Add maxhullvert attribute to mjcPhysics MeshCollisionAPI.

PiperOrigin-RevId: 781482346
Change-Id: I0d53f9ad99ac842629243b0375907b2f91bd3b61

include/mujoco/experimental/usd/mjcPhysics/meshCollisionAPI.h

@@ -40,7 +40,7 @@ class SdfAssetPath;
 
 /// \class MjcPhysicsMeshCollisionAPI
 ///
-/// API describing a Mujoco mesh collider.
+/// API describing a MuJoCo mesh collider.
 ///
 /// 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
@@ -173,6 +173,31 @@ class MjcPhysicsMeshCollisionAPI : public UsdAPISchemaBase {
   UsdAttribute CreateInertiaAttr(VtValue const &defaultValue = VtValue(),
                                  bool writeSparsely = false) const;
 
+ public:
+  // --------------------------------------------------------------------- //
+  // MAXHULLVERT
+  // --------------------------------------------------------------------- //
+  /// Sets an upper limit on the number of vertices in the meshes convex hull.
+  /// The default value of -1 means unlimited.
+  ///
+  /// | ||
+  /// | -- | -- |
+  /// | Declaration | `uniform int mjc:maxhullvert = -1` |
+  /// | C++ Type | int |
+  /// | \ref Usd_Datatypes "Usd Type" | SdfValueTypeNames->Int |
+  /// | \ref SdfVariability "Variability" | SdfVariabilityUniform |
+  MJCPHYSICS_API
+  UsdAttribute GetMaxHullVertAttr() const;
+
+  /// See GetMaxHullVertAttr(), 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.
+  MJCPHYSICS_API
+  UsdAttribute CreateMaxHullVertAttr(VtValue const &defaultValue = VtValue(),
+                                     bool writeSparsely = false) const;
+
  public:
   // ===================================================================== //
   // Feel free to add custom code below this line, it will be preserved by

include/mujoco/experimental/usd/mjcPhysics/tokens.h

@@ -356,6 +356,10 @@ struct MjcPhysicsTokensType {
   ///
   /// MjcPhysicsJointAPI
   const TfToken mjcMargin;
+  /// \brief "mjc:maxhullvert"
+  ///
+  /// MjcPhysicsMeshCollisionAPI
+  const TfToken mjcMaxhullvert;
   /// \brief "mjc:mpos"
   ///
   /// MjcPhysicsKeyframe

src/experimental/usd/mjcPhysics/generatedSchema.usda

@@ -245,6 +245,10 @@ class "MjcMeshCollisionAPI" (
         displayName = "Inertia"
         doc = "Controls how a mesh is used when mass and inertia are inferred from geometry."
     )
+    uniform int mjc:maxhullvert = -1 (
+        displayName = "Maximum Hull Vertices"
+        doc = "Sets an upper limit on the number of vertices in the meshes convex hull. The default value of -1 means unlimited."
+    )
 }
 
 class "MjcActuatorAPI" (

src/experimental/usd/mjcPhysics/meshCollisionAPI.cpp

@@ -88,6 +88,17 @@ UsdAttribute MjcPhysicsMeshCollisionAPI::CreateInertiaAttr(
       /* custom = */ false, SdfVariabilityUniform, defaultValue, writeSparsely);
 }
 
+UsdAttribute MjcPhysicsMeshCollisionAPI::GetMaxHullVertAttr() const {
+  return GetPrim().GetAttribute(MjcPhysicsTokens->mjcMaxhullvert);
+}
+
+UsdAttribute MjcPhysicsMeshCollisionAPI::CreateMaxHullVertAttr(
+    VtValue const &defaultValue, bool writeSparsely) const {
+  return UsdSchemaBase::_CreateAttr(
+      MjcPhysicsTokens->mjcMaxhullvert, SdfValueTypeNames->Int,
+      /* custom = */ false, SdfVariabilityUniform, defaultValue, writeSparsely);
+}
+
 namespace {
 static inline TfTokenVector _ConcatenateAttributeNames(
     const TfTokenVector &left, const TfTokenVector &right) {
@@ -104,6 +115,7 @@ const TfTokenVector &MjcPhysicsMeshCollisionAPI::GetSchemaAttributeNames(
     bool includeInherited) {
   static TfTokenVector localNames = {
       MjcPhysicsTokens->mjcInertia,
+      MjcPhysicsTokens->mjcMaxhullvert,
   };
   static TfTokenVector allNames = _ConcatenateAttributeNames(
       UsdAPISchemaBase::GetSchemaAttributeNames(true), localNames);

src/experimental/usd/mjcPhysics/schema.usda

@@ -559,6 +559,14 @@ class "MjcMeshCollisionAPI"
         displayName = "Inertia"
         doc = """Controls how a mesh is used when mass and inertia are inferred from geometry."""
     )
+
+    uniform int mjc:maxhullvert = -1 (
+        customData = {
+            string apiName = "MaxHullVert"
+        }
+        displayName = "Maximum Hull Vertices"
+        doc = """Sets an upper limit on the number of vertices in the meshes convex hull. The default value of -1 means unlimited."""
+    )
 }
 
 class "MjcActuatorAPI"

src/experimental/usd/mjcPhysics/tokens.cpp

@@ -89,6 +89,7 @@ MjcPhysicsTokensType::MjcPhysicsTokensType()
       mjcLengthRangeMax("mjc:lengthRange:max", TfToken::Immortal),
       mjcLengthRangeMin("mjc:lengthRange:min", TfToken::Immortal),
       mjcMargin("mjc:margin", TfToken::Immortal),
+      mjcMaxhullvert("mjc:maxhullvert", TfToken::Immortal),
       mjcMpos("mjc:mpos", TfToken::Immortal),
       mjcMquat("mjc:mquat", TfToken::Immortal),
       mjcOptionActuatorgroupdisable("mjc:option:actuatorgroupdisable",
@@ -222,6 +223,7 @@ MjcPhysicsTokensType::MjcPhysicsTokensType()
                  mjcLengthRangeMax,
                  mjcLengthRangeMin,
                  mjcMargin,
+                 mjcMaxhullvert,
                  mjcMpos,
                  mjcMquat,
                  mjcOptionActuatorgroupdisable,

src/experimental/usd/plugins/mjcf/mujoco_to_usd.cc

@@ -360,6 +360,10 @@ class ModelWriter {
 
       WriteUniformAttribute(mesh_path, pxr::SdfValueTypeNames->Token,
                             MjcPhysicsTokens->mjcInertia, inertia);
+
+      WriteUniformAttribute(mesh_path, pxr::SdfValueTypeNames->Int,
+                            MjcPhysicsTokens->mjcMaxhullvert,
+                            mesh->maxhullvert);
     }
 
     // NOTE: The geometry data taken from the spec is the post-compilation

src/experimental/usd/usd_to_mjspec.cc

@@ -546,6 +546,11 @@ void ParseMjcPhysicsMeshCollisionAPI(
       mesh->inertia = mjtMeshInertia::mjMESH_INERTIA_LEGACY;
     }
   }
+
+  auto maxhullvert_attr = mesh_collision_api.GetMaxHullVertAttr();
+  if (maxhullvert_attr.HasAuthoredValue()) {
+    maxhullvert_attr.Get(&mesh->maxhullvert);
+  }
 }
 
 void ParseMjcPhysicsGeneralActuatorAPI(mjSpec* spec,

test/experimental/usd/plugins/mjcf/mjcf_file_format_test.cc

@@ -1440,6 +1440,7 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestMjcPhysicsMeshCollisionAPI) {
       <mesh name="tet_exact" inertia="exact" vertex="0 0 0  1 0 0  0 1 0  0 0 1"/>
       <mesh name="tet_convex" inertia="convex" vertex="0 0 0  1 0 0  0 1 0  0 0 1"/>
       <mesh name="tet_shell" inertia="shell" vertex="0 0 0  1 0 0  0 1 0  0 0 1"/>
+      <mesh name="tet_max_vert" inertia="shell" maxhullvert="12" vertex="0 0 0  1 0 0  0 1 0  0 0 1"/>
     </asset>
     <worldbody>
       <body name="body">
@@ -1447,6 +1448,7 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestMjcPhysicsMeshCollisionAPI) {
         <geom name="tet_exact" type="mesh" mesh="tet_exact"/>
         <geom name="tet_convex" type="mesh" mesh="tet_convex"/>
         <geom name="tet_shell" type="mesh" mesh="tet_shell"/>
+        <geom name="tet_max_vert" type="mesh" mesh="tet_max_vert"/>
       </body>
     </worldbody>
   </mujoco>
@@ -1461,6 +1463,8 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestMjcPhysicsMeshCollisionAPI) {
                        MjcPhysicsTokens->convex);
   ExpectAttributeEqual(stage, "/test/body/tet_shell/Mesh.mjc:inertia",
                        MjcPhysicsTokens->shell);
+  ExpectAttributeEqual(stage, "/test/body/tet_max_vert/Mesh.mjc:maxhullvert",
+                       12);
 }
 
 TEST_F(MjcfSdfFileFormatPluginTest, TestMassAPIApplied) {