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feat: glTF Export for Unity versions older than 2020.2
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@atteneder
atteneder committed Feb 23, 2022
1 parent 82bcecc commit b526840
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1 change: 1 addition & 0 deletions ChangeLog.md
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
## [Unreleased]
### Added
- (Export) Runtime glTF export to files
- (Export) Export for Unity versions older than 2020.2
- (Export) Save to `System.IO.Stream`
- (Export) Occlusion map support
- (Export) Metallic-gloss map support (converted to roughness-metallic)
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347 changes: 346 additions & 1 deletion Runtime/Scripts/Export/GltfWriter.cs
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Expand Up @@ -498,7 +498,7 @@ async Task<bool> Bake(string bufferPath, string directory) {
#if GLTFAST_MESH_DATA
await BakeMeshes();
#else
throw new NotImplementedException("glTF export (containing meshes) is currently not supported on Unity 2020.1 and older");
await BakeMeshesLegacy();
#endif
}

Expand Down Expand Up @@ -924,7 +924,352 @@ int AddAccessor(Accessor accessor) {
m_Accessors.Add(accessor);
return accessorId;
}
#else

async Task BakeMeshesLegacy() {
Profiler.BeginSample("BakeMeshesLegacy");
for (var meshId = 0; meshId < m_Meshes.Count; meshId++) {
BakeMeshLegacy(meshId);
await m_DeferAgent.BreakPoint();
}
Profiler.EndSample();
}

void BakeMeshLegacy(int meshId) {

Profiler.BeginSample("BakeMeshLegacy");

var mesh = m_Meshes[meshId];
var uMesh = m_UnityMeshes[meshId];

var attributes = new Attributes();
var vertexAttributes = uMesh.GetVertexAttributes();
var attrDataDict = new Dictionary<VertexAttribute, AttributeData>();

for (var streamId = 0; streamId<vertexAttributes.Length; streamId++) {

var attribute = vertexAttributes[streamId];

switch (attribute.attribute) {
case VertexAttribute.Color:
case VertexAttribute.BlendWeight:
case VertexAttribute.BlendIndices:
Debug.LogWarning($"Vertex attribute {attribute.attribute} is not supported yet");
continue;
}

var attrData = new AttributeData {
offset = 0,
stream = streamId
};

var accessor = new Accessor {
byteOffset = attrData.offset,
componentType = Accessor.GetComponentType(attribute.format),
count = uMesh.vertexCount,
typeEnum = Accessor.GetAccessorAttributeType(attribute.dimension),
};

var accessorId = AddAccessor(accessor);

attrData.accessorId = accessorId;
attrDataDict[attribute.attribute] = attrData;

switch (attribute.attribute) {
case VertexAttribute.Position:
Assert.AreEqual(VertexAttributeFormat.Float32,attribute.format);
Assert.AreEqual(3,attribute.dimension);
var bounds = uMesh.bounds;
var max = bounds.max;
var min = bounds.min;
accessor.min = new[] { -max.x, min.y, min.z };
accessor.max = new[] { -min.x, max.y, max.z };
attributes.POSITION = accessorId;
break;
case VertexAttribute.Normal:
Assert.AreEqual(VertexAttributeFormat.Float32,attribute.format);
Assert.AreEqual(3,attribute.dimension);
attributes.NORMAL = accessorId;
break;
case VertexAttribute.Tangent:
Assert.AreEqual(VertexAttributeFormat.Float32,attribute.format);
Assert.AreEqual(4,attribute.dimension);
attributes.TANGENT = accessorId;
break;
case VertexAttribute.Color:
attributes.COLOR_0 = accessorId;
break;
case VertexAttribute.TexCoord0:
attributes.TEXCOORD_0 = accessorId;
break;
case VertexAttribute.TexCoord1:
attributes.TEXCOORD_1 = accessorId;
break;
case VertexAttribute.TexCoord2:
attributes.TEXCOORD_2 = accessorId;
break;
case VertexAttribute.TexCoord3:
attributes.TEXCOORD_3 = accessorId;
break;
case VertexAttribute.TexCoord4:
attributes.TEXCOORD_4 = accessorId;
break;
case VertexAttribute.TexCoord5:
attributes.TEXCOORD_5 = accessorId;
break;
case VertexAttribute.TexCoord6:
attributes.TEXCOORD_6 = accessorId;
break;
case VertexAttribute.TexCoord7:
attributes.TEXCOORD_7 = accessorId;
break;
case VertexAttribute.BlendWeight:
attributes.WEIGHTS_0 = accessorId;
break;
case VertexAttribute.BlendIndices:
attributes.JOINTS_0 = accessorId;
break;
default:
throw new ArgumentOutOfRangeException();
}
}

var streamCount = attrDataDict.Count;
var indexComponentType = uMesh.indexFormat == IndexFormat.UInt16 ? GLTFComponentType.UnsignedShort : GLTFComponentType.UnsignedInt;
mesh.primitives = new MeshPrimitive[uMesh.subMeshCount];
var indexAccessors = new Accessor[uMesh.subMeshCount];
var indexOffset = 0;
MeshTopology? topology = null;
var totalIndexCount = 0u;
for (var subMeshIndex = 0; subMeshIndex < uMesh.subMeshCount; subMeshIndex++) {
var subMesh = uMesh.GetSubMesh(subMeshIndex);
if (!topology.HasValue) {
topology = subMesh.topology;
} else {
Assert.AreEqual(topology.Value, subMesh.topology, "Mixed topologies are not supported!");
}
var mode = GetDrawMode(subMesh.topology);
if (!mode.HasValue) {
m_Logger?.Error(LogCode.TopologyUnsupported, subMesh.topology.ToString());
mode = DrawMode.Points;
}

Accessor indexAccessor;

indexAccessor = new Accessor {
typeEnum = GLTFAccessorAttributeType.SCALAR,
byteOffset = indexOffset,
componentType = indexComponentType,
count = subMesh.indexCount,

// min = new []{}, // TODO
// max = new []{}, // TODO
};

if (subMesh.topology == MeshTopology.Quads) {
indexAccessor.count = indexAccessor.count / 2 * 3;
}

var indexAccessorId = AddAccessor(indexAccessor);
indexAccessors[subMeshIndex] = indexAccessor;

indexOffset += indexAccessor.count * Accessor.GetComponentTypeSize(indexComponentType);

mesh.primitives[subMeshIndex] = new MeshPrimitive {
mode = mode.Value,
attributes = attributes,
indices = indexAccessorId,
};

totalIndexCount += uMesh.GetIndexCount(subMeshIndex);
}
Assert.IsTrue(topology.HasValue);

Profiler.BeginSample("ExportIndices");
int indexBufferViewId;
var totalFaceCount = topology==MeshTopology.Quads ? (uint)(totalIndexCount * 1.5) : totalIndexCount;
if (uMesh.indexFormat == IndexFormat.UInt16) {
var destIndices = new NativeArray<ushort>((int)totalFaceCount,Allocator.TempJob);
var offset = 0;
for (var subMeshIndex = 0; subMeshIndex < uMesh.subMeshCount; subMeshIndex++) {
var indexData16 = uMesh.GetIndices(subMeshIndex);
switch (topology) {
case MeshTopology.Triangles: {
var triCount = indexData16.Length / 3;
for (var i = 0; i < triCount; i++) {
destIndices[offset+i*3] = (ushort) indexData16[i*3];
destIndices[offset+i*3+1] = (ushort) indexData16[i*3+2];
destIndices[offset+i*3+2] = (ushort) indexData16[i*3+1];
}
offset += indexData16.Length;
break;
}
case MeshTopology.Quads: {
var quadCount = indexData16.Length / 4;
for (var i = 0; i < quadCount; i++) {
destIndices[offset+i*6+0] = (ushort) indexData16[i*4+0];
destIndices[offset+i*6+1] = (ushort) indexData16[i*4+2];
destIndices[offset+i*6+2] = (ushort) indexData16[i*4+1];
destIndices[offset+i*6+3] = (ushort) indexData16[i*4+2];
destIndices[offset+i*6+4] = (ushort) indexData16[i*4+0];
destIndices[offset+i*6+5] = (ushort) indexData16[i*4+3];
}
offset += quadCount*6;
break;
}
default: {
for (var i = 0; i < indexData16.Length; i++) {
destIndices[offset+i] = (ushort) indexData16[i];
}
offset += indexData16.Length;
break;
}
}
}
indexBufferViewId = WriteBufferViewToBuffer(
destIndices.Reinterpret<byte>(sizeof(ushort)),
byteAlignment:sizeof(ushort)
);
destIndices.Dispose();
} else {
var destIndices = new NativeArray<uint>((int)totalFaceCount,Allocator.TempJob);
var offset = 0;
for (var subMeshIndex = 0; subMeshIndex < uMesh.subMeshCount; subMeshIndex++) {
var indexData16 = uMesh.GetIndices(subMeshIndex);
switch (topology) {
case MeshTopology.Triangles: {
var triCount = indexData16.Length / 3;
for (var i = 0; i < triCount; i++) {
destIndices[offset+i*3] = (uint) indexData16[i*3];
destIndices[offset+i*3+1] = (uint) indexData16[i*3+2];
destIndices[offset+i*3+2] = (uint) indexData16[i*3+1];
}
offset += indexData16.Length;
break;
}
case MeshTopology.Quads:{
var quadCount = indexData16.Length / 4;
for (var i = 0; i < quadCount; i++) {
destIndices[offset+i*6+0] = (uint) indexData16[i*4+0];
destIndices[offset+i*6+1] = (uint) indexData16[i*4+2];
destIndices[offset+i*6+2] = (uint) indexData16[i*4+1];
destIndices[offset+i*6+3] = (uint) indexData16[i*4+2];
destIndices[offset+i*6+4] = (uint) indexData16[i*4+0];
destIndices[offset+i*6+5] = (uint) indexData16[i*4+3];
}
offset += quadCount*6;
break;
}
default: {
for (var i = 0; i < indexData16.Length; i++) {
destIndices[offset+i] = (uint) indexData16[i];
}
offset += indexData16.Length;
break;
}
}
}
indexBufferViewId = WriteBufferViewToBuffer(
destIndices.Reinterpret<byte>(sizeof(uint)),
byteAlignment:sizeof(uint)
);
destIndices.Dispose();
}
Profiler.EndSample();

foreach (var accessor in indexAccessors) {
accessor.bufferView = indexBufferViewId;
}

Profiler.BeginSample("ExportVertexAttributes");
foreach (var pair in attrDataDict) {
var vertexAttribute = pair.Key;
var attrData = pair.Value;
var bufferViewId = -1;
switch (vertexAttribute) {
case VertexAttribute.Position: {
var vertices = new List<Vector3>();
uMesh.GetVertices(vertices);
var outStream = new NativeArray<Vector3>(vertices.Count, Allocator.TempJob);
for (var i = 0; i < vertices.Count; i++) {
outStream[i] = new Vector3(-vertices[i].x,vertices[i].y,vertices[i].z);
}
bufferViewId = WriteBufferViewToBuffer(
outStream.Reinterpret<byte>(12),
12
);
outStream.Dispose();
break;
}
case VertexAttribute.Normal: {
var normals = new List<Vector3>();
uMesh.GetNormals(normals);
var outStream = new NativeArray<Vector3>(normals.Count, Allocator.TempJob);
for (var i = 0; i < normals.Count; i++) {
outStream[i] = new Vector3(-normals[i].x,normals[i].y,normals[i].z);
}
bufferViewId = WriteBufferViewToBuffer(
outStream.Reinterpret<byte>(12),
12
);
outStream.Dispose();
break;
}
case VertexAttribute.Tangent: {
var tangents = new List<Vector4>();
uMesh.GetTangents(tangents);
var outStream = new NativeArray<Vector4>(tangents.Count, Allocator.TempJob);
for (var i = 0; i < tangents.Count; i++) {
outStream[i] = new Vector4(tangents[i].x,tangents[i].y,-tangents[i].z,tangents[i].w);
}
bufferViewId = WriteBufferViewToBuffer(
outStream.Reinterpret<byte>(16),
16
);
outStream.Dispose();
break;
}
case VertexAttribute.Color:
break;
case VertexAttribute.TexCoord0:
case VertexAttribute.TexCoord1:
case VertexAttribute.TexCoord2:
case VertexAttribute.TexCoord3:
case VertexAttribute.TexCoord4:
case VertexAttribute.TexCoord5:
case VertexAttribute.TexCoord6:
case VertexAttribute.TexCoord7: {
var uvs = new List<Vector2>();
var channel = (int)vertexAttribute - (int)VertexAttribute.TexCoord0;
uMesh.GetUVs( channel, uvs);
var outStream = new NativeArray<Vector2>(uvs.Count, Allocator.TempJob);
for (var i = 0; i < uvs.Count; i++) {
outStream[i] = uvs[i];
}
bufferViewId = WriteBufferViewToBuffer(
outStream.Reinterpret<byte>(8),
8
);
outStream.Dispose();
break;
}
case VertexAttribute.BlendWeight:
break;
case VertexAttribute.BlendIndices:
break;
}
m_Accessors[attrData.accessorId].bufferView = bufferViewId;
}
Profiler.EndSample();
Profiler.EndSample();
}

int AddAccessor(Accessor accessor) {
m_Accessors = m_Accessors ?? new List<Accessor>();
var accessorId = m_Accessors.Count;
m_Accessors.Add(accessor);
return accessorId;
}
#endif // #if GLTFAST_MESH_DATA

async Task<bool> BakeImages(string directory) {
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