From 026324779e2f0a2b1284d7e448de8cf0176af95c Mon Sep 17 00:00:00 2001
From: Magnus Norddahl <dpjudas@users.noreply.github.com>
Date: Fri, 20 Dec 2019 05:12:39 +0100
Subject: [PATCH] Speed up linedef processing by not relying on a hashmap

---
 Source/Core/Map/Linedef.cs            |  6 +++++-
 Source/Core/VisualModes/VisualMode.cs | 20 ++++++++++++--------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/Source/Core/Map/Linedef.cs b/Source/Core/Map/Linedef.cs
index 60c6337..3239cfd 100644
--- a/Source/Core/Map/Linedef.cs
+++ b/Source/Core/Map/Linedef.cs
@@ -77,6 +77,9 @@ namespace CodeImp.DoomBuilder.Map
 
 		// Clone
 		private int serializedindex;
+
+        // Rendering
+        private int lastProcessed;
 		
 		#endregion
 
@@ -111,7 +114,8 @@ namespace CodeImp.DoomBuilder.Map
 		public RectangleF Rect { get { return rect; } }
 		public int[] Args { get { return args; } }
 		internal int SerializedIndex { get { return serializedindex; } set { serializedindex = value; } }
-		internal bool FrontInterior { get { return frontinterior; } set { frontinterior = value; } }
+        internal int LastProcessed { get { return lastProcessed; } set { lastProcessed = value; } }
+        internal bool FrontInterior { get { return frontinterior; } set { frontinterior = value; } }
 		internal bool ImpassableFlag { get { return impassableflag; } }
 		internal int ColorPresetIndex { get { return colorPresetIndex; } } //mxd
 		internal bool ExtraFloorFlag; //mxd
diff --git a/Source/Core/VisualModes/VisualMode.cs b/Source/Core/VisualModes/VisualMode.cs
index 18b5520..3c9ee79 100644
--- a/Source/Core/VisualModes/VisualMode.cs
+++ b/Source/Core/VisualModes/VisualMode.cs
@@ -510,15 +510,18 @@ namespace CodeImp.DoomBuilder.VisualModes
 
 		//mxd. Should move selected things in specified direction
 		protected virtual void MoveSelectedThings(Vector2D direction, bool absolutePosition) { }
-		
-		#endregion
 
-		#region ================== Visibility Culling
-		
+        #endregion
+
+        #region ================== Visibility Culling
+
+        int lastProcessed = 0;
+
 		// This preforms visibility culling
 		protected void DoCulling()
 		{
-			HashSet<Linedef> visiblelines = new HashSet<Linedef>();
+            lastProcessed++;
+			List<Linedef> visiblelines = new List<Linedef>();
 			Vector2D campos2d = General.Map.VisualCamera.Position;
 			
 			// Make collections
@@ -538,10 +541,11 @@ namespace CodeImp.DoomBuilder.VisualModes
 					foreach(Linedef ld in block.Lines)
 					{
 						// Line not already processed?
-						if(!visiblelines.Contains(ld))
+						if (ld.LastProcessed != lastProcessed)//if(!visiblelines.Contains(ld))
 						{
-							// Add line if not added yet
-							visiblelines.Add(ld);
+                            // Add line if not added yet
+                            ld.LastProcessed = lastProcessed;
+                            visiblelines.Add(ld);
 
 							// Which side of the line is the camera on?
 							if(ld.SideOfLine(campos2d) < 0)