LOOKDEVX-2672 - Add default value concept to USD datamodel for UFE

cmake/modules/FindUFE.cmake

@@ -12,6 +12,7 @@
 # UFE_LIGHTS_SUPPORT        Presence of UFE lights support
 # UFE_MATERIALS_SUPPORT     Presence of UFE materials support
 # UFE_SCENE_SEGMENT_SUPPORT Presence of UFE scene segment support
+# UFE_DEFAULT_VALUE_SUPPORT Presence of UFE default value support
 # UFE_PREVIEW_FEATURES      List of all features introduced gradually in the UFE preview version
 #
 
@@ -163,6 +164,15 @@ if(UFE_INCLUDE_DIR AND EXISTS "${UFE_INCLUDE_DIR}/ufe/attribute.h")
     endif()
 endif()
 
+set(UFE_DEFAULT_VALUE_SUPPORT FALSE CACHE INTERNAL "ufeHasDefaultValue")
+if(UFE_INCLUDE_DIR AND EXISTS "${UFE_INCLUDE_DIR}/ufe/attribute.h")
+    file(STRINGS ${UFE_INCLUDE_DIR}/ufe/attribute.h UFE_HAS_API REGEX "isDefault")
+    if(UFE_HAS_API)
+        set(UFE_DEFAULT_VALUE_SUPPORT TRUE CACHE INTERNAL "ufeHasDefaultValue")
+        message(STATUS "Maya has UFE Attribute default value support")
+    endif()
+endif()
+
 set(UFE_HAS_NATIVE_TYPE_METADATA FALSE CACHE INTERNAL "ufeHasNativeTypeMetadata")
 if(UFE_INCLUDE_DIR AND EXISTS "${UFE_INCLUDE_DIR}/ufe/attributeDef.h")
     file(STRINGS ${UFE_INCLUDE_DIR}/ufe/attributeDef.h UFE_HAS_API REGEX "NativeType")

lib/mayaUsd/CMakeLists.txt

@@ -70,6 +70,13 @@ if (UFE_HAS_DISPLAY_NAME)
     )
 endif()
 
+if (UFE_DEFAULT_VALUE_SUPPORT)
+    target_compile_definitions(${PROJECT_NAME}
+    PRIVATE
+    UFE_DEFAULT_VALUE_SUPPORT=1
+    )
+endif()
+
 if (UFE_HAS_NATIVE_TYPE_METADATA)
     target_compile_definitions(${PROJECT_NAME}
     PRIVATE

lib/mayaUsd/ufe/UsdAttribute.cpp

@@ -353,6 +353,12 @@ bool UsdAttribute::set(const PXR_NS::VtValue& value, PXR_NS::UsdTimeCode time)
     return _attrHolder->set(value, time);
 }
 
+#ifdef UFE_DEFAULT_VALUE_SUPPORT
+bool UsdAttribute::_isDefault() const { return _attrHolder->isDefault(); }
+
+void UsdAttribute::_reset() { _attrHolder->reset(); }
+#endif
+
 #ifdef UFE_V4_FEATURES_AVAILABLE
 bool UsdAttribute::_hasValue() const
 #else

lib/mayaUsd/ufe/UsdAttribute.h

@@ -129,6 +129,10 @@ class MAYAUSD_CORE_PUBLIC UsdAttribute
     bool        get(PXR_NS::VtValue& value, PXR_NS::UsdTimeCode time) const;
     bool        set(const PXR_NS::VtValue& value, PXR_NS::UsdTimeCode time);
 
+#ifdef UFE_DEFAULT_VALUE_SUPPORT
+    bool _isDefault() const;
+    void _reset();
+#endif
 #ifdef UFE_V4_FEATURES_AVAILABLE
     bool        _hasValue() const;
     std::string _name() const;
@@ -198,6 +202,14 @@ class UsdAttributeGeneric
     static const std::string& nativeSdrTypeMetadata();
 }; // UsdAttributeGeneric
 
+#ifdef UFE_DEFAULT_VALUE_SUPPORT
+#define UFE_DEFAULT_VALUE_OVERRIDES                                        \
+    bool isDefault() const override { return UsdAttribute::_isDefault(); } \
+    void reset() override { UsdAttribute::_reset(); }
+#else
+#define UFE_DEFAULT_VALUE_OVERRIDES
+#endif
+
 #ifdef UFE_V4_FEATURES_AVAILABLE
 //! \brief Interface for USD token attributes.
 class UsdAttributeFilename
@@ -216,6 +228,9 @@ class UsdAttributeFilename
     // Ufe::Attribute overrides
     UFE_ATTRIBUTE_OVERRIDES
 
+    // Ufe default value overrides
+    UFE_DEFAULT_VALUE_OVERRIDES
+
     // Ufe::AttributeFilename overrides
     std::string               get() const override;
     void                      set(const std::string& value) override;
@@ -244,6 +259,9 @@ class UsdAttributeEnumString
     // Ufe::Attribute overrides
     UFE_ATTRIBUTE_OVERRIDES
 
+    // Ufe default value overrides
+    UFE_DEFAULT_VALUE_OVERRIDES
+
     // Ufe::AttributeEnumString overrides
     std::string               get() const override;
     void                      set(const std::string& value) override;
@@ -272,6 +290,9 @@ class UsdAttributeEnumToken
     // Ufe::Attribute overrides
     UFE_ATTRIBUTE_OVERRIDES
 
+    // Ufe default value overrides
+    UFE_DEFAULT_VALUE_OVERRIDES
+
     // Ufe::AttributeEnumString overrides
     std::string               get() const override;
     void                      set(const std::string& value) override;
@@ -296,6 +317,9 @@ class TypedUsdAttribute
     // Ufe::Attribute overrides
     UFE_ATTRIBUTE_OVERRIDES
 
+    // Ufe default value overrides
+    UFE_DEFAULT_VALUE_OVERRIDES
+
     // Ufe::TypedAttribute overrides
     T                         get() const override;
     void                      set(const T& value) override;
@@ -376,6 +400,9 @@ class UsdAttributeString
     // Ufe::Attribute overrides
     UFE_ATTRIBUTE_OVERRIDES
 
+    // Ufe default value overrides
+    UFE_DEFAULT_VALUE_OVERRIDES
+
     // Ufe::TypedAttribute overrides
     std::string               get() const override;
     void                      set(const std::string& value) override;
@@ -403,6 +430,9 @@ class UsdAttributeToken
     // Ufe::Attribute overrides
     UFE_ATTRIBUTE_OVERRIDES
 
+    // Ufe default value overrides
+    UFE_DEFAULT_VALUE_OVERRIDES
+
     // Ufe::TypedAttribute overrides
     std::string               get() const override;
     void                      set(const std::string& value) override;

lib/mayaUsd/ufe/UsdAttributeHolder.cpp

@@ -183,6 +183,19 @@ bool UsdAttributeHolder::set(const PXR_NS::VtValue& value, PXR_NS::UsdTimeCode t
     return _usdAttr.Set(value, time);
 }
 
+bool UsdAttributeHolder::isDefault()
+{
+    // Checks both authored default value and authored time samples
+    return !_usdAttr.HasAuthoredValue();
+}
+
+void UsdAttributeHolder::reset()
+{
+    // Will clear all values, including time samples.
+    _usdAttr.Clear();
+    _usdAttr.GetPrim().RemoveProperty(_usdAttr.GetName());
+}
+
 bool UsdAttributeHolder::hasValue() const { return isValid() ? _usdAttr.HasValue() : false; }
 
 std::string UsdAttributeHolder::name() const

lib/mayaUsd/ufe/UsdAttributeHolder.h

@@ -43,6 +43,8 @@ class UsdAttributeHolder
     virtual std::string nativeType() const;
     virtual bool        get(PXR_NS::VtValue& value, PXR_NS::UsdTimeCode time) const;
     virtual bool        set(const PXR_NS::VtValue& value, PXR_NS::UsdTimeCode time);
+    virtual bool        isDefault();
+    virtual void        reset();
 
     virtual bool        hasValue() const;
     virtual std::string name() const;

test/lib/ufe/testAttribute.py

@@ -2067,6 +2067,38 @@ def testAttributeNiceNames(self):
             self.assertIsNotNone(attr)
             self.assertEqual(attr.getMetadata("uiname"), niceName)
 
+    @unittest.skipUnless(hasattr(ufe.AttributeFloat, "isDefault"), 'Requires default value support')
+    def testDefaultValue(self):
+        cmds.file(new=True, force=True)
+        testFile = testUtils.getTestScene("UsdPreviewSurface", "DisplayColorCube.usda")
+        testDagPath, testStage = mayaUtils.createProxyFromFile(testFile)
+        mayaPathSegment = mayaUtils.createUfePathSegment(testDagPath)
+        usdPathSegment = usdUtils.createUfePathSegment("/DisplayColorCube/Looks/usdPreviewSurface1SG/usdPreviewSurface1")
+        shaderPath = ufe.Path([mayaPathSegment, usdPathSegment])
+        shaderItem = ufe.Hierarchy.createItem(shaderPath)
+        shaderAttrs = ufe.Attributes.attributes(shaderItem)
+
+        self.assertTrue(shaderAttrs.hasAttribute("inputs:roughness"))
+        shaderAttr = shaderAttrs.attribute("inputs:roughness")
+        self.assertAlmostEqual(shaderAttr.get(), 0.5)
+        self.assertTrue(shaderAttr.isDefault())
+        shaderAttr.set(0.75)
+        self.assertAlmostEqual(shaderAttr.get(), 0.75)        
+        self.assertFalse(shaderAttr.isDefault())
+        shaderAttr.reset()
+        self.assertAlmostEqual(shaderAttr.get(), 0.5)
+        self.assertTrue(shaderAttr.isDefault())
+
+        self.assertTrue(shaderAttrs.hasAttribute("inputs:emissiveColor"))
+        shaderAttr = shaderAttrs.attribute("inputs:emissiveColor")
+        self.assertAlmostEqual(shaderAttr.get().r(), 0)
+        self.assertTrue(shaderAttr.isDefault())
+        shaderAttr.set(ufe.Color3f(0.75, 0.75, 0.75))
+        self.assertAlmostEqual(shaderAttr.get().r(), 0.75)        
+        self.assertFalse(shaderAttr.isDefault())
+        shaderAttr.reset()
+        self.assertAlmostEqual(shaderAttr.get().r(), 0)
+        self.assertTrue(shaderAttr.isDefault())
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)