Implement Hazel3D-style dual-manager asset system with async loading and specialized serializers

Core/Source/Lux/Asset/AssetImporter.cpp

@@ -4,42 +4,77 @@
 #include "TextureImporter.h"
 #include "SceneImporter.h"
 #include "AudioImporter.h"
+#include "TextureSerializer.h"
+#include "MeshSerializer.h"
+#include "MaterialSerializer.h"
 
 #include <map>
+#include <memory>
 
 namespace Lux {
 
-	using AssetImportFunction = std::function<Ref<Asset>(AssetHandle, const AssetMetadata&)>;
-	static std::map<AssetType, AssetImportFunction> s_AssetImportFunctions = {
-		{AssetType::Texture, TextureImporter::ImportTexture },
-		{ AssetType::Scene, SceneImporter::ImportScene },
-		{ AssetType::Audio, AudioImporter::ImportAudio },/*
-		{ AssetType::ObjModel, ObjModelImporter::ImportObjModel },
-		{ AssetType::ScriptFile, SceneImporter::ImportScript }*/
-	};
+	// Serializer-based dispatch table (Hazel-style).
+	// Each entry owns its AssetSerializer instance.
+	static std::map<AssetType, std::unique_ptr<AssetSerializer>> s_Serializers;
+
+	static void InitSerializers()
+	{
+		// Texture
+		s_Serializers[AssetType::Texture]    = std::make_unique<TextureSerializer>();
+		s_Serializers[AssetType::EnvMap]     = std::make_unique<TextureSerializer>();
+
+		// Mesh
+		s_Serializers[AssetType::MeshSource] = std::make_unique<MeshSourceSerializer>();
+		s_Serializers[AssetType::Mesh]       = std::make_unique<MeshSerializer>();
+		s_Serializers[AssetType::StaticMesh] = std::make_unique<StaticMeshSerializer>();
+
+		// Material
+		s_Serializers[AssetType::Material]   = std::make_unique<MaterialSerializer>();
+	}
 
 	Ref<Asset> AssetImporter::ImportAsset(AssetHandle handle, const AssetMetadata& metadata)
 	{
 		LUX_PROFILE_FUNCTION_COLOR("AssetImporter::ImportAsset", 0xF2FA8A);
 
+		// Lazy-initialise the serializer table once.
+		static std::once_flag s_InitFlag;
+		std::call_once(s_InitFlag, InitSerializers);
+
+		// ── Serializer-based types ────────────────────────────────────────────
+		auto serializerIt = s_Serializers.find(metadata.Type);
+		if (serializerIt != s_Serializers.end())
 		{
-			LUX_PROFILE_SCOPE_COLOR("AssetImporter::ImportAsset Scope", 0x27628A);
+			// Build a metadata copy that carries the handle (in case the
+			// metadata came in without it already set).
+			AssetMetadata meta = metadata;
+			if (meta.Handle == 0)
+				meta.Handle = handle;
 
-			if (s_AssetImportFunctions.find(metadata.Type) == s_AssetImportFunctions.end())
-			{
-				LUX_CORE_ERROR("No importer available for asset type: {}", (uint16_t)metadata.Type);
-				return nullptr;
-			}
+			Ref<Asset> asset;
+			if (serializerIt->second->TryLoadData(meta, asset))
+				return asset;
+
+			LUX_CORE_ERROR("AssetImporter: serializer failed for type {} (handle {})",
+				(uint16_t)metadata.Type, (uint64_t)handle);
+			return nullptr;
 		}
 
-		auto& result = s_AssetImportFunctions.at(metadata.Type);//(metadata.Type)(handle, metadata);
+		// ── Legacy function-pointer importers ─────────────────────────────────
+		using AssetImportFunction = std::function<Ref<Asset>(AssetHandle, const AssetMetadata&)>;
+		static const std::map<AssetType, AssetImportFunction> s_LegacyImportFunctions = {
+			{ AssetType::Scene, SceneImporter::ImportScene },
+			{ AssetType::Audio, AudioImporter::ImportAudio },
+		};
 
+		auto legacyIt = s_LegacyImportFunctions.find(metadata.Type);
+		if (legacyIt == s_LegacyImportFunctions.end())
 		{
-			LUX_PROFILE_SCOPE_COLOR("AssetImporter::ImportAsset 2 Scope", 0xD1C48A);
-
-			return result(handle, metadata);
+			LUX_CORE_ERROR("AssetImporter: no importer for asset type {} (handle {})",
+				(uint16_t)metadata.Type, (uint64_t)handle);
+			return nullptr;
 		}
 
+		return legacyIt->second(handle, metadata);
 	}
 
 }

Core/Source/Lux/Asset/AssetImporter.h

@@ -1,9 +1,12 @@
 #pragma once
 
 #include "AssetMetadata.h"
+#include "AssetSerializer.h"
 
 namespace Lux
 {
+	// Routes asset load requests to the appropriate AssetSerializer (or legacy
+	// importer function) based on the asset type stored in the metadata.
 	class AssetImporter
 	{
 	public:

Core/Source/Lux/Asset/AssetMetadata.h

@@ -8,6 +8,7 @@ namespace Lux
 {
 	struct AssetMetadata
 	{
+		AssetHandle Handle = 0;
 		AssetType Type = AssetType::None;
 		std::filesystem::path FilePath = "";
 

Core/Source/Lux/Asset/AssetSerializer.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "AssetMetadata.h"
+
+namespace Lux
+{
+	// Abstract interface that every asset type's serializer must satisfy.
+	// Editor serializers load data from disk (e.g. via YAML / Assimp).
+	// Runtime serializers read from packed binary streams produced at build time.
+	class AssetSerializer
+	{
+	public:
+		virtual ~AssetSerializer() = default;
+
+		// Serialize the asset back to its source representation (YAML, binary, etc.)
+		virtual void Serialize(const AssetMetadata& metadata, const Ref<Asset>& asset) const = 0;
+
+		// Attempt to load the asset described by metadata.
+		// Returns true and sets asset on success; returns false on failure.
+		virtual bool TryLoadData(const AssetMetadata& metadata, Ref<Asset>& asset) const = 0;
+	};
+}

Core/Source/Lux/Asset/AssimpMeshImporter.cpp

@@ -0,0 +1,213 @@
+#include "lpch.h"
+#include "AssimpMeshImporter.h"
+
+#include "Lux/Core/Math/AABB.h"
+#include "Lux/Renderer/VertexBuffer.h"
+#include "Lux/Renderer/IndexBuffer.h"
+
+#include <assimp/Importer.hpp>
+#include <assimp/scene.h>
+#include <assimp/postprocess.h>
+
+#define GLM_ENABLE_EXPERIMENTAL
+#include <glm/glm.hpp>
+#include <glm/gtx/quaternion.hpp>
+#include <glm/gtc/type_ptr.hpp>
+
+namespace Lux
+{
+	static constexpr uint32_t s_InvalidParentIndex = 0xffffffffu;
+
+	static glm::mat4 AssimpMat4ToGlm(const aiMatrix4x4& m)
+	{
+		glm::mat4 result;
+		result[0][0] = m.a1; result[1][0] = m.a2; result[2][0] = m.a3; result[3][0] = m.a4;
+		result[0][1] = m.b1; result[1][1] = m.b2; result[2][1] = m.b3; result[3][1] = m.b4;
+		result[0][2] = m.c1; result[1][2] = m.c2; result[2][2] = m.c3; result[3][2] = m.c4;
+		result[0][3] = m.d1; result[1][3] = m.d2; result[2][3] = m.d3; result[3][3] = m.d4;
+		return result;
+	}
+
+	AssimpMeshImporter::AssimpMeshImporter(const std::filesystem::path& path)
+		: m_Path(path)
+	{
+	}
+
+	void AssimpMeshImporter::TraverseNodes(Ref<MeshSource> meshSource,
+		aiNode* node,
+		const glm::mat4& parentTransform,
+		uint32_t parentIndex)
+	{
+		glm::mat4 localTransform = AssimpMat4ToGlm(node->mTransformation);
+		glm::mat4 worldTransform = parentTransform * localTransform;
+
+		MeshNode luxNode;
+		luxNode.Name = node->mName.C_Str();
+		luxNode.LocalTransform = localTransform;
+		luxNode.Parent = parentIndex;
+
+		uint32_t nodeIndex = (uint32_t)meshSource->m_Nodes.size();
+		meshSource->m_Nodes.push_back(luxNode);
+
+		if (parentIndex != s_InvalidParentIndex)
+			meshSource->m_Nodes[parentIndex].Children.push_back(nodeIndex);
+
+		auto& currentNode = meshSource->m_Nodes[nodeIndex];
+
+		for (uint32_t i = 0; i < node->mNumMeshes; i++)
+		{
+			uint32_t submeshIndex = node->mMeshes[i];
+			currentNode.Submeshes.push_back(submeshIndex);
+			meshSource->m_Submeshes[submeshIndex].Transform = worldTransform;
+			meshSource->m_Submeshes[submeshIndex].LocalTransform = localTransform;
+			meshSource->m_Submeshes[submeshIndex].NodeName = node->mName.C_Str();
+		}
+
+		for (uint32_t i = 0; i < node->mNumChildren; i++)
+			TraverseNodes(meshSource, node->mChildren[i], worldTransform, nodeIndex);
+	}
+
+	Ref<MeshSource> AssimpMeshImporter::ImportToMeshSource()
+	{
+		Ref<MeshSource> meshSource = Ref<MeshSource>::Create();
+		meshSource->m_FilePath = m_Path.string();
+
+		Assimp::Importer importer;
+		importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_PRESERVE_PIVOTS, false);
+
+		constexpr uint32_t meshImportFlags =
+			aiProcess_CalcTangentSpace |
+			aiProcess_Triangulate |
+			aiProcess_SortByPType |
+			aiProcess_GenNormals |
+			aiProcess_GenUVCoords |
+			aiProcess_OptimizeMeshes |
+			aiProcess_JoinIdenticalVertices |
+			aiProcess_LimitBoneWeights |
+			aiProcess_ValidateDataStructure |
+			aiProcess_GlobalScale;
+
+		const aiScene* scene = importer.ReadFile(m_Path.string(), meshImportFlags);
+		if (!scene || !scene->HasMeshes())
+		{
+			LUX_CORE_ERROR("AssimpMeshImporter: Failed to import mesh from '{}'", m_Path.string());
+			LUX_CORE_ERROR("  Assimp error: {}", importer.GetErrorString());
+			return nullptr;
+		}
+
+		// ── Reserve submeshes ─────────────────────────────────────────────────
+		meshSource->m_Submeshes.reserve(scene->mNumMeshes);
+
+		uint32_t vertexCount = 0;
+		uint32_t indexCount = 0;
+
+		meshSource->m_BoundingBox.Min = { FLT_MAX,  FLT_MAX,  FLT_MAX };
+		meshSource->m_BoundingBox.Max = { -FLT_MAX, -FLT_MAX, -FLT_MAX };
+
+		for (uint32_t m = 0; m < scene->mNumMeshes; m++)
+		{
+			aiMesh* mesh = scene->mMeshes[m];
+
+			Submesh& submesh = meshSource->m_Submeshes.emplace_back();
+			submesh.BaseVertex    = vertexCount;
+			submesh.BaseIndex     = indexCount;
+			submesh.MaterialIndex = mesh->mMaterialIndex;
+			submesh.IndexCount    = mesh->mNumFaces * 3;
+			submesh.VertexCount   = mesh->mNumVertices;
+			submesh.MeshName      = mesh->mName.C_Str();
+
+			vertexCount += mesh->mNumVertices;
+			indexCount  += submesh.IndexCount;
+
+			// ── AABB per submesh ──────────────────────────────────────────────
+			AABB& aabb = submesh.BoundingBox;
+			aabb.Min = { FLT_MAX,  FLT_MAX,  FLT_MAX };
+			aabb.Max = { -FLT_MAX, -FLT_MAX, -FLT_MAX };
+
+			for (uint32_t v = 0; v < mesh->mNumVertices; v++)
+			{
+				Vertex vertex;
+				vertex.Position  = { mesh->mVertices[v].x,  mesh->mVertices[v].y,  mesh->mVertices[v].z };
+				vertex.Normal    = { mesh->mNormals[v].x,   mesh->mNormals[v].y,   mesh->mNormals[v].z };
+
+				if (mesh->HasTangentsAndBitangents())
+				{
+					vertex.Tangent  = { mesh->mTangents[v].x,   mesh->mTangents[v].y,   mesh->mTangents[v].z };
+					vertex.Binormal = { mesh->mBitangents[v].x, mesh->mBitangents[v].y, mesh->mBitangents[v].z };
+				}
+
+				if (mesh->HasTextureCoords(0))
+					vertex.Texcoord = { mesh->mTextureCoords[0][v].x, mesh->mTextureCoords[0][v].y };
+				else
+					vertex.Texcoord = { 0.0f, 0.0f };
+
+				aabb.Min.x = glm::min(vertex.Position.x, aabb.Min.x);
+				aabb.Min.y = glm::min(vertex.Position.y, aabb.Min.y);
+				aabb.Min.z = glm::min(vertex.Position.z, aabb.Min.z);
+				aabb.Max.x = glm::max(vertex.Position.x, aabb.Max.x);
+				aabb.Max.y = glm::max(vertex.Position.y, aabb.Max.y);
+				aabb.Max.z = glm::max(vertex.Position.z, aabb.Max.z);
+
+				meshSource->m_Vertices.push_back(vertex);
+			}
+
+			meshSource->m_BoundingBox.Min.x = glm::min(aabb.Min.x, meshSource->m_BoundingBox.Min.x);
+			meshSource->m_BoundingBox.Min.y = glm::min(aabb.Min.y, meshSource->m_BoundingBox.Min.y);
+			meshSource->m_BoundingBox.Min.z = glm::min(aabb.Min.z, meshSource->m_BoundingBox.Min.z);
+			meshSource->m_BoundingBox.Max.x = glm::max(aabb.Max.x, meshSource->m_BoundingBox.Max.x);
+			meshSource->m_BoundingBox.Max.y = glm::max(aabb.Max.y, meshSource->m_BoundingBox.Max.y);
+			meshSource->m_BoundingBox.Max.z = glm::max(aabb.Max.z, meshSource->m_BoundingBox.Max.z);
+
+			// ── Indices ───────────────────────────────────────────────────────
+			for (uint32_t f = 0; f < mesh->mNumFaces; f++)
+			{
+				const aiFace& face = mesh->mFaces[f];
+				LUX_CORE_ASSERT(face.mNumIndices == 3, "Only triangles are supported!");
+				Index idx;
+				idx.V1 = face.mIndices[0];
+				idx.V2 = face.mIndices[1];
+				idx.V3 = face.mIndices[2];
+				meshSource->m_Indices.push_back(idx);
+			}
+		}
+
+		// ── Node hierarchy ────────────────────────────────────────────────────
+		// Insert sentinel root so every real node has a valid parentIndex
+		meshSource->m_Nodes.emplace_back(); // root placeholder
+		TraverseNodes(meshSource, scene->mRootNode, glm::mat4(1.0f), s_InvalidParentIndex);
+
+		// ── Materials (allocate zero-material placeholders) ───────────────────
+		meshSource->m_Materials.resize(scene->mNumMaterials, 0);
+
+		// ── Triangle cache ────────────────────────────────────────────────────
+		for (uint32_t i = 0; i < (uint32_t)meshSource->m_Submeshes.size(); i++)
+		{
+			const Submesh& sm = meshSource->m_Submeshes[i];
+			for (uint32_t f = 0; f < sm.IndexCount / 3; f++)
+			{
+				const Index& idx = meshSource->m_Indices[sm.BaseIndex / 3 + f];
+				meshSource->m_TriangleCache[i].emplace_back(
+					meshSource->m_Vertices[sm.BaseVertex + idx.V1],
+					meshSource->m_Vertices[sm.BaseVertex + idx.V2],
+					meshSource->m_Vertices[sm.BaseVertex + idx.V3]);
+			}
+		}
+
+		// ── GPU buffers ───────────────────────────────────────────────────────
+		meshSource->m_VertexBuffer = VertexBuffer::Create(
+			Buffer(meshSource->m_Vertices.data(),
+				(uint32_t)(meshSource->m_Vertices.size() * sizeof(Vertex))));
+
+		meshSource->m_IndexBuffer = IndexBuffer::Create(
+			Buffer(meshSource->m_Indices.data(),
+				(uint32_t)(meshSource->m_Indices.size() * sizeof(Index))));
+
+		LUX_CORE_INFO("AssimpMeshImporter: Loaded '{}' – {} submeshes, {} vertices, {} indices",
+			m_Path.filename().string(),
+			meshSource->m_Submeshes.size(),
+			meshSource->m_Vertices.size(),
+			meshSource->m_Indices.size() * 3);
+
+		return meshSource;
+	}
+}

Core/Source/Lux/Asset/AssimpMeshImporter.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include "Lux/Core/Base.h"
+#include "Lux/Renderer/Mesh.h"
+
+#include <assimp/scene.h>
+#include <filesystem>
+
+namespace Lux
+{
+	// Imports a mesh file from disk using the Assimp library and populates
+	// a MeshSource asset with vertices, indices, submeshes and basic material handles.
+	class AssimpMeshImporter
+	{
+	public:
+		explicit AssimpMeshImporter(const std::filesystem::path& path);
+
+		// Load the mesh source.  Returns nullptr on failure.
+		Ref<MeshSource> ImportToMeshSource();
+
+	private:
+		void TraverseNodes(Ref<MeshSource> meshSource, aiNode* node, const glm::mat4& parentTransform, uint32_t parentIndex);
+
+		std::filesystem::path m_Path;
+	};
+}