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using System; |
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using System.Collections.Generic; |
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|
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namespace Oni.Akira |
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{ |
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internal class AlphaBspBuilder |
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{ |
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private PolygonMesh mesh; |
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private bool debug; |
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|
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public static AlphaBspNode Build(PolygonMesh mesh, bool debug) |
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{ |
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var builder = new AlphaBspBuilder |
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{ |
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mesh = mesh, |
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debug = debug |
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}; |
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|
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return builder.Build(); |
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} |
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|
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private AlphaBspNode Build() |
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{ |
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var transparent = new List<Polygon>(1024); |
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|
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transparent.AddRange(mesh.Polygons.Where(p => p.IsTransparent)); |
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|
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if (debug) |
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transparent.AddRange(mesh.Ghosts.Where(p => p.IsTransparent)); |
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|
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Console.Error.WriteLine("Building bsp tree for {0} transparent polygons...", transparent.Count); |
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return Build(transparent); |
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} |
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|
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private AlphaBspNode Build(List<Polygon> polygons) |
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{ |
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if (polygons.Count == 0) |
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return null; |
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|
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var separator = polygons[0].Plane; |
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AlphaBspNode frontNode = null, backNode = null; |
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|
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if (polygons.Count > 1) |
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{ |
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var front = new List<Polygon>(polygons.Count); |
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var back = new List<Polygon>(polygons.Count); |
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|
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for (int i = 1; i < polygons.Count; i++) |
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{ |
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var polygon = polygons[i]; |
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var plane = polygon.Plane; |
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|
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bool isFront = false; |
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bool isBack = false; |
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|
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if (Math.Abs(plane.D - separator.D) < 0.001f |
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&& Vector3.Distance(plane.Normal, separator.Normal) < 0.001f) |
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{ |
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isFront = true; |
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} |
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else |
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{ |
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foreach (var point in polygon.Points) |
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{ |
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if (separator.DotCoordinate(point) > 0.0f) |
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isFront = true; |
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else |
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isBack = true; |
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} |
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} |
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|
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if (isFront) |
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front.Add(polygon); |
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|
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if (isBack) |
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back.Add(polygon); |
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} |
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|
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frontNode = Build(front); |
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backNode = Build(back); |
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} |
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|
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return new AlphaBspNode(polygons[0], frontNode, backNode); |
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} |
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} |
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} |
