Add support for tileset materials

exts/cesium.usd.plugins/schemas/cesium_schemas.usda

@@ -165,7 +165,7 @@ class CesiumGeoreferencePrim "CesiumGeoreferencePrim" (
 
 class CesiumTilesetPrim "CesiumTilesetPrim" (
     doc = """A prim representing a tileset."""
-    inherits = </Boundable>
+    inherits = </Gprim>
     customData = {
         string className = "Tileset"
 

src/core/include/cesium/omniverse/FabricResourceManager.h

@@ -41,7 +41,10 @@ class FabricResourceManager {
         return instance;
     }
 
-    bool shouldAcquireMaterial(const CesiumGltf::MeshPrimitive& primitive, bool hasImagery) const;
+    bool shouldAcquireMaterial(
+        const CesiumGltf::MeshPrimitive& primitive,
+        bool hasImagery,
+        const pxr::SdfPath& materialPath) const;
 
     std::shared_ptr<FabricGeometry>
     acquireGeometry(const CesiumGltf::Model& model, const CesiumGltf::MeshPrimitive& primitive, bool smoothNormals);

src/core/include/cesium/omniverse/OmniTileset.h

@@ -65,6 +65,7 @@ class OmniTileset {
     [[nodiscard]] float getMainThreadLoadingTimeLimit() const;
     [[nodiscard]] bool getShowCreditsOnScreen() const;
     [[nodiscard]] pxr::CesiumGeoreference getGeoreference() const;
+    [[nodiscard]] pxr::SdfPath getMaterialPath() const;
 
     [[nodiscard]] int64_t getTilesetId() const;
     [[nodiscard]] TilesetStatistics getStatistics() const;

src/core/src/Context.cpp

@@ -11,6 +11,7 @@
 #include "cesium/omniverse/OmniImagery.h"
 #include "cesium/omniverse/OmniTileset.h"
 #include "cesium/omniverse/TaskProcessor.h"
+#include "cesium/omniverse/Tokens.h"
 #include "cesium/omniverse/UsdUtil.h"
 
 #ifdef CESIUM_OMNI_MSVC
@@ -317,7 +318,8 @@ void Context::processCesiumTilesetChanged(const ChangedPrim& changedPrim) {
         name == pxr::CesiumTokens->cesiumCulledScreenSpaceError ||
         name == pxr::CesiumTokens->cesiumSmoothNormals ||
         name == pxr::CesiumTokens->cesiumMainThreadLoadingTimeLimit ||
-        name == pxr::CesiumTokens->cesiumShowCreditsOnScreen) {
+        name == pxr::CesiumTokens->cesiumShowCreditsOnScreen ||
+        name == UsdTokens::material_binding) {
         tileset.value()->reload();
     }
     // clang-format on

src/core/src/FabricPrepareRenderResources.cpp

@@ -19,6 +19,7 @@
 #include <Cesium3DTilesSelection/Tile.h>
 #include <Cesium3DTilesSelection/Tileset.h>
 #include <CesiumAsync/AsyncSystem.h>
+#include <omni/fabric/FabricUSD.h>
 #include <omni/ui/ImageProvider/DynamicTextureProvider.h>
 
 namespace cesium::omniverse {
@@ -93,8 +94,11 @@ gatherMeshes(const OmniTileset& tileset, const glm::dmat4& tileTransform, const
     return meshes;
 }
 
-std::vector<FabricMesh>
-acquireFabricMeshes(const CesiumGltf::Model& model, const std::vector<MeshInfo>& meshes, bool hasImagery) {
+std::vector<FabricMesh> acquireFabricMeshes(
+    const CesiumGltf::Model& model,
+    const std::vector<MeshInfo>& meshes,
+    bool hasImagery,
+    const OmniTileset& tileset) {
     CESIUM_TRACE("FabricPrepareRenderResources::acquireFabricMeshes");
     std::vector<FabricMesh> fabricMeshes;
     fabricMeshes.reserve(meshes.size());
@@ -108,8 +112,8 @@ acquireFabricMeshes(const CesiumGltf::Model& model, const std::vector<MeshInfo>&
         const auto fabricGeometry = fabricResourceManager.acquireGeometry(model, primitive, mesh.smoothNormals);
         fabricMesh.geometry = fabricGeometry;
 
-        const auto shouldAcquireMaterial =
-            FabricResourceManager::getInstance().shouldAcquireMaterial(primitive, hasImagery);
+        const auto shouldAcquireMaterial = FabricResourceManager::getInstance().shouldAcquireMaterial(
+            primitive, hasImagery, tileset.getMaterialPath());
 
         if (shouldAcquireMaterial) {
             const auto materialInfo = GltfUtil::getMaterialInfo(model, primitive);
@@ -151,11 +155,13 @@ void setFabricMeshes(
     const CesiumGltf::Model& model,
     const std::vector<MeshInfo>& meshes,
     std::vector<FabricMesh>& fabricMeshes,
-    bool hasImagery) {
+    bool hasImagery,
+    const OmniTileset& tileset) {
     CESIUM_TRACE("FabricPrepareRenderResources::setFabricMeshes");
     for (size_t i = 0; i < meshes.size(); i++) {
         const auto& meshInfo = meshes[i];
         const auto& primitive = model.meshes[meshInfo.meshId].primitives[meshInfo.primitiveId];
+        const auto& materialPath = tileset.getMaterialPath();
 
         auto& mesh = fabricMeshes[i];
         auto& geometry = mesh.geometry;
@@ -180,6 +186,8 @@ void setFabricMeshes(
             if (baseColorTexture != nullptr && materialInfo.baseColorTexture.has_value()) {
                 material->setBaseColorTexture(baseColorTexture, materialInfo.baseColorTexture.value());
             }
+        } else if (!materialPath.IsEmpty()) {
+            geometry->setMaterial(omni::fabric::Path(omni::fabric::asInt(materialPath)));
         }
     }
 }
@@ -213,9 +221,9 @@ FabricPrepareRenderResources::prepareInLoadThread(
 
     return asyncSystem
         .runInMainThread(
-            [hasImagery, meshes = std::move(meshes), tileLoadResult = std::move(tileLoadResult)]() mutable {
+            [this, hasImagery, meshes = std::move(meshes), tileLoadResult = std::move(tileLoadResult)]() mutable {
                 const auto pModel = std::get_if<CesiumGltf::Model>(&tileLoadResult.contentKind);
-                auto fabricMeshes = acquireFabricMeshes(*pModel, meshes, hasImagery);
+                auto fabricMeshes = acquireFabricMeshes(*pModel, meshes, hasImagery, _tileset);
                 return IntermediateLoadThreadResult{
                     std::move(tileLoadResult),
                     std::move(meshes),
@@ -261,7 +269,7 @@ void* FabricPrepareRenderResources::prepareInMainThread(Cesium3DTilesSelection::
 
     const auto& model = pRenderContent->getModel();
 
-    setFabricMeshes(model, meshes, fabricMeshes, hasImagery);
+    setFabricMeshes(model, meshes, fabricMeshes, hasImagery, _tileset);
 
     return new TileRenderResources{
         tileTransform,

src/core/src/FabricResourceManager.cpp

@@ -28,11 +28,18 @@ FabricResourceManager::FabricResourceManager() {
 
 FabricResourceManager::~FabricResourceManager() = default;
 
-bool FabricResourceManager::shouldAcquireMaterial(const CesiumGltf::MeshPrimitive& primitive, bool hasImagery) const {
+bool FabricResourceManager::shouldAcquireMaterial(
+    const CesiumGltf::MeshPrimitive& primitive,
+    bool hasImagery,
+    const pxr::SdfPath& materialPath) const {
     if (_disableMaterials) {
         return false;
     }
 
+    if (!materialPath.IsEmpty()) {
+        return false;
+    }
+
     return hasImagery || GltfUtil::hasMaterial(primitive);
 }
 

src/core/src/OmniTileset.cpp

@@ -27,6 +27,7 @@
 #include <pxr/usd/usd/prim.h>
 #include <pxr/usd/usd/stage.h>
 #include <pxr/usd/usdGeom/boundable.h>
+#include <pxr/usd/usdShade/materialBindingAPI.h>
 
 namespace cesium::omniverse {
 
@@ -243,6 +244,16 @@ pxr::CesiumGeoreference OmniTileset::getGeoreference() const {
     return UsdUtil::getCesiumGeoreference(georeferencePath);
 }
 
+pxr::SdfPath OmniTileset::getMaterialPath() const {
+    auto tileset = UsdUtil::getCesiumTileset(_tilesetPath);
+
+    const auto materialBindingApi = pxr::UsdShadeMaterialBindingAPI(tileset);
+    const auto materialBinding = materialBindingApi.GetDirectBinding();
+    const auto& materialPath = materialBinding.GetMaterialPath();
+
+    return materialPath;
+}
+
 int64_t OmniTileset::getTilesetId() const {
     return _tilesetId;
 }

src/plugins/CesiumUsdSchemas/generatedSchema.usda.in

@@ -166,6 +166,25 @@ class CesiumTilesetPrim "CesiumTilesetPrim" (
         displayName = "URL"
         doc = "The URL of this tileset's tileset.json file. Usually blank if this is an ion asset."
     )
+    uniform bool doubleSided = 0 (
+        doc = """Although some renderers treat all parametric or polygonal
+        surfaces as if they were effectively laminae with outward-facing
+        normals on both sides, some renderers derive significant optimizations
+        by considering these surfaces to have only a single outward side,
+        typically determined by control-point winding order and/or 
+        orientation.  By doing so they can perform \"backface culling\" to
+        avoid drawing the many polygons of most closed surfaces that face away
+        from the viewer.
+
+        However, it is often advantageous to model thin objects such as paper
+        and cloth as single, open surfaces that must be viewable from both
+        sides, always.  Setting a gprim's doubleSided attribute to 
+        \\c true instructs all renderers to disable optimizations such as
+        backface culling for the gprim, and attempt (not all renderers are able
+        to do so, but the USD reference GL renderer always will) to provide
+        forward-facing normals on each side of the surface for lighting
+        calculations."""
+    )
     float3[] extent (
         doc = """Extent is a three dimensional range measuring the geometric
         extent of the authored gprim in its own local space (i.e. its own
@@ -184,6 +203,27 @@ class CesiumTilesetPrim "CesiumTilesetPrim" (
         the extent of all children, as they will be pruned from BBox computation
         during traversal."""
     )
+    uniform token orientation = "rightHanded" (
+        allowedTokens = ["rightHanded", "leftHanded"]
+        doc = """Orientation specifies whether the gprim's surface normal 
+        should be computed using the right hand rule, or the left hand rule.
+        Please see for a deeper explanation and
+        generalization of orientation to composed scenes with transformation
+        hierarchies."""
+    )
+    color3f[] primvars:displayColor (
+        doc = '''It is useful to have an "official" colorSet that can be used
+        as a display or modeling color, even in the absence of any specified
+        shader for a gprim.  DisplayColor serves this role; because it is a
+        UsdGeomPrimvar, it can also be used as a gprim override for any shader
+        that consumes a displayColor parameter.'''
+    )
+    float[] primvars:displayOpacity (
+        doc = """Companion to displayColor that specifies opacity, broken
+        out as an independent attribute rather than an rgba color, both so that
+        each can be independently overridden, and because shaders rarely consume
+        rgba parameters."""
+    )
     rel proxyPrim (
         doc = '''The proxyPrim relationship allows us to link a
         prim whose purpose is "render" to its (single target)

src/plugins/CesiumUsdSchemas/plugInfo.json.in

@@ -52,7 +52,7 @@
                         }, 
                         "autoGenerated": true, 
                         "bases": [
-                            "UsdGeomBoundable"
+                            "UsdGeomGprim"
                         ], 
                         "schemaKind": "concreteTyped"
                     }

src/plugins/CesiumUsdSchemas/src/CesiumUsdSchemas/tileset.cpp

@@ -11,7 +11,7 @@ PXR_NAMESPACE_OPEN_SCOPE
 TF_REGISTRY_FUNCTION(TfType)
 {
     TfType::Define<CesiumTileset,
-        TfType::Bases< UsdGeomBoundable > >();
+        TfType::Bases< UsdGeomGprim > >();
 
     // Register the usd prim typename as an alias under UsdSchemaBase. This
     // enables one to call
@@ -455,7 +455,7 @@ CesiumTileset::GetSchemaAttributeNames(bool includeInherited)
     };
     static TfTokenVector allNames =
         _ConcatenateAttributeNames(
-            UsdGeomBoundable::GetSchemaAttributeNames(true),
+            UsdGeomGprim::GetSchemaAttributeNames(true),
             localNames);
 
     if (includeInherited)

src/plugins/CesiumUsdSchemas/src/CesiumUsdSchemas/tileset.h

@@ -5,7 +5,7 @@
 
 #include "pxr/pxr.h"
 #include ".//api.h"
-#include "pxr/usd/usdGeom/boundable.h"
+#include "pxr/usd/usdGeom/gprim.h"
 #include "pxr/usd/usd/prim.h"
 #include "pxr/usd/usd/stage.h"
 #include ".//tokens.h"
@@ -36,7 +36,7 @@ class SdfAssetPath;
 /// So to set an attribute to the value "rightHanded", use CesiumTokens->rightHanded
 /// as the value.
 ///
-class CesiumTileset : public UsdGeomBoundable
+class CesiumTileset : public UsdGeomGprim
 {
 public:
     /// Compile time constant representing what kind of schema this class is.
@@ -49,15 +49,15 @@ class CesiumTileset : public UsdGeomBoundable
     /// for a \em valid \p prim, but will not immediately throw an error for
     /// an invalid \p prim
     explicit CesiumTileset(const UsdPrim& prim=UsdPrim())
-        : UsdGeomBoundable(prim)
+        : UsdGeomGprim(prim)
     {
     }
 
     /// Construct a CesiumTileset on the prim held by \p schemaObj .
     /// Should be preferred over CesiumTileset(schemaObj.GetPrim()),
     /// as it preserves SchemaBase state.
     explicit CesiumTileset(const UsdSchemaBase& schemaObj)
-        : UsdGeomBoundable(schemaObj)
+        : UsdGeomGprim(schemaObj)
     {
     }
 

src/plugins/CesiumUsdSchemas/src/CesiumUsdSchemas/wrapTileset.cpp

@@ -174,7 +174,7 @@ void wrapCesiumTileset()
 {
     typedef CesiumTileset This;
 
-    class_<This, bases<UsdGeomBoundable> >
+    class_<This, bases<UsdGeomGprim> >
         cls("Tileset");
 
     cls