Merge pull request #538 from CesiumGS/custom-vertex-attributes

Add support for custom vertex attributes

CHANGES.md

@@ -1,5 +1,9 @@
 # Change Log
 
+### v0.14.0 - 2023-12-01
+
+* Added support for custom vertex attributes. Custom attributes can be accessed by their glTF attribute name with the primvar lookup functions in MDL, e.g. `data_lookup_int` and `data_lookup_float`.
+
 ### v0.13.0 - 2023-11-01
 
 * Changing certain tileset properties no longer triggers a tileset reload.

exts/cesium.omniverse/mdl/cesium.mdl

@@ -213,7 +213,7 @@ float4 compute_base_color(
 
     auto base_color = base_color_texture.valid ? base_color_texture.value : float4(1.0);
     base_color *= float4(base_color_factor_float3.x, base_color_factor_float3.y, base_color_factor_float3.z, base_alpha);
-    base_color *= ::scene::data_lookup_float4("vertexColor", float4(1.0));
+    base_color *= ::scene::data_lookup_float4("COLOR_0", float4(1.0));
     base_color = alpha_blend(imagery_layers_texture.value, base_color);
     base_color *= tile_color;
 

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

@@ -1,6 +1,9 @@
 #pragma once
 
+#include "cesium/omniverse/GltfUtil.h"
+
 #include <cstdint>
+#include <set>
 
 namespace CesiumGltf {
 struct MeshPrimitive;
@@ -19,13 +22,17 @@ class FabricGeometryDefinition {
     [[nodiscard]] bool hasNormals() const;
     [[nodiscard]] bool hasVertexColors() const;
     [[nodiscard]] uint64_t getTexcoordSetCount() const;
+    [[nodiscard]] const std::set<VertexAttributeInfo>& getCustomVertexAttributes() const;
 
     bool operator==(const FabricGeometryDefinition& other) const;
 
   private:
     bool _hasNormals{false};
     bool _hasVertexColors{false};
     uint64_t _texcoordSetCount{0};
+
+    // std::set is sorted which is important for checking FabricGeometryDefinition equality
+    std::set<VertexAttributeInfo> _customVertexAttributes;
 };
 
 } // namespace cesium::omniverse

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

@@ -1,5 +1,7 @@
 #pragma once
 
+#include "cesium/omniverse/VertexAttributeType.h"
+
 #ifdef CESIUM_OMNI_MSVC
 #pragma push_macro("OPAQUE")
 #undef OPAQUE
@@ -89,7 +91,14 @@ class VertexColorsAccessor {
     VertexColorsAccessor(const CesiumGltf::AccessorView<glm::fvec3>& float32Vec3View);
     VertexColorsAccessor(const CesiumGltf::AccessorView<glm::fvec4>& float32Vec4View);
 
-    void fill(const gsl::span<glm::fvec4>& values) const;
+    /**
+     * @brief Copy accessor values to the given output values, including any data transformations.
+     *
+     * @param values The output values.
+     * @param repeat Indicates how many times each value in the accessor should be repeated in the output. Typically repeat is 1, but for voxel point clouds repeat is 8.
+     */
+    void fill(const gsl::span<glm::fvec4>& values, uint64_t repeat = 1) const;
+
     [[nodiscard]] uint64_t size() const;
 
   private:
@@ -115,4 +124,19 @@ class FaceVertexCountsAccessor {
     uint64_t _size;
 };
 
+template <VertexAttributeType T> class VertexAttributeAccessor {
+  public:
+    VertexAttributeAccessor();
+    VertexAttributeAccessor(const CesiumGltf::AccessorView<GetNativeType<T>>& view, bool normalized);
+
+    void fill(const gsl::span<GetFabricType<T>>& values, uint64_t repeat = 1) const;
+
+    [[nodiscard]] uint64_t size() const;
+
+  private:
+    CesiumGltf::AccessorView<GetNativeType<T>> _view;
+    uint64_t _size;
+    bool _normalized;
+};
+
 } // namespace cesium::omniverse

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

@@ -1,8 +1,13 @@
 #pragma once
 
 #include "cesium/omniverse/GltfAccessors.h"
+#include "cesium/omniverse/VertexAttributeType.h"
 
+#include <CesiumGltf/Accessor.h>
 #include <glm/glm.hpp>
+#include <omni/fabric/core/FabricTypes.h>
+
+#include <set>
 
 namespace CesiumGltf {
 struct ImageCesium;
@@ -49,6 +54,16 @@ struct MaterialInfo {
     bool operator==(const MaterialInfo& other) const;
 };
 
+struct VertexAttributeInfo {
+    VertexAttributeType type;
+    omni::fabric::Token fabricAttributeName;
+    std::string gltfAttributeName;
+
+    // Make sure to update this function when adding new fields to the struct
+    bool operator==(const VertexAttributeInfo& other) const;
+    bool operator<(const VertexAttributeInfo& other) const;
+};
+
 } // namespace cesium::omniverse
 
 namespace cesium::omniverse::GltfUtil {
@@ -81,11 +96,20 @@ getImageryTexcoords(const CesiumGltf::Model& model, const CesiumGltf::MeshPrimit
 VertexColorsAccessor
 getVertexColors(const CesiumGltf::Model& model, const CesiumGltf::MeshPrimitive& primitive, uint64_t setIndex);
 
+template <VertexAttributeType T>
+VertexAttributeAccessor<T> getVertexAttributeValues(
+    const CesiumGltf::Model& model,
+    const CesiumGltf::MeshPrimitive& primitive,
+    const std::string& attributeName);
+
 const CesiumGltf::ImageCesium*
 getBaseColorTextureImage(const CesiumGltf::Model& model, const CesiumGltf::MeshPrimitive& primitive);
 
 MaterialInfo getMaterialInfo(const CesiumGltf::Model& model, const CesiumGltf::MeshPrimitive& primitive);
 
+std::set<VertexAttributeInfo>
+getCustomVertexAttributes(const CesiumGltf::Model& model, const CesiumGltf::MeshPrimitive& primitive);
+
 MaterialInfo getDefaultMaterialInfo();
 TextureInfo getDefaultTextureInfo();
 

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

@@ -125,7 +125,7 @@ __pragma(warning(push)) __pragma(warning(disable : 4003))
     ((primvars_st_7, "primvars:st_7")) \
     ((primvars_st_8, "primvars:st_8")) \
     ((primvars_st_9, "primvars:st_9")) \
-    ((primvars_vertexColor, "primvars:vertexColor")) \
+    ((primvars_COLOR_0, "primvars:COLOR_0")) \
     ((xformOp_transform_cesium, "xformOp:transform:cesium"))
 
 TF_DECLARE_PUBLIC_TOKENS(UsdTokens, USD_TOKENS);
@@ -250,7 +250,7 @@ const omni::fabric::Type primvarInterpolations(omni::fabric::BaseDataType::eToke
 const omni::fabric::Type primvars(omni::fabric::BaseDataType::eToken, 1, 1, omni::fabric::AttributeRole::eNone);
 const omni::fabric::Type primvars_normals(omni::fabric::BaseDataType::eFloat, 3, 1, omni::fabric::AttributeRole::eNormal);
 const omni::fabric::Type primvars_st(omni::fabric::BaseDataType::eFloat, 2, 1, omni::fabric::AttributeRole::eTexCoord);
-const omni::fabric::Type primvars_vertexColor(omni::fabric::BaseDataType::eFloat, 4, 1, omni::fabric::AttributeRole::eNone);
+const omni::fabric::Type primvars_COLOR_0(omni::fabric::BaseDataType::eFloat, 4, 1, omni::fabric::AttributeRole::eNone);
 const omni::fabric::Type Shader(omni::fabric::BaseDataType::eTag, 1, 0, omni::fabric::AttributeRole::ePrimTypeName);
 const omni::fabric::Type subdivisionScheme(omni::fabric::BaseDataType::eToken, 1, 0, omni::fabric::AttributeRole::eNone);
 const omni::fabric::Type _cesium_localToEcefTransform(omni::fabric::BaseDataType::eDouble, 16, 0, omni::fabric::AttributeRole::eMatrix);

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

@@ -0,0 +1,89 @@
+#pragma once
+
+#include <glm/glm.hpp>
+#include <omni/fabric/FabricTypes.h>
+
+#include <optional>
+#include <string>
+
+namespace cesium::omniverse {
+
+enum class VertexAttributeType {
+    UINT8,
+    INT8,
+    UINT16,
+    INT16,
+    FLOAT32,
+    VEC2_UINT8,
+    VEC2_INT8,
+    VEC2_UINT16,
+    VEC2_INT16,
+    VEC2_FLOAT32,
+    VEC3_UINT8,
+    VEC3_INT8,
+    VEC3_UINT16,
+    VEC3_INT16,
+    VEC3_FLOAT32,
+    VEC4_UINT8,
+    VEC4_INT8,
+    VEC4_UINT16,
+    VEC4_INT16,
+    VEC4_FLOAT32,
+};
+
+std::optional<VertexAttributeType> getVertexAttributeTypeFromGltf(const std::string& type, int32_t componentType);
+omni::fabric::Type getFabricType(VertexAttributeType type);
+
+template <VertexAttributeType T> struct GetNativeTypeImpl;
+template <> struct GetNativeTypeImpl<VertexAttributeType::UINT8> { using Type = glm::u8vec1; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::INT8> { using Type = glm::i8vec1; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::UINT16> { using Type = glm::u16vec1; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::INT16> { using Type = glm::i16vec1; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::FLOAT32> { using Type = glm::f32vec1; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC2_UINT8> { using Type = glm::u8vec2; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC2_INT8> { using Type = glm::i8vec2; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC2_UINT16> { using Type = glm::u16vec2; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC2_INT16> { using Type = glm::i16vec2; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC2_FLOAT32> { using Type = glm::f32vec2; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC3_UINT8> { using Type = glm::u8vec3; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC3_INT8> { using Type = glm::i8vec3; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC3_UINT16> { using Type = glm::u16vec3; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC3_INT16> { using Type = glm::i16vec3; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC3_FLOAT32> { using Type = glm::f32vec3; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC4_UINT8> { using Type = glm::u8vec4; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC4_INT8> { using Type = glm::i8vec4; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC4_UINT16> { using Type = glm::u16vec4; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC4_INT16> { using Type = glm::i16vec4; };
+template <> struct GetNativeTypeImpl<VertexAttributeType::VEC4_FLOAT32> { using Type = glm::f32vec4; };
+
+// Integer primvar lookup doesn't seem to work so cast all data types to float. This is safe to do since
+// FLOAT32 can represent all possible UINT8, INT8, UINT16, and INT16 values. Also not a significant memory
+// overhead since Fabric doesn't support INT8, UINT16, and INT16 types anyways.
+//
+// Float is also a convenient data type for storing normalized attributes, which are normalized prior to Fabric upload
+template <VertexAttributeType T> struct GetFabricTypeImpl;
+template <> struct GetFabricTypeImpl<VertexAttributeType::UINT8> { using Type = glm::f32vec1; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::INT8> { using Type = glm::f32vec1; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::UINT16> { using Type = glm::f32vec1; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::INT16> { using Type = glm::f32vec1; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::FLOAT32> { using Type = glm::f32vec1; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC2_UINT8> { using Type = glm::f32vec2; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC2_INT8> { using Type = glm::f32vec2; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC2_UINT16> { using Type = glm::f32vec2; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC2_INT16> { using Type = glm::f32vec2; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC2_FLOAT32> { using Type = glm::f32vec2; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC3_UINT8> { using Type = glm::f32vec3; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC3_INT8> { using Type = glm::f32vec3; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC3_UINT16> { using Type = glm::f32vec3; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC3_INT16> { using Type = glm::f32vec3; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC3_FLOAT32> { using Type = glm::f32vec3; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC4_UINT8> { using Type = glm::f32vec4; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC4_INT8> { using Type = glm::f32vec4; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC4_UINT16> { using Type = glm::f32vec4; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC4_INT16> { using Type = glm::f32vec4; };
+template <> struct GetFabricTypeImpl<VertexAttributeType::VEC4_FLOAT32> { using Type = glm::f32vec4; };
+
+template <VertexAttributeType T> using GetNativeType = typename GetNativeTypeImpl<T>::Type;
+template <VertexAttributeType T> using GetFabricType = typename GetFabricTypeImpl<T>::Type;
+
+} // namespace cesium::omniverse