[Assets] add base classes and functionnalities

include/Nazara/Core/Asset.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <Nazara/Core/AssetDescriptor.hpp>
+
+namespace Nz
+{
+	template <typename TResource>
+	class Asset final
+	{
+	public:
+		const std::shared_ptr<TResource>& Get() const { return m_resource; }
+		explicit operator bool() const noexcept { return !!m_resource; }
+
+	protected:
+		AssetDescriptor<TResource> m_descriptor;
+		std::shared_ptr<TResource> m_resource;
+
+		friend class AssetCatalog;
+	};
+}

include/Nazara/Core/AssetCatalog.hpp

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <Nazara/Core/Asset.hpp>
+#include <Nazara/Core/Export.hpp>
+
+namespace Nz
+{
+	class NAZARA_CORE_API AssetCatalog
+	{
+	public:
+		template <typename TResource>
+		static Asset<TResource> LoadFromFile(const std::filesystem::path& path);
+	};
+}
+
+#include <Nazara/Core/AssetCatalog.inl>

include/Nazara/Core/AssetCatalog.inl

@@ -0,0 +1,31 @@
+#include <Nazara/Core/ApplicationBase.hpp>
+#include <Nazara/Core/FilesystemAppComponent.hpp>
+#include <Nazara/Core/JsonSerialization.hpp>
+
+namespace Nz
+{
+	template <typename TResource>
+	Asset<TResource> AssetCatalog::LoadFromFile(const std::filesystem::path& path)
+	{
+		Asset<TResource> asset;
+
+		JsonSerializationContext json;
+		if (!json.Load(path))
+			return {};
+
+		if (!Unserialize(json, "", &asset.m_descriptor))
+			return {};
+
+		FilesystemAppComponent* fs = ApplicationBase::Instance()->TryGetComponent<FilesystemAppComponent>();
+		if (fs) // first try using a FileSystem component to load the asset
+		{
+			std::string filepath = asset.m_descriptor.path.string();
+			asset.m_resource = fs->Load<TResource>(std::string_view(filepath), asset.m_descriptor.parameters);
+		}
+
+		if (!asset) // if it fails, use the default loader
+			asset.m_resource = TResource::LoadFromFile(asset.m_descriptor.path, asset.m_descriptor.parameters);
+
+		return asset;
+	}
+}

include/Nazara/Core/AssetDescriptor.hpp

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <Nazara/Core/Serialization.hpp>
+#include <NazaraUtils/TypeName.hpp>
+
+namespace Nz
+{
+	template <typename TResource>
+	struct AssetDescriptor
+	{
+		constexpr static std::string_view Type = TypeName<TResource>();
+
+		int version;
+		std::string type;
+		std::string name;
+		std::filesystem::path path;
+		TResource::Params parameters;
+	};
+
+	template <typename TResource> bool Serialize(SerializationContext& context, const AssetDescriptor<TResource>& descriptor, TypeTag<AssetDescriptor<TResource>>);
+	template <typename TResource> bool Unserialize(SerializationContext& context, AssetDescriptor<TResource>* descriptor, TypeTag<AssetDescriptor<TResource>>);
+}
+
+#include <Nazara/Core/AssetDescriptor.inl>

include/Nazara/Core/AssetDescriptor.inl

@@ -0,0 +1,37 @@
+namespace Nz
+{
+	template <typename TResource>
+	bool Serialize(SerializationContext& context, const AssetDescriptor<TResource>& descriptor, TypeTag<AssetDescriptor<TResource>>)
+	{
+		Serialize(context, "version", descriptor.version);
+		Serialize(context, "type", descriptor.type);
+		Serialize(context, "name", descriptor.name);
+		Serialize(context, "path", descriptor.path);
+		Serialize(context, "parameters", descriptor.parameters);
+		return true;
+	}
+
+	template <typename TResource>
+	bool Unserialize(SerializationContext& context, AssetDescriptor<TResource>* descriptor, TypeTag<AssetDescriptor<TResource>>)
+	{
+		if (!Unserialize(context, "version", &descriptor->version))
+			return false;
+
+		if (!Unserialize(context, "type", &descriptor->type))
+			return false;
+
+		if (AssetDescriptor<TResource>::Type != descriptor->type)
+			return false;
+
+		if (!Unserialize(context, "name", &descriptor->name))
+			return false;
+
+		if (!Unserialize(context, "path", &descriptor->path))
+			return false;
+
+		if (!Unserialize(context, "parameters", &descriptor->parameters))
+			return false;
+
+		return true;
+	}
+}