Bringing back UsdSkel Dual Quarternion support

This change was reverted in change 2251901 because of failures in usd opensrc manual testing.

Made some small changes to the original change 2248847 to get DQ skinning to work
in the CPU (PrMan/Embree) codepath.
Also added unit test cases to usdSkel(SkinningQuery & BakeSkinning) and regression tests for
LBS & DQ skinning in the CPU (Prman/Embree) and GPU (Storm) codepaths.

(Internal change: 2254108)

pxr/usd/usdSkel/bakeSkinning.h

@@ -47,22 +47,22 @@ struct UsdSkelBakeSkinningParms
 {
     /// Flags for identifying different deformation paths.
     enum DeformationFlags {
-        DeformPointsWithLBS = 1 << 0,
-        DeformNormalsWithLBS = 1 << 1,
-        DeformXformWithLBS = 1 << 2,
+        DeformPointsWithSkinning = 1 << 0,
+        DeformNormalsWithSkinning = 1 << 1,
+        DeformXformWithSkinning = 1 << 2,
         DeformPointsWithBlendShapes = 1 << 3,
         DeformNormalsWithBlendShapes = 1 << 4,
-        DeformWithLBS = (DeformPointsWithLBS|
-                         DeformNormalsWithLBS|
-                         DeformXformWithLBS),
+        DeformWithSkinning = (DeformPointsWithSkinning|
+                              DeformNormalsWithSkinning|
+                              DeformXformWithSkinning),
         DeformWithBlendShapes = (DeformPointsWithBlendShapes|
                                  DeformNormalsWithBlendShapes),
-        DeformAll = DeformWithLBS|DeformWithBlendShapes,
+        DeformAll = DeformWithSkinning|DeformWithBlendShapes,
         /// Flags indicating which components of skinned prims may be
         /// modified, based on the active deformations.
-        ModifiesPoints = DeformPointsWithLBS|DeformPointsWithBlendShapes,
-        ModifiesNormals = DeformNormalsWithLBS|DeformNormalsWithBlendShapes,
-        ModifiesXform = DeformXformWithLBS
+        ModifiesPoints = DeformPointsWithSkinning|DeformPointsWithBlendShapes,
+        ModifiesNormals = DeformNormalsWithSkinning|DeformNormalsWithBlendShapes,
+        ModifiesXform = DeformXformWithSkinning
     };
 
     /// Flags determining which deformation paths are enabled.

pxr/usd/usdSkel/bindingAPI.cpp

@@ -108,6 +108,23 @@ UsdSkelBindingAPI::_GetTfType() const
     return _GetStaticTfType();
 }
 
+UsdAttribute
+UsdSkelBindingAPI::GetSkinningMethodAttr() const
+{
+    return GetPrim().GetAttribute(UsdSkelTokens->primvarsSkelSkinningMethod);
+}
+
+UsdAttribute
+UsdSkelBindingAPI::CreateSkinningMethodAttr(VtValue const &defaultValue, bool writeSparsely) const
+{
+    return UsdSchemaBase::_CreateAttr(UsdSkelTokens->primvarsSkelSkinningMethod,
+                       SdfValueTypeNames->Token,
+                       /* custom = */ false,
+                       SdfVariabilityUniform,
+                       defaultValue,
+                       writeSparsely);
+}
+
 UsdAttribute
 UsdSkelBindingAPI::GetGeomBindTransformAttr() const
 {
@@ -249,6 +266,7 @@ const TfTokenVector&
 UsdSkelBindingAPI::GetSchemaAttributeNames(bool includeInherited)
 {
     static TfTokenVector localNames = {
+        UsdSkelTokens->primvarsSkelSkinningMethod,
         UsdSkelTokens->primvarsSkelGeomBindTransform,
         UsdSkelTokens->skelJoints,
         UsdSkelTokens->primvarsSkelJointIndices,

pxr/usd/usdSkel/bindingAPI.h

@@ -64,6 +64,11 @@ class SdfAssetPath;
 /// documentation for more about bindings and how they apply in a scene graph.
 /// 
 ///
+/// For any described attribute \em Fallback \em Value or \em Allowed \em Values below
+/// that are text/tokens, the actual token is published and defined in \ref UsdSkelTokens.
+/// So to set an attribute to the value "rightHanded", use UsdSkelTokens->rightHanded
+/// as the value.
+///
 class UsdSkelBindingAPI : public UsdAPISchemaBase
 {
 public:
@@ -172,6 +177,30 @@ class UsdSkelBindingAPI : public UsdAPISchemaBase
     USDSKEL_API
     const TfType &_GetTfType() const override;
 
+public:
+    // --------------------------------------------------------------------- //
+    // SKINNINGMETHOD 
+    // --------------------------------------------------------------------- //
+    /// The skinningMethod specifies the skinning method for the prim.
+    ///
+    /// | ||
+    /// | -- | -- |
+    /// | Declaration | `uniform token primvars:skel:skinningMethod = "classicLinear"` |
+    /// | C++ Type | TfToken |
+    /// | \ref Usd_Datatypes "Usd Type" | SdfValueTypeNames->Token |
+    /// | \ref SdfVariability "Variability" | SdfVariabilityUniform |
+    /// | \ref UsdSkelTokens "Allowed Values" | classicLinear, dualQuaternion |
+    USDSKEL_API
+    UsdAttribute GetSkinningMethodAttr() const;
+
+    /// See GetSkinningMethodAttr(), and also 
+    /// \ref Usd_Create_Or_Get_Property for when to use Get vs Create.
+    /// If specified, author \p defaultValue as the attribute's default,
+    /// sparsely (when it makes sense to do so) if \p writeSparsely is \c true -
+    /// the default for \p writeSparsely is \c false.
+    USDSKEL_API
+    UsdAttribute CreateSkinningMethodAttr(VtValue const &defaultValue = VtValue(), bool writeSparsely=false) const;
+
 public:
     // --------------------------------------------------------------------- //
     // GEOMBINDTRANSFORM 

pxr/usd/usdSkel/cacheImpl.cpp

@@ -176,7 +176,7 @@ UsdSkel_CacheImpl::ReadScope::_FindOrCreateSkinningQuery(
         skelQuery ? skelQuery.GetJointOrder() : VtTokenArray(),
         animQuery ? animQuery.GetBlendShapeOrder() : VtTokenArray(),
         key.jointIndicesAttr, key.jointWeightsAttr,
-        key.geomBindTransformAttr, key.jointsAttr,
+        key.skinningMethodAttr, key.geomBindTransformAttr, key.jointsAttr,
         key.blendShapesAttr, key.blendShapeTargetsRel);
 }
 
@@ -300,7 +300,14 @@ UsdSkel_CacheImpl::ReadScope::Populate(const UsdSkelRoot& root,
                 key.jointWeightsAttr = std::move(attr);
             }
         }
-
+
+        if (UsdAttribute attr = binding.GetSkinningMethodAttr()) {
+            if (attr.HasAuthoredValue()) {
+                _DeprecatedBindingCheck(hasBindingAPI, attr);
+                key.skinningMethodAttr = std::move(attr);
+            }
+        }
+
         if (UsdAttribute attr = _GetAttrInPrototype(
                 binding.GetGeomBindTransformAttr())) {
             if (attr.HasAuthoredValue()) {

pxr/usd/usdSkel/cacheImpl.h

@@ -77,6 +77,7 @@ class UsdSkel_CacheImpl
     struct _SkinningQueryKey {
         UsdAttribute jointIndicesAttr;
         UsdAttribute jointWeightsAttr;
+        UsdAttribute skinningMethodAttr;
         UsdAttribute geomBindTransformAttr;
         UsdAttribute jointsAttr;
         UsdAttribute blendShapesAttr;

pxr/usd/usdSkel/generatedSchema.usda

@@ -304,6 +304,10 @@ class "SkelBindingAPI" (
         *jointWeights* must match that of *jointIndices*. See UsdGeomPrimvar
         for more information on interpolation and elementSize."""
     )
+    uniform token primvars:skel:skinningMethod = "classicLinear" (
+        allowedTokens = ["classicLinear", "dualQuaternion"]
+        doc = "The skinningMethod specifies the skinning method for the prim."
+    )
     rel skel:animationSource (
         doc = """Animation source to be bound to Skeleton primitives at or
         beneath the location at which this property is defined.

pxr/usd/usdSkel/schema.usda

@@ -184,6 +184,14 @@ class "SkelBindingAPI" (
         Skeleton."""
     )
 
+    uniform token primvars:skel:skinningMethod = "classicLinear" (
+        customData = {
+            string apiName = "skinningMethod"
+        }
+        allowedTokens = ["classicLinear", "dualQuaternion"]
+        doc = """The skinningMethod specifies the skinning method for the prim."""
+    )
+
     matrix4d primvars:skel:geomBindTransform (
         customData = {
             string apiName = "geomBindTransform"

pxr/usd/usdSkel/skinningQuery.cpp

@@ -61,6 +61,7 @@ UsdSkelSkinningQuery::UsdSkelSkinningQuery(
     const VtTokenArray& animBlendShapeOrder,
     const UsdAttribute& jointIndices,
     const UsdAttribute& jointWeights,
+    const UsdAttribute& skinningMethod,
     const UsdAttribute& geomBindTransform,
     const UsdAttribute& joints,
     const UsdAttribute& blendShapes,
@@ -69,6 +70,7 @@ UsdSkelSkinningQuery::UsdSkelSkinningQuery(
       _interpolation(UsdGeomTokens->constant),
       _jointIndicesPrimvar(jointIndices),
       _jointWeightsPrimvar(jointWeights),
+      _skinningMethodAttr(skinningMethod),
       _geomBindTransformAttr(geomBindTransform),
       _blendShapes(blendShapes),
       _blendShapeTargets(blendShapeTargets)
@@ -352,10 +354,11 @@ UsdSkelSkinningQuery::ComputeSkinnedPoints(const VtArray<Matrix4>& xforms,
         }
 
         const Matrix4 geomBindXform(GetGeomBindTransform(time));
-        return UsdSkelSkinPointsLBS(geomBindXform, orderedXforms,
-                                    jointIndices, jointWeights,
-                                    _numInfluencesPerComponent,
-                                    *points);
+        const TfToken skinningMethod = GetSkinningMethod();
+        return UsdSkelSkinPoints(skinningMethod, geomBindXform, orderedXforms,
+                                 jointIndices, jointWeights,
+                                 _numInfluencesPerComponent,
+                                 *points);
     }
     return false;
 }
@@ -430,12 +433,13 @@ UsdSkelSkinningQuery::ComputeSkinnedNormals(const VtArray<Matrix4>& xforms,
         const Matrix4 geomBindXform(GetGeomBindTransform(time));
         const Matrix3 geomBindInvTransposeXform =
             geomBindXform.ExtractRotationMatrix().GetInverse().GetTranspose();
+        const TfToken skinningMethod = GetSkinningMethod();
 
-        return UsdSkelSkinNormalsLBS(geomBindInvTransposeXform,
-                                     invTransposeXforms,
-                                     jointIndices, jointWeights,
-                                     _numInfluencesPerComponent,
-                                     *normals);
+        return UsdSkelSkinNormals(skinningMethod, geomBindInvTransposeXform,
+                                  invTransposeXforms,
+                                  jointIndices, jointWeights,
+                                  _numInfluencesPerComponent,
+                                  *normals);
     }
     return false;
 }
@@ -484,8 +488,9 @@ UsdSkelSkinningQuery::ComputeSkinnedTransform(const VtArray<Matrix4>& xforms,
         }
 
         const Matrix4 geomBindXform(GetGeomBindTransform(time));
-        return UsdSkelSkinTransformLBS(geomBindXform, orderedXforms,
-                                       jointIndices, jointWeights, xform);
+        const TfToken skinningMethod = GetSkinningMethod();
+        return UsdSkelSkinTransform(skinningMethod, geomBindXform, orderedXforms,
+                                    jointIndices, jointWeights, xform);
     }
     return false;
 }
@@ -550,6 +555,19 @@ UsdSkelSkinningQuery::ComputeExtentsPadding(
     const VtArray<GfMatrix4f>&, const UsdGeomBoundable&) const;
 
 
+TfToken
+UsdSkelSkinningQuery::GetSkinningMethod() const
+{
+    // skinning method attr is optional.
+    TfToken skinningMethod;
+    if (!_skinningMethodAttr ||
+        !_skinningMethodAttr.Get(&skinningMethod)) {
+        skinningMethod = UsdSkelTokens->classicLinear;
+    }
+    return skinningMethod;
+}
+
+
 GfMatrix4d
 UsdSkelSkinningQuery::GetGeomBindTransform(UsdTimeCode time) const
 {

pxr/usd/usdSkel/skinningQuery.h

@@ -63,6 +63,7 @@ class UsdSkelSkinningQuery
                          const VtTokenArray& blendShapeOrder,
                          const UsdAttribute& jointIndices,
                          const UsdAttribute& jointWeights,
+                         const UsdAttribute& skinningMethod,
                          const UsdAttribute& geomBindTransform,
                          const UsdAttribute& joints,
                          const UsdAttribute& blendShapes,
@@ -100,6 +101,10 @@ class UsdSkelSkinningQuery
     USDSKEL_API
     bool IsRigidlyDeformed() const;
 
+    const UsdAttribute& GetSkinningMethodAttr() const {
+        return _skinningMethodAttr;
+    }
+
     const UsdAttribute& GetGeomBindTransformAttr() const {
         return _geomBindTransformAttr;
     }
@@ -190,7 +195,8 @@ class UsdSkelSkinningQuery
              VtFloatArray* weights,
              UsdTimeCode time=UsdTimeCode::Default()) const;
 
-    /// Compute skinned points using linear blend skinning.
+    /// Compute skinned points using specified skinning method attr
+    /// (fallback to linear blend skinning if not specified)
     /// Both \p xforms and \p points are given in _skeleton space_,
     /// using the joint order of the bound skeleton.
     /// Joint influences and the (optional) binding transform are computed
@@ -203,7 +209,8 @@ class UsdSkelSkinningQuery
                               VtVec3fArray* points,
                               UsdTimeCode time=UsdTimeCode::Default()) const;
 
-    /// Compute skinned normals using linear blend skinning.
+    /// Compute skinned normals using specified skinning method attr
+    /// (fallback to linear blend skinning if not specified)
     /// Both \p xforms and \p points are given in _skeleton space_,
     /// using the joint order of the bound skeleton.
     /// Joint influences and the (optional) binding transform are computed
@@ -216,7 +223,8 @@ class UsdSkelSkinningQuery
                               VtVec3fArray* points,
                               UsdTimeCode time=UsdTimeCode::Default()) const;
 
-    /// Compute a skinning transform using linear blend skinning.
+    /// Compute a skinning transform using specified skinning method attr
+    /// (fallback to linear blend skinning if not specified)
     /// The \p xforms are given in _skeleton space_, using the joint order of
     /// the bound skeleton.
     /// Joint influences and the (optional) binding transform are computed
@@ -242,6 +250,9 @@ class UsdSkelSkinningQuery
     float ComputeExtentsPadding(const VtArray<Matrix4>& skelRestXforms,
                                 const UsdGeomBoundable& boundable) const;
 
+    USDSKEL_API
+    TfToken GetSkinningMethod() const;
+
     USDSKEL_API
     GfMatrix4d
     GetGeomBindTransform(UsdTimeCode time=UsdTimeCode::Default()) const;
@@ -266,6 +277,7 @@ class UsdSkelSkinningQuery
 
     UsdGeomPrimvar _jointIndicesPrimvar;
     UsdGeomPrimvar _jointWeightsPrimvar;
+    UsdAttribute _skinningMethodAttr;
     UsdAttribute _geomBindTransformAttr;
     UsdAttribute _blendShapes;
     UsdRelationship _blendShapeTargets;

pxr/usd/usdSkel/testenv/testUsdSkelBakeSkinning.py

@@ -28,6 +28,25 @@
 
 class TestUsdSkelBakeSkinning(unittest.TestCase):
 
+    def test_DQSkinning(self):
+        testFile = "dqs.usda"
+        stage = Usd.Stage.Open(testFile)
+
+        self.assertTrue(UsdSkel.BakeSkinning(stage.Traverse()))
+
+        stage.GetRootLayer().Export("dqs.baked.usda")
+
+
+    def test_DQSkinningWithInterval(self):
+        testFile = "dqs.usda"
+        stage = Usd.Stage.Open(testFile)
+
+        self.assertTrue(UsdSkel.BakeSkinning(
+            stage.Traverse(), Gf.Interval(1, 10)))
+
+        stage.GetRootLayer().Export("dqs.bakedInterval.usda")
+
+
     def test_LinearBlendSkinning(self):
         testFile = "lbs.usda"
         stage = Usd.Stage.Open(testFile)