private GLTFMesh ExportMesh(BabylonMesh babylonMesh, GLTF gltf, BabylonScene babylonScene)
{
RaiseMessage("GLTFExporter.Mesh | Export mesh named: " + babylonMesh.name, 1);
// --------------------------
// --- Mesh from babylon ----
// --------------------------
if (babylonMesh.positions == null || babylonMesh.positions.Length == 0)
{
RaiseMessage("GLTFExporter.Mesh | Mesh is a dummy", 2);
return(null);
}
RaiseMessage("GLTFExporter.Mesh | Mesh from babylon", 2);
// Retreive general data from babylon mesh
int nbVertices = babylonMesh.positions.Length / 3;
bool hasUV = babylonMesh.uvs != null && babylonMesh.uvs.Length > 0;
bool hasUV2 = babylonMesh.uvs2 != null && babylonMesh.uvs2.Length > 0;
bool hasColor = babylonMesh.colors != null && babylonMesh.colors.Length > 0;
bool hasBones = babylonMesh.matricesIndices != null && babylonMesh.matricesIndices.Length > 0;
bool hasBonesExtra = babylonMesh.matricesIndicesExtra != null && babylonMesh.matricesIndicesExtra.Length > 0;
bool hasTangents = babylonMesh.tangents != null && babylonMesh.tangents.Length > 0;
RaiseMessage("GLTFExporter.Mesh | nbVertices=" + nbVertices, 3);
RaiseMessage("GLTFExporter.Mesh | hasUV=" + hasUV, 3);
RaiseMessage("GLTFExporter.Mesh | hasUV2=" + hasUV2, 3);
RaiseMessage("GLTFExporter.Mesh | hasColor=" + hasColor, 3);
RaiseMessage("GLTFExporter.Mesh | hasBones=" + hasBones, 3);
RaiseMessage("GLTFExporter.Mesh | hasBonesExtra=" + hasBonesExtra, 3);
// Retreive vertices data from babylon mesh
List <GLTFGlobalVertex> globalVertices = new List <GLTFGlobalVertex>();
for (int indexVertex = 0; indexVertex < nbVertices; indexVertex++)
{
GLTFGlobalVertex globalVertex = new GLTFGlobalVertex();
globalVertex.Position = BabylonVector3.FromArray(babylonMesh.positions, indexVertex);
globalVertex.Normal = BabylonVector3.FromArray(babylonMesh.normals, indexVertex);
if (hasTangents)
{
globalVertex.Tangent = BabylonQuaternion.FromArray(babylonMesh.tangents, indexVertex);
// Switch coordinate system at object level
globalVertex.Tangent.Z *= -1;
// Invert W to switch to right handed system
globalVertex.Tangent.W *= -1;
}
// Switch coordinate system at object level
globalVertex.Position.Z *= -1;
globalVertex.Normal.Z *= -1;
if (hasUV)
{
globalVertex.UV = BabylonVector2.FromArray(babylonMesh.uvs, indexVertex);
// For glTF, the origin of the UV coordinates (0, 0) corresponds to the upper left corner of a texture image
// While for Babylon, it corresponds to the lower left corner of a texture image
globalVertex.UV.Y = 1 - globalVertex.UV.Y;
}
if (hasUV2)
{
globalVertex.UV2 = BabylonVector2.FromArray(babylonMesh.uvs2, indexVertex);
// For glTF, the origin of the UV coordinates (0, 0) corresponds to the upper left corner of a texture image
// While for Babylon, it corresponds to the lower left corner of a texture image
globalVertex.UV2.Y = 1 - globalVertex.UV2.Y;
}
if (hasColor)
{
globalVertex.Color = Tools.SubArrayFromEntity(babylonMesh.colors, indexVertex, 4);
}
if (hasBones)
{
// In babylon, the 4 bones indices are stored in a single int
// Each bone index is 8-bit offset from the next
int bonesIndicesMerged = babylonMesh.matricesIndices[indexVertex];
int bone3 = bonesIndicesMerged >> 24;
bonesIndicesMerged -= bone3 << 24;
int bone2 = bonesIndicesMerged >> 16;
bonesIndicesMerged -= bone2 << 16;
int bone1 = bonesIndicesMerged >> 8;
bonesIndicesMerged -= bone1 << 8;
int bone0 = bonesIndicesMerged >> 0;
bonesIndicesMerged -= bone0 << 0;
var bonesIndicesArray = new ushort[] { (ushort)bone0, (ushort)bone1, (ushort)bone2, (ushort)bone3 };
globalVertex.BonesIndices = bonesIndicesArray;
globalVertex.BonesWeights = Tools.SubArrayFromEntity(babylonMesh.matricesWeights, indexVertex, 4);
}
globalVertices.Add(globalVertex);
}
var babylonMorphTargetManager = GetBabylonMorphTargetManager(babylonScene, babylonMesh);
// Retreive indices from babylon mesh
List <int> babylonIndices = babylonMesh.indices.ToList();
// --------------------------
// ------- Init glTF --------
// --------------------------
RaiseMessage("GLTFExporter.Mesh | Init glTF", 2);
// Mesh
var gltfMesh = new GLTFMesh {
name = babylonMesh.name
};
gltfMesh.index = gltf.MeshesList.Count;
gltf.MeshesList.Add(gltfMesh);
gltfMesh.idGroupInstance = babylonMesh.idGroupInstance;
if (hasBones)
{
gltfMesh.idBabylonSkeleton = babylonMesh.skeletonId;
}
// --------------------------
// ---- glTF primitives -----
// --------------------------
RaiseMessage("GLTFExporter.Mesh | glTF primitives", 2);
var meshPrimitives = new List <GLTFMeshPrimitive>();
foreach (BabylonSubMesh babylonSubMesh in babylonMesh.subMeshes)
{
// --------------------------
// ------ SubMesh data ------
// --------------------------
List <GLTFGlobalVertex> globalVerticesSubMesh = globalVertices.GetRange(babylonSubMesh.verticesStart, babylonSubMesh.verticesCount);
var gltfIndices = babylonIndices.GetRange(babylonSubMesh.indexStart, babylonSubMesh.indexCount);
// In gltf, indices of each mesh primitive are 0-based (ie: min value is 0)
// Thus, the gltf indices list is a concatenation of sub lists all 0-based
// Example for 2 triangles, each being a submesh:
// babylonIndices = {0,1,2, 3,4,5} gives as result gltfIndicies = {0,1,2, 0,1,2}
var minIndiceValue = gltfIndices.Min(); // Should be equal to babylonSubMesh.indexStart
for (int indexIndice = 0; indexIndice < gltfIndices.Count; indexIndice++)
{
gltfIndices[indexIndice] -= minIndiceValue;
}
// --------------------------
// ----- Mesh primitive -----
// --------------------------
// MeshPrimitive
var meshPrimitive = new GLTFMeshPrimitive
{
attributes = new Dictionary <string, int>()
};
meshPrimitives.Add(meshPrimitive);
// Material
if (babylonMesh.materialId != null)
{
RaiseMessage("GLTFExporter.Mesh | Material", 3);
// Retreive the babylon material
BabylonMaterial babylonMaterial;
var babylonMaterialId = babylonMesh.materialId;
// From multi materials first, if any
// Loop recursively even though it shouldn't be a real use case
var babylonMultiMaterials = new List <BabylonMultiMaterial>(babylonScene.multiMaterials);
BabylonMultiMaterial babylonMultiMaterial;
do
{
babylonMultiMaterial = babylonMultiMaterials.Find(_babylonMultiMaterial => _babylonMultiMaterial.id == babylonMaterialId);
if (babylonMultiMaterial != null)
{
babylonMaterialId = babylonMultiMaterial.materials[babylonSubMesh.materialIndex];
}
}while (babylonMultiMaterial != null);
// Then from materials
var babylonMaterials = new List <BabylonMaterial>(babylonScene.materials);
babylonMaterial = babylonMaterials.Find(_babylonMaterial => _babylonMaterial.id == babylonMaterialId);
// If babylon material was exported successfully
if (babylonMaterial != null)
{
// Update primitive material index
var indexMaterial = babylonMaterialsToExport.FindIndex(_babylonMaterial => _babylonMaterial == babylonMaterial);
if (indexMaterial == -1)
{
// Store material for exportation
indexMaterial = babylonMaterialsToExport.Count;
babylonMaterialsToExport.Add(babylonMaterial);
}
meshPrimitive.material = indexMaterial;
}
// TODO - Add and retreive info from babylon material
meshPrimitive.mode = GLTFMeshPrimitive.FillMode.TRIANGLES;
}
// --------------------------
// ------- Accessors --------
// --------------------------
RaiseMessage("GLTFExporter.Mesh | Geometry", 3);
// Buffer
var buffer = GLTFBufferService.Instance.GetBuffer(gltf);
// --- Indices ---
var componentType = GLTFAccessor.ComponentType.UNSIGNED_SHORT;
if (nbVertices >= 65536)
{
componentType = GLTFAccessor.ComponentType.UNSIGNED_INT;
}
var accessorIndices = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewScalar(gltf, buffer),
"accessorIndices",
componentType,
GLTFAccessor.TypeEnum.SCALAR
);
meshPrimitive.indices = accessorIndices.index;
// Populate accessor
if (componentType == GLTFAccessor.ComponentType.UNSIGNED_INT)
{
gltfIndices.ForEach(n => accessorIndices.bytesList.AddRange(BitConverter.GetBytes(n)));
}
else
{
var gltfIndicesShort = gltfIndices.ConvertAll(new Converter <int, ushort>(n => (ushort)n));
gltfIndicesShort.ForEach(n => accessorIndices.bytesList.AddRange(BitConverter.GetBytes(n)));
}
accessorIndices.count = gltfIndices.Count;
// --- Positions ---
var accessorPositions = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewFloatVec3(gltf, buffer),
"accessorPositions",
GLTFAccessor.ComponentType.FLOAT,
GLTFAccessor.TypeEnum.VEC3
);
meshPrimitive.attributes.Add(GLTFMeshPrimitive.Attribute.POSITION.ToString(), accessorPositions.index);
// Populate accessor
accessorPositions.min = new float[] { float.MaxValue, float.MaxValue, float.MaxValue };
accessorPositions.max = new float[] { float.MinValue, float.MinValue, float.MinValue };
globalVerticesSubMesh.ForEach((globalVertex) =>
{
var positions = globalVertex.Position.ToArray();
// Store values as bytes
foreach (var position in positions)
{
accessorPositions.bytesList.AddRange(BitConverter.GetBytes(position));
}
// Update min and max values
GLTFBufferService.UpdateMinMaxAccessor(accessorPositions, positions);
});
accessorPositions.count = globalVerticesSubMesh.Count;
// --- Tangents ---
if (hasTangents)
{
var accessorTangents = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewFloatVec4(gltf, buffer),
"accessorTangents",
GLTFAccessor.ComponentType.FLOAT,
GLTFAccessor.TypeEnum.VEC4
);
meshPrimitive.attributes.Add(GLTFMeshPrimitive.Attribute.TANGENT.ToString(), accessorTangents.index);
// Populate accessor
List <float> tangents = globalVerticesSubMesh.SelectMany(v => v.Tangent.ToArray()).ToList();
tangents.ForEach(n => accessorTangents.bytesList.AddRange(BitConverter.GetBytes(n)));
accessorTangents.count = globalVerticesSubMesh.Count;
}
// --- Normals ---
var accessorNormals = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewFloatVec3(gltf, buffer),
"accessorNormals",
GLTFAccessor.ComponentType.FLOAT,
GLTFAccessor.TypeEnum.VEC3
);
meshPrimitive.attributes.Add(GLTFMeshPrimitive.Attribute.NORMAL.ToString(), accessorNormals.index);
// Populate accessor
List <float> normals = globalVerticesSubMesh.SelectMany(v => v.Normal.ToArray()).ToList();
normals.ForEach(n => accessorNormals.bytesList.AddRange(BitConverter.GetBytes(n)));
accessorNormals.count = globalVerticesSubMesh.Count;
// --- Colors ---
if (hasColor)
{
var accessorColors = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewFloatVec4(gltf, buffer),
"accessorColors",
GLTFAccessor.ComponentType.FLOAT,
GLTFAccessor.TypeEnum.VEC4
);
meshPrimitive.attributes.Add(GLTFMeshPrimitive.Attribute.COLOR_0.ToString(), accessorColors.index);
// Populate accessor
List <float> colors = globalVerticesSubMesh.SelectMany(v => new[] { v.Color[0], v.Color[1], v.Color[2], v.Color[3] }).ToList();
colors.ForEach(n => accessorColors.bytesList.AddRange(BitConverter.GetBytes(n)));
accessorColors.count = globalVerticesSubMesh.Count;
}
// --- UV ---
if (hasUV)
{
var accessorUVs = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewFloatVec2(gltf, buffer),
"accessorUVs",
GLTFAccessor.ComponentType.FLOAT,
GLTFAccessor.TypeEnum.VEC2
);
meshPrimitive.attributes.Add(GLTFMeshPrimitive.Attribute.TEXCOORD_0.ToString(), accessorUVs.index);
// Populate accessor
List <float> uvs = globalVerticesSubMesh.SelectMany(v => v.UV.ToArray()).ToList();
uvs.ForEach(n => accessorUVs.bytesList.AddRange(BitConverter.GetBytes(n)));
accessorUVs.count = globalVerticesSubMesh.Count;
}
// --- UV2 ---
if (hasUV2)
{
var accessorUV2s = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewFloatVec2(gltf, buffer),
"accessorUV2s",
GLTFAccessor.ComponentType.FLOAT,
GLTFAccessor.TypeEnum.VEC2
);
meshPrimitive.attributes.Add(GLTFMeshPrimitive.Attribute.TEXCOORD_1.ToString(), accessorUV2s.index);
// Populate accessor
List <float> uvs2 = globalVerticesSubMesh.SelectMany(v => v.UV2.ToArray()).ToList();
uvs2.ForEach(n => accessorUV2s.bytesList.AddRange(BitConverter.GetBytes(n)));
accessorUV2s.count = globalVerticesSubMesh.Count;
}
// --- Bones ---
if (hasBones)
{
RaiseMessage("GLTFExporter.Mesh | Bones", 3);
// --- Joints ---
var accessorJoints = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewUnsignedShortVec4(gltf, buffer),
"accessorJoints",
GLTFAccessor.ComponentType.UNSIGNED_SHORT,
GLTFAccessor.TypeEnum.VEC4
);
meshPrimitive.attributes.Add(GLTFMeshPrimitive.Attribute.JOINTS_0.ToString(), accessorJoints.index);
// Populate accessor
List <ushort> joints = globalVerticesSubMesh.SelectMany(v => new[] { v.BonesIndices[0], v.BonesIndices[1], v.BonesIndices[2], v.BonesIndices[3] }).ToList();
joints.ForEach(n => accessorJoints.bytesList.AddRange(BitConverter.GetBytes(n)));
accessorJoints.count = globalVerticesSubMesh.Count;
// --- Weights ---
var accessorWeights = GLTFBufferService.Instance.CreateAccessor(
gltf,
GLTFBufferService.Instance.GetBufferViewFloatVec4(gltf, buffer),
"accessorWeights",
GLTFAccessor.ComponentType.FLOAT,
GLTFAccessor.TypeEnum.VEC4
);
meshPrimitive.attributes.Add(GLTFMeshPrimitive.Attribute.WEIGHTS_0.ToString(), accessorWeights.index);
// Populate accessor
List <float> weightBones = globalVerticesSubMesh.SelectMany(v => new[] { v.BonesWeights[0], v.BonesWeights[1], v.BonesWeights[2], v.BonesWeights[3] }).ToList();
weightBones.ForEach(n => accessorWeights.bytesList.AddRange(BitConverter.GetBytes(n)));
accessorWeights.count = globalVerticesSubMesh.Count;
}
if (hasBonesExtra)
{
RaiseWarning("Too many bones influences per vertex. glTF only support up to 4 bones influences per vertex. The result may not be as expected.", 3);
}
// Morph targets positions and normals
if (babylonMorphTargetManager != null)
{
RaiseMessage("GLTFExporter.Mesh | Morph targets", 3);
_exportMorphTargets(babylonMesh, babylonSubMesh, babylonMorphTargetManager, gltf, buffer, meshPrimitive);
}
}
gltfMesh.primitives = meshPrimitives.ToArray();
// Morph targets weights
if (babylonMorphTargetManager != null)
{
var weights = new List <float>();
foreach (BabylonMorphTarget babylonMorphTarget in babylonMorphTargetManager.targets)
{
weights.Add(babylonMorphTarget.influence);
}
gltfMesh.weights = weights.ToArray();
}
return(gltfMesh);
}
