Formalize GaussianSplat scene extraction

engine/CMakeLists.txt

@@ -449,6 +449,7 @@ add_library(XCEngine STATIC
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Components/GameObject.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Components/CameraComponent.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Components/LightComponent.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Components/GaussianSplatRendererComponent.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Components/MeshFilterComponent.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Components/MeshRendererComponent.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Components/VolumeRendererComponent.h
@@ -460,6 +461,7 @@ add_library(XCEngine STATIC
     ${CMAKE_CURRENT_SOURCE_DIR}/src/Components/GameObject.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/Components/CameraComponent.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/Components/LightComponent.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/src/Components/GaussianSplatRendererComponent.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/Components/MeshFilterComponent.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/Components/MeshRendererComponent.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/Components/VolumeRendererComponent.cpp
@@ -477,6 +479,7 @@ add_library(XCEngine STATIC
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Rendering/Execution/SceneRenderer.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Rendering/FrameData/RenderCameraData.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Rendering/FrameData/RenderSceneData.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Rendering/FrameData/VisibleGaussianSplatItem.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Rendering/FrameData/VisibleRenderItem.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Rendering/FrameData/VisibleVolumeItem.h
     ${CMAKE_CURRENT_SOURCE_DIR}/include/XCEngine/Rendering/Planning/CameraRenderRequest.h

engine/include/XCEngine/Components/GaussianSplatRendererComponent.h

@@ -0,0 +1,77 @@
+#pragma once
+
+#include <XCEngine/Components/Component.h>
+#include <XCEngine/Core/Asset/AssetRef.h>
+#include <XCEngine/Core/Asset/ResourceHandle.h>
+#include <XCEngine/Resources/GaussianSplat/GaussianSplat.h>
+#include <XCEngine/Resources/Material/Material.h>
+
+#include <memory>
+#include <string>
+
+namespace XCEngine {
+namespace Components {
+
+class GaussianSplatRendererComponent : public Component {
+public:
+    std::string GetName() const override { return "GaussianSplatRenderer"; }
+
+    Resources::GaussianSplat* GetGaussianSplat() const;
+    const Resources::ResourceHandle<Resources::GaussianSplat>& GetGaussianSplatHandle() const;
+    const std::string& GetGaussianSplatPath() const { return m_gaussianSplatPath; }
+    const Resources::AssetRef& GetGaussianSplatAssetRef() const { return m_gaussianSplatRef; }
+
+    void SetGaussianSplatPath(const std::string& gaussianSplatPath);
+    void SetGaussianSplat(const Resources::ResourceHandle<Resources::GaussianSplat>& gaussianSplat);
+    void SetGaussianSplat(Resources::GaussianSplat* gaussianSplat);
+    void ClearGaussianSplat();
+
+    Resources::Material* GetMaterial() const;
+    const Resources::ResourceHandle<Resources::Material>& GetMaterialHandle() const;
+    const std::string& GetMaterialPath() const { return m_materialPath; }
+    const Resources::AssetRef& GetMaterialAssetRef() const { return m_materialRef; }
+
+    void SetMaterialPath(const std::string& materialPath);
+    void SetMaterial(const Resources::ResourceHandle<Resources::Material>& material);
+    void SetMaterial(Resources::Material* material);
+    void ClearMaterial();
+
+    bool GetCastShadows() const { return m_castShadows; }
+    void SetCastShadows(bool value) { m_castShadows = value; }
+
+    bool GetReceiveShadows() const { return m_receiveShadows; }
+    void SetReceiveShadows(bool value) { m_receiveShadows = value; }
+
+    void Serialize(std::ostream& os) const override;
+    void Deserialize(std::istream& is) override;
+
+private:
+    struct PendingGaussianSplatLoadState;
+    struct PendingMaterialLoadState;
+
+    void BeginAsyncGaussianSplatLoad(const std::string& gaussianSplatPath);
+    void EnsureDeferredAsyncGaussianSplatLoadStarted();
+    void ResolvePendingGaussianSplat();
+
+    void BeginAsyncMaterialLoad(const std::string& materialPath);
+    void EnsureDeferredAsyncMaterialLoadStarted();
+    void ResolvePendingMaterial();
+
+    Resources::ResourceHandle<Resources::GaussianSplat> m_gaussianSplat;
+    std::string m_gaussianSplatPath;
+    Resources::AssetRef m_gaussianSplatRef;
+    std::shared_ptr<PendingGaussianSplatLoadState> m_pendingGaussianSplatLoad;
+    bool m_asyncGaussianSplatLoadRequested = false;
+
+    Resources::ResourceHandle<Resources::Material> m_material;
+    std::string m_materialPath;
+    Resources::AssetRef m_materialRef;
+    std::shared_ptr<PendingMaterialLoadState> m_pendingMaterialLoad;
+    bool m_asyncMaterialLoadRequested = false;
+
+    bool m_castShadows = true;
+    bool m_receiveShadows = true;
+};
+
+} // namespace Components
+} // namespace XCEngine

engine/include/XCEngine/Rendering/Extraction/RenderSceneExtractor.h

@@ -42,6 +42,7 @@ private:
         const Math::Vector3& cameraPosition,
         uint32_t cullingMask,
         std::vector<VisibleRenderItem>& outVisibleItems,
+        std::vector<VisibleGaussianSplatItem>& outVisibleGaussianSplats,
         std::vector<VisibleVolumeItem>& outVisibleVolumes) const;
 };
 

engine/include/XCEngine/Rendering/Extraction/RenderSceneUtility.h

@@ -2,6 +2,7 @@
 
 #include <XCEngine/Core/Math/Vector3.h>
 #include <XCEngine/Rendering/FrameData/RenderCameraData.h>
+#include <XCEngine/Rendering/FrameData/VisibleGaussianSplatItem.h>
 #include <XCEngine/Rendering/FrameData/VisibleRenderItem.h>
 #include <XCEngine/Rendering/FrameData/VisibleVolumeItem.h>
 
@@ -33,10 +34,19 @@ void AppendVisibleVolumesForGameObject(
     const Math::Vector3& cameraPosition,
     std::vector<VisibleVolumeItem>& outVisibleVolumes);
 
+void AppendVisibleGaussianSplatsForGameObject(
+    Components::GameObject& gameObject,
+    const Math::Vector3& cameraPosition,
+    std::vector<VisibleGaussianSplatItem>& outVisibleGaussianSplats);
+
 bool CompareVisibleRenderItemsStable(
     const VisibleRenderItem& lhs,
     const VisibleRenderItem& rhs);
 
+bool CompareVisibleGaussianSplatsStable(
+    const VisibleGaussianSplatItem& lhs,
+    const VisibleGaussianSplatItem& rhs);
+
 bool CompareVisibleVolumesStable(
     const VisibleVolumeItem& lhs,
     const VisibleVolumeItem& rhs);

engine/include/XCEngine/Rendering/FrameData/RenderSceneData.h

@@ -4,6 +4,7 @@
 #include <XCEngine/Core/Math/Vector4.h>
 #include <XCEngine/Rendering/FrameData/RenderCameraData.h>
 #include <XCEngine/Rendering/FrameData/RenderEnvironmentData.h>
+#include <XCEngine/Rendering/FrameData/VisibleGaussianSplatItem.h>
 #include <XCEngine/Rendering/FrameData/VisibleRenderItem.h>
 #include <XCEngine/Rendering/FrameData/VisibleVolumeItem.h>
 #include <XCEngine/Resources/Shader/ShaderKeywordTypes.h>
@@ -88,6 +89,7 @@ struct RenderSceneData {
     RenderLightingData lighting;
     Resources::ShaderKeywordSet globalShaderKeywords;
     std::vector<VisibleRenderItem> visibleItems;
+    std::vector<VisibleGaussianSplatItem> visibleGaussianSplats;
     std::vector<VisibleVolumeItem> visibleVolumes;
 
     bool HasCamera() const {

engine/include/XCEngine/Rendering/FrameData/VisibleGaussianSplatItem.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <XCEngine/Core/Math/Matrix4.h>
+#include <XCEngine/Core/Types.h>
+
+namespace XCEngine {
+namespace Components {
+class GameObject;
+class GaussianSplatRendererComponent;
+} // namespace Components
+
+namespace Resources {
+class GaussianSplat;
+class Material;
+} // namespace Resources
+
+namespace Rendering {
+
+struct VisibleGaussianSplatItem {
+    Components::GameObject* gameObject = nullptr;
+    Components::GaussianSplatRendererComponent* gaussianSplatRenderer = nullptr;
+    Resources::GaussianSplat* gaussianSplat = nullptr;
+    const Resources::Material* material = nullptr;
+    Core::int32 renderQueue = 0;
+    float cameraDistanceSq = 0.0f;
+    Math::Matrix4x4 localToWorld = Math::Matrix4x4::Identity();
+};
+
+} // namespace Rendering
+} // namespace XCEngine

engine/src/Components/ComponentFactoryRegistry.cpp

@@ -3,6 +3,7 @@
 #include "Components/AudioListenerComponent.h"
 #include "Components/AudioSourceComponent.h"
 #include "Components/CameraComponent.h"
+#include "Components/GaussianSplatRendererComponent.h"
 #include "Components/GameObject.h"
 #include "Components/LightComponent.h"
 #include "Components/MeshFilterComponent.h"
@@ -34,6 +35,7 @@ ComponentFactoryRegistry::ComponentFactoryRegistry() {
     RegisterFactory("AudioListener", &CreateBuiltInComponent<AudioListenerComponent>);
     RegisterFactory("MeshFilter", &CreateBuiltInComponent<MeshFilterComponent>);
     RegisterFactory("MeshRenderer", &CreateBuiltInComponent<MeshRendererComponent>);
+    RegisterFactory("GaussianSplatRenderer", &CreateBuiltInComponent<GaussianSplatRendererComponent>);
     RegisterFactory("VolumeRenderer", &CreateBuiltInComponent<VolumeRendererComponent>);
     RegisterFactory("ScriptComponent", &CreateBuiltInComponent<XCEngine::Scripting::ScriptComponent>);
 }

engine/src/Components/GaussianSplatRendererComponent.cpp

@@ -0,0 +1,420 @@
+#include "Components/GaussianSplatRendererComponent.h"
+
+#include "Core/Asset/ResourceManager.h"
+
+namespace XCEngine {
+namespace Components {
+
+namespace {
+
+std::string ToStdString(const Containers::String& value) {
+    return std::string(value.CStr());
+}
+
+bool HasVirtualPathScheme(const std::string& path) {
+    return path.find("://") != std::string::npos;
+}
+
+std::string EncodeAssetRef(const Resources::AssetRef& assetRef) {
+    if (!assetRef.IsValid()) {
+        return std::string();
+    }
+
+    return ToStdString(assetRef.assetGuid.ToString()) + "," +
+           std::to_string(assetRef.localID) + "," +
+           std::to_string(static_cast<int>(assetRef.resourceType));
+}
+
+bool TryDecodeAssetRef(const std::string& value, Resources::AssetRef& outRef) {
+    const size_t firstComma = value.find(',');
+    const size_t secondComma = firstComma == std::string::npos ? std::string::npos : value.find(',', firstComma + 1);
+    if (firstComma == std::string::npos || secondComma == std::string::npos) {
+        return false;
+    }
+
+    const Containers::String guidText(value.substr(0, firstComma).c_str());
+    outRef.assetGuid = Resources::AssetGUID::ParseOrDefault(guidText);
+    outRef.localID = static_cast<Resources::LocalID>(std::stoull(value.substr(firstComma + 1, secondComma - firstComma - 1)));
+    outRef.resourceType = static_cast<Resources::ResourceType>(std::stoi(value.substr(secondComma + 1)));
+    return outRef.IsValid();
+}
+
+std::string GaussianSplatPathFromHandle(const Resources::ResourceHandle<Resources::GaussianSplat>& gaussianSplat) {
+    return gaussianSplat.Get() != nullptr ? ToStdString(gaussianSplat->GetPath()) : std::string();
+}
+
+std::string MaterialPathFromHandle(const Resources::ResourceHandle<Resources::Material>& material) {
+    return material.Get() != nullptr ? ToStdString(material->GetPath()) : std::string();
+}
+
+} // namespace
+
+struct GaussianSplatRendererComponent::PendingGaussianSplatLoadState {
+    Resources::LoadResult result;
+    bool completed = false;
+};
+
+struct GaussianSplatRendererComponent::PendingMaterialLoadState {
+    Resources::LoadResult result;
+    bool completed = false;
+};
+
+Resources::GaussianSplat* GaussianSplatRendererComponent::GetGaussianSplat() const {
+    const_cast<GaussianSplatRendererComponent*>(this)->EnsureDeferredAsyncGaussianSplatLoadStarted();
+    const_cast<GaussianSplatRendererComponent*>(this)->ResolvePendingGaussianSplat();
+    return m_gaussianSplat.Get();
+}
+
+const Resources::ResourceHandle<Resources::GaussianSplat>& GaussianSplatRendererComponent::GetGaussianSplatHandle() const {
+    const_cast<GaussianSplatRendererComponent*>(this)->EnsureDeferredAsyncGaussianSplatLoadStarted();
+    const_cast<GaussianSplatRendererComponent*>(this)->ResolvePendingGaussianSplat();
+    return m_gaussianSplat;
+}
+
+void GaussianSplatRendererComponent::SetGaussianSplatPath(const std::string& gaussianSplatPath) {
+    m_pendingGaussianSplatLoad.reset();
+    m_asyncGaussianSplatLoadRequested = false;
+    m_gaussianSplatPath = gaussianSplatPath;
+    if (m_gaussianSplatPath.empty()) {
+        m_gaussianSplat.Reset();
+        m_gaussianSplatRef.Reset();
+        return;
+    }
+
+    m_gaussianSplat = Resources::ResourceManager::Get().Load<Resources::GaussianSplat>(m_gaussianSplatPath.c_str());
+    if (!Resources::ResourceManager::Get().TryGetAssetRef(
+            m_gaussianSplatPath.c_str(),
+            Resources::ResourceType::GaussianSplat,
+            m_gaussianSplatRef)) {
+        m_gaussianSplatRef.Reset();
+    }
+}
+
+void GaussianSplatRendererComponent::SetGaussianSplat(
+    const Resources::ResourceHandle<Resources::GaussianSplat>& gaussianSplat) {
+    m_pendingGaussianSplatLoad.reset();
+    m_asyncGaussianSplatLoadRequested = false;
+    m_gaussianSplat = gaussianSplat;
+    m_gaussianSplatPath = GaussianSplatPathFromHandle(gaussianSplat);
+    if (m_gaussianSplatPath.empty() ||
+        !Resources::ResourceManager::Get().TryGetAssetRef(
+            m_gaussianSplatPath.c_str(),
+            Resources::ResourceType::GaussianSplat,
+            m_gaussianSplatRef)) {
+        m_gaussianSplatRef.Reset();
+    }
+}
+
+void GaussianSplatRendererComponent::SetGaussianSplat(Resources::GaussianSplat* gaussianSplat) {
+    SetGaussianSplat(Resources::ResourceHandle<Resources::GaussianSplat>(gaussianSplat));
+}
+
+void GaussianSplatRendererComponent::ClearGaussianSplat() {
+    m_pendingGaussianSplatLoad.reset();
+    m_asyncGaussianSplatLoadRequested = false;
+    m_gaussianSplat.Reset();
+    m_gaussianSplatPath.clear();
+    m_gaussianSplatRef.Reset();
+}
+
+Resources::Material* GaussianSplatRendererComponent::GetMaterial() const {
+    const_cast<GaussianSplatRendererComponent*>(this)->EnsureDeferredAsyncMaterialLoadStarted();
+    const_cast<GaussianSplatRendererComponent*>(this)->ResolvePendingMaterial();
+    return m_material.Get();
+}
+
+const Resources::ResourceHandle<Resources::Material>& GaussianSplatRendererComponent::GetMaterialHandle() const {
+    const_cast<GaussianSplatRendererComponent*>(this)->EnsureDeferredAsyncMaterialLoadStarted();
+    const_cast<GaussianSplatRendererComponent*>(this)->ResolvePendingMaterial();
+    return m_material;
+}
+
+void GaussianSplatRendererComponent::SetMaterialPath(const std::string& materialPath) {
+    m_pendingMaterialLoad.reset();
+    m_asyncMaterialLoadRequested = false;
+    m_materialPath = materialPath;
+    if (m_materialPath.empty()) {
+        m_material.Reset();
+        m_materialRef.Reset();
+        return;
+    }
+
+    m_material = Resources::ResourceManager::Get().Load<Resources::Material>(m_materialPath.c_str());
+    if (!Resources::ResourceManager::Get().TryGetAssetRef(
+            m_materialPath.c_str(),
+            Resources::ResourceType::Material,
+            m_materialRef)) {
+        m_materialRef.Reset();
+    }
+}
+
+void GaussianSplatRendererComponent::SetMaterial(
+    const Resources::ResourceHandle<Resources::Material>& material) {
+    m_pendingMaterialLoad.reset();
+    m_asyncMaterialLoadRequested = false;
+    m_material = material;
+    m_materialPath = MaterialPathFromHandle(material);
+    if (m_materialPath.empty() ||
+        !Resources::ResourceManager::Get().TryGetAssetRef(
+            m_materialPath.c_str(),
+            Resources::ResourceType::Material,
+            m_materialRef)) {
+        m_materialRef.Reset();
+    }
+}
+
+void GaussianSplatRendererComponent::SetMaterial(Resources::Material* material) {
+    SetMaterial(Resources::ResourceHandle<Resources::Material>(material));
+}
+
+void GaussianSplatRendererComponent::ClearMaterial() {
+    m_pendingMaterialLoad.reset();
+    m_asyncMaterialLoadRequested = false;
+    m_material.Reset();
+    m_materialPath.clear();
+    m_materialRef.Reset();
+}
+
+void GaussianSplatRendererComponent::Serialize(std::ostream& os) const {
+    Resources::AssetRef gaussianSplatRef = m_gaussianSplatRef;
+    if (!gaussianSplatRef.IsValid() &&
+        !m_gaussianSplatPath.empty() &&
+        !HasVirtualPathScheme(m_gaussianSplatPath) &&
+        Resources::ResourceManager::Get().TryGetAssetRef(
+            m_gaussianSplatPath.c_str(),
+            Resources::ResourceType::GaussianSplat,
+            gaussianSplatRef)) {
+    }
+
+    Resources::AssetRef materialRef = m_materialRef;
+    if (!materialRef.IsValid() &&
+        !m_materialPath.empty() &&
+        !HasVirtualPathScheme(m_materialPath) &&
+        Resources::ResourceManager::Get().TryGetAssetRef(
+            m_materialPath.c_str(),
+            Resources::ResourceType::Material,
+            materialRef)) {
+    }
+
+    os << "gaussianSplatRef=" << EncodeAssetRef(gaussianSplatRef) << ";";
+    if (!gaussianSplatRef.IsValid() && !m_gaussianSplatPath.empty() && HasVirtualPathScheme(m_gaussianSplatPath)) {
+        os << "gaussianSplatPath=" << m_gaussianSplatPath << ";";
+    }
+
+    os << "materialRef=" << EncodeAssetRef(materialRef) << ";";
+    if (!materialRef.IsValid() && !m_materialPath.empty() && HasVirtualPathScheme(m_materialPath)) {
+        os << "materialPath=" << m_materialPath << ";";
+    }
+
+    os << "castShadows=" << (m_castShadows ? 1 : 0) << ";";
+    os << "receiveShadows=" << (m_receiveShadows ? 1 : 0) << ";";
+}
+
+void GaussianSplatRendererComponent::Deserialize(std::istream& is) {
+    ClearGaussianSplat();
+    ClearMaterial();
+    m_castShadows = true;
+    m_receiveShadows = true;
+
+    std::string token;
+    std::string pendingGaussianSplatPath;
+    Resources::AssetRef pendingGaussianSplatRef;
+    std::string pendingMaterialPath;
+    Resources::AssetRef pendingMaterialRef;
+    while (std::getline(is, token, ';')) {
+        if (token.empty()) {
+            continue;
+        }
+
+        const size_t eqPos = token.find('=');
+        if (eqPos == std::string::npos) {
+            continue;
+        }
+
+        const std::string key = token.substr(0, eqPos);
+        const std::string value = token.substr(eqPos + 1);
+
+        if (key == "gaussianSplatPath") {
+            pendingGaussianSplatPath = value;
+        } else if (key == "gaussianSplatRef") {
+            TryDecodeAssetRef(value, pendingGaussianSplatRef);
+        } else if (key == "materialPath") {
+            pendingMaterialPath = value;
+        } else if (key == "materialRef") {
+            TryDecodeAssetRef(value, pendingMaterialRef);
+        } else if (key == "castShadows") {
+            m_castShadows = (std::stoi(value) != 0);
+        } else if (key == "receiveShadows") {
+            m_receiveShadows = (std::stoi(value) != 0);
+        }
+    }
+
+    if (pendingGaussianSplatRef.IsValid()) {
+        bool restoredOrQueued = false;
+        m_gaussianSplatRef = pendingGaussianSplatRef;
+        if (Resources::ResourceManager::Get().IsDeferredSceneLoadEnabled()) {
+            Containers::String resolvedPath;
+            if (Resources::ResourceManager::Get().TryResolveAssetPath(pendingGaussianSplatRef, resolvedPath)) {
+                m_gaussianSplatPath = ToStdString(resolvedPath);
+                restoredOrQueued = true;
+            }
+        }
+
+        if (!restoredOrQueued) {
+            m_gaussianSplat = Resources::ResourceManager::Get().Load<Resources::GaussianSplat>(pendingGaussianSplatRef);
+            m_gaussianSplatPath = m_gaussianSplat.Get() != nullptr
+                ? GaussianSplatPathFromHandle(m_gaussianSplat)
+                : pendingGaussianSplatPath;
+        }
+    } else if (!pendingGaussianSplatPath.empty() && HasVirtualPathScheme(pendingGaussianSplatPath)) {
+        if (Resources::ResourceManager::Get().IsDeferredSceneLoadEnabled()) {
+            m_gaussianSplatPath = pendingGaussianSplatPath;
+        } else {
+            SetGaussianSplatPath(pendingGaussianSplatPath);
+        }
+    }
+
+    if (pendingMaterialRef.IsValid()) {
+        bool restoredOrQueued = false;
+        m_materialRef = pendingMaterialRef;
+        if (Resources::ResourceManager::Get().IsDeferredSceneLoadEnabled()) {
+            Containers::String resolvedPath;
+            if (Resources::ResourceManager::Get().TryResolveAssetPath(pendingMaterialRef, resolvedPath)) {
+                m_materialPath = ToStdString(resolvedPath);
+                restoredOrQueued = true;
+            }
+        }
+
+        if (!restoredOrQueued) {
+            m_material = Resources::ResourceManager::Get().Load<Resources::Material>(pendingMaterialRef);
+            m_materialPath = m_material.Get() != nullptr
+                ? MaterialPathFromHandle(m_material)
+                : pendingMaterialPath;
+        }
+    } else if (!pendingMaterialPath.empty() && HasVirtualPathScheme(pendingMaterialPath)) {
+        if (Resources::ResourceManager::Get().IsDeferredSceneLoadEnabled()) {
+            m_materialPath = pendingMaterialPath;
+        } else {
+            SetMaterialPath(pendingMaterialPath);
+        }
+    }
+}
+
+void GaussianSplatRendererComponent::BeginAsyncGaussianSplatLoad(const std::string& gaussianSplatPath) {
+    if (gaussianSplatPath.empty()) {
+        m_pendingGaussianSplatLoad.reset();
+        m_asyncGaussianSplatLoadRequested = false;
+        m_gaussianSplat.Reset();
+        return;
+    }
+
+    m_asyncGaussianSplatLoadRequested = true;
+    m_gaussianSplat.Reset();
+    m_pendingGaussianSplatLoad = std::make_shared<PendingGaussianSplatLoadState>();
+    std::weak_ptr<PendingGaussianSplatLoadState> weakState = m_pendingGaussianSplatLoad;
+    Resources::ResourceManager::Get().LoadAsync(
+        gaussianSplatPath.c_str(),
+        Resources::ResourceType::GaussianSplat,
+        [weakState](Resources::LoadResult result) {
+            if (std::shared_ptr<PendingGaussianSplatLoadState> state = weakState.lock()) {
+                state->result = std::move(result);
+                state->completed = true;
+            }
+        });
+}
+
+void GaussianSplatRendererComponent::EnsureDeferredAsyncGaussianSplatLoadStarted() {
+    if (m_asyncGaussianSplatLoadRequested || m_gaussianSplat.Get() != nullptr || m_gaussianSplatPath.empty()) {
+        return;
+    }
+
+    BeginAsyncGaussianSplatLoad(m_gaussianSplatPath);
+}
+
+void GaussianSplatRendererComponent::ResolvePendingGaussianSplat() {
+    if (!m_pendingGaussianSplatLoad || !m_pendingGaussianSplatLoad->completed) {
+        return;
+    }
+
+    std::shared_ptr<PendingGaussianSplatLoadState> completedLoad = std::move(m_pendingGaussianSplatLoad);
+    m_pendingGaussianSplatLoad.reset();
+
+    if (!completedLoad->result || completedLoad->result.resource == nullptr) {
+        return;
+    }
+
+    m_gaussianSplat = Resources::ResourceHandle<Resources::GaussianSplat>(
+        static_cast<Resources::GaussianSplat*>(completedLoad->result.resource));
+    if (m_gaussianSplat.Get() == nullptr) {
+        return;
+    }
+
+    m_gaussianSplatPath = GaussianSplatPathFromHandle(m_gaussianSplat);
+    if (!Resources::ResourceManager::Get().TryGetAssetRef(
+            m_gaussianSplatPath.c_str(),
+            Resources::ResourceType::GaussianSplat,
+            m_gaussianSplatRef)) {
+        m_gaussianSplatRef.Reset();
+    }
+}
+
+void GaussianSplatRendererComponent::BeginAsyncMaterialLoad(const std::string& materialPath) {
+    if (materialPath.empty()) {
+        m_pendingMaterialLoad.reset();
+        m_asyncMaterialLoadRequested = false;
+        m_material.Reset();
+        return;
+    }
+
+    m_asyncMaterialLoadRequested = true;
+    m_material.Reset();
+    m_pendingMaterialLoad = std::make_shared<PendingMaterialLoadState>();
+    std::weak_ptr<PendingMaterialLoadState> weakState = m_pendingMaterialLoad;
+    Resources::ResourceManager::Get().LoadAsync(
+        materialPath.c_str(),
+        Resources::ResourceType::Material,
+        [weakState](Resources::LoadResult result) {
+            if (std::shared_ptr<PendingMaterialLoadState> state = weakState.lock()) {
+                state->result = std::move(result);
+                state->completed = true;
+            }
+        });
+}
+
+void GaussianSplatRendererComponent::EnsureDeferredAsyncMaterialLoadStarted() {
+    if (m_asyncMaterialLoadRequested || m_material.Get() != nullptr || m_materialPath.empty()) {
+        return;
+    }
+
+    BeginAsyncMaterialLoad(m_materialPath);
+}
+
+void GaussianSplatRendererComponent::ResolvePendingMaterial() {
+    if (!m_pendingMaterialLoad || !m_pendingMaterialLoad->completed) {
+        return;
+    }
+
+    std::shared_ptr<PendingMaterialLoadState> completedLoad = std::move(m_pendingMaterialLoad);
+    m_pendingMaterialLoad.reset();
+
+    if (!completedLoad->result || completedLoad->result.resource == nullptr) {
+        return;
+    }
+
+    m_material = Resources::ResourceHandle<Resources::Material>(
+        static_cast<Resources::Material*>(completedLoad->result.resource));
+    if (m_material.Get() == nullptr) {
+        return;
+    }
+
+    m_materialPath = MaterialPathFromHandle(m_material);
+    if (!Resources::ResourceManager::Get().TryGetAssetRef(
+            m_materialPath.c_str(),
+            Resources::ResourceType::Material,
+            m_materialRef)) {
+        m_materialRef.Reset();
+    }
+}
+
+} // namespace Components
+} // namespace XCEngine

engine/src/Rendering/Extraction/RenderSceneExtractor.cpp

@@ -119,6 +119,12 @@ bool CompareVisibleVolumes(const VisibleVolumeItem& lhs, const VisibleVolumeItem
     return CompareVisibleVolumesStable(lhs, rhs);
 }
 
+bool CompareVisibleGaussianSplats(
+    const VisibleGaussianSplatItem& lhs,
+    const VisibleGaussianSplatItem& rhs) {
+    return CompareVisibleGaussianSplatsStable(lhs, rhs);
+}
+
 } // namespace
 
 RenderSceneData RenderSceneExtractor::Extract(
@@ -143,6 +149,7 @@ RenderSceneData RenderSceneExtractor::Extract(
             cameraPosition,
             cullingMask,
             sceneData.visibleItems,
+            sceneData.visibleGaussianSplats,
             sceneData.visibleVolumes);
     }
 
@@ -150,6 +157,10 @@ RenderSceneData RenderSceneExtractor::Extract(
         sceneData.visibleItems.begin(),
         sceneData.visibleItems.end(),
         CompareVisibleItems);
+    std::stable_sort(
+        sceneData.visibleGaussianSplats.begin(),
+        sceneData.visibleGaussianSplats.end(),
+        CompareVisibleGaussianSplats);
     std::stable_sort(
         sceneData.visibleVolumes.begin(),
         sceneData.visibleVolumes.end(),
@@ -181,6 +192,7 @@ RenderSceneData RenderSceneExtractor::ExtractForCamera(
             cameraPosition,
             cullingMask,
             sceneData.visibleItems,
+            sceneData.visibleGaussianSplats,
             sceneData.visibleVolumes);
     }
 
@@ -188,6 +200,10 @@ RenderSceneData RenderSceneExtractor::ExtractForCamera(
         sceneData.visibleItems.begin(),
         sceneData.visibleItems.end(),
         CompareVisibleItems);
+    std::stable_sort(
+        sceneData.visibleGaussianSplats.begin(),
+        sceneData.visibleGaussianSplats.end(),
+        CompareVisibleGaussianSplats);
     std::stable_sort(
         sceneData.visibleVolumes.begin(),
         sceneData.visibleVolumes.end(),
@@ -308,6 +324,7 @@ void RenderSceneExtractor::ExtractVisibleContent(
     const Math::Vector3& cameraPosition,
     uint32_t cullingMask,
     std::vector<VisibleRenderItem>& visibleItems,
+    std::vector<VisibleGaussianSplatItem>& visibleGaussianSplats,
     std::vector<VisibleVolumeItem>& visibleVolumes) const {
     if (gameObject == nullptr || !gameObject->IsActiveInHierarchy()) {
         return;
@@ -318,11 +335,12 @@ void RenderSceneExtractor::ExtractVisibleContent(
 
     if (isVisibleInCameraMask) {
         AppendRenderItemsForGameObject(*gameObject, cameraPosition, visibleItems);
+        AppendVisibleGaussianSplatsForGameObject(*gameObject, cameraPosition, visibleGaussianSplats);
         AppendVisibleVolumesForGameObject(*gameObject, cameraPosition, visibleVolumes);
     }
 
     for (Components::GameObject* child : gameObject->GetChildren()) {
-        ExtractVisibleContent(child, cameraPosition, cullingMask, visibleItems, visibleVolumes);
+        ExtractVisibleContent(child, cameraPosition, cullingMask, visibleItems, visibleGaussianSplats, visibleVolumes);
     }
 }
 

engine/src/Rendering/Extraction/RenderSceneUtility.cpp

@@ -1,6 +1,7 @@
 #include "Rendering/Extraction/RenderSceneUtility.h"
 
 #include "Components/CameraComponent.h"
+#include "Components/GaussianSplatRendererComponent.h"
 #include "Components/GameObject.h"
 #include "Components/LightComponent.h"
 #include "Components/MeshFilterComponent.h"
@@ -175,6 +176,41 @@ void AppendVisibleVolumesForGameObject(
     outVisibleVolumes.push_back(visibleVolume);
 }
 
+void AppendVisibleGaussianSplatsForGameObject(
+    Components::GameObject& gameObject,
+    const Math::Vector3& cameraPosition,
+    std::vector<VisibleGaussianSplatItem>& outVisibleGaussianSplats) {
+    if (!gameObject.IsActiveInHierarchy()) {
+        return;
+    }
+
+    auto* gaussianSplatRenderer = gameObject.GetComponent<Components::GaussianSplatRendererComponent>();
+    if (gaussianSplatRenderer == nullptr || !gaussianSplatRenderer->IsEnabled()) {
+        return;
+    }
+
+    Resources::GaussianSplat* gaussianSplat = gaussianSplatRenderer->GetGaussianSplat();
+    Resources::Material* material = gaussianSplatRenderer->GetMaterial();
+    if (gaussianSplat == nullptr ||
+        !gaussianSplat->IsValid() ||
+        material == nullptr) {
+        return;
+    }
+
+    const Math::Matrix4x4 localToWorld = gameObject.GetTransform()->GetLocalToWorldMatrix();
+    const Math::Vector3 worldPosition = localToWorld.GetTranslation();
+
+    VisibleGaussianSplatItem visibleGaussianSplat = {};
+    visibleGaussianSplat.gameObject = &gameObject;
+    visibleGaussianSplat.gaussianSplatRenderer = gaussianSplatRenderer;
+    visibleGaussianSplat.gaussianSplat = gaussianSplat;
+    visibleGaussianSplat.material = material;
+    visibleGaussianSplat.renderQueue = ResolveMaterialRenderQueue(material);
+    visibleGaussianSplat.cameraDistanceSq = (worldPosition - cameraPosition).SqrMagnitude();
+    visibleGaussianSplat.localToWorld = localToWorld;
+    outVisibleGaussianSplats.push_back(visibleGaussianSplat);
+}
+
 bool CompareVisibleRenderItemsStable(
     const VisibleRenderItem& lhs,
     const VisibleRenderItem& rhs) {
@@ -210,6 +246,29 @@ bool CompareVisibleRenderItemsStable(
     return false;
 }
 
+bool CompareVisibleGaussianSplatsStable(
+    const VisibleGaussianSplatItem& lhs,
+    const VisibleGaussianSplatItem& rhs) {
+    if (lhs.renderQueue != rhs.renderQueue) {
+        return lhs.renderQueue < rhs.renderQueue;
+    }
+
+    const bool isTransparentQueue = IsTransparentRenderQueue(lhs.renderQueue);
+    if (lhs.cameraDistanceSq != rhs.cameraDistanceSq) {
+        return isTransparentQueue
+            ? lhs.cameraDistanceSq > rhs.cameraDistanceSq
+            : lhs.cameraDistanceSq < rhs.cameraDistanceSq;
+    }
+
+    const Core::uint64 lhsObjectId = lhs.gameObject != nullptr ? lhs.gameObject->GetID() : 0u;
+    const Core::uint64 rhsObjectId = rhs.gameObject != nullptr ? rhs.gameObject->GetID() : 0u;
+    if (lhsObjectId != rhsObjectId) {
+        return lhsObjectId < rhsObjectId;
+    }
+
+    return false;
+}
+
 bool CompareVisibleVolumesStable(
     const VisibleVolumeItem& lhs,
     const VisibleVolumeItem& rhs) {