static void LoadPrimvars(Scene scene,
Mesh unityMesh,
string usdMeshPath,
List <string> primvars,
int[] faceVertexCounts,
int[] faceVertexIndices)
{
if (primvars == null || primvars.Count == 0)
{
return;
}
var prim = scene.GetPrimAtPath(usdMeshPath);
for (int i = 0; i < primvars.Count; i++)
{
var attr = prim.GetAttribute(new TfToken("primvars:" + primvars[i]));
if (!attr)
{
continue;
}
// Read the raw values.
VtValue val = attr.Get(0.0);
if (val.IsEmpty())
{
continue;
}
VtVec2fArray vec2fArray = UsdCs.VtValueToVtVec2fArray(val);
Vector2[] values = UnityTypeConverter.FromVtArray(vec2fArray);
// Unroll indexed primvars.
var pv = new UsdGeomPrimvar(attr);
VtIntArray vtIndices = new VtIntArray();
if (pv.GetIndices(vtIndices, 0.0))
{
int[] indices = UnityTypeConverter.FromVtArray(vtIndices);
values = indices.Select(idx => values[idx]).ToArray();
}
// Handle primvar interpolation modes.
TfToken interp = pv.GetInterpolation();
if (interp == UsdGeomTokens.constant)
{
Debug.Assert(values.Length == 1);
var newValues = new Vector2[unityMesh.vertexCount];
for (int idx = 0; idx < values.Length; idx++)
{
newValues[idx] = values[0];
}
values = newValues;
}
else if (interp == UsdGeomTokens.uniform)
{
Debug.Assert(values.Length == faceVertexCounts.Length);
for (int faceIndex = 0; faceIndex < values.Length; faceIndex++)
{
var faceColor = values[faceIndex];
int idx = 0;
var newValues = new Vector2[unityMesh.vertexCount];
for (int f = 0; f < faceVertexCounts[faceIndex]; f++)
{
int vertexInFaceIdx = faceVertexIndices[idx++];
newValues[vertexInFaceIdx] = faceColor;
}
values = newValues;
}
}
else if (interp == UsdGeomTokens.faceVarying)
{
values = UnrollFaceVarying(unityMesh.vertexCount, values, faceVertexCounts, faceVertexIndices);
}
// Send them to Unity.
unityMesh.SetUVs(i, values.ToList());
}
}
public static void BuildSkinnedMesh(string meshPath,
string skelPath,
SkeletonSample skeleton,
UsdSkelSkinningQuery skinningQuery,
GameObject go,
PrimMap primMap,
SceneImportOptions options)
{
// The mesh renderer must already exist, since hte mesh also must already exist.
var smr = go.GetComponent <SkinnedMeshRenderer>();
if (!smr)
{
throw new Exception(
"Error importing "
+ meshPath
+ " SkinnnedMeshRenderer not present on GameObject"
);
}
// Get and validate the joint weights and indices informations.
UsdGeomPrimvar jointWeights = skinningQuery.GetJointWeightsPrimvar();
UsdGeomPrimvar jointIndices = skinningQuery.GetJointIndicesPrimvar();
if (!jointWeights.IsDefined() || !jointIndices.IsDefined())
{
throw new Exception("Joints information (indices and/or weights) are missing for: " + meshPath);
}
// TODO: Both indices and weights attributes can be animated. It's not handled yet.
// TODO: Having something that convert a UsdGeomPrimvar into a PrimvarSample could help simplify this code.
int[] indices = IntrinsicTypeConverter.FromVtArray((VtIntArray)jointIndices.GetAttr().Get());
int indicesElementSize = jointIndices.GetElementSize();
pxr.TfToken indicesInterpolation = jointIndices.GetInterpolation();
if (indices.Length == 0 ||
indicesElementSize == 0 ||
indices.Length % indicesElementSize != 0 ||
!pxr.UsdGeomPrimvar.IsValidInterpolation(indicesInterpolation))
{
throw new Exception("Joint indices information are invalid or empty for: " + meshPath);
}
float[] weights = IntrinsicTypeConverter.FromVtArray((VtFloatArray)jointWeights.GetAttr().Get());
int weightsElementSize = jointWeights.GetElementSize();
pxr.TfToken weightsInterpolation = jointWeights.GetInterpolation();
if (weights.Length == 0 ||
weightsElementSize == 0 ||
weights.Length % weightsElementSize != 0 ||
!pxr.UsdGeomPrimvar.IsValidInterpolation(weightsInterpolation))
{
throw new Exception("Joints weights information are invalid or empty for: " + meshPath);
}
// Get and validate the local list of joints.
VtTokenArray jointsAttr = new VtTokenArray();
skinningQuery.GetJointOrder(jointsAttr);
// If jointsAttr wasn't define, GetJointOrder return an empty array and FromVtArray as well.
string[] joints = IntrinsicTypeConverter.FromVtArray(jointsAttr);
// WARNING: Do not mutate skeleton values.
string[] skelJoints = skeleton.joints;
if (joints == null || joints.Length == 0)
{
if (skelJoints == null || skelJoints.Length == 0)
{
throw new Exception("Joints array empty: " + meshPath);
}
else
{
joints = skelJoints;
}
}
var mesh = smr.sharedMesh;
// TODO: bind transform attribute can be animated. It's not handled yet.
Matrix4x4 geomXf = UnityTypeConverter.FromMatrix(skinningQuery.GetGeomBindTransform());
// If the joints list is a different length than the bind transforms, then this is likely
// a mesh using a subset of the total bones in the skeleton and the bindTransforms must be
// reconstructed.
var bindPoses = skeleton.bindTransforms;
if (!JointsMatch(skeleton.joints, joints))
{
var boneToPose = new Dictionary <string, Matrix4x4>();
bindPoses = new Matrix4x4[joints.Length];
for (int i = 0; i < skelJoints.Length; i++)
{
boneToPose[skelJoints[i]] = skeleton.bindTransforms[i];
}
for (int i = 0; i < joints.Length; i++)
{
bindPoses[i] = boneToPose[joints[i]];
}
}
// When geomXf is identity, we can take a shortcut and just use the exact skeleton bindPoses.
if (!ImporterBase.ApproximatelyEqual(geomXf, Matrix4x4.identity))
{
// Note that the bind poses were transformed when the skeleton was imported, but the
// geomBindTransform is per-mesh, so it must be transformed here so it is in the same space
// as the bind pose.
XformImporter.ImportXform(ref geomXf, options);
// Make a copy only if we haven't already copied the bind poses earlier.
if (bindPoses == skeleton.bindTransforms)
{
var newBindPoses = new Matrix4x4[skeleton.bindTransforms.Length];
Array.Copy(bindPoses, newBindPoses, bindPoses.Length);
bindPoses = newBindPoses;
}
// Concatenate the geometry bind transform with the skeleton bind poses.
for (int i = 0; i < bindPoses.Length; i++)
{
// The geometry transform should be applied to the points before any other transform,
// hence the right hand multiply here.
bindPoses[i] = bindPoses[i] * geomXf;
}
}
mesh.bindposes = bindPoses;
var bones = new Transform[joints.Length];
var sdfSkelPath = new SdfPath(skelPath);
for (int i = 0; i < joints.Length; i++)
{
var jointPath = new SdfPath(joints[i]);
if (joints[i] == "/")
{
jointPath = sdfSkelPath;
}
else if (jointPath.IsAbsolutePath())
{
Debug.LogException(new Exception("Unexpected absolute joint path: " + jointPath));
jointPath = new SdfPath(joints[i].TrimStart('/'));
jointPath = sdfSkelPath.AppendPath(jointPath);
}
else
{
jointPath = sdfSkelPath.AppendPath(jointPath);
}
var jointGo = primMap[jointPath];
if (!jointGo)
{
Debug.LogError("Error importing " + meshPath + " "
+ "Joint not found: " + joints[i]);
continue;
}
bones[i] = jointGo.transform;
}
smr.bones = bones;
bool isConstant = weightsInterpolation.GetString() == pxr.UsdGeomTokens.constant;
// Unity 2019 supports many-bone rigs, older versions of Unity only support four bones.
#if UNITY_2019
var bonesPerVertex = new NativeArray <byte>(mesh.vertexCount, Allocator.Persistent);
var boneWeights1 = new NativeArray <BoneWeight1>(mesh.vertexCount * weightsElementSize, Allocator.Persistent);
for (int i = 0; i < mesh.vertexCount; i++)
{
int unityIndex = i * weightsElementSize;
int usdIndex = isConstant
? 0
: unityIndex;
bonesPerVertex[i] = (byte)weightsElementSize;
for (int wi = 0; wi < weightsElementSize; wi++)
{
var bw = boneWeights1[unityIndex + wi];
bw.boneIndex = indices[usdIndex + wi];
bw.weight = weights[usdIndex + wi];
boneWeights1[unityIndex + wi] = bw;
}
}
// TODO: Investigate if bone weights should be normalized before this line.
mesh.SetBoneWeights(bonesPerVertex, boneWeights1);
bonesPerVertex.Dispose();
boneWeights1.Dispose();
#else
var boneWeights = new BoneWeight[mesh.vertexCount];
for (int i = 0; i < boneWeights.Length; i++)
{
// When interpolation is constant, the base usdIndex should always be zero.
// When non-constant, the offset is the index times the number of weights per vertex.
int usdIndex = isConstant
? 0
: i * weightsElementSize;
var boneWeight = boneWeights[i];
if (usdIndex >= indices.Length)
{
Debug.Log("UsdIndex out of bounds: " + usdIndex
+ " indices.Length: " + indices.Length
+ " boneWeights.Length: " + boneWeights.Length
+ " mesh: " + meshPath);
}
boneWeight.boneIndex0 = indices[usdIndex];
boneWeight.weight0 = weights[usdIndex];
if (indicesElementSize >= 2)
{
boneWeight.boneIndex1 = indices[usdIndex + 1];
boneWeight.weight1 = weights[usdIndex + 1];
}
if (indicesElementSize >= 3)
{
boneWeight.boneIndex2 = indices[usdIndex + 2];
boneWeight.weight2 = weights[usdIndex + 2];
}
if (indicesElementSize >= 4)
{
boneWeight.boneIndex3 = indices[usdIndex + 3];
boneWeight.weight3 = weights[usdIndex + 3];
}
// If weights are less than 1, Unity will not automatically renormalize.
// If weights are greater than 1, Unity will renormalize.
// Only normalize when less than one to make it easier to diff bone weights which were
// round-tripped and were being normalized by Unity.
float sum = boneWeight.weight0 + boneWeight.weight1 + boneWeight.weight2 + boneWeight.weight3;
if (sum < 1)
{
boneWeight.weight0 /= sum;
boneWeight.weight1 /= sum;
boneWeight.weight2 /= sum;
boneWeight.weight3 /= sum;
}
boneWeights[i] = boneWeight;
}
mesh.boneWeights = boneWeights;
#endif
}