Add support for mjcPhysics keyframes to USD interop.

PiperOrigin-RevId: 778552679
Change-Id: I04026599f7a2836e3fe1cf0d553bcc86a5795f98

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

@@ -48,6 +48,7 @@
 #include <pxr/usd/usd/prim.h>
 #include <pxr/usd/usd/primRange.h>  // IWYU pragma: keep, used for TraverseAll
 #include <pxr/usd/usd/stage.h>
+#include <pxr/usd/usd/timeCode.h>
 #include <pxr/usd/usdGeom/capsule.h>
 #include <pxr/usd/usdGeom/cube.h>
 #include <pxr/usd/usdGeom/cylinder.h>
@@ -1993,6 +1994,38 @@ TEST_F(MjcfSdfFileFormatPluginTest, TestPhysicsUnsupportedJoint) {
 
   EXPECT_PRIM_INVALID(stage, "/test/parent/ball_joint");
 }
+
+TEST_F(MjcfSdfFileFormatPluginTest, TestMjcPhysicsKeyframe) {
+  static constexpr char xml[] = R"(
+  <mujoco model="test">
+      <worldbody>
+        <frame name="frame"/>
+        <body name="body">
+          <joint/>
+          <geom size="0.1"/>
+        </body>
+      </worldbody>
+      <keyframe>
+        <key name="home" qpos="1"/>
+        <key time="1" qpos="2"/>
+        <key time="2" qpos="3"/>
+      </keyframe>
+    </mujoco>)";
+  auto stage = OpenStageWithPhysics(xml);
+
+  EXPECT_PRIM_VALID(stage, "/test/Keyframes/home");
+  EXPECT_PRIM_VALID(stage, "/test/Keyframes/Keyframe");
+  ExpectAttributeEqual(stage, "/test/Keyframes/home.mjc:qpos",
+                       pxr::VtDoubleArray({1}));
+
+  // Check time samples are correctly authored.
+  ExpectAttributeEqual(stage, "/test/Keyframes/Keyframe.mjc:qpos",
+                       pxr::VtDoubleArray({2}), pxr::UsdTimeCode(1.0));
+
+  ExpectAttributeEqual(stage, "/test/Keyframes/Keyframe.mjc:qpos",
+                       pxr::VtDoubleArray({3}), pxr::UsdTimeCode(2.0));
+}
+
 }  // namespace
 }  // namespace usd
 }  // namespace mujoco

test/experimental/usd/test_utils.cc

@@ -30,6 +30,7 @@
 #include <pxr/usd/usd/common.h>
 #include <pxr/usd/usd/modelAPI.h>
 #include <pxr/usd/usd/stage.h>
+#include <pxr/usd/usd/timeCode.h>
 #include <pxr/usd/usdGeom/mesh.h>
 #include <pxr/usd/usdGeom/primvarsAPI.h>
 namespace mujoco {
@@ -59,7 +60,8 @@ pxr::UsdStageRefPtr OpenStageWithPhysics(const std::string& xml) {
 template <>
 void ExpectAttributeEqual<pxr::SdfAssetPath>(pxr::UsdStageRefPtr stage,
                                              pxr::SdfPath path,
-                                             const pxr::SdfAssetPath& value) {
+                                             const pxr::SdfAssetPath& value,
+                                             const pxr::UsdTimeCode time) {
   auto attr = stage->GetAttributeAtPath(path);
   EXPECT_TRUE(attr.IsValid());
   pxr::SdfAssetPath attr_value;

test/experimental/usd/test_utils.h

@@ -26,6 +26,7 @@
 #include <pxr/usd/usd/common.h>
 #include <pxr/usd/usd/modelAPI.h>
 #include <pxr/usd/usd/stage.h>
+#include <pxr/usd/usd/timeCode.h>
 
 #define EXPECT_PRIM_VALID(stage, path) \
   EXPECT_TRUE((stage)->GetPrimAtPath(SdfPath(path)).IsValid());
@@ -101,20 +102,22 @@ pxr::SdfLayerRefPtr LoadLayer(
 pxr::UsdStageRefPtr OpenStageWithPhysics(const std::string& xml);
 
 template <typename T>
-void ExpectAttributeEqual(pxr::UsdStageRefPtr stage, pxr::SdfPath path,
-                          const T& value) {
+void ExpectAttributeEqual(
+    pxr::UsdStageRefPtr stage, pxr::SdfPath path, const T& value,
+    const pxr::UsdTimeCode time = pxr::UsdTimeCode::Default()) {
   auto attr = stage->GetAttributeAtPath(pxr::SdfPath(path));
   EXPECT_TRUE(attr.IsValid()) << "Attribute " << path << " is not valid";
   T attr_value;
-  attr.Get(&attr_value);
+  attr.Get(&attr_value, time);
   EXPECT_EQ(attr_value, value) << "Attribute " << path << " has value "
                                << attr_value << ". Expected: " << value;
 }
 
 template <typename T>
-void ExpectAttributeEqual(pxr::UsdStageRefPtr stage, const char* path,
-                          const T& value) {
-  ExpectAttributeEqual(stage, pxr::SdfPath(path), value);
+void ExpectAttributeEqual(
+    pxr::UsdStageRefPtr stage, const char* path, const T& value,
+    const pxr::UsdTimeCode time = pxr::UsdTimeCode::Default()) {
+  ExpectAttributeEqual(stage, pxr::SdfPath(path), value, time);
 }
 
 // Specialization for SdfAssetPath, so that we can compare only the asset path
@@ -122,9 +125,9 @@ void ExpectAttributeEqual(pxr::UsdStageRefPtr stage, const char* path,
 // Otherwise the default operator== would fail because it tests for equality of
 // the asset path AND the resolved path.
 template <>
-void ExpectAttributeEqual<pxr::SdfAssetPath>(pxr::UsdStageRefPtr stage,
-                                             pxr::SdfPath,
-                                             const pxr::SdfAssetPath& value);
+void ExpectAttributeEqual<pxr::SdfAssetPath>(
+    pxr::UsdStageRefPtr stage, pxr::SdfPath, const pxr::SdfAssetPath& value,
+    pxr::UsdTimeCode time);
 
 void ExpectAttributeHasConnection(pxr::UsdStageRefPtr stage, const char* path,
                                   const char* connection_path);