/PhysicsEngines/Jitter/Helpers.cs

using System.Collections.Generic;

using Delta.Rendering.Models;

using Delta.Utilities.Datatypes;

using Jitter.Collision;

using Jitter.Collision.Shapes;

using Jitter.LinearMath;



namespace Delta.PhysicsEngines.Jitter

{

	public static class Helpers

	{

		#region CreateFrom (Static)

		/// <summary>

		/// Helper method used for creation of Jitter TriangleMeshShape by 

		/// populating data with vertices and indices gathered from out Mesh.

		/// </summary>

		/// <param name="mesh">The mesh.</param>

		/// <param name="localSpaceMatrix">The local space matrix.</param>

		/// <param name="invertTriangles">

		/// if set to <c>true</c> we invert winding order of triangles.

		/// </param>

		/// <returns>

		/// New created jitter TriangleMeshShape created from Delta engine mesh.

		/// </returns>

		public static TriangleMeshShape CreateFrom(Mesh mesh,

			Matrix localSpaceMatrix, bool invertTriangles)

		{

			// extract the data from the physics mesh

			List<JVector> triangleVertex = new List<JVector>();

			List<TriangleVertexIndices> triangleVertexIndices =

				new List<TriangleVertexIndices>();



			// apply the local transform of the mesh so we get correct coordinates

			Matrix TransMat = localSpaceMatrix;



			JVector tempVector;

			for (int num = 0; num < mesh.Geometry.Data.NumberOfUsedVertices; num++)

			{

				Vector transformed = Vector.Transform(

					mesh.Geometry.Data.GetPosition(num), TransMat);

				JitterDatatypesMapping.Convert(ref transformed, out tempVector);

				triangleVertex.Add(tempVector);

			}



			// set inverted tris if needed

			ushort[] Indices = mesh.Geometry.Data.Indices;

			if (invertTriangles)

			{

				for (int i = 0; i < Indices.Length; i = i + 3)

				{

					triangleVertexIndices.Add(new TriangleVertexIndices(

						Indices[i + 2],

						Indices[i + 1],

						Indices[i]));

				}

			}

			else

			{

				for (int i = 0; i < Indices.Length; i = i + 3)

				{

					triangleVertexIndices.Add(new TriangleVertexIndices(

						Indices[i],

						Indices[i + 1],

						Indices[i + 2]));

				}

			}



			// create the triangle mesh of the level and add it to the physics world

			Octree ocTree = new Octree(triangleVertex, triangleVertexIndices);

			TriangleMeshShape triangleMesh = new TriangleMeshShape(ocTree);



			return triangleMesh;

		}

		#endregion

	}

}