chore: set vertex color to 1.0 when no value read from gltf

src/ObjLoading/XModel/Gltf/GltfLoader.cpp

@@ -214,6 +214,7 @@ namespace
 
             const auto vertexCount = positionAccessor->GetCount();
             NullAccessor nullAccessor(vertexCount);
+            OnesAccessor onesAccessor(vertexCount);
 
             // clang-format off
             auto* normalAccessor = GetAccessorForIndex(
@@ -237,7 +238,7 @@ namespace
                 accessorsForVertex.colorAccessor,
                 {JsonAccessorType::VEC3, JsonAccessorType::VEC4},
                 {JsonAccessorComponentType::FLOAT, JsonAccessorComponentType::UNSIGNED_BYTE, JsonAccessorComponentType::UNSIGNED_SHORT}
-            ).value_or(&nullAccessor);
+            ).value_or(&onesAccessor);
             VerifyAccessorVertexCount("COLOR_0", colorAccessor, vertexCount);
 
             auto* jointsAccessor = GetAccessorForIndex(

src/ObjLoading/XModel/Gltf/Internal/GltfAccessor.cpp

@@ -81,6 +81,85 @@ size_t NullAccessor::GetCount() const
     return m_count;
 }
 
+OnesAccessor::OnesAccessor(const size_t count)
+    : m_count(count)
+{
+}
+
+bool OnesAccessor::GetFloatVec2(const size_t index, float (&out)[2]) const
+{
+    if (index >= m_count)
+        return false;
+
+    out[0] = 1.0f;
+    out[1] = 1.0f;
+
+    return true;
+}
+
+bool OnesAccessor::GetFloatVec3(const size_t index, float (&out)[3]) const
+{
+    if (index >= m_count)
+        return false;
+
+    out[0] = 1.0f;
+    out[1] = 1.0f;
+    out[2] = 1.0f;
+
+    return true;
+}
+
+bool OnesAccessor::GetFloatVec4(const size_t index, float (&out)[4]) const
+{
+    if (index >= m_count)
+        return false;
+
+    out[0] = 1.0f;
+    out[1] = 1.0f;
+    out[2] = 1.0f;
+    out[3] = 1.0f;
+
+    return true;
+}
+
+bool OnesAccessor::GetUnsigned(const size_t index, unsigned& out) const
+{
+    if (index >= m_count)
+        return false;
+
+    out = 0xFFFFFFFFu;
+
+    return true;
+}
+
+bool OnesAccessor::GetUnsignedVec4(const size_t index, unsigned (&out)[4]) const
+{
+    if (index >= m_count)
+        return false;
+
+    out[0] = 0xFFFFFFFFu;
+    out[1] = 0xFFFFFFFFu;
+    out[2] = 0xFFFFFFFFu;
+    out[3] = 0xFFFFFFFFu;
+
+    return true;
+}
+
+std::optional<JsonAccessorComponentType> OnesAccessor::GetComponentType() const
+{
+    return std::nullopt;
+}
+
+std::optional<JsonAccessorType> OnesAccessor::GetType() const
+{
+    return std::nullopt;
+}
+
+size_t OnesAccessor::GetCount() const
+{
+    return m_count;
+}
+
 FloatAccessor::FloatAccessor(const BufferView* bufferView, const JsonAccessorType type, size_t byteOffset, const size_t count)
     : m_buffer_view(bufferView),
       m_type(type),

src/ObjLoading/XModel/Gltf/Internal/GltfAccessor.h

@@ -46,6 +46,25 @@ namespace gltf
         size_t m_count;
     };
 
+    class OnesAccessor final : public Accessor
+    {
+    public:
+        explicit OnesAccessor(size_t count);
+
+        [[nodiscard]] std::optional<JsonAccessorType> GetType() const override;
+        [[nodiscard]] std::optional<JsonAccessorComponentType> GetComponentType() const override;
+        [[nodiscard]] size_t GetCount() const override;
+
+        [[nodiscard]] bool GetFloatVec2(size_t index, float (&out)[2]) const override;
+        [[nodiscard]] bool GetFloatVec3(size_t index, float (&out)[3]) const override;
+        [[nodiscard]] bool GetFloatVec4(size_t index, float (&out)[4]) const override;
+        [[nodiscard]] bool GetUnsigned(size_t index, unsigned& out) const override;
+        [[nodiscard]] bool GetUnsignedVec4(size_t index, unsigned (&out)[4]) const override;
+
+    private:
+        size_t m_count;
+    };
+
     class FloatAccessor final : public Accessor
     {
     public: