt.Thing.GetHashCode()))
					{
						selection.Add(receiver);
						added.Add(vt.Thing.GetHashCode());
					}
				}
			}

			// Vertices selected?
			obj = GetSelectedObjects(false, false, false, true, false);
			if(obj.Count > 0)
			{
				targettypes.Add(MapElementType.VERTEX);

				// Don't add duplicates
				added = new HashSet<int>();
				foreach(IVisualEventReceiver receiver in obj)
				{
					VisualVertex vv = (VisualVertex)receiver;
					if(vv != null && !added.Contains(vv.Vertex.GetHashCode()))
					{
						selection.Add(receiver);
						added.Add(vv.Vertex.GetHashCode());
					}
				}
			}

			// Anything selected?
			if(selection.Count == 0)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "This action requires highlight or selection!");
				return;
			}

			// Show the form
			PastePropertiesOptionsForm form = new PastePropertiesOptionsForm();
			if(form.Setup(targettypes) && form.ShowDialog(General.Interface) == DialogResult.OK)
			{
				// Paste properties
				PreAction(UndoGroup.None);
				foreach(IVisualEventReceiver i in selection)i.OnPasteProperties(true);
				PostAction();
			}
		}

		//mxd. now we can insert things in Visual modes
		[BeginAction("insertitem", BaseAction = true)] 
		public void InsertThing()
		{
			Vector2D hitpos = GetHitPosition();

			if(!hitpos.IsFinite()) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Cannot insert thing here!");
				return;
			}
			
			ClearSelection();
			PreActionNoChange();
			General.Map.UndoRedo.ClearAllRedos();
			General.Map.UndoRedo.CreateUndo("Insert thing");

			Thing t = CreateThing(new Vector2D(hitpos.x, hitpos.y));

			if(t == null) 
			{
				General.Map.UndoRedo.WithdrawUndo();
				return;
			}

			// Edit the thing?
			if(BuilderPlug.Me.EditNewThing) General.Interface.ShowEditThings(new List<Thing> { t });

			//add thing to blockmap
			blockmap.AddThing(t);

			General.Interface.DisplayStatus(StatusType.Action, "Inserted a new thing.");
			PostAction();
		}

		//mxd
		[BeginAction("deleteitem", BaseAction = true)]
		public void Delete()
		{
			PreAction(UndoGroup.None);
			List<IVisualEventReceiver> objs = GetSelectedObjects(true, true, true, true, false);
            foreach (IVisualEventReceiver i in objs)
            {
				if (i is BaseVisualThing)
				{
					visiblethings.Remove((BaseVisualThing)i); // [ZZ] if any
					allthings.Remove(((BaseVisualThing)i).Thing);
				}
                i.OnDelete();
            }
            PostAction();

			ClearSelection();
		}

		//mxd
		[BeginAction("copyselection", BaseAction = true)]
		public void CopySelection() 
		{
			List<IVisualEventReceiver> objs = GetSelectedObjects(false, false, true, false, false);
			if(objs.Count == 0) return;

			copybuffer.Clear();
			foreach(IVisualEventReceiver i in objs) 
			{
				VisualThing vt = (VisualThing)i;
				if(vt != null) copybuffer.Add(new ThingCopyData(vt.Thing));
			}

			string rest = copybuffer.Count + (copybuffer.Count > 1 ? " things." : " thing.");
			General.Interface.DisplayStatus(StatusType.Info, "Copied " + rest);
		}

		//mxd
		[BeginAction("cutselection", BaseAction = true)]
		public void CutSelection() 
		{
			CopySelection();

			//Create undo
			string rest = copybuffer.Count + (copybuffer.Count > 1 ? " things." : " thing.");
			CreateUndo("Cut " + rest);
			General.Interface.DisplayStatus(StatusType.Info, "Cut " + rest);

			List<IVisualEventReceiver> objs = GetSelectedObjects(false, false, true, false, false);
			foreach(IVisualEventReceiver i in objs) 
			{
				BaseVisualThing thing = (BaseVisualThing)i;
                visiblethings.Remove(thing); // [ZZ] if any
                thing.Thing.Fields.BeforeFieldsChange();
				thing.Thing.Dispose();
				thing.Dispose();
			}

			General.Map.IsChanged = true;
			General.Map.ThingsFilter.Update();

            // [ZZ] Clear selected things.
            ClearSelection(false, false, true, false, false, false);

            // Update event lines
            renderer.SetEventLines(LinksCollector.GetHelperShapes(General.Map.ThingsFilter.VisibleThings, blockmap));
		}

		//mxd. We'll just use currently selected objects 
		[BeginAction("pasteselection", BaseAction = true)]
		public void PasteSelection() 
		{
			if(copybuffer.Count == 0)
			{
				TexturePaste(); // I guess we may paste a texture or two instead
				return;
			}
			
			Vector2D hitpos = GetHitPosition();

			if(!hitpos.IsFinite()) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Cannot paste here!");
				return;
			}

			string rest = copybuffer.Count + (copybuffer.Count > 1 ? " things." : " thing.");
			General.Map.UndoRedo.CreateUndo("Paste " + rest);
			General.Interface.DisplayStatus(StatusType.Info, "Pasted " + rest);
			
			PreActionNoChange();
			ClearSelection();

			//get translated positions
			Vector3D[] coords = new Vector3D[copybuffer.Count];
			for(int i = 0; i < copybuffer.Count; i++ )
				coords[i] = copybuffer[i].Position;

			Vector3D[] translatedCoords = TranslateCoordinates(coords, hitpos, true);

			//create things from copyBuffer
			for(int i = 0; i < copybuffer.Count; i++) 
			{
				Thing t = CreateThing(new Vector2D());
				if(t != null) 
				{
					copybuffer[i].ApplyTo(t);
					t.Move(translatedCoords[i]);
					//add thing to blockmap
					blockmap.AddThing(t);
				}
			}

			General.Map.IsChanged = true;
			General.Map.ThingsFilter.Update();

			PostAction();
		}

		//mxd. Rotate clockwise
		[BeginAction("rotateclockwise")]
		public void RotateCW() 
		{
			RotateThingsAndTextures(General.Map.Config.DoomThingRotationAngles ? 45 : 5, 5);
		}

		//mxd. Rotate counterclockwise
		[BeginAction("rotatecounterclockwise")]
		public void RotateCCW() 
		{
			RotateThingsAndTextures(General.Map.Config.DoomThingRotationAngles ? -45 : -5, - 5);
		}

		//mxd
		private void RotateThingsAndTextures(int thingangleincrement, int textureangleincrement) 
		{
			PreAction(UndoGroup.ThingAngleChange);

			List<IVisualEventReceiver> selection = GetSelectedObjects(true, false, true, false, false);
			if(selection.Count == 0) return;

			foreach(IVisualEventReceiver obj in selection) 
			{
				if(obj is BaseVisualThing) 
				{
					BaseVisualThing t = (BaseVisualThing)obj;

					int newangle = t.Thing.AngleDoom + thingangleincrement;
					if(General.Map.Config.DoomThingRotationAngles) newangle = newangle / 45 * 45;
					t.SetAngle(General.ClampAngle(newangle));

					// Visual sectors may be affected by this thing...
					if(thingdata.ContainsKey(t.Thing))
					{
						// Update what must be updated
						ThingData td = GetThingData(t.Thing);
						foreach(KeyValuePair<Sector, bool> s in td.UpdateAlso)
						{
							if(VisualSectorExists(s.Key))
							{
								BaseVisualSector vs = (BaseVisualSector)GetVisualSector(s.Key);
								vs.UpdateSectorGeometry(s.Value);
							}
						}
					}
				}
				else if(obj is VisualFloor) 
				{
					VisualFloor vf = (VisualFloor)obj;
					vf.OnChangeTextureRotation(General.ClampAngle(vf.GetControlSector().Fields.GetValue("rotationfloor", 0.0) + textureangleincrement));
				} 
				else if(obj is VisualCeiling) 
				{
					VisualCeiling vc = (VisualCeiling)obj;
					vc.OnChangeTextureRotation(General.ClampAngle(vc.GetControlSector().Fields.GetValue("rotationceiling", 0.0) + textureangleincrement));
				}
			}

			PostAction();
		}

		//mxd. Change pitch clockwise
		[BeginAction("pitchclockwise")]
		public void PitchCW() 
		{
			ChangeThingsPitch(-5);
		}

		//mxd. Change pitch counterclockwise
		[BeginAction("pitchcounterclockwise")]
		public void PitchCCW() 
		{
			ChangeThingsPitch(5);
		}

		//mxd
		private void ChangeThingsPitch(int increment) 
		{
			PreAction(UndoGroup.ThingPitchChange);

			List<IVisualEventReceiver> selection = GetSelectedObjects(false, false, true, false, false);
			if(selection.Count == 0) return;

			foreach(IVisualEventReceiver obj in selection) 
			{
				BaseVisualThing t = (BaseVisualThing)obj;
				if(t != null) t.SetPitch(General.ClampAngle(t.Thing.Pitch + increment));
			}

			PostAction();
		}

		//mxd. Change pitch clockwise
		[BeginAction("rollclockwise")]
		public void RollCW() 
		{
			ChangeThingsRoll(-5);
		}

		//mxd. Change pitch counterclockwise
		[BeginAction("rollcounterclockwise")]
		public void RollCCW() 
		{
			ChangeThingsRoll(5);
		}

		//mxd
		private void ChangeThingsRoll(int increment) 
		{
			PreAction(UndoGroup.ThingRollChange);

			List<IVisualEventReceiver> selection = GetSelectedObjects(false, false, true, false, false);
			if(selection.Count == 0) return;

			foreach(IVisualEventReceiver obj in selection) 
			{
				BaseVisualThing t = (BaseVisualThing)obj;
				if(t != null) t.SetRoll(General.ClampAngle(t.Thing.Roll + increment));
			}

			PostAction();
		}

		//mxd
		[BeginAction("gztoggleenhancedrendering", BaseAction = true)]
		public void ToggleEnhancedRendering() 
		{
			// Actual toggling is done in MainForm.ToggleEnhancedRendering(), so we only need to update the view here
			RebuildElementData();
			UpdateChangedObjects();
		}

		//mxd
		[BeginAction("thingaligntowall")]
		public void AlignThingsToWall() 
		{
			List<VisualThing> visualThings = GetSelectedVisualThings(true);

			if(visualThings.Count == 0) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "This action requires selected Things!");
				return;
			}

			List<Thing> things = new List<Thing>();

			foreach(VisualThing vt in visualThings)
				things.Add(vt.Thing);

			// Make undo
			if(things.Count > 1) 
			{
				General.Map.UndoRedo.CreateUndo("Align " + things.Count + " things");
				General.Interface.DisplayStatus(StatusType.Action, "Aligned " + things.Count + " things.");
			} 
			else 
			{
				General.Map.UndoRedo.CreateUndo("Align thing");
				General.Interface.DisplayStatus(StatusType.Action, "Aligned a thing.");
			}

			//align things
			foreach(Thing t in things) 
			{
				HashSet<Linedef> excludedLines = new HashSet<Linedef>();
				bool aligned;

				do 
				{
					Linedef l = General.Map.Map.NearestLinedef(t.Position, excludedLines);
					aligned = Tools.TryAlignThingToLine(t, l);

					if(!aligned) 
					{
						excludedLines.Add(l);

						if(excludedLines.Count == General.Map.Map.Linedefs.Count) 
						{
							ThingTypeInfo tti = General.Map.Data.GetThingInfo(t.Type);
							General.ErrorLogger.Add(ErrorType.Warning, "Unable to align " + tti.Title + " (index " + t.Index + ") to any linedef!");
							aligned = true;
						}
					}
				} while(!aligned);
			}

			//apply changes to Visual Things
			for(int i = 0; i < visualThings.Count; i++) 
			{
				BaseVisualThing t = (BaseVisualThing)visualThings[i];
				t.Changed = true;

				// Update what must be updated
				ThingData td = GetThingData(t.Thing);
				foreach(KeyValuePair<Sector, bool> s in td.UpdateAlso) 
				{
					if(VisualSectorExists(s.Key)) 
					{
						BaseVisualSector vs = (BaseVisualSector)GetVisualSector(s.Key);
						vs.UpdateSectorGeometry(s.Value);
					}
				}
			}

			UpdateChangedObjects();
			ShowTargetInfo();
		}

		//mxd
		[BeginAction("lookthroughthing")]
		public void LookThroughThing() 
		{
			List<VisualThing> visualThings = GetSelectedVisualThings(true);

			if(visualThings.Count != 1) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Look Through Selection action requires 1 selected Thing!");
				return;
			}

			//set position and angles
			Thing t = visualThings[0].Thing;
			if((t.Type == 9072 || t.Type == 9073) && t.Args[3] > 0) //AimingCamera or MovingCamera with target?
			{ 
				//position
				if(t.Type == 9072 && (t.Args[0] > 0 || t.Args[1] > 0)) //positon MovingCamera at targeted interpolation point
				{ 
					int ipTag = t.Args[0] + (t.Args[1] << 8);
					Thing ip = null;

					//find interpolation point
					foreach(Thing tgt in General.Map.Map.Things) 
					{
						if(tgt.Tag == ipTag && tgt.Type == 9070) 
						{
							ip = tgt;
							break;
						}
					}

					if(ip != null) 
					{
						VisualThing vTarget = !VisualThingExists(ip) ? CreateVisualThing(ip) : GetVisualThing(ip);
						Vector3D targetPos;
						if(vTarget == null) 
						{
							targetPos = ip.Position;
							if(ip.Sector != null) targetPos.z += ip.Sector.FloorHeight;
						} 
						else 
						{
							targetPos = vTarget.CenterV3D;
						}

						General.Map.VisualCamera.Position = targetPos; //position at interpolation point
					} 
					else 
					{
						General.Map.VisualCamera.Position = visualThings[0].CenterV3D; //position at camera
					}

				}
				else
				{
					General.Map.VisualCamera.Position = visualThings[0].CenterV3D; //position at camera
				}

				//angle
				Thing target = null;

				foreach(Thing tgt in General.Map.Map.Things) 
				{
					if(tgt.Tag == t.Args[3]) 
					{
						target = tgt;
						break;
					}
				}

				if(target == null) 
				{
					General.Interface.DisplayStatus(StatusType.Warning, "Camera target with Tag " + t.Args[3] + " does not exist!");
					General.Map.VisualCamera.AngleXY = t.Angle - Angle2D.PI;
					General.Map.VisualCamera.AngleZ = Angle2D.PI;
				} 
				else 
				{
					VisualThing vTarget = !VisualThingExists(target) ? CreateVisualThing(target) : GetVisualThing(target);
					Vector3D targetPos;
					if(vTarget == null) 
					{
						targetPos = target.Position;
						if(target.Sector != null) targetPos.z += target.Sector.FloorHeight;
					} 
					else 
					{
						targetPos = vTarget.CenterV3D;
					}

					bool pitch = (t.Args[2] & 4) != 0;
					Vector3D delta = General.Map.VisualCamera.Position - targetPos;
					General.Map.VisualCamera.AngleXY = delta.GetAngleXY();
					General.Map.VisualCamera.AngleZ = pitch ? -delta.GetAngleZ() : Angle2D.PI;
				}
			} 
			else if((t.Type == 9025 || t.Type == 9073 || t.Type == 9070) && t.Args[0] != 0) //InterpolationPoint, SecurityCamera or AimingCamera with pitch?
			{ 
				General.Map.VisualCamera.Position = visualThings[0].CenterV3D; //position at camera
				General.Map.VisualCamera.AngleXY = t.Angle - Angle2D.PI;
				General.Map.VisualCamera.AngleZ = Angle2D.PI + Angle2D.DegToRad(t.Args[0]);
			} 
			else //nope, just a generic thing
			{ 
				General.Map.VisualCamera.Position = visualThings[0].CenterV3D; //position at thing
				General.Map.VisualCamera.AngleXY = t.Angle - Angle2D.PI;
				General.Map.VisualCamera.AngleZ = Angle2D.PI;
			}
		}

		//mxd
		[BeginAction("toggleslope")]
		public void ToggleSlope() 
		{
			List<VisualGeometry> selection = GetSelectedSurfaces();

			if(selection.Count == 0) 
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Toggle Slope action requires selected surfaces!");
				return;
			}

			List<BaseVisualSector> toUpdate = new List<BaseVisualSector>();
			General.Map.UndoRedo.CreateUndo("Toggle Slope");

			//check selection
			foreach(VisualGeometry vg in selection) 
			{
				bool update = false;

				//assign/remove action
				if(vg.GeometryType == VisualGeometryType.WALL_LOWER) 
				{
					if(vg.Sidedef.Line.Action == 0 || (vg.Sidedef.Line.Action == 700 && vg.Sidedef.Line.Args[0] == 0)) 
					{
						//check if the sector already has floor slopes
						foreach(Sidedef side in vg.Sidedef.Sector.Sidedefs) 
						{
							if(side == vg.Sidedef || side.Line.Action != 700) continue;

							int arg = (side == side.Line.Front ? 1 : 2);

							if(side.Line.Args[0] == arg) 
							{
								//if only floor is affected, remove action
								if(side.Line.Args[1] == 0)
									side.Line.Action = 0;
								else //clear floor alignment
									side.Line.Args[0] = 0;
							}
						}

						//set action
						vg.Sidedef.Line.Action = 700;
						vg.Sidedef.Line.Args[0] = (vg.Sidedef == vg.Sidedef.Line.Front ? 1 : 2);
						update = true;
					}
				} 
				else if(vg.GeometryType == VisualGeometryType.WALL_UPPER) 
				{
					if(vg.Sidedef.Line.Action == 0 || (vg.Sidedef.Line.Action == 700 && vg.Sidedef.Line.Args[1] == 0)) 
					{
						//check if the sector already has ceiling slopes
						foreach(Sidedef side in vg.Sidedef.Sector.Sidedefs) 
						{
							if(side == vg.Sidedef || side.Line.Action != 700) continue;

							int arg = (side == side.Line.Front ? 1 : 2);

							if(side.Line.Args[1] == arg) 
							{
								//if only ceiling is affected, remove action
								if(side.Line.Args[0] == 0)
									side.Line.Action = 0;
								else //clear ceiling alignment
									side.Line.Args[1] = 0;
							}
						}

						//set action
						vg.Sidedef.Line.Action = 700;
						vg.Sidedef.Line.Args[1] = (vg.Sidedef == vg.Sidedef.Line.Front ? 1 : 2);
						update = true;
					}
				} 
				else if(vg.GeometryType == VisualGeometryType.CEILING) 
				{
					//check if the sector has ceiling slopes
					foreach(Sidedef side in vg.Sector.Sector.Sidedefs) 
					{
						if(side.Line.Action != 700)	continue;

						int arg = (side == side.Line.Front ? 1 : 2);

						if(side.Line.Args[1] == arg) 
						{
							//if only ceiling is affected, remove action
							if(side.Line.Args[0] == 0)
								side.Line.Action = 0;
							else //clear ceiling alignment
								side.Line.Args[1] = 0;

							update = true;
						}
					}
				} 
				else if(vg.GeometryType == VisualGeometryType.FLOOR) 
				{
					//check if the sector has floor slopes
					foreach(Sidedef side in vg.Sector.Sector.Sidedefs) 
					{
						if(side.Line.Action != 700)	continue;

						int arg = (side == side.Line.Front ? 1 : 2);

						if(side.Line.Args[0] == arg) 
						{
							//if only floor is affected, remove action
							if(side.Line.Args[1] == 0)
								side.Line.Action = 0;
							else //clear floor alignment
								side.Line.Args[0] = 0;

							update = true;
						}
					}
				}

				//add to update list
				if(update) toUpdate.Add((BaseVisualSector)vg.Sector);
			}

			//update changed geometry
			if(toUpdate.Count > 0) 
			{
				RebuildElementData();

				foreach(BaseVisualSector vs in toUpdate)
					vs.UpdateSectorGeometry(true);

				UpdateChangedObjects();
				ClearSelection();
				ShowTargetInfo();
			}

			General.Interface.DisplayStatus(StatusType.Action, "Toggled Slope for " + toUpdate.Count + (toUpdate.Count == 1 ? " surface." : " surfaces."));
		}

		//mxd
		[BeginAction("alphabasedtexturehighlighting")]
		public void ToggleAlphaBasedTextureHighlighting()
		{
			BuilderPlug.Me.AlphaBasedTextureHighlighting = !BuilderPlug.Me.AlphaBasedTextureHighlighting;
			General.Interface.DisplayStatus(StatusType.Info, "Alpha-based textures highlighting is " + (BuilderPlug.Me.AlphaBasedTextureHighlighting ? "ENABLED" : "DISABLED"));
		}

		// biwa
		[BeginAction("visualpaintselect")]
		protected virtual void OnPaintSelectBegin()
		{
			paintselectpressed = true;
			GetTargetEventReceiver(true).OnPaintSelectBegin();
		}

		// biwa
		[EndAction("visualpaintselect")]
		protected virtual void OnPaintSelectEnd()
		{
			paintselectpressed = false;
			paintselecttype = null;
			GetTargetEventReceiver(true).OnPaintSelectEnd();
		}

		[BeginAction("togglevisualslopepicking")]
		public void ToggleVisualSidedefSlopePicking()
		{
			if (!General.Map.UDMF)
			{
				General.ToastManager.ShowToast(ToastMessages.VISUALSLOPING, ToastType.WARNING, "Visual sloping", "Visual sloping is supported in UDMF only.");
				return;
			}
			else if(!General.Map.Config.PlaneEquationSupport)
			{
				General.ToastManager.ShowToast(ToastMessages.VISUALSLOPING, ToastType.WARNING, "Visual sloping", "Visual sloping is not supported in this game configuration.");
				return;
			}

			if (pickingmode != PickingMode.SidedefSlopeHandles)
				pickingmode = PickingMode.SidedefSlopeHandles;
			else
			{
				pickingmode = PickingMode.Default;

				// Clear smart pivot handles, otherwise it will keep being displayed
				foreach (KeyValuePair<Sector, List<VisualSlope>> kvp in allslopehandles)
					foreach (VisualSlope checkhandle in kvp.Value)
						if (checkhandle.SmartPivot && !(checkhandle.Selected || checkhandle.Pivot))
						{
							checkhandle.SmartPivot = false;
							usedslopehandles.Remove(checkhandle);
						}
			}
		}

		[BeginAction("togglevisualvertexslopepicking")]
		public void ToggleVisualVertexSlopePicking()
		{
			if (!General.Map.UDMF)
			{
				General.ToastManager.ShowToast(ToastMessages.VISUALSLOPING, ToastType.WARNING, "Visual sloping", "Visual sloping is supported in UDMF only.");
				return;
			}
			else if (!General.Map.Config.PlaneEquationSupport)
			{
				General.ToastManager.ShowToast(ToastMessages.VISUALSLOPING, ToastType.WARNING, "Visual sloping", "Visual sloping is not supported in this game configuration.");
				return;
			}

			if (pickingmode != PickingMode.VertexSlopeHandles)
				pickingmode = PickingMode.VertexSlopeHandles;
			else
			{
				pickingmode = PickingMode.Default;

				// Clear smart pivot handles, otherwise it will keep being displayed
				foreach (KeyValuePair<Sector, List<VisualSlope>> kvp in allslopehandles)
					foreach (VisualSlope checkhandle in kvp.Value)
						if (checkhandle.SmartPivot && !(checkhandle.Selected || checkhandle.Pivot))
						{
							checkhandle.SmartPivot = false;
							usedslopehandles.Remove(checkhandle);
						}
			}
		}

		[BeginAction("togglevisualvertexslopeadjacentselection")]
		public void ToggleVisualVertexSlopeAdjacentSelection()
		{
			if (!General.Map.UDMF)
			{
				General.ToastManager.ShowToast(ToastMessages.VISUALSLOPING, ToastType.WARNING, "Visual sloping", "Visual sloping is not supported in this game configuration.");
				return;
			}
			else if (!General.Map.Config.PlaneEquationSupport)
			{
				General.ToastManager.ShowToast(ToastMessages.VISUALSLOPING, ToastType.WARNING, "Visual sloping", "Visual sloping is not supported in this game configuration.");
				return;
			}

			BuilderPlug.Me.SelectAdjacentVisualVertexSlopeHandles = !BuilderPlug.Me.SelectAdjacentVisualVertexSlopeHandles;

			General.Interface.DisplayStatus(StatusType.Action, "Adjacant selection of visual vertex slop handles is " + (BuilderPlug.Me.SelectAdjacentVisualVertexSlopeHandles ? "ENABLED" : "DISABLED"));
		}


		[BeginAction("resetslope")]
		public void ResetSlope()
		{
			List<IVisualEventReceiver> selectedsectors = GetSelectedObjects(true, false, false, false, false);
			if (selectedsectors.Count == 0)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "You need to select at least one floor or ceiling to reset slope.");
				return;
			}

			General.Map.UndoRedo.CreateUndo("Reset plane slope");

			int numfloors = 0;
			int numceilings = 0;

			// Reset slope
			foreach (BaseVisualGeometrySector bvgs in selectedsectors)
			{
				SectorLevel level = bvgs.Level;
				bool applytoceiling = false;
				if (level.extrafloor)
				{
					// The top side of 3D floors is the ceiling of the sector, but it's a "floor" in UDB, so the
					// ceiling of the control sector has to be modified
					if (level.type == SectorLevelType.Floor)
						applytoceiling = true;
				}
				else
				{
					if (level.type == SectorLevelType.Ceiling)
						applytoceiling = true;
				}

				if (applytoceiling)
				{
					// Set the ceiling height to something hopefully sensible
					// biwa. Do not reset to the z position of the plane of the center of the sector anymore, since 
					// that will result in pretty crazy values of 3D floor control sectors
					//level.sector.CeilHeight = (int)Math.Round(level.plane.GetZ(level.sector.BBox.X + level.sector.BBox.Width / 2, level.sector.BBox.Y + level.sector.BBox.Height / 2));

					level.sector.CeilSlopeOffset = double.NaN;
					level.sector.CeilSlope = new Vector3D();
					numceilings++;
				}
				else
				{
					// Set the floor height to something hopefully sensible
					// biwa. Do not reset to the z position of the plane of the center of the sector anymore, since 
					// that will result in pretty crazy values of 3D floor control sectors
					//level.sector.FloorHeight = (int)Math.Round(level.plane.GetZ(level.sector.BBox.X + level.sector.BBox.Width / 2, level.sector.BBox.Y + level.sector.BBox.Height / 2));

					level.sector.FloorSlopeOffset = double.NaN;
					level.sector.FloorSlope = new Vector3D();
					numfloors++;
				}

				// Rebuild sector
				BaseVisualSector vs;
				if (VisualSectorExists(level.sector))
				{
					vs = (BaseVisualSector)GetVisualSector(level.sector);
				}
				else
				{
					vs = CreateBaseVisualSector(level.sector);
				}

				if (vs != null) vs.UpdateSectorGeometry(true);
			}

			string ptype = "plane";
			if (numfloors == 0) ptype = "ceiling";
			else if (numceilings == 0) ptype = "floor";

			UpdateChangedObjects();

			General.Interface.DisplayStatus(StatusType.Action, string.Format("{1} {0} slopes reset.", ptype, numfloors+numceilings));
		}

		[BeginAction("slopebetweenhandles")]
		public void SlopeBetweenHandles()
		{
			List<IVisualEventReceiver> selectedsectors = GetSelectedObjects(true, false, false, false, false);
			if (selectedsectors.Count == 0)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "You need to select floors or ceilings to slope between slope handles.");
				return;
			}

			List<VisualSidedefSlope> handles = GetSlopeHandlePair();

			if (handles.Count != 2)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "You need to select exactly two slope handles.");
				return;
			}

			General.Map.UndoRedo.CreateUndo("Slope between slope handles");

			// Create the new plane
			Vector3D p1 = new Vector3D(handles[0].Sidedef.Line.Start.Position, handles[0].Level.plane.GetZ(handles[0].Sidedef.Line.Start.Position));
			Vector3D p2 = new Vector3D(handles[0].Sidedef.Line.End.Position, handles[0].Level.plane.GetZ(handles[0].Sidedef.Line.End.Position));
			Vector3D p3 = new Vector3D(handles[1].Sidedef.Line.Line.GetCoordinatesAt(0.5f), handles[1].Level.plane.GetZ(handles[1].Sidedef.Line.Line.GetCoordinatesAt(0.5f)));
			Plane plane = new Plane(p1, p2, p3, true);

			// Apply slope
			foreach (BaseVisualGeometrySector bvgs in selectedsectors)
			{
				VisualSidedefSlope.ApplySlope(bvgs.Level, plane, this);
				bvgs.Sector.UpdateSectorGeometry(true);
			}

			UpdateChangedObjects();

			General.Interface.DisplayStatus(StatusType.Action, "Sloped between slope handles.");
		}

		/// <summary>
		/// Applies plane equation slopes to selected sectors, based on the selected slope handles
		/// </summary>
		[BeginAction("archbetweenhandles")]
		public void ArchBetweenHandles()
		{
			List<IVisualEventReceiver> selectedsectors = GetSelectedObjects(true, false, false, false, false);

			if (selectedsectors.Count < 2)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "You need to select at least two floors and ceilings to slope arch between slope handles.");
				return;
			}

			List<VisualSidedefSlope> handles = GetSlopeHandlePair();

			if (handles.Count != 2)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "You need to select exactly two slope handles.");
				return;
			}

			General.Map.UndoRedo.CreateUndo("Arch between slope handles");

			Vector3D p1 = handles[0].GetCenterPoint();
			Vector3D p2 = handles[1].GetCenterPoint();
			double linelength = Line2D.GetLength(p2.x - p1.x, p2.y - p1.y);
			double zdiff = Math.Abs(p1.z - p2.z);
			double theta;
			double offsetangle;

			// Compute theta and the offset angle. Special handling if the slope handles are at the same height
			if (zdiff == 0.0)
			{
				theta = Math.PI;
				offsetangle = 0.0;
			}
			else
			{
				theta = Math.Atan(zdiff / linelength) * 2;
				offsetangle = Math.PI / 2.0;

				if (p2.z < p1.z)
					offsetangle -= theta;
			}

			SlopeArcher sa = new SlopeArcher(this, selectedsectors, handles[0], handles[1], theta, offsetangle, 1.0);

			SlopeArchForm saf = new SlopeArchForm(sa);
			saf.UpdateChangedObjects += Interface_OnUpdateChangedObjects;
			DialogResult result = saf.ShowDialog();
			saf.UpdateChangedObjects -= Interface_OnUpdateChangedObjects;

			if (result == DialogResult.Cancel)
				General.Map.UndoRedo.WithdrawUndo();
			else
			{
				UpdateChangedObjects();

				General.Interface.DisplayStatus(StatusType.Action, "Arched between slope handles.");
			}
		}

		/// <summary>
		/// Applies the Visual Mode's current camera pitch and yaw to the selected things
		/// </summary>
		[BeginAction("applycamerarotationtothings")]
		public void ApplyCameraRotationToThings()
		{
			List<Thing> things = GetSelectedThings();

			if(things.Count == 0)
			{
				General.Interface.DisplayStatus(StatusType.Warning, "Can't apply camera rotation to things: no things selected.");
				return;
			}

			General.Map.UndoRedo.CreateUndo("Apply camera rotation to things");

			foreach (Thing t in things)
			{
				t.Rotate(General.Map.VisualCamera.AngleXY - Angle2D.PI);
				t.SetPitch((int)Angle2D.RadToDeg(General.Map.VisualCamera.AngleZ - Angle2D.PI));
				((BaseVisualThing)allthings[t]).Rebuild();
			}
		}

		#endregion

		#region ================== Texture Alignment

		//mxd. If checkSelectedSidedefParts is set to true, only selected linedef parts will be aligned (when a sidedef has both top and bottom parts, but only bottom is selected, top texture won't be aligned)
		internal void AutoAlignTextures(BaseVisualGeometrySidedef start, ImageData texture, bool alignx, bool aligny, bool resetsidemarks, bool checkSelectedSidedefParts) 
		{
			if(General.Map.UDMF && General.Map.Config.UseLocalSidedefTextureOffsets)
				AutoAlignTexturesUDMF(start, texture, alignx, aligny, resetsidemarks, checkSelectedSidedefParts);
			else
				AutoAlignTextures(start, texture, alignx, aligny, resetsidemarks);
		}

		//mxd. Moved here from Tools
		// This performs texture alignment along all walls that match with the same texture
		// NOTE: This method uses the sidedefs marking to indicate which sides have been aligned
		// When resetsidemarks is set to true, all sidedefs will first be marked false (not aligned).
		// Setting resetsidemarks to false is usefull to align only within a specific selection
		// (set the marked property to true for the sidedefs outside the selection)
		private void AutoAlignTextures(BaseVisualGeometrySidedef start, ImageData texture, bool alignx, bool aligny, bool resetsidemarks) 
		{
			Stack<SidedefAlignJob> todo = new Stack<SidedefAlignJob>(50);
			double scalex = (General.Map.Config.ScaledTextureOffsets && !texture.WorldPanning) ? texture.Scale.x : 1.0f;
			double scaley = (General.Map.Config.ScaledTextureOffsets && !texture.WorldPanning) ? texture.Scale.y : 1.0f;

			// Mark all sidedefs false (they will be marked true when the texture is aligned).
			if(resetsidemarks) General.Map.Map.ClearMarkedSidedefs(false);

			// Begin with first sidedef
			SidedefAlignJob first = new SidedefAlignJob();
			first.sidedef = start.Sidedef;
			first.offsetx = start.Sidedef.OffsetX;
			int ystartalign = start.Sidedef.OffsetY; //mxd

			//mxd
			if(start.GeometryType == VisualGeometryType.WALL_MIDDLE_3D) 
			{
				first.controlSide = start.GetControlLinedef().Front;
				//first.offsetx += first.controlSide.OffsetX;
				//ystartalign += first.controlSide.OffsetY;
				ystartalign = first.controlSide.OffsetY;
			} 
			else 
			{
				first.controlSide = start.Sidedef;
			}

			// We potentially need to deal with 2 textures (because of long and short texture names). This is even important
			// for classic texture alignments, since for example Eternity Engine doesn't support local sidedef texture offsets,
			// but full texture names from a /textures directory
			HashSet<long> texturehashes = new HashSet<long> { texture.LongName };
			switch (start.GeometryType)
			{
				case VisualGeometryType.WALL_LOWER:
					texturehashes.Add(first.controlSide.LongLowTexture);
					break;

				case VisualGeometryType.WALL_MIDDLE:
				case VisualGeometryType.WALL_MIDDLE_3D:
					texturehashes.Add(first.controlSide.LongMiddleTexture);
					break;

				case VisualGeometryType.WALL_UPPER:
					texturehashes.Add(first.controlSide.LongHighTexture);
					break;
			}

			first.forward = true;
			todo.Push(first);

			// Continue until nothing more to align
			while(todo.Count > 0) 
			{
				// Get the align job to do
				SidedefAlignJob j = todo.Pop();

				// Make sure to not align already aligned textures. This prevents unexpected
				// results when aligning textures on circular shapes
				if (j.sidedef.Marked)
					continue;

				if(j.forward) 
				{
					// Apply alignment
					//if(alignx) j.controlSide.OffsetX = (int)j.offsetx;
					//if(aligny) j.sidedef.OffsetY = (int)Math.Round((first.ceilingHeight - j.ceilingHeight) / scaley) + ystartalign;
					if (alignx) j.sidedef.OffsetX = (int)j.offsetx;
					if (aligny) j.controlSide.OffsetY = (int)Math.Round((first.ceilingHeight - j.ceilingHeight) / scaley) + ystartalign;
					int forwardoffset = (int)j.offsetx + (int)Math.Round(j.sidedef.Line.Length / scalex);
					int backwardoffset = (int)j.offsetx;

					j.sidedef.Marked = true;

					// Wrap the value within the width of the texture (to prevent ridiculous values)
					// NOTE: We don't use ScaledWidth here because the texture offset is in pixels, not mappixels
					if(texture.IsImageLoaded && BuilderModesTools.SidedefTextureMatch(this, j.sidedef, texturehashes)) 
					{
						if(alignx) j.sidedef.OffsetX %= texture.Width;
						//if(aligny) j.sidedef.OffsetY %= texture.Height;
						if(aligny) j.controlSide.OffsetY %= texture.Height;
					}

					// Add sidedefs backward (connected to the left vertex)
					Vertex v = j.sidedef.IsFront ? j.sidedef.Line.Start : j.sidedef.Line.End;
					AddSidedefsForAlignment(todo, v, false, backwardoffset, 1.0f, texturehashes, false);

					// Add sidedefs forward (connected to the right vertex)
					v = j.sidedef.IsFront ? j.sidedef.Line.End : j.sidedef.Line.Start;
					AddSidedefsForAlignment(todo, v, true, forwardoffset, 1.0f, texturehashes, false);
				}
				else 
				{
					// Apply alignment
					//if(alignx) j.controlSide.OffsetX = (int)j.offsetx - (int)Math.Round(j.sidedef.Line.Length / scalex);
					//if(aligny) j.sidedef.OffsetY = (int)Math.Round((first.ceilingHeight - j.ceilingHeight) / scaley) + ystartalign;
					if (alignx) j.sidedef.OffsetX = (int)j.offsetx - (int)Math.Round(j.sidedef.Line.Length / scalex);
					if (aligny) j.controlSide.OffsetY = (int)Math.Round((first.ceilingHeight - j.ceilingHeight) / scaley) + ystartalign;
					int forwardoffset = (int)j.offsetx;
					int backwardoffset = (int)j.offsetx - (int)Math.Round(j.sidedef.Line.Length / scalex);

					j.sidedef.Marked = true;

					// Wrap the value within the width of the texture (to prevent ridiculous values)
					// NOTE: We don't use ScaledWidth here because the texture offset is in pixels, not mappixels
					if(texture.IsImageLoaded && BuilderModesTools.SidedefTextureMatch(this, j.sidedef, texturehashes)) 
					{
						if(alignx) j.sidedef.OffsetX %= texture.Width;
						//if(aligny) j.sidedef.OffsetY %= texture.Height;
						if (aligny) j.controlSide.OffsetY %= texture.Height;
					}

					// Add sidedefs forward (connected to the right vertex)
					Vertex v = j.sidedef.IsFront ? j.sidedef.Line.End : j.sidedef.Line.Start;
					AddSidedefsForAlignment(todo, v, true, forwardoffset, 1.0f, texturehashes, false);

					// Add sidedefs backward (connected to the left vertex)
					v = j.sidedef.IsFront ? j.sidedef.Line.Start : j.sidedef.Line.End;
					AddSidedefsForAlignment(todo, v, false, backwardoffset, 1.0f, texturehashes, false);
				}
			}
		}

		//mxd. Moved here from GZDoomEditing plugin
		// This performs UDMF texture alignment along all walls that match with the same texture
		// NOTE: This method uses the sidedefs marking to indicate which sides have been aligned
		// When resetsidemarks is set to true, all sidedefs will first be marked false (not aligned).
		// Setting resetsidemarks to false is usefull to align only within a specific selection
		// (set the marked property to true for the sidedefs outside the selection)
		private void AutoAlignTexturesUDMF(BaseVisualGeometrySidedef start, ImageData texture, bool alignx, bool aligny, bool resetsidemarks, bool checkselectedsidedefparts) 
		{
			HashSet<long> alignedsides = new HashSet<long>(100);
			// Mark all sidedefs false (they will be marked true when the texture is aligned)
			if(resetsidemarks) General.Map.Map.ClearMarkedSidedefs(false);
			if(!texture.IsImageLoaded) return;

			bool worldpanning = texture.WorldPanning || General.Map.Data.MapInfo.ForceWorldPanning;

			Stack<SidedefAlignJob> todo = new Stack<SidedefAlignJob>(50);
			double scalex = (General.Map.Config.ScaledTextureOffsets && !texture.WorldPanning) ? texture.Scale.x : 1.0f;
			double scaley = (General.Map.Config.ScaledTextureOffsets && !texture.WorldPanning) ? texture.Scale.y : 1.0f;

			SidedefAlignJob first = new SidedefAlignJob { sidedef = start.Sidedef, offsetx = start.Sidedef.OffsetX };
			first.controlSide = (start.GeometryType == VisualGeometryType.WALL_MIDDLE_3D ? start.GetControlLinedef().Front : start.Sidedef);

			//mxd. We potentially need to deal with 2 textures (because of long and short texture names)...
			HashSet<long> texturehashes = new HashSet<long> { texture.LongName };
			switch(start.GeometryType)
			{
				case VisualGeometryType.WALL_LOWER:
					texturehashes.Add(first.controlSide.LongLowTexture);
					break;

				case VisualGeometryType.WALL_MIDDLE:
				case VisualGeometryType.WALL_MIDDLE_3D:
					texturehashes.Add(first.controlSide.LongMiddleTexture);
					break;

				case VisualGeometryType.WALL_UPPER:
					texturehashes.Add(first.controlSide.LongHighTexture);
					break;
			}

			//mxd
			List<BaseVisualGeometrySidedef> selectedVisualSides = new List<BaseVisualGeometrySidedef>();
			if(checkselectedsidedefparts && !singleselection) 
			{
				foreach(IVisualEventReceiver i in selectedobjects)
				{
					BaseVisualGeometrySidedef side = i as BaseVisualGeometrySidedef;
					if(side != null && !selectedVisualSides.Contains(side)) selectedVisualSides.Add(side);
				}
			}
			
			//mxd. Scale
			switch(start.GeometryType) 
			{
				case VisualGeometryType.WALL_UPPER:
					first.scaleX = start.Sidedef.Fields.GetValue("scalex_top", 1.0);
					first.scaleY = start.Sidedef.Fields.GetValue("scaley_top", 1.0);
					break;
				case VisualGeometryType.WALL_MIDDLE:
				case VisualGeometryType.WALL_MIDDLE_3D:
					first.scaleX = first.controlSide.Fields.GetValue("scalex_mid", 1.0);
					first.scaleY = first.controlSide.Fields.GetValue("scaley_mid", 1.0);
					break;
				case VisualGeometryType.WALL_LOWER:
					first.scaleX = start.Sidedef.Fields.GetValue("scalex_bottom", 1.0);
					first.scaleY = start.Sidedef.Fields.GetValue("scaley_bottom", 1.0);
					break;
			}

			// biwa
			double vwidth = worldpanning ? texture.ScaledWidth / first.scaleX : texture.Width;
			double vheight = worldpanning ? texture.ScaledHeight / first.scaleY : texture.Height;

			// Determine the Y alignment
			double ystartalign = start.Sidedef.OffsetY;
			switch(start.GeometryType) 
			{
				case VisualGeometryType.WALL_UPPER:
					ystartalign += Tools.GetSidedefTopOffsetY(start.Sidedef, start.Sidedef.Fields.GetValue("offsety_top", 0.0), worldpanning ? 1.0 : first.scaleY / scaley, false);//mxd
					break;
				case VisualGeometryType.WALL_MIDDLE:
					ystartalign += Tools.GetSidedefMiddleOffsetY(start.Sidedef, start.Sidedef.Fields.GetValue("offsety_mid", 0.0), worldpanning ? 1.0 : first.scaleY / scaley, false);//mxd
					break;
				case VisualGeometryType.WALL_MIDDLE_3D: //mxd. 3d-floors are not affected by Lower/Upper unpegged flags
					ystartalign += first.controlSide.OffsetY - (start.Sidedef.Sector.CeilHeight - first.ceilingHeight);
					ystartalign += start.Sidedef.Fields.GetValue("offsety_mid", 0.0);
					ystartalign += first.controlSide.Fields.GetValue("offsety_mid", 0.0);
					break;
				case VisualGeometryType.WALL_LOWER:
					ystartalign += Tools.GetSidedefBottomOffsetY(start.Sidedef, start.Sidedef.Fields.GetValue("offsety_bottom", 0.0), worldpanning ? 1.0 : first.scaleY / scaley, false);//mxd
					break;
			}

			// Begin with first sidedef
			switch(start.GeometryType) 
			{
				case VisualGeometryType.WALL_UPPER:
					first.offsetx += start.Sidedef.Fields.GetValue("offsetx_top", 0.0);
					break;
				case VisualGeometryType.WALL_MIDDLE:
					first.offsetx += start.Sidedef.Fields.GetValue("offsetx_mid", 0.0);
					break;
				case VisualGeometryType.WALL_MIDDLE_3D: //mxd. Yup, 4 sets of texture offsets are used
					first.offsetx += start.Sidedef.Fields.GetValue("offsetx_mid", 0.0);
					first.offsetx += first.controlSide.OffsetX;
					first.offsetx += first.controlSide.Fields.GetValue("offsetx_mid", 0.0);
					break;
				case VisualGeometryType.WALL_LOWER:
					first.offsetx += start.Sidedef.Fields.GetValue("offsetx_bottom", 0.0);
					break;
			}
			first.forward = true;
			todo.Push(first);

			// Continue until nothing more to align
			while(todo.Count > 0) 
			{
				Vertex v;
				double forwardoffset, backwardoffset;
				bool matchtop = false;
				bool matchmid = false;
				bool matchbottom = false;

				// Get the align job to do
				SidedefAlignJob j = todo.Pop();

				// Make sure that each combination of sidedef and control side is only aligned once. 
				// This prevents unexpected results when aligning textures on circular shapes
				long checksum = (long)j.sidedef.Index << 32 | (long)j.controlSide.Index;
				if (alignedsides.Contains(checksum))
					continue;
				else
					alignedsides.Add(checksum);

				//mxd. Get visual parts
				if (VisualSectorExists(j.sidedef.Sector))
				{
					VisualSidedefParts parts = ((BaseVisualSector)GetVisualSector(j.sidedef.Sector)).GetSidedefParts(j.sidedef);
					//VisualSidedefParts controlparts = (j.sidedef != j.controlSide ? ((BaseVisualSector)GetVisualSector(j.controlSide.Sector)).GetSidedefParts(j.controlSide) : parts);

					matchtop = (!j.sidedef.Marked && (!singleselection || texturehashes.Contains(j.sidedef.LongHighTexture)) && (parts.upper != null && parts.upper.Triangles > 0));
					matchbottom = (!j.sidedef.Marked && (!singleselection || texturehashes.Contains(j.sidedef.LongLowTexture)) && (parts.lower != null && parts.lower.Triangles > 0));
					matchmid = ((!singleselection || texturehashes.Contains(j.controlSide.LongMiddleTexture))
						&& ((parts.middledouble != null && parts.middledouble.Triangles > 0) || (parts.middlesingle != null && parts.middlesingle.Triangles > 0))); //mxd

					// "Normal" sidedef parts didn't match? Check 3D floors
					if(matchmid == false && parts.middle3d != null && parts.middle3d.Count > 0)
					{
						foreach(VisualMiddle3D vm3d in parts.middle3d)
						{
							if(vm3d.Triangles > 0 && texturehashes.Contains(vm3d.Texture.LongName))
							{
								matchmid = true;
								break;
							}
						}
					}


					//mxd. If there's a selection, check if matched part is actually selected
					if(checkselectedsidedefparts && !singleselection)
					{
						if(matchtop) matchtop = parts.upper.Selected;
						if(matchbottom) matchbottom = parts.lower.Selected;
						if(matchmid) matchmid = ((parts.middledouble != null && parts.middledouble.Selected)
											  || (parts.middlesingle != null && parts.middlesingle.Selected)
											  || SidePartIsSelected(selectedVisualSides, j.sidedef, VisualGeometryType.WALL_MIDDLE_3D));
					}
				}

				if(!matchbottom && !matchtop && !matchmid) continue; //mxd

				//mxd. We want to skip realigning of the starting wall part
				if(matchtop) matchtop = (j.sidedef != start.Sidedef || start.GeometryType != VisualGeometryType.WALL_UPPER);
				if(matchmid) matchmid = (j.sidedef != start.Sidedef || (start.GeometryType != VisualGeometryType.WALL_MIDDLE && start.GeometryType != VisualGeometryType.WALL_MIDDLE_3D));
				if(matchbottom) matchbottom = (j.sidedef != start.Sidedef || start.GeometryType != VisualGeometryType.WALL_LOWER);

				if(matchbottom || matchtop || matchmid)
				{
					j.sidedef.Fields.BeforeFieldsChange();
					if(j.sidedef.Index != j.controlSide.Index) j.controlSide.Fields.BeforeFieldsChange(); //mxd
				}
				
				//mxd. Apply Scale
				if(matchtop)
				{
					UniFields.SetFloat(j.sidedef.Fields, "scalex_top", first.scaleX, 1.0);
					UniFields.SetFloat(j.sidedef.Fields, "scaley_top", j.scaleY, 1.0);
				}
				if(matchmid)
				{
					UniFields.SetFloat(j.controlSide.Fields, "scalex_mid", first.scaleX, 1.0);
					UniFields.SetFloat(j.controlSide.Fields, "scaley_mid", j.scaleY, 1.0);
				}
				if(matchbottom)
				{
					UniFields.SetFloat(j.sidedef.Fields, "scalex_bottom", first.scaleX, 1.0);
					UniFields.SetFloat(j.sidedef.Fields, "scaley_bottom", j.scaleY, 1.0);
				}

				if(j.forward) 
				{
					// Apply alignment
					if(alignx) 
					{
						double offset = j.offsetx;
						offset -= j.sidedef.OffsetX;

						if(matchtop)
						{
							ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongHighTexture);
							int texwidth = (tex != null && tex.IsImageLoaded) ? tex.Width : 1;
							j.sidedef.Fields["offsetx_top"] = new UniValue(UniversalType.Float, Math.Round(offset % vwidth, General.Map.FormatInterface.VertexDecimals));
						}
						if(matchbottom)
						{
							ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongLowTexture);
							int texwidth = (tex != null && tex.IsImageLoaded) ? tex.Width : 1;
							j.sidedef.Fields["offsetx_bottom"] = new UniValue(UniversalType.Float, Math.Round(offset % vwidth, General.Map.FormatInterface.VertexDecimals));
						}
						if(matchmid) 
						{
							if(j.sidedef.Index != j.controlSide.Index) //mxd. if it's a part of 3d-floor 
							{ 
								offset -= j.controlSide.OffsetX;
								offset -= j.controlSide.Fields.GetValue("offsetx_mid", 0.0);
							}

							ImageData tex = General.Map.Data.GetTextureImage(j.controlSide.LongMiddleTexture);
							int texwidth = (tex != null && tex.IsImageLoaded) ? tex.Width : 1;
							j.sidedef.Fields["offsetx_mid"] = new UniValue(UniversalType.Float, Math.Round(offset % vwidth, General.Map.FormatInterface.VertexDecimals));
						}
					}

					if(aligny) 
					{
						double offset;

						if (!texture.WorldPanning && !General.Map.Data.MapInfo.ForceWorldPanning)
							offset = ((start.Sidedef.Sector.CeilHeight - j.ceilingHeight) / scaley) * Math.Abs(j.scaleY)  + ystartalign - j.sidedef.OffsetY; //mxd
						else
							offset = (start.Sidedef.Sector.CeilHeight - j.ceilingHeight + ystartalign - j.sidedef.OffsetY);

						if (matchtop)
						{
							ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongHighTexture);
							int texheight = (tex != null && tex.IsImageLoaded) ? tex.Height : 1;
							double scale = !worldpanning ? j.scaleY / scaley : 1.0f;

							j.sidedef.Fields["offsety_top"] = new UniValue(UniversalType.Float,
								Math.Round(Tools.GetSidedefTopOffsetY(j.sidedef, offset, scale, true) % vheight, General.Map.FormatInterface.VertexDecimals)); //mxd

						}
						if (matchbottom)
						{
							ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongLowTexture);
							int texheight = (tex != null && tex.IsImageLoaded) ? tex.Height : 1;
							double scale = !worldpanning ? j.scaleY / scaley : 1.0f;

							j.sidedef.Fields["offsety_bottom"] = new UniValue(UniversalType.Float,
								Math.Round(Tools.GetSidedefBottomOffsetY(j.sidedef, offset, scale, true) % vheight, General.Map.FormatInterface.VertexDecimals)); //mxd
						}
						if(matchmid) 
						{
							//mxd. Side is part of a 3D floor?
							if(j.sidedef.Index != j.controlSide.Index) 
							{
								offset -= j.controlSide.OffsetY;
								offset -= j.controlSide.Fields.GetValue("offsety_mid", 0.0);

								ImageData tex = General.Map.Data.GetTextureImage(j.controlSide.LongMiddleTexture);
								int texheight = (tex != null && tex.IsImageLoaded) ? tex.Height : 1;
								j.sidedef.Fields["offsety_mid"] = new UniValue(UniversalType.Float,
									Math.Round(offset % vheight, General.Map.FormatInterface.VertexDecimals));
							} 
							else
							{
								ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongMiddleTexture);
								double scale = !worldpanning ? j.scaleY / scaley : 1.0f;
								offset = Tools.GetSidedefMiddleOffsetY(j.sidedef, offset, scale, true);

								if (tex != null && tex.IsImageLoaded)
								{
									bool startisnonwrappedmidtex = (start.Sidedef.Other != null && start.GeometryType == VisualGeometryType.WALL_MIDDLE && !start.Sidedef.IsFlagSet("wrapmidtex") && !start.Sidedef.Line.IsFlagSet("wrapmidtex"));
									bool cursideisnonwrappedmidtex = (j.sidedef.Other != null && !j.sidedef.IsFlagSet("wrapmidtex") && !j.sidedef.Line.IsFlagSet("wrapmidtex"));
									
									//mxd. Only clamp when the texture is wrapped 
									if(!cursideisnonwrappedmidtex) offset %= vheight;

									if(!startisnonwrappedmidtex && cursideisnonwrappedmidtex)
									{
										//mxd. This should be doublesided non-wrapped line. Find the nearset aligned position
										double curoffset = UniFields.GetFloat(j.sidedef.Fields, "offsety_mid") + j.sidedef.OffsetY;
										offset += vheight * Math.Round(curoffset / vheight - 0.5f * Math.Sign(j.scaleY));

										// Make sure the surface stays between floor and ceiling
										if(j.sidedef.Line.IsFlagSet(General.Map.Config.PegMidtextureFlag) || Math.Sign(j.scaleY) == -1)
										{
											if(offset < -vheight)
												offset += vheight;
											else if(offset > j.sidedef.GetMiddleHeight())
												offset -= vheight;
										}
										else
										{
											if(offset < -(j.sidedef.GetMiddleHeight() + vheight))
												offset += vheight;
											else if(offset > vheight)
												offset -= vheight;
										}
									}
								}

								j.sidedef.Fields["offsety_mid"] = new UniValue(UniversalType.Float, 
									Math.Round(offset, General.Map.FormatInterface.VertexDecimals)); //mxd
							}
						}
					}

					backwardoffset = j.offsetx;

					if (!worldpanning)
					{
						// If the texture gets replaced with a "hires" texture it adds more fuckery
						if (texture is HiResImage)
							forwardoffset = j.offsetx + Math.Round((Math.Round(j.sidedef.Line.Length) / scalex) % vwidth, General.Map.FormatInterface.VertexDecimals);
						else
							forwardoffset = j.offsetx + Math.Round((Math.Round(j.sidedef.Line.Length) / scalex * Math.Abs(first.scaleX)) % vwidth, General.Map.FormatInterface.VertexDecimals);
					}
					else
						forwardoffset = Math.Round((j.offsetx + Math.Round(j.sidedef.Line.Length)) % vwidth, General.Map.FormatInterface.VertexDecimals); 

					// Done this sidedef
					j.sidedef.Marked = true;
					j.controlSide.Marked = true;

					// Add sidedefs backward (connected to the left vertex)
					v = j.sidedef.IsFront ? j.sidedef.Line.Start : j.sidedef.Line.End;
					AddSidedefsForAlignment(todo, v, false, backwardoffset, j.scaleY, texturehashes, true);

					// Add sidedefs forward (connected to the right vertex)
					v = j.sidedef.IsFront ? j.sidedef.Line.End : j.sidedef.Line.Start;
					AddSidedefsForAlignment(todo, v, true, forwardoffset, j.scaleY, texturehashes, true);
				} 
				else // backward
				{
					// Apply alignment
					if(alignx) 
					{
						double offset;
						
						if(!worldpanning)
						{
							// If the texture gets replaced with a "hires" texture it adds more fuckery
							if (texture is HiResImage)
								offset = Math.Round((j.offsetx - j.sidedef.OffsetX - Math.Round(j.sidedef.Line.Length) / scalex) % vwidth, General.Map.FormatInterface.VertexDecimals);
							else
								offset = Math.Round((j.offsetx - j.sidedef.OffsetX - Math.Round(j.sidedef.Line.Length) / scalex * first.scaleX) % vwidth, General.Map.FormatInterface.VertexDecimals);
						}
						else
							offset = Math.Round((j.offsetx - j.sidedef.OffsetX - Math.Round(j.sidedef.Line.Length)) % vwidth, General.Map.FormatInterface.VertexDecimals);

						if(matchtop)
						{
							ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongHighTexture);
							int texwidth = (tex != null && tex.IsImageLoaded) ? tex.Width : 1;
							j.sidedef.Fields["offsetx_top"] = new UniValue(UniversalType.Float,
								Math.Round(offset % vwidth, General.Map.FormatInterface.VertexDecimals));
						}
						if(matchbottom)
						{
							ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongLowTexture);
							int texwidth = (tex != null && tex.IsImageLoaded) ? tex.Width : 1;
							j.sidedef.Fields["offsetx_bottom"] = new UniValue(UniversalType.Float,
								Math.Round(offset % vwidth, General.Map.FormatInterface.VertexDecimals));
						}
						if(matchmid) 
						{
							if(j.sidedef.Index != j.controlSide.Index) //mxd
							{ 
								offset -= j.controlSide.OffsetX;
								offset -= j.controlSide.Fields.GetValue("offsetx_mid", 0.0);
							}

							ImageData tex = General.Map.Data.GetTextureImage(j.controlSide.LongMiddleTexture);
							int texwidth = (tex != null && tex.IsImageLoaded) ? tex.Width : 1;
							j.sidedef.Fields["offsetx_mid"] = new UniValue(UniversalType.Float, 
								Math.Round(offset % vwidth, General.Map.FormatInterface.VertexDecimals));
						}
					}

					if(aligny) 
					{
						double offset = ((start.Sidedef.Sector.CeilHeight - j.ceilingHeight) / scaley) * Math.Abs(j.scaleY) + ystartalign; //mxd
						offset -= j.sidedef.OffsetY; //mxd

						if(matchtop)
						{
							ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongHighTexture);
							int texheight = (tex != null && tex.IsImageLoaded) ? tex.Height : 1;
							double scale = !worldpanning ? j.scaleY / scaley : 1.0f;

							j.sidedef.Fields["offsety_top"] = new UniValue(UniversalType.Float, 
								Math.Round(Tools.GetSidedefTopOffsetY(j.sidedef, offset, scale, true) % vheight, General.Map.FormatInterface.VertexDecimals)); //mxd
						}
						if(matchbottom)
						{
							ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongLowTexture);
							int texheight = (tex != null && tex.IsImageLoaded) ? tex.Height : 1;
							double scale = !worldpanning ? j.scaleY / scaley : 1.0f;

							j.sidedef.Fields["offsety_bottom"] = new UniValue(UniversalType.Float,
								Math.Round(Tools.GetSidedefBottomOffsetY(j.sidedef, offset, scale, true) % vheight, General.Map.FormatInterface.VertexDecimals)); //mxd
						}
						if(matchmid) 
						{
							//mxd. Side is part of a 3D floor?
							if(j.sidedef.Index != j.controlSide.Index) 
							{
								offset -= j.controlSide.OffsetY;
								offset -= j.controlSide.Fields.GetValue("offsety_mid", 0.0);

								ImageData tex = General.Map.Data.GetTextureImage(j.controlSide.LongMiddleTexture);
								int texheight = (tex != null && tex.IsImageLoaded) ? tex.Height : 1;
								j.sidedef.Fields["offsety_mid"] = new UniValue(UniversalType.Float,
									Math.Round(offset % vheight, General.Map.FormatInterface.VertexDecimals)); //mxd
							} 
							else 
							{
								ImageData tex = General.Map.Data.GetTextureImage(j.sidedef.LongMiddleTexture);
								double scale = !worldpanning ? j.scaleY / scaley : 1.0;
								offset = Tools.GetSidedefMiddleOffsetY(j.sidedef, offset, scale, true);

								if(tex != null && tex.IsImageLoaded)
								{
									bool startisnonwrappedmidtex = (start.Sidedef.Other != null && start.GeometryType == VisualGeometryType.WALL_MIDDLE && !start.Sidedef.IsFlagSet("wrapmidtex") && !start.Sidedef.Line.IsFlagSet("wrapmidtex"));
									bool cursideisnonwrappedmidtex = (j.sidedef.Other != null && !j.sidedef.IsFlagSet("wrapmidtex") && !j.sidedef.Line.IsFlagSet("wrapmidtex"));
									
									//mxd. Only clamp when the texture is wrapped 
									if(!cursideisnonwrappedmidtex) offset %= vheight;

									if(!startisnonwrappedmidtex && cursideisnonwrappedmidtex)
									{
										//mxd. This should be doublesided non-wrapped line. Find the nearset aligned position
										double curoffset = UniFields.GetFloat(j.sidedef.Fields, "offsety_mid") + j.sidedef.OffsetY;
										offset += tex.Height * Math.Round(curoffset / vheight - 0.5f * Math.Sign(j.scaleY));

										// Make sure the surface stays between floor and ceiling
										if(j.sidedef.Line.IsFlagSet(General.Map.Config.PegMidtextureFlag) || Math.Sign(j.scaleY) == -1)
										{
											if(offset < -vheight)
												offset += vheight;
											else if(offset > j.sidedef.GetMiddleHeight())
												offset -= vheight;
										}
										else
										{
											if(offset < -(j.sidedef.GetMiddleHeight() + vheight))
												offset += vheight;
											else if(offset > vheight)
												offset -= vheight;
										}
									}
								}

								j.sidedef.Fields["offsety_mid"] = new UniValue(UniversalType.Float, 
									Math.Round(offset, General.Map.FormatInterface.VertexDecimals)); //mxd
							}
						}
					}

					forwardoffset = j.offsetx;

					if (!worldpanning)
					{
						// If the texture gets replaced with a "hires" texture it adds more fuckery
						if (texture is HiResImage)
							backwardoffset = Math.Round((j.offsetx - Math.Round(j.sidedef.Line.Length) / scalex) % vwidth, General.Map.FormatInterface.VertexDecimals);
						else
							backwardoffset = Math.Round((j.offsetx - Math.Round(j.sidedef.Line.Length) / scalex * Math.Abs(first.scaleX)) % vwidth, General.Map.FormatInterface.VertexDecimals);
					}
					else
						backwardoffset = Math.Round((j.offsetx - Math.Round(j.sidedef.Line.Length)) % vwidth, General.Map.FormatInterface.VertexDecimals);

					// Done this sidedef
					j.sidedef.Marked = true;
					j.controlSide.Marked = true;

					// Add sidedefs forward (connected to the right vertex)
					v = j.sidedef.IsFront ? j.sidedef.Line.End : j.sidedef.Line.Start;
					AddSidedefsForAlignment(todo, v, true, forwardoffset, j.scaleY, texturehashes, true);

					// Add sidedefs backward (connected to the left vertex)
					v = j.sidedef.IsFront ? j.sidedef.Line.Start : j.sidedef.Line.End;
					AddSidedefsForAlignment(todo, v, false, backwardoffset, j.scaleY, texturehashes, true);
				}
			}
		}

		// This adds the matching, unmarked sidedefs from a vertex for texture alignment
		private void AddSidedefsForAlignment(Stack<SidedefAlignJob> stack, Vertex v, bool forward, double offsetx, double scaleY, HashSet<long> texturelongnames, bool udmf) 
		{
			foreach(Linedef ld in v.Linedefs)
			{
				Sidedef side1 = forward ? ld.Front : ld.Back;
				Sidedef side2 = forward ? ld.Back : ld.Front;

                // [ZZ] I don't know what logic here is.
                //      I'm going to check if any side is marked, and if so, don't add.
                if ((side1 != null && side1.Marked) ||
                    (side2 != null && side2.Marked)) continue;

				if((ld.Start == v) && (side1 != null) && !side1.Marked) 
				{
					List<Sidedef> controlSides = GetControlSides(side1, udmf); //mxd

					foreach(Sidedef s in controlSides)
					{
						if(!singleselection || BuilderModesTools.SidedefTextureMatch(this, s, texturelongnames)) 
						{
							SidedefAlignJob nj = new SidedefAlignJob();
							nj.forward = forward;
							nj.offsetx = offsetx;
							nj.scaleY = scaleY; //mxd
							nj.sidedef = side1;
							nj.controlSide = s; //mxd
							stack.Push(nj);
						}
					}
				} 
				else if((ld.End == v) && (side2 != null) && !side2.Marked) 
				{
					List<Sidedef> controlSides = GetControlSides(side2, udmf); //mxd

					foreach(Sidedef s in controlSides) 
					{
						if(!singleselection || BuilderModesTools.SidedefTextureMatch(this, s, texturelongnames)) 
						{
							SidedefAlignJob nj = new SidedefAlignJob();
							nj.forward = forward;
							nj.offsetx = offsetx;
							nj.scaleY = scaleY; //mxd
							nj.sidedef = side2;
							nj.controlSide = s; //mxd
							stack.Push(nj);
						}
					}
				}
			}
		}

		//mxd
		private static bool SidePartIsSelected(List<BaseVisualGeometrySidedef> selection, Sidedef side, VisualGeometryType geoType) 
		{
			foreach(BaseVisualGeometrySidedef vs in selection) 
				if(vs.GeometryType == geoType && vs.Sidedef.Index == side.Index) return true;
			return false;
		}

		//mxd
		private List<Sidedef> GetControlSides(Sidedef side, bool udmf) 
		{
			if(side.Other == null) return new List<Sidedef> { side };
			if(side.Other.Sector.Tag == 0) return new List<Sidedef> { side };

			SectorData data = GetSectorDataEx(side.Other.Sector);
			if(data == null || data.ExtraFloors.Count == 0) return new List<Sidedef> { side };

			List<Sidedef> sides = new List<Sidedef>();
			foreach(Effect3DFloor ef in data.ExtraFloors)
				sides.Add(ef.Linedef.Front);

			if(udmf)
				sides.Add(side); //UDMF map format
			else
				sides.Insert(0, side); //Doom/Hexen map format: if a sidedef has lower/upper parts, they take predecence in alignment

			return sides;
		}

		#endregion
	}
}