private void EvaluateNormals(IndexedMesh indexedMesh)
{
foreach (var bufferAndPrimitives in indexedMesh.GroupPrimitives())
{
var bufferView = bufferAndPrimitives.BufferView;
var existingNormals = bufferView.GetStream(StreamKey.Normal);
if (existingNormals != null)
{
continue;
}
var positions = bufferView.GetStreamReader <Vector3>(StreamKey.Position);
var normals = new ArrayMeshStream <Vector3>(positions.Count, StreamConverterFactory.Default);
foreach (var primitive in bufferAndPrimitives)
{
primitive.SetIndexStream(StreamKey.Normal, primitive.GetIndexReader(StreamKey.Position).ToList());
}
{
foreach (var face in indexedMesh.Primitives.SelectMany(_ => _.GetFaces(StreamKey.Position)))
{
var a = positions[face.Item1];
var b = positions[face.Item2];
var c = positions[face.Item3];
var n = Vector3.Cross(b - a, c - a);
normals[face.Item1] += n;
normals[face.Item2] += n;
normals[face.Item3] += n;
}
for (var index = 0; index < normals.Count; index++)
{
var normal = normals[index];
if (normal != Vector3.Zero)
{
normals[index] = Vector3.Normalize(normal);
}
}
bufferView.SetStream(StreamKey.Normal, normals);
}
foreach (var primitive in bufferAndPrimitives)
{
primitive.SetIndexStream(StreamKey.Normal, primitive.GetIndexReader(StreamKey.Position).ToList());
}
}
}
private IEnumerable <IMesh> PaintSeparateStreamMesh(IndexedMesh mesh)
{
foreach (var bufferAndPrimitives in mesh.GroupPrimitives())
{
var bufferView = bufferAndPrimitives.BufferView;
if (bufferView.GetStream(StreamKey.Color) != null)
{
continue;
}
var streamConverterFactory = bufferView.GetStream(StreamKey.Position).ConverterFactory;
bufferView.SetStream(StreamKey.Color,
new ArrayMeshStream <Vector4>(new[] { _color }, streamConverterFactory));
foreach (var primitiveAndIndex in bufferAndPrimitives.Primitives)
{
var submesh = primitiveAndIndex.Primitive;
var positionIndices = submesh.GetIndexReader(StreamKey.Position);
var indices = new int[positionIndices.Count];
submesh.SetIndexStream(StreamKey.Color, indices);
}
}
yield return(mesh);
}