Implement initial Unity-style asset library cache

engine/src/Resources/Material/MaterialLoader.cpp

@@ -1,10 +1,12 @@
 #include <XCEngine/Resources/Material/MaterialLoader.h>
+#include <XCEngine/Resources/BuiltinResources.h>
 #include <XCEngine/Core/Asset/ResourceManager.h>
 #include <XCEngine/Core/Asset/ResourceTypes.h>
 #include <XCEngine/Resources/Shader/ShaderLoader.h>
 
 #include <cctype>
 #include <cstdlib>
+#include <filesystem>
 #include <string>
 
 namespace XCEngine {
@@ -531,6 +533,24 @@ ResourceHandle<Shader> LoadShaderHandle(const Containers::String& shaderPath) {
     return ResourceHandle<Shader>(static_cast<Shader*>(shaderResult.resource));
 }
 
+bool MaterialFileExists(const Containers::String& path) {
+    const std::filesystem::path inputPath(path.CStr());
+    if (std::filesystem::exists(inputPath)) {
+        return true;
+    }
+
+    if (inputPath.is_absolute()) {
+        return false;
+    }
+
+    const Containers::String& resourceRoot = ResourceManager::Get().GetResourceRoot();
+    if (resourceRoot.Empty()) {
+        return false;
+    }
+
+    return std::filesystem::exists(std::filesystem::path(resourceRoot.CStr()) / inputPath);
+}
+
 } // namespace
 
 MaterialLoader::MaterialLoader() = default;
@@ -546,6 +566,10 @@ Containers::Array<Containers::String> MaterialLoader::GetSupportedExtensions() c
 }
 
 bool MaterialLoader::CanLoad(const Containers::String& path) const {
+    if (IsBuiltinMaterialPath(path)) {
+        return true;
+    }
+
     Containers::String ext = GetExtension(path);
     return ext == "mat" || ext == "material" || ext == "json";
 }
@@ -553,17 +577,22 @@ bool MaterialLoader::CanLoad(const Containers::String& path) const {
 LoadResult MaterialLoader::Load(const Containers::String& path, const ImportSettings* settings) {
     (void)settings;
 
-    Containers::Array<Core::uint8> data = ReadFileData(path);
-    if (data.Empty()) {
-        return LoadResult("Failed to read material file: " + path);
+    if (IsBuiltinMaterialPath(path)) {
+        return CreateBuiltinMaterialResource(path);
     }
 
+    Containers::Array<Core::uint8> data = ReadFileData(path);
     Material* material = new Material();
     material->m_path = path;
     material->m_name = path;
     material->m_guid = ResourceGUID::Generate(path);
 
-    if (!ParseMaterialData(data, material)) {
+    if (data.Empty() && !MaterialFileExists(path)) {
+        delete material;
+        return LoadResult("Failed to read material file: " + path);
+    }
+
+    if (!data.Empty() && !ParseMaterialData(data, material)) {
         delete material;
         return LoadResult("Failed to parse material file: " + path);
     }