/// <summary>
/// Initializes a new instance of the <see cref="MeshReader"/> class.
/// </summary>
/// <param name="mesh">The mesh.</param>
/// <param name="definition">The mesh's definition data.</param>
public MeshReader(Mesh mesh, RenderGeometryResourceDefinition definition)
{
Mesh = mesh;
Definition = definition;
VertexStreams = new VertexBufferDefinition[StreamCount];
IndexBuffers = new IndexBufferDefinition[IndexBufferCount];
BindVertexStreams();
BindIndexBuffers();
}
/// <summary>
/// Get an Assimp matrix for the mesh of a rendermesh.
/// This is an approximation of the logic applied by the
/// game to scaling the model using the assigned node.
/// </summary>
public static Assimp.Matrix4x4 getMatForMesh(RenderModel model, Mesh mesh)
{
var rot_mat = Assimp.Matrix3x3.Identity;
int node_idx = mesh.RigidNodeIndex;
if (node_idx < 0) {
node_idx = 0;
}
if (node_idx < model.Nodes.Count)
{
float s = model.Nodes[node_idx].DefaultScale;
RenderModel.Node node = model.Nodes[node_idx];
rot_mat = new Assimp.Matrix3x3(node.InverseForward.X *s , node.InverseForward.Y * s, node.InverseForward.Z*s,
node.InverseLeft.X*s, node.InverseLeft.Y*s, node.InverseLeft.Z*s,
node.InverseUp.X*s, node.InverseUp.Y*s, node.InverseUp.Z*s);
//Console.WriteLine("Loaded matrix: {0}", rot_mat);
}
var matrix_local = new Assimp.Matrix4x4(rot_mat);
return matrix_local;
}
/// <summary>
/// Reads the index buffer data and converts it into a triangle list if necessary.
/// </summary>
/// <param name="reader">The mesh reader to use.</param>
/// <param name="part">The mesh part to read.</param>
/// <param name="resourceStream">A stream open on the resource data.</param>
/// <returns>The index buffer converted into a triangle list.</returns>
private static uint[] ReadIndexes(MeshReader reader, Mesh.Part part, Stream resourceStream)
{
// Use index buffer 0
var indexBuffer = reader.IndexBuffers[0];
if (indexBuffer == null)
throw new InvalidOperationException("Index buffer 0 is null");
// Read the indexes
var indexStream = reader.OpenIndexBufferStream(indexBuffer, resourceStream);
indexStream.Position = part.FirstIndex;
switch (indexBuffer.Type)
{
case PrimitiveType.TriangleList:
return indexStream.ReadIndexes(part.IndexCount);
case PrimitiveType.TriangleStrip:
return indexStream.ReadTriangleStrip(part.IndexCount);
default:
throw new InvalidOperationException("Unsupported index buffer type: " + indexBuffer.Type);
}
}
