252 lines
9.7 KiB
C#
252 lines
9.7 KiB
C#
using Microsoft.Xna.Framework;
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using Microsoft.Xna.Framework.Graphics;
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using System.Collections.Generic;
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using System.Linq;
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namespace Subsurface.Lights
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{
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class ConvexHull
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{
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public static List<ConvexHull> list = new List<ConvexHull>();
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static BasicEffect fowEffect;
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static BasicEffect shadowEffect;
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private VertexPositionColor[] vertices;
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private short[] indices;
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int primitiveCount;
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bool[] backFacing;
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VertexPositionColor[] shadowVertices;
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public bool Enabled
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{
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get;
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set;
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}
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public ConvexHull(Vector2[] points, Color color)
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{
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int vertexCount = points.Length;
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vertices = new VertexPositionColor[vertexCount + 1];
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Vector2 center = Vector2.Zero;
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for (int i = 0; i < vertexCount; i++)
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{
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vertices[i] = new VertexPositionColor(new Vector3(points[i], 0), color);
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center += points[i];
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}
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center /= points.Length;
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vertices[vertexCount] = new VertexPositionColor(new Vector3(center, 0), color);
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primitiveCount = points.Length;
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indices = new short[primitiveCount * 3];
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for (int i = 0; i < primitiveCount; i++)
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{
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indices[3 * i] = (short)i;
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indices[3 * i + 1] = (short)((i + 1) % vertexCount);
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indices[3 * i + 2] = (short)vertexCount;
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}
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backFacing = new bool[vertexCount];
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Enabled = true;
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list.Add(this);
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}
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public void Move(Vector2 amount)
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{
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for (int i = 0; i < vertices.Count(); i++)
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{
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vertices[i].Position = new Vector3(vertices[i].Position.X + amount.X, vertices[i].Position.Y + amount.Y, vertices[i].Position.Z);
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}
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}
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public void SetVertices(Vector2[] points)
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{
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int vertexCount = points.Length;
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vertices = new VertexPositionColor[vertexCount + 1];
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for (int i = 0; i < vertexCount; i++)
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{
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vertices[i] = new VertexPositionColor(new Vector3(points[i], 0), Color.Black);
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}
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}
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//public void Draw(GameTime gameTime)
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//{
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// device.RasterizerState = RasterizerState.CullNone;
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// device.BlendState = BlendState.Opaque;
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// drawingEffect.World = Matrix.CreateTranslation(position.X, position.Y, 0);
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// foreach (EffectPass pass in drawingEffect.CurrentTechnique.Passes)
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// {
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// pass.Apply();
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// device.DrawUserIndexedPrimitives<VertexPositionColor>(PrimitiveType.TriangleList, vertices, 0, vertices.Length, indices, 0, primitiveCount);
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// }
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//}
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public void DrawShadows(GraphicsDevice graphicsDevice, Camera cam, Vector2 lightSourcePos, bool fow = true)
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{
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if (!Enabled) return;
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if (fowEffect == null)
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{
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fowEffect = new BasicEffect(graphicsDevice);
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fowEffect.VertexColorEnabled = true;
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}
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if (shadowEffect==null)
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{
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shadowEffect = new BasicEffect(graphicsDevice);
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shadowEffect.TextureEnabled = true;
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//shadowEffect.VertexColorEnabled = true;
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shadowEffect.LightingEnabled = false;
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shadowEffect.Texture = Game1.TextureLoader.FromFile("Content/lights/penumbra.png");
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}
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//compute facing of each edge, using N*L
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for (int i = 0; i < primitiveCount; i++)
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{
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Vector2 firstVertex = new Vector2(vertices[i].Position.X, vertices[i].Position.Y);
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int secondIndex = (i + 1) % primitiveCount;
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Vector2 secondVertex = new Vector2(vertices[secondIndex].Position.X, vertices[secondIndex].Position.Y);
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Vector2 middle = (firstVertex + secondVertex) / 2;
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Vector2 L = lightSourcePos - middle;
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Vector2 N = new Vector2();
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N.X = -(secondVertex.Y - firstVertex.Y);
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N.Y = secondVertex.X - firstVertex.X;
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backFacing[i] = (Vector2.Dot(N, L) < 0);
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}
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//find beginning and ending vertices which
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//belong to the shadow
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int startingIndex = 0;
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int endingIndex = 0;
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for (int i = 0; i < primitiveCount; i++)
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{
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int currentEdge = i;
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int nextEdge = (i + 1) % primitiveCount;
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if (backFacing[currentEdge] && !backFacing[nextEdge])
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endingIndex = nextEdge;
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if (!backFacing[currentEdge] && backFacing[nextEdge])
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startingIndex = nextEdge;
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}
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VertexPositionTexture[] penumbraVertices = new VertexPositionTexture[6];
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if (fow)
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{
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for (int n = 0; n < 4; n+=3)
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{
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Vector3 penumbraStart = (n == 0) ? vertices[startingIndex].Position : vertices[endingIndex].Position;
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penumbraVertices[n] = new VertexPositionTexture();
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penumbraVertices[n].Position = penumbraStart;
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penumbraVertices[n].TextureCoordinate = new Vector2(0.0f, 1.0f);
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//penumbraVertices[0].te = fow ? Color.Black : Color.Transparent;
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for (int i = 0; i < 2; i++ )
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{
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penumbraVertices[n + i + 1] = new VertexPositionTexture();
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Vector3 vertexDir = penumbraStart - new Vector3(lightSourcePos, 0);
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vertexDir.Normalize();
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Vector3 normal = (i == 0) ? new Vector3(-vertexDir.Y, vertexDir.X, 0.0f) : new Vector3(vertexDir.Y, -vertexDir.X, 0.0f)*0.05f;
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if (n > 0) normal = -normal;
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vertexDir = penumbraStart - (new Vector3(lightSourcePos, 0) - normal * 20.0f);
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vertexDir.Normalize();
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penumbraVertices[n + i + 1].Position = new Vector3(lightSourcePos, 0) + vertexDir * 9000;
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if (i==0)
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{
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//penumbraVertices[n].Position -= normal*2.0f;
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}
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if (fow)
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{
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penumbraVertices[n + i + 1].TextureCoordinate = (i == 0) ? new Vector2(0.05f, 0.0f) : new Vector2(1.0f, 0.0f);
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}
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else
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{
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penumbraVertices[n + i + 1].TextureCoordinate = (i == 0) ? new Vector2(1.0f, 0.0f):Vector2.Zero;
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}
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//penumbraVertices[i+1].Color = Color.Black;
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}
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if (n>0)
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{
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var temp = penumbraVertices[4];
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penumbraVertices[4] = penumbraVertices[5];
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penumbraVertices[5] = temp;
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}
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}
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}
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int shadowVertexCount;
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//nr of vertices that are in the shadow
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if (endingIndex > startingIndex)
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shadowVertexCount = endingIndex - startingIndex + 1;
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else
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shadowVertexCount = primitiveCount + 1 - startingIndex + endingIndex;
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shadowVertices = new VertexPositionColor[shadowVertexCount * 2];
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//create a triangle strip that has the shape of the shadow
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int currentIndex = startingIndex;
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int svCount = 0;
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while (svCount != shadowVertexCount * 2)
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{
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Vector3 vertexPos = vertices[currentIndex].Position;
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//one vertex on the hull
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shadowVertices[svCount] = new VertexPositionColor();
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shadowVertices[svCount].Color = fow ? Color.Black : Color.Transparent;
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shadowVertices[svCount].Position = vertexPos;
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//one extruded by the light direction
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shadowVertices[svCount + 1] = new VertexPositionColor();
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shadowVertices[svCount + 1].Color = fow ? Color.Black : Color.Transparent;
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Vector3 L2P = vertexPos - new Vector3(lightSourcePos, 0);
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L2P.Normalize();
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shadowVertices[svCount + 1].Position = new Vector3(lightSourcePos, 0) + L2P * 9000;
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svCount += 2;
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currentIndex = (currentIndex + 1) % primitiveCount;
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}
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fowEffect.World = cam.ShaderTransform
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* Matrix.CreateOrthographic(Game1.GraphicsWidth, Game1.GraphicsHeight, -1, 1) * 0.5f;
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fowEffect.CurrentTechnique.Passes[0].Apply();
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graphicsDevice.DrawUserPrimitives<VertexPositionColor>(PrimitiveType.TriangleStrip, shadowVertices, 0, shadowVertexCount * 2 - 2);
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if (fow)
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{
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shadowEffect.World = cam.ShaderTransform
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* Matrix.CreateOrthographic(Game1.GraphicsWidth, Game1.GraphicsHeight, -1, 1) * 0.5f;
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shadowEffect.CurrentTechnique.Passes[0].Apply();
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graphicsDevice.DrawUserPrimitives<VertexPositionTexture>(PrimitiveType.TriangleList, penumbraVertices, 0, 2, VertexPositionTexture.VertexDeclaration);
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}
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}
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public void Remove()
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{
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list.Remove(this);
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}
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}
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}
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