/// <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 ushort[] ReadIndices(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 indices
var indexStream = reader.OpenIndexBufferStream(indexBuffer, resourceStream);
indexStream.Position = part.FirstIndexOld;
switch (indexBuffer.Format)
{
case IndexBufferFormat.TriangleList:
return(indexStream.ReadIndices(part.IndexCountOld));
case IndexBufferFormat.TriangleStrip:
return(indexStream.ReadTriangleStrip(part.IndexCountOld));
default:
throw new InvalidOperationException("Unsupported index buffer type: " + indexBuffer.Format);
}
}
private static List <GenericVertex> ReadVertices(MeshReader reader, Stream resourceStream)
{
// Open a vertex reader on stream 0 (main vertex data)
var mainBuffer = reader.VertexStreams[0];
if (mainBuffer == null)
{
return(new List <GenericVertex>());
}
var vertexReader = reader.OpenVertexStream(mainBuffer, resourceStream);
switch (reader.Mesh.Type)
{
case VertexType.Rigid:
return(ReadRigidVertices(vertexReader, mainBuffer.Count));
case VertexType.Skinned:
return(ReadSkinnedVertices(vertexReader, mainBuffer.Count));
case VertexType.DualQuat:
return(ReadDualQuatVertices(vertexReader, mainBuffer.Count));
case VertexType.World:
return(ReadWorldVertices(vertexReader, mainBuffer.Count));
default:
throw new InvalidOperationException("Only Rigid, Skinned, DualQuat and World meshes are supported");
}
}
/// <summary>
/// Writes mesh data to the .obj.
/// </summary>
/// <param name="reader">The mesh reader to use.</param>
/// <param name="compressor">The vertex compressor to use.</param>
/// <param name="resourceStream">A stream open on the resource data.</param>
public void ExtractMesh(MeshReader reader, VertexCompressor compressor, Stream resourceStream)
{
// Read the vertex buffer and decompress each vertex
var vertices = ReadVertices(reader, resourceStream);
DecompressVertices(vertices, compressor);
// Write out the vertices
WriteVertices(vertices);
// Read and write out the triangles for each part
foreach (var part in reader.Mesh.Parts)
{
var indexes = ReadIndexes(reader, part, resourceStream);
WriteTriangles(indexes);
}
_baseIndex += (uint)vertices.Count;
}
private Assimp.Mesh ExtractMeshPartGeometry(int meshIndex, int partIndex)
{
// create new assimp mesh
Assimp.Mesh mesh = new Assimp.Mesh();
// Add support for multiple UV layers
var textureCoordinateIndex = 0;
mesh.UVComponentCount[textureCoordinateIndex] = 2;
// prepare vertex extraction
var meshReader = new MeshReader(CacheContext.Version, RenderModel.Geometry.Meshes[meshIndex], RenderModelResourceDefinition);
var vertexCompressor = new VertexCompressor(RenderModel.Geometry.Compression[0]);
var geometryMesh = RenderModel.Geometry.Meshes[meshIndex];
var geometryPart = geometryMesh.Parts[partIndex];
mesh.MaterialIndex = geometryPart.MaterialIndex;
// optimize this part to not load and decompress all mesh vertices everytime
var vertices = ReadVertices(meshReader, RenderModelResourceStream);
DecompressVertices(vertices, vertexCompressor);
// get offset in the list of all vertices for the mesh
var vertexOffset = GetPartVertexOffset(meshIndex, partIndex);
//vertices = vertices.GetRange(vertexOffset, geometryPart.VertexCount);
var indices = ReadIndices(meshReader, geometryPart, RenderModelResourceStream);
var int_indices = indices.Select(b => (int)b).ToArray();
var indexCount = indices.Length;
if (indexCount == 0)
{
Console.WriteLine($"Failed to extract mesh, no indices.");
return(null);
}
// set index list, maybe require adjustment for vertex buffer offset
mesh.SetIndices(int_indices, 3);
// build skeleton for each mesh (meh)
// create a list of all the mesh bones available in the scene
foreach (var node in RenderModel.Nodes)
{
Bone bone = new Bone();
bone.Name = CacheContext.GetString(node.Name);
bone.OffsetMatrix = new Matrix4x4();
mesh.Bones.Add(bone);
}
for (int i = vertexOffset; i < vertexOffset + geometryPart.VertexCount; i++)
{
var vertex = vertices[i];
mesh.Vertices.Add(vertex.Position);
if (vertex.Normal != null)
{
mesh.Normals.Add(vertex.Normal);
}
if (vertex.TexCoords != null)
{
mesh.TextureCoordinateChannels[textureCoordinateIndex].Add(vertex.TexCoords);
}
if (vertex.Tangents != null)
{
mesh.Tangents.Add(vertex.Tangents);
}
if (vertex.Binormals != null)
{
mesh.BiTangents.Add(vertex.Binormals);
}
if (vertex.Indices != null)
{
for (int j = 0; j < vertex.Indices.Length; j++)
{
var index = vertex.Indices[j];
var bone = mesh.Bones[index];
Matrix4x4 inverseTransform = new Matrix4x4(1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1);
var currentNode = BoneNodes[index];
while (currentNode != null)
{
Matrix4x4 inverse = (currentNode.Transform.DeepClone());
inverse.Inverse();
inverseTransform = inverse * inverseTransform;
currentNode = currentNode.Parent;
}
bone.OffsetMatrix = inverseTransform;
bone.VertexWeights.Add(new VertexWeight(i - vertexOffset, vertex.Weights[j]));
}
}
// Add skinned mesh support and more
}
// create faces
mesh.Faces.Clear();
GenerateFaces(int_indices, vertexOffset, mesh.Faces);
return(mesh);
}
/// <summary>
/// Writes mesh data to the .obj.
/// </summary>
/// <param name="reader">The mesh reader to use.</param>
/// <param name="compressor">The vertex compressor to use.</param>
/// <param name="resourceStream">A stream open on the resource data.</param>
/// <param name="name">The name of the mesh.</param>
public void ExtractMesh(MeshReader reader, VertexCompressor compressor, Stream resourceStream, string name = null)
{
var vertices = ReadVertices(reader, resourceStream);
DecompressVertices(vertices, compressor);
var indicesList = new List <ushort[]>();
var indexCount = 0;
for (var i = 0; i < (reader?.Mesh?.Parts?.Count ?? -1); i++)
{
var part = reader.Mesh.Parts[i];
var indices = ReadIndices(reader, part, resourceStream);
indicesList.Add(indices);
if (part.IndexCountOld > 0)
{
indexCount += indices.Length;
}
}
if (indexCount == 0)
{
return;
}
foreach (var vertex in vertices)
{
_writer.WriteLine("v {0} {1} {2}", vertex.Position.I, vertex.Position.J, vertex.Position.K);
}
foreach (var vertex in vertices)
{
_writer.WriteLine("vn {0} {1} {2}", vertex.Normal.I, vertex.Normal.J, vertex.Normal.K);
}
foreach (var vertex in vertices)
{
_writer.WriteLine("vt {0} {1}", vertex.TexCoords.I, 1 - vertex.TexCoords.J);
}
var partIndex = 0;
foreach (var indices in indicesList)
{
var triangles = GenerateTriangles(indices);
if (triangles.Count() != 0)
{
_writer.WriteLine($"g {name}_part_{partIndex++}");
}
foreach (var triangle in triangles)
{
_writer.WriteLine(triangle);
}
}
_baseIndex += (uint)vertices.Count;
}