WIP: implement KHR_gaussian_splatting extension

Author: pablode

README.md

@@ -70,8 +70,8 @@ Name                                | Status      
 ------------------------------------|----------
 EXT_meshopt_compression             | ✅ Complete
 KHR_draco_mesh_compression          | ✅ Complete
-KHR_gaussian_splatting              | 🚧 In Progress
-KHR_lights_punctual                 | ✅ Partial <sup>1</sup>
+KHR_gaussian_splatting              | ✅ Complete <sup>1</sup>
+KHR_lights_punctual                 | ✅ Partial <sup>2</sup>
 KHR_materials_clearcoat             | ✅ Complete
 KHR_materials_emissive_strength     | ✅ Complete
 KHR_materials_ior                   | ✅ Complete
@@ -81,12 +81,13 @@ KHR_materials_specular              | ✅ Complete
 KHR_materials_transmission          | ✅ Complete
 KHR_materials_unlit                 | ✅ Complete
 KHR_materials_variants              | ✅ Complete
-KHR_materials_volume                | ✅ Partial <sup>2</sup>
+KHR_materials_volume                | ✅ Partial <sup>3</sup>
 KHR_mesh_quantization               | ✅ Complete
 KHR_texture_transform               | ✅ Complete
 
-<sup>\[1\]</sup> Spotlight cone falloff is ignored.  
-<sup>\[2\]</sup> Thickness is not supported by the MaterialX glTF PBR implementation.
+<sup>\[1\]</sup> Requires USD v26.03+.  
+<sup>\[2\]</sup> Spotlight cone falloff is ignored.  
+<sup>\[3\]</sup> Thickness is not supported by the MaterialX glTF PBR implementation.
 
 ### License
 

src/libguc/CMakeLists.txt

@@ -41,7 +41,7 @@ set(LIBGUC_DEFINES
 if(TARGET usd_ms)
   set(LIBGUC_USD_LIBS usd_ms)
 else()
-  set(LIBGUC_USD_LIBS usd usdGeom usdLux usdShade usdUtils usdMtlx usdUI)
+  set(LIBGUC_USD_LIBS usd usdGeom usdLux usdVol usdShade usdUtils usdMtlx usdUI)
 endif()
 
 set(LIBGUC_SHARED_LIBRARIES

src/libguc/src/cgltf_util.cpp

@@ -51,6 +51,9 @@ namespace detail
     return strcmp(name, GLTF_EXT_MESHOPT_COMPRESSION_EXTENSION_NAME) == 0 ||
 #ifdef GUC_USE_DRACO
            strcmp(name, GLTF_KHR_DRACO_MESH_COMPRESSION_EXTENSION_NAME) == 0 ||
+#endif
+#if PXR_VERSION >= 2603
+           strcmp(name, "KHR_gaussian_splatting") == 0 ||
 #endif
            strcmp(name, "KHR_lights_punctual") == 0 ||
            strcmp(name, "KHR_materials_clearcoat") == 0 ||