private static Geometry ConvertAssimpMeshToGeometry(Ai.Mesh aiMesh, Ai.Material material, Dictionary <string, NodeInfo> nodeLookup, ref int nextBoneIndex, Dictionary <int, List <int> > nodeToBoneIndices, List <Matrix4x4> boneInverseBindMatrices, ref Matrix4x4 nodeWorldTransform, ref Matrix4x4 nodeInverseWorldTransform, List <Vector3> transformedVertices, SceneConverterOptions options)
{
if (!aiMesh.HasVertices)
{
throw new Exception("Assimp mesh has no vertices");
}
var geometry = new Geometry();
var geometryTransformedVertices = new Vector3[aiMesh.VertexCount];
geometry.Vertices = aiMesh.Vertices
.Select(x => new Vector3(x.X, x.Y, x.Z))
.ToArray();
for (int i = 0; i < geometry.Vertices.Length; i++)
{
geometryTransformedVertices[i] = Vector3.Transform(geometry.Vertices[i], nodeWorldTransform);
}
transformedVertices.AddRange(geometryTransformedVertices);
if (aiMesh.HasNormals)
{
geometry.Normals = aiMesh.Normals
.Select(x => new Vector3(x.X, x.Y, x.Z))
.ToArray();
}
if (aiMesh.HasTextureCoords(0))
{
geometry.TexCoordsChannel0 = aiMesh.TextureCoordinateChannels[0]
.Select(x => new Vector2(x.X, x.Y))
.ToArray();
}
if (aiMesh.HasTextureCoords(1))
{
geometry.TexCoordsChannel1 = aiMesh.TextureCoordinateChannels[1]
.Select(x => new Vector2(x.X, x.Y))
.ToArray();
}
if (aiMesh.HasTextureCoords(2))
{
geometry.TexCoordsChannel2 = aiMesh.TextureCoordinateChannels[2]
.Select(x => new Vector2(x.X, x.Y))
.ToArray();
}
if (aiMesh.HasVertexColors(0))
{
geometry.ColorChannel0 = aiMesh.VertexColorChannels[0]
.Select(x => ( uint )(( byte )(x.B * 255f) | ( byte )(x.G * 255f) << 8 | ( byte )(x.R * 255f) << 16 | ( byte )(x.A * 255f) << 24))
.ToArray();
}
else if (options.GenerateVertexColors)
{
geometry.ColorChannel0 = new uint[geometry.VertexCount];
for (int i = 0; i < geometry.ColorChannel0.Length; i++)
{
geometry.ColorChannel0[i] = 0xFFFFFFFF;
}
}
if (aiMesh.HasVertexColors(1))
{
geometry.ColorChannel1 = aiMesh.VertexColorChannels[1]
.Select(x => ( uint )(( byte )(x.B * 255f) | ( byte )(x.G * 255f) << 8 | ( byte )(x.R * 255f) << 16 | ( byte )(x.A * 255f) << 24))
.ToArray();
}
if (aiMesh.HasFaces)
{
geometry.TriangleIndexType = aiMesh.VertexCount <= ushort.MaxValue ? TriangleIndexType.UInt16 : TriangleIndexType.UInt32;
geometry.Triangles = aiMesh.Faces
.Select(x => new Triangle(( uint )x.Indices[0], ( uint )x.Indices[1], ( uint )x.Indices[2]))
.ToArray();
}
if (aiMesh.HasBones)
{
geometry.VertexWeights = new VertexWeight[geometry.VertexCount];
for (int i = 0; i < geometry.VertexWeights.Length; i++)
{
geometry.VertexWeights[i].Indices = new byte[4];
geometry.VertexWeights[i].Weights = new float[4];
}
var vertexWeightCounts = new int[geometry.VertexCount];
for (var i = 0; i < aiMesh.Bones.Count; i++)
{
var aiMeshBone = aiMesh.Bones[i];
// Find node index for the bone
var boneLookupData = nodeLookup[AssimpConverterCommon.UnescapeName(aiMeshBone.Name)];
int nodeIndex = boneLookupData.Index;
// Calculate inverse bind matrix
var boneNode = boneLookupData.Node;
var bindMatrix = boneNode.WorldTransform * nodeInverseWorldTransform;
if (options.ConvertSkinToZUp)
{
bindMatrix *= YToZUpMatrix;
}
Matrix4x4.Invert(bindMatrix, out var inverseBindMatrix);
// Get bone index
int boneIndex;
if (!nodeToBoneIndices.TryGetValue(nodeIndex, out var boneIndices))
{
// No entry for the node was found, so we add a new one
boneIndex = nextBoneIndex++;
nodeToBoneIndices.Add(nodeIndex, new List <int>()
{
boneIndex
});
boneInverseBindMatrices.Add(inverseBindMatrix);
}
else
{
// Entry for the node was found
// Try to find the bone index based on whether the inverse bind matrix matches
boneIndex = -1;
foreach (int index in boneIndices)
{
if (boneInverseBindMatrices[index].Equals(inverseBindMatrix))
{
boneIndex = index;
}
}
if (boneIndex == -1)
{
// None matching inverse bind matrix was found, so we add a new entry
boneIndex = nextBoneIndex++;
nodeToBoneIndices[nodeIndex].Add(boneIndex);
boneInverseBindMatrices.Add(inverseBindMatrix);
}
}
foreach (var aiVertexWeight in aiMeshBone.VertexWeights)
{
int vertexWeightCount = vertexWeightCounts[aiVertexWeight.VertexID]++;
geometry.VertexWeights[aiVertexWeight.VertexID].Indices[vertexWeightCount] = ( byte )boneIndex;
geometry.VertexWeights[aiVertexWeight.VertexID].Weights[vertexWeightCount] = aiVertexWeight.Weight;
}
}
}
geometry.MaterialName = AssimpConverterCommon.UnescapeName(material.Name);
geometry.BoundingBox = BoundingBox.Calculate(geometry.Vertices);
geometry.BoundingSphere = BoundingSphere.Calculate(geometry.BoundingBox.Value, geometry.Vertices);
geometry.Flags |= GeometryFlags.Flag80000000;
return(geometry);
}
