GLTFLoader: support MSFT DDS texture sources (MSFT_texture_dds)

AssetLoader/src/GLTFLoader.cpp

@@ -1117,6 +1117,94 @@ void Model::InitMaterialTextureAddressingAttribs(Material& Mat, Uint32 TextureIn
     }
 }
 
+namespace MSFTTextureDDS
+{
+
+constexpr const char* MSFTTextureDDSExtension = "MSFT_texture_dds";
+
+bool IsValidImageSource(const tinygltf::Model& gltf_model, int Source)
+{
+    return Source >= 0 && Source < static_cast<int>(gltf_model.images.size());
+}
+
+bool IsImageAvailable(const tinygltf::Image& gltf_image, const std::string& BaseDir)
+{
+    if (!gltf_image.image.empty() || gltf_image.bufferView >= 0)
+        return true;
+
+    if (gltf_image.uri.empty())
+        return false;
+
+    const std::string ImagePath = FileSystem::SimplifyPath((BaseDir + gltf_image.uri).c_str());
+    return FileSystem::FileExists(ImagePath.c_str());
+}
+
+bool GetSource(const tinygltf::Texture& gltf_tex,
+               const tinygltf::Model&   gltf_model,
+               const std::string&       BaseDir,
+               int&                     Source)
+{
+    const auto ExtIt = gltf_tex.extensions.find(MSFTTextureDDSExtension);
+    if (ExtIt == gltf_tex.extensions.end() || !ExtIt->second.IsObject())
+        return false;
+
+    const tinygltf::Value& SourceValue = ExtIt->second.Get("source");
+    if (!SourceValue.IsInt())
+        return false;
+
+    const int DDSSource = SourceValue.GetNumberAsInt();
+    if (!IsValidImageSource(gltf_model, DDSSource))
+        return false;
+
+    if (!IsImageAvailable(gltf_model.images[DDSSource], BaseDir))
+        return false;
+
+    Source = DDSSource;
+    return true;
+}
+
+void EraseAll(std::string& Str, const std::string& Substr)
+{
+    size_t Pos = 0;
+    while ((Pos = Str.find(Substr, Pos)) != std::string::npos)
+    {
+        Str.erase(Pos, Substr.length());
+    }
+}
+
+void RemoveWarnings(const tinygltf::Model& gltf_model,
+                    const std::string&     BaseDir,
+                    std::string&           Warning)
+{
+    if (Warning.empty())
+        return;
+
+    for (const tinygltf::Texture& gltf_tex : gltf_model.textures)
+    {
+        int DDSSource = -1;
+        if (!GetSource(gltf_tex, gltf_model, BaseDir, DDSSource))
+            continue;
+
+        if (!IsValidImageSource(gltf_model, gltf_tex.source))
+            continue;
+
+        const tinygltf::Image& StandardImage = gltf_model.images[gltf_tex.source];
+        if (StandardImage.uri.empty())
+            continue;
+
+        const std::string StandardImagePath = FileSystem::SimplifyPath((BaseDir + StandardImage.uri).c_str());
+        if (FileSystem::FileExists(StandardImagePath.c_str()))
+            continue;
+
+        EraseAll(Warning, FormatString("File not found : ", StandardImage.uri, "\n"));
+        EraseAll(Warning, FormatString("File not found : ", StandardImage.uri));
+        EraseAll(Warning, FormatString("Failed to load external 'uri' for image[", gltf_tex.source, "] name = \"", StandardImage.uri, "\"\n"));
+        EraseAll(Warning, FormatString("Failed to load external 'uri' for image[", gltf_tex.source, "] name = \"", StandardImage.uri, "\""));
+    }
+}
+
+} // namespace MSFTTextureDDS
+
 void Model::LoadTextures(IRenderDevice*         pDevice,
                          const tinygltf::Model& gltf_model,
                          const std::string&     BaseDir,
@@ -1127,7 +1215,12 @@ void Model::LoadTextures(IRenderDevice*         pDevice,
     Textures.reserve(gltf_model.textures.size());
     for (const tinygltf::Texture& gltf_tex : gltf_model.textures)
     {
-        const tinygltf::Image& gltf_image = gltf_model.images[gltf_tex.source];
+        int ImageSource = gltf_tex.source;
+        int DDSSource   = -1;
+        if (MSFTTextureDDS::GetSource(gltf_tex, gltf_model, BaseDir, DDSSource))
+            ImageSource = DDSSource;
+
+        const tinygltf::Image& gltf_image = gltf_model.images[ImageSource];
         const std::string      CacheId    = !gltf_image.uri.empty() ? FileSystem::SimplifyPath((BaseDir + gltf_image.uri).c_str()) : "";
 
         ImageData Image;
@@ -1877,7 +1970,6 @@ struct LoaderData
     ModelCreateInfo::ReadWholeFileCallbackType ReadWholeFile = nullptr;
 };
 
-
 bool LoadImageData(tinygltf::Image*     gltf_image,
                    const int            gltf_image_idx,
                    std::string*         error,
@@ -2242,6 +2334,7 @@ void Model::LoadFromFile(IRenderDevice*         pDevice,
     {
         LOG_ERROR_AND_THROW("Failed to load gltf file ", filename, ": ", error);
     }
+    MSFTTextureDDS::RemoveWarnings(gltf_model, LoaderData.BaseDir, warning);
     if (!warning.empty())
     {
         LOG_WARNING_MESSAGE("Loaded gltf file ", filename, " with the following warning:", warning);