mirror of
https://git.do.srb2.org/STJr/UltimateZoneBuilder.git
synced 2024-11-27 14:12:16 +00:00
195 lines
4.7 KiB
C#
195 lines
4.7 KiB
C#
|
|
#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.Drawing;
|
|
|
|
#endregion
|
|
|
|
namespace CodeImp.DoomBuilder.Geometry
|
|
{
|
|
public sealed class EarClipPolygon : LinkedList<EarClipVertex>
|
|
{
|
|
#region ================== Variables
|
|
|
|
// Tree variables
|
|
private List<EarClipPolygon> children;
|
|
private bool inner;
|
|
|
|
#endregion
|
|
|
|
#region ================== Properties
|
|
|
|
public List<EarClipPolygon> Children { get { return children; } }
|
|
public bool Inner { get { return inner; } set { inner = value; } }
|
|
|
|
#endregion
|
|
|
|
#region ================== Constructors
|
|
|
|
// Constructor
|
|
internal EarClipPolygon()
|
|
{
|
|
// Initialize
|
|
children = new List<EarClipPolygon>();
|
|
}
|
|
|
|
// Constructor
|
|
internal EarClipPolygon(EarClipPolygon p, EarClipVertex add) : base(p)
|
|
{
|
|
// Initialize
|
|
base.AddLast(add);
|
|
children = new List<EarClipPolygon>();
|
|
}
|
|
|
|
#endregion
|
|
|
|
#region ================== Methods
|
|
|
|
// This merges a polygon into this one
|
|
public void Add(EarClipPolygon p)
|
|
{
|
|
// Initialize
|
|
foreach(EarClipVertex v in p) base.AddLast(v);
|
|
}
|
|
|
|
// This calculates the area
|
|
public float CalculateArea()
|
|
{
|
|
// Multiply the x coordinate of each vertex by the y coordinate of the next vertex.
|
|
// Multiply the y coordinate of each vertex by the x coordinate of the next vertex.
|
|
// Subtract these.
|
|
float result = 0.0f;
|
|
int firstcalculated = 0;
|
|
LinkedListNode<EarClipVertex> n1 = base.First;
|
|
while(firstcalculated < 2)
|
|
{
|
|
LinkedListNode<EarClipVertex> n2 = n1.Next ?? base.First;
|
|
float a = n1.Value.Position.x * n2.Value.Position.y;
|
|
float b = n1.Value.Position.y * n2.Value.Position.x;
|
|
result += a - b;
|
|
n1 = n2;
|
|
if(n2 == base.First) firstcalculated++;
|
|
}
|
|
return Math.Abs(result / 2.0f);
|
|
}
|
|
|
|
// This creates a bounding box from the outer polygon
|
|
public RectangleF CreateBBox()
|
|
{
|
|
float left = float.MaxValue;
|
|
float right = float.MinValue;
|
|
float top = float.MaxValue;
|
|
float bottom = float.MinValue;
|
|
foreach(EarClipVertex v in this)
|
|
{
|
|
if(v.Position.x < left) left = v.Position.x;
|
|
if(v.Position.x > right) right = v.Position.x;
|
|
if(v.Position.y < top) top = v.Position.y;
|
|
if(v.Position.y > bottom) bottom = v.Position.y;
|
|
}
|
|
return new RectangleF(left, top, right - left, bottom - top);
|
|
}
|
|
|
|
// Point inside the polygon?
|
|
// See: http://local.wasp.uwa.edu.au/~pbourke/geometry/insidepoly/
|
|
public bool Intersect(Vector2D p)
|
|
{
|
|
Vector2D v1 = base.Last.Value.Position;
|
|
Vector2D v2;
|
|
LinkedListNode<EarClipVertex> n = base.First;
|
|
uint c = 0;
|
|
|
|
// Go for all vertices
|
|
while(n != null)
|
|
{
|
|
// Get next vertex
|
|
v2 = n.Value.Position;
|
|
|
|
// Determine min/max values
|
|
float miny = Math.Min(v1.y, v2.y);
|
|
float maxy = Math.Max(v1.y, v2.y);
|
|
float maxx = Math.Max(v1.x, v2.x);
|
|
|
|
// Check for intersection
|
|
if((p.y > miny) && (p.y <= maxy))
|
|
{
|
|
if(p.x <= maxx)
|
|
{
|
|
if(v1.y != v2.y)
|
|
{
|
|
float xint = (p.y - v1.y) * (v2.x - v1.x) / (v2.y - v1.y) + v1.x;
|
|
if((v1.x == v2.x) || (p.x <= xint)) c++;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Move to next
|
|
v1 = v2;
|
|
n = n.Next;
|
|
}
|
|
|
|
// Inside this polygon?
|
|
if((c & 0x00000001UL) != 0)
|
|
{
|
|
// Check if not inside the children
|
|
foreach(EarClipPolygon child in children)
|
|
{
|
|
// Inside this child? Then it is not inside this polygon.
|
|
if(child.Intersect(p)) return false;
|
|
}
|
|
|
|
// Inside polygon!
|
|
return true;
|
|
}
|
|
else
|
|
{
|
|
// Not inside the polygon
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// This inserts a polygon if it is a child of this one
|
|
public bool InsertChild(EarClipPolygon p)
|
|
{
|
|
// Polygon must have at least 1 vertex
|
|
if(p.Count == 0) return false;
|
|
|
|
// Check if it can be inserted at a lower level
|
|
foreach(EarClipPolygon child in children)
|
|
{
|
|
if(child.InsertChild(p)) return true;
|
|
}
|
|
|
|
// Check if it can be inserted here
|
|
if(this.Intersect(p.First.Value.Position))
|
|
{
|
|
// Make the polygon the inverse of this one
|
|
p.Inner = !inner;
|
|
children.Add(p);
|
|
return true;
|
|
}
|
|
|
|
// Can't insert it as a child
|
|
return false;
|
|
}
|
|
|
|
#endregion
|
|
}
|
|
}
|