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());
}
}