///<summary> /// Constructs a new Terrain. ///</summary> ///<param name="shape">Shape to use for the terrain.</param> ///<param name="worldTransform">Transform to use for the terrain.</param> public Terrain(TerrainShape shape, AffineTransform worldTransform) { WorldTransform = worldTransform; Shape = shape; Events = new ContactEventManager <Terrain>(); }
public override void GetMeshData(List <VertexPositionNormalTexture> vertices, List <ushort> indices) { int numColumns = DisplayedObject.Shape.Heights.GetLength(0); int numRows = DisplayedObject.Shape.Heights.GetLength(1); TerrainShape shape = DisplayedObject.Shape; //The terrain can be transformed arbitrarily. However, the collision against the triangles is always oriented such that the transformed local //up vector points in the same direction as the collidable surfaces. //To make sure the graphics match the terrain collision, try transforming the local space up direction into world space. Treat it as a normal- it requires an adjugate transpose, not a regular transformation. var normalTransform = Matrix3x3.AdjugateTranspose(DisplayedObject.WorldTransform.LinearTransform); var reverseWinding = Vector3.Dot(normalTransform.Up, DisplayedObject.WorldTransform.LinearTransform.Up) < 0; for (int j = 0; j < numRows; j++) { for (int i = 0; i < numColumns; i++) { VertexPositionNormalTexture v; Vector3 position, n; DisplayedObject.GetPosition(i, j, out position); shape.GetLocalNormal(i, j, out n); Matrix3x3.Transform(ref n, ref normalTransform, out n); n.Normalize(); MathConverter.Convert(ref position, out v.Position); MathConverter.Convert(ref n, out v.Normal); if (reverseWinding) { Microsoft.Xna.Framework.Vector3.Negate(ref v.Normal, out v.Normal); } v.TextureCoordinate = new Microsoft.Xna.Framework.Vector2(i, j); vertices.Add(v); if (i < numColumns - 1 && j < numRows - 1) { if (shape.QuadTriangleOrganization == QuadTriangleOrganization.BottomLeftUpperRight) { //v3 v4 //v1 v2 //v1 v2 v3 indices.Add((ushort)(numColumns * j + i)); if (reverseWinding) { indices.Add((ushort)(numColumns * (j + 1) + i)); indices.Add((ushort)(numColumns * j + i + 1)); } else { indices.Add((ushort)(numColumns * j + i + 1)); indices.Add((ushort)(numColumns * (j + 1) + i)); } //v2 v4 v3 indices.Add((ushort)(numColumns * j + i + 1)); if (reverseWinding) { indices.Add((ushort)(numColumns * (j + 1) + i)); indices.Add((ushort)(numColumns * (j + 1) + i + 1)); } else { indices.Add((ushort)(numColumns * (j + 1) + i + 1)); indices.Add((ushort)(numColumns * (j + 1) + i)); } } else if (shape.QuadTriangleOrganization == QuadTriangleOrganization.BottomRightUpperLeft) { //v1 v2 v4 indices.Add((ushort)(numColumns * j + i)); if (reverseWinding) { indices.Add((ushort)(numColumns * (j + 1) + i + 1)); indices.Add((ushort)(numColumns * j + i + 1)); } else { indices.Add((ushort)(numColumns * j + i + 1)); indices.Add((ushort)(numColumns * (j + 1) + i + 1)); } //v1 v4 v3 indices.Add((ushort)(numColumns * j + i)); if (reverseWinding) { indices.Add((ushort)(numColumns * (j + 1) + i)); indices.Add((ushort)(numColumns * (j + 1) + i + 1)); } else { indices.Add((ushort)(numColumns * (j + 1) + i + 1)); indices.Add((ushort)(numColumns * (j + 1) + i)); } } } } } }