Refactor MjcPhysics EqualityJointAPI polynomial coefficients.

The single array attribute `mjc:polycoef` has been replaced by five individual double attributes: `mjc:coef0`, `mjc:coef1`, `mjc:coef2`, `mjc:coef3`, and `mjc:coef4`.

PiperOrigin-RevId: 865947359
Change-Id: If9d14a77b0a06e5dc712eeadd6e9402411570706

src/experimental/usd/mjcPhysics/equalityJointAPI.cpp

@@ -77,14 +77,58 @@ const TfType& MjcPhysicsEqualityJointAPI::_GetTfType() const {
   return _GetStaticTfType();
 }
 
-UsdAttribute MjcPhysicsEqualityJointAPI::GetPolycoefAttr() const {
-  return GetPrim().GetAttribute(MjcPhysicsTokens->mjcPolycoef);
+UsdAttribute MjcPhysicsEqualityJointAPI::GetCoef0Attr() const {
+  return GetPrim().GetAttribute(MjcPhysicsTokens->mjcCoef0);
 }
 
-UsdAttribute MjcPhysicsEqualityJointAPI::CreatePolycoefAttr(
+UsdAttribute MjcPhysicsEqualityJointAPI::CreateCoef0Attr(
     VtValue const& defaultValue, bool writeSparsely) const {
   return UsdSchemaBase::_CreateAttr(
-      MjcPhysicsTokens->mjcPolycoef, SdfValueTypeNames->DoubleArray,
+      MjcPhysicsTokens->mjcCoef0, SdfValueTypeNames->Double,
+      /* custom = */ false, SdfVariabilityUniform, defaultValue, writeSparsely);
+}
+
+UsdAttribute MjcPhysicsEqualityJointAPI::GetCoef1Attr() const {
+  return GetPrim().GetAttribute(MjcPhysicsTokens->mjcCoef1);
+}
+
+UsdAttribute MjcPhysicsEqualityJointAPI::CreateCoef1Attr(
+    VtValue const& defaultValue, bool writeSparsely) const {
+  return UsdSchemaBase::_CreateAttr(
+      MjcPhysicsTokens->mjcCoef1, SdfValueTypeNames->Double,
+      /* custom = */ false, SdfVariabilityUniform, defaultValue, writeSparsely);
+}
+
+UsdAttribute MjcPhysicsEqualityJointAPI::GetCoef2Attr() const {
+  return GetPrim().GetAttribute(MjcPhysicsTokens->mjcCoef2);
+}
+
+UsdAttribute MjcPhysicsEqualityJointAPI::CreateCoef2Attr(
+    VtValue const& defaultValue, bool writeSparsely) const {
+  return UsdSchemaBase::_CreateAttr(
+      MjcPhysicsTokens->mjcCoef2, SdfValueTypeNames->Double,
+      /* custom = */ false, SdfVariabilityUniform, defaultValue, writeSparsely);
+}
+
+UsdAttribute MjcPhysicsEqualityJointAPI::GetCoef3Attr() const {
+  return GetPrim().GetAttribute(MjcPhysicsTokens->mjcCoef3);
+}
+
+UsdAttribute MjcPhysicsEqualityJointAPI::CreateCoef3Attr(
+    VtValue const& defaultValue, bool writeSparsely) const {
+  return UsdSchemaBase::_CreateAttr(
+      MjcPhysicsTokens->mjcCoef3, SdfValueTypeNames->Double,
+      /* custom = */ false, SdfVariabilityUniform, defaultValue, writeSparsely);
+}
+
+UsdAttribute MjcPhysicsEqualityJointAPI::GetCoef4Attr() const {
+  return GetPrim().GetAttribute(MjcPhysicsTokens->mjcCoef4);
+}
+
+UsdAttribute MjcPhysicsEqualityJointAPI::CreateCoef4Attr(
+    VtValue const& defaultValue, bool writeSparsely) const {
+  return UsdSchemaBase::_CreateAttr(
+      MjcPhysicsTokens->mjcCoef4, SdfValueTypeNames->Double,
       /* custom = */ false, SdfVariabilityUniform, defaultValue, writeSparsely);
 }
 
@@ -103,7 +147,9 @@ static inline TfTokenVector _ConcatenateAttributeNames(
 const TfTokenVector& MjcPhysicsEqualityJointAPI::GetSchemaAttributeNames(
     bool includeInherited) {
   static TfTokenVector localNames = {
-      MjcPhysicsTokens->mjcPolycoef,
+      MjcPhysicsTokens->mjcCoef0, MjcPhysicsTokens->mjcCoef1,
+      MjcPhysicsTokens->mjcCoef2, MjcPhysicsTokens->mjcCoef3,
+      MjcPhysicsTokens->mjcCoef4,
   };
   static TfTokenVector allNames = _ConcatenateAttributeNames(
       UsdAPISchemaBase::GetSchemaAttributeNames(true), localNames);

src/experimental/usd/mjcPhysics/generatedSchema.usda

@@ -588,16 +588,26 @@ class "MjcEqualityJointAPI" (
     or angle. Only scalar joint types (slide and hinge) can be used."""
 )
 {
-    uniform double[] mjc:polycoef = [0, 1, 0, 0, 0] (
-        displayName = "Polynomial Coefficients"
-        doc = """Coefficients a0 through a4 of the quartic polynomial. If the joint values
-        of the constrained joint and reference joint are respectively y and x, and their
-        reference positions (corresponding to the joint values in the initial model
-        configuration) are y0 and x0, the constraint is:
-        y = y0 + a0 + a1*(x-x0) + a2*(x-x0)^2 + a3*(x-x0)^3 + a4*(x-x0)^4.
-        Omitting the target joint (joint2) is equivalent to setting x = x0, in which case
-        the constraint is y = y0 + a0. The default [0, 1, 0, 0, 0] creates a simple 1:1
-        mimic constraint where y tracks x with the same offset from their references."""
+    uniform double mjc:coef0 = 0 (
+        displayName = "Coefficient 0"
+        doc = """Constant coefficient a0 of the quartic polynomial. The constraint is:
+        y = y0 + a0 + a1*(x-x0) + a2*(x-x0)^2 + a3*(x-x0)^3 + a4*(x-x0)^4."""
+    )
+    uniform double mjc:coef1 = 1 (
+        displayName = "Coefficient 1"
+        doc = "Linear coefficient a1 of the quartic polynomial."
+    )
+    uniform double mjc:coef2 = 0 (
+        displayName = "Coefficient 2"
+        doc = "Quadratic coefficient a2 of the quartic polynomial."
+    )
+    uniform double mjc:coef3 = 0 (
+        displayName = "Coefficient 3"
+        doc = "Cubic coefficient a3 of the quartic polynomial."
+    )
+    uniform double mjc:coef4 = 0 (
+        displayName = "Coefficient 4"
+        doc = "Quartic coefficient a4 of the quartic polynomial."
     )
 }
 

src/experimental/usd/mjcPhysics/schema.usda

@@ -1121,19 +1121,45 @@ class "MjcEqualityJointAPI" (
     inherits = </APISchemaBase>
 )
 {
-    uniform double[] mjc:polycoef = [0, 1, 0, 0, 0] (
+    uniform double mjc:coef0 = 0 (
         customData = {
-            string apiName = "Polycoef"
+            string apiName = "Coef0"
         }
-        displayName = "Polynomial Coefficients"
-        doc = """Coefficients a0 through a4 of the quartic polynomial. If the joint values
-        of the constrained joint and reference joint are respectively y and x, and their
-        reference positions (corresponding to the joint values in the initial model
-        configuration) are y0 and x0, the constraint is:
-        y = y0 + a0 + a1*(x-x0) + a2*(x-x0)^2 + a3*(x-x0)^3 + a4*(x-x0)^4.
-        Omitting the target joint (joint2) is equivalent to setting x = x0, in which case
-        the constraint is y = y0 + a0. The default [0, 1, 0, 0, 0] creates a simple 1:1
-        mimic constraint where y tracks x with the same offset from their references."""
+        displayName = "Coefficient 0"
+        doc = """Constant coefficient a0 of the quartic polynomial. The constraint is:
+        y = y0 + a0 + a1*(x-x0) + a2*(x-x0)^2 + a3*(x-x0)^3 + a4*(x-x0)^4."""
+    )
+
+    uniform double mjc:coef1 = 1 (
+        customData = {
+            string apiName = "Coef1"
+        }
+        displayName = "Coefficient 1"
+        doc = """Linear coefficient a1 of the quartic polynomial."""
+    )
+
+    uniform double mjc:coef2 = 0 (
+        customData = {
+            string apiName = "Coef2"
+        }
+        displayName = "Coefficient 2"
+        doc = """Quadratic coefficient a2 of the quartic polynomial."""
+    )
+
+    uniform double mjc:coef3 = 0 (
+        customData = {
+            string apiName = "Coef3"
+        }
+        displayName = "Coefficient 3"
+        doc = """Cubic coefficient a3 of the quartic polynomial."""
+    )
+
+    uniform double mjc:coef4 = 0 (
+        customData = {
+            string apiName = "Coef4"
+        }
+        displayName = "Coefficient 4"
+        doc = """Quartic coefficient a4 of the quartic polynomial."""
     )
 }
 

src/experimental/usd/mjcPhysics/tokens.cpp

@@ -47,6 +47,11 @@ MjcPhysicsTokensType::MjcPhysicsTokensType()
       mjcArmature("mjc:armature", TfToken::Immortal),
       mjcBiasPrm("mjc:biasPrm", TfToken::Immortal),
       mjcBiasType("mjc:biasType", TfToken::Immortal),
+      mjcCoef0("mjc:coef0", TfToken::Immortal),
+      mjcCoef1("mjc:coef1", TfToken::Immortal),
+      mjcCoef2("mjc:coef2", TfToken::Immortal),
+      mjcCoef3("mjc:coef3", TfToken::Immortal),
+      mjcCoef4("mjc:coef4", TfToken::Immortal),
       mjcCompilerAlignFree("mjc:compiler:alignFree", TfToken::Immortal),
       mjcCompilerAngle("mjc:compiler:angle", TfToken::Immortal),
       mjcCompilerAutoLimits("mjc:compiler:autoLimits", TfToken::Immortal),
@@ -150,7 +155,6 @@ MjcPhysicsTokensType::MjcPhysicsTokensType()
       mjcPathDivisors("mjc:path:divisors", TfToken::Immortal),
       mjcPathIndices("mjc:path:indices", TfToken::Immortal),
       mjcPathSegments("mjc:path:segments", TfToken::Immortal),
-      mjcPolycoef("mjc:polycoef", TfToken::Immortal),
       mjcPriority("mjc:priority", TfToken::Immortal),
       mjcQpos("mjc:qpos", TfToken::Immortal),
       mjcQvel("mjc:qvel", TfToken::Immortal),
@@ -235,6 +239,11 @@ MjcPhysicsTokensType::MjcPhysicsTokensType()
                  mjcArmature,
                  mjcBiasPrm,
                  mjcBiasType,
+                 mjcCoef0,
+                 mjcCoef1,
+                 mjcCoef2,
+                 mjcCoef3,
+                 mjcCoef4,
                  mjcCompilerAlignFree,
                  mjcCompilerAngle,
                  mjcCompilerAutoLimits,
@@ -331,7 +340,6 @@ MjcPhysicsTokensType::MjcPhysicsTokensType()
                  mjcPathDivisors,
                  mjcPathIndices,
                  mjcPathSegments,
-                 mjcPolycoef,
                  mjcPriority,
                  mjcQpos,
                  mjcQvel,