diff --git a/CMakeLists.txt b/CMakeLists.txt
index d3604cb1..b9fbf462 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,4 +5,5 @@ set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 add_subdirectory(engine)
-add_subdirectory(tests/D3D12)
+add_subdirectory(tests)
+add_subdirectory(tests/OpenGL)
diff --git a/engine/include/XCEngine/RHI/D3D12/D3D12DescriptorHeap.h b/engine/include/XCEngine/RHI/D3D12/D3D12DescriptorHeap.h
index 519cf422..9d6c9f77 100644
--- a/engine/include/XCEngine/RHI/D3D12/D3D12DescriptorHeap.h
+++ b/engine/include/XCEngine/RHI/D3D12/D3D12DescriptorHeap.h
@@ -28,11 +28,7 @@ public:
     uint32_t GetDescriptorCount() const override;
     DescriptorType GetType() const override;
 
-    D3D12_CPU_DESCRIPTOR_HANDLE GetCPUDescriptorHandle(uint32_t index) const;
-    D3D12_GPU_DESCRIPTOR_HANDLE GetGPUDescriptorHandle(uint32_t index) const;
-
     uint32_t GetDescriptorSize() const { return m_descriptorSize; }
-
     D3D12_CPU_DESCRIPTOR_HANDLE GetCPUDescriptorHandleForHeapStart() const;
     D3D12_GPU_DESCRIPTOR_HANDLE GetGPUDescriptorHandleForHeapStart() const;
 
diff --git a/engine/include/XCEngine/RHI/D3D12/D3D12Shader.h b/engine/include/XCEngine/RHI/D3D12/D3D12Shader.h
index 733f2211..549479af 100644
--- a/engine/include/XCEngine/RHI/D3D12/D3D12Shader.h
+++ b/engine/include/XCEngine/RHI/D3D12/D3D12Shader.h
@@ -1,9 +1,11 @@
 #pragma once
 
 #include <d3d12.h>
+#include <dxgi1_4.h>
 #include <wrl/client.h>
 #include <string>
 
+#include "../SwapChain.h"
 #include "D3D12Enum.h"
 
 using Microsoft::WRL::ComPtr;
@@ -11,7 +13,7 @@ using Microsoft::WRL::ComPtr;
 namespace XCEngine {
 namespace RHI {
 
-class D3D12Shader {
+class D3D12Shader : public IShader {
 public:
     D3D12Shader();
     ~D3D12Shader();
@@ -20,13 +22,17 @@ public:
     bool Compile(const void* sourceData, size_t sourceSize, const char* entryPoint, const char* target);
     void Shutdown();
 
-    const D3D12_SHADER_BYTECODE GetBytecode() const;
-    ShaderType GetType() const { return m_type; }
+    const D3D12_SHADER_BYTECODE GetD3D12Bytecode() const;
+    virtual const void* GetBytecode() const override;
+    virtual size_t GetBytecodeSize() const override;
+    virtual ShaderType GetType() const override;
+    virtual const InputLayoutDesc& GetInputLayout() const override;
 
 private:
     ComPtr<ID3DBlob> m_bytecode;
     ComPtr<ID3DBlob> m_error;
     ShaderType m_type;
+    InputLayoutDesc m_inputLayout;
 };
 
 } // namespace RHI
diff --git a/engine/include/XCEngine/RHI/D3D12/D3D12SwapChain.h b/engine/include/XCEngine/RHI/D3D12/D3D12SwapChain.h
index bd91e43b..24bb6c09 100644
--- a/engine/include/XCEngine/RHI/D3D12/D3D12SwapChain.h
+++ b/engine/include/XCEngine/RHI/D3D12/D3D12SwapChain.h
@@ -4,15 +4,16 @@
 #include <dxgi1_4.h>
 #include <wrl/client.h>
 
-#include "../Enums.h"
+#include "../SwapChain.h"
 #include "D3D12Enum.h"
+#include "D3D12Texture.h"
 
 using Microsoft::WRL::ComPtr;
 
 namespace XCEngine {
 namespace RHI {
 
-class D3D12SwapChain {
+class D3D12SwapChain : public ISwapChain {
 public:
     D3D12SwapChain();
     ~D3D12SwapChain();
@@ -21,10 +22,13 @@ public:
     bool Initialize(IDXGISwapChain* swapChain, uint32_t width, uint32_t height);
     void Shutdown();
 
-    uint32_t GetCurrentBackBufferIndex() const;
-    ID3D12Resource* GetBackBuffer(uint32_t index) const;
-    void Present(uint32_t syncInterval, uint32_t flags);
-    void Resize(uint32_t width, uint32_t height);
+    uint32_t GetCurrentBackBufferIndex() const override;
+    IResource* GetBackBuffer(uint32_t index) const override;
+    void Present(uint32_t syncInterval, uint32_t flags) override;
+    void Resize(uint32_t width, uint32_t height) override;
+    void SetFullscreen(bool fullscreen) override;
+    bool IsFullscreen() const override;
+    void* GetNativeHandle() const override;
 
     IDXGISwapChain3* GetSwapChain() const { return m_swapChain.Get(); }
 
@@ -35,6 +39,7 @@ private:
     uint32_t m_width;
     uint32_t m_height;
     uint32_t m_bufferCount;
+    std::vector<D3D12Texture> m_backBuffers;
 };
 
 } // namespace RHI
diff --git a/engine/include/XCEngine/RHI/SwapChain.h b/engine/include/XCEngine/RHI/SwapChain.h
index 00d6fb4e..dbf6b1de 100644
--- a/engine/include/XCEngine/RHI/SwapChain.h
+++ b/engine/include/XCEngine/RHI/SwapChain.h
@@ -11,8 +11,8 @@ class ISwapChain {
 public:
     virtual ~ISwapChain() = default;
     
-    virtual uint32_t GetCurrentBackBufferIndex() = 0;
-    virtual IResource* GetBackBuffer(uint32_t index) = 0;
+    virtual uint32_t GetCurrentBackBufferIndex() const = 0;
+    virtual IResource* GetBackBuffer(uint32_t index) const = 0;
     virtual void Present(uint32_t syncInterval, uint32_t flags) = 0;
     virtual void Resize(uint32_t width, uint32_t height) = 0;
     virtual void SetFullscreen(bool fullscreen) = 0;
diff --git a/engine/src/RHI/D3D12/D3D12DescriptorHeap.cpp b/engine/src/RHI/D3D12/D3D12DescriptorHeap.cpp
index 2aa9efa4..201f7d39 100644
--- a/engine/src/RHI/D3D12/D3D12DescriptorHeap.cpp
+++ b/engine/src/RHI/D3D12/D3D12DescriptorHeap.cpp
@@ -38,18 +38,6 @@ void D3D12DescriptorHeap::Shutdown() {
     m_descriptorHeap.Reset();
 }
 
-D3D12_CPU_DESCRIPTOR_HANDLE D3D12DescriptorHeap::GetCPUDescriptorHandle(uint32_t index) const {
-    D3D12_CPU_DESCRIPTOR_HANDLE handle = m_descriptorHeap->GetCPUDescriptorHandleForHeapStart();
-    handle.ptr += index * m_descriptorSize;
-    return handle;
-}
-
-D3D12_GPU_DESCRIPTOR_HANDLE D3D12DescriptorHeap::GetGPUDescriptorHandle(uint32_t index) const {
-    D3D12_GPU_DESCRIPTOR_HANDLE handle = m_descriptorHeap->GetGPUDescriptorHandleForHeapStart();
-    handle.ptr += index * m_descriptorSize;
-    return handle;
-}
-
 D3D12_CPU_DESCRIPTOR_HANDLE D3D12DescriptorHeap::GetCPUDescriptorHandleForHeapStart() const {
     return m_descriptorHeap->GetCPUDescriptorHandleForHeapStart();
 }
@@ -59,15 +47,19 @@ D3D12_GPU_DESCRIPTOR_HANDLE D3D12DescriptorHeap::GetGPUDescriptorHandleForHeapSt
 }
 
 CPUDescriptorHandle D3D12DescriptorHeap::GetCPUDescriptorHandle(uint32_t index) {
-    CPUDescriptorHandle handle;
-    handle.ptr = GetCPUDescriptorHandle(index).ptr;
-    return handle;
+    D3D12_CPU_DESCRIPTOR_HANDLE handle = m_descriptorHeap->GetCPUDescriptorHandleForHeapStart();
+    handle.ptr += index * m_descriptorSize;
+    CPUDescriptorHandle result;
+    result.ptr = handle.ptr;
+    return result;
 }
 
 GPUDescriptorHandle D3D12DescriptorHeap::GetGPUDescriptorHandle(uint32_t index) {
-    GPUDescriptorHandle handle;
-    handle.ptr = GetGPUDescriptorHandle(index).ptr;
-    return handle;
+    D3D12_GPU_DESCRIPTOR_HANDLE handle = m_descriptorHeap->GetGPUDescriptorHandleForHeapStart();
+    handle.ptr += index * m_descriptorSize;
+    GPUDescriptorHandle result;
+    result.ptr = handle.ptr;
+    return result;
 }
 
 DescriptorType D3D12DescriptorHeap::GetType() const {
diff --git a/engine/src/RHI/D3D12/D3D12Shader.cpp b/engine/src/RHI/D3D12/D3D12Shader.cpp
index 1ff2dcff..150f1d62 100644
--- a/engine/src/RHI/D3D12/D3D12Shader.cpp
+++ b/engine/src/RHI/D3D12/D3D12Shader.cpp
@@ -57,7 +57,7 @@ void D3D12Shader::Shutdown() {
     m_error.Reset();
 }
 
-const D3D12_SHADER_BYTECODE D3D12Shader::GetBytecode() const {
+const D3D12_SHADER_BYTECODE D3D12Shader::GetD3D12Bytecode() const {
     D3D12_SHADER_BYTECODE bytecode = {};
     if (m_bytecode) {
         bytecode.pShaderBytecode = m_bytecode->GetBufferPointer();
@@ -66,5 +66,27 @@ const D3D12_SHADER_BYTECODE D3D12Shader::GetBytecode() const {
     return bytecode;
 }
 
+const void* D3D12Shader::GetBytecode() const {
+    if (m_bytecode) {
+        return m_bytecode->GetBufferPointer();
+    }
+    return nullptr;
+}
+
+size_t D3D12Shader::GetBytecodeSize() const {
+    if (m_bytecode) {
+        return m_bytecode->GetBufferSize();
+    }
+    return 0;
+}
+
+const InputLayoutDesc& D3D12Shader::GetInputLayout() const {
+    return m_inputLayout;
+}
+
+ShaderType D3D12Shader::GetType() const {
+    return m_type;
+}
+
 } // namespace RHI
 } // namespace XCEngine
diff --git a/engine/src/RHI/D3D12/D3D12SwapChain.cpp b/engine/src/RHI/D3D12/D3D12SwapChain.cpp
index e812daaf..6e502906 100644
--- a/engine/src/RHI/D3D12/D3D12SwapChain.cpp
+++ b/engine/src/RHI/D3D12/D3D12SwapChain.cpp
@@ -56,6 +56,13 @@ bool D3D12SwapChain::Initialize(IDXGISwapChain* swapChain, uint32_t width, uint3
     m_width = width;
     m_height = height;
 
+    m_backBuffers.resize(m_bufferCount);
+    for (uint32_t i = 0; i < m_bufferCount; ++i) {
+        ID3D12Resource* resource = nullptr;
+        m_swapChain->GetBuffer(i, IID_PPV_ARGS(&resource));
+        m_backBuffers[i].InitializeFromExisting(resource);
+    }
+
     return true;
 }
 
@@ -67,10 +74,11 @@ uint32_t D3D12SwapChain::GetCurrentBackBufferIndex() const {
     return m_swapChain->GetCurrentBackBufferIndex();
 }
 
-ID3D12Resource* D3D12SwapChain::GetBackBuffer(uint32_t index) const {
-    ID3D12Resource* resource = nullptr;
-    m_swapChain->GetBuffer(index, IID_PPV_ARGS(&resource));
-    return resource;
+IResource* D3D12SwapChain::GetBackBuffer(uint32_t index) const {
+    if (index < m_backBuffers.size()) {
+        return const_cast<D3D12Texture*>(&m_backBuffers[index]);
+    }
+    return nullptr;
 }
 
 void D3D12SwapChain::Present(uint32_t syncInterval, uint32_t flags) {
@@ -83,5 +91,19 @@ void D3D12SwapChain::Resize(uint32_t width, uint32_t height) {
     m_height = height;
 }
 
+void D3D12SwapChain::SetFullscreen(bool fullscreen) {
+    m_swapChain->SetFullscreenState(fullscreen, nullptr);
+}
+
+bool D3D12SwapChain::IsFullscreen() const {
+    BOOL fullscreen = FALSE;
+    m_swapChain->GetFullscreenState(&fullscreen, nullptr);
+    return fullscreen != FALSE;
+}
+
+void* D3D12SwapChain::GetNativeHandle() const {
+    return reinterpret_cast<void*>(m_swapChain.Get());
+}
+
 } // namespace RHI
 } // namespace XCEngine
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 093692ef..ff6e7831 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -27,12 +27,6 @@ FetchContent_MakeAvailable(googletest)
 
 enable_testing()
 
-# ============================================================
-# Engine Library
-# ============================================================
-
-add_subdirectory(../engine engine)
-
 # ============================================================
 # Test Subdirectories
 # ============================================================
diff --git a/tests/D3D12/main.cpp b/tests/D3D12/main.cpp
index 5d60dec9..71421902 100644
--- a/tests/D3D12/main.cpp
+++ b/tests/D3D12/main.cpp
@@ -577,7 +577,7 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine
 	gVertexShader.CompileFromFile(L"Res/Shader/gs.hlsl", "MainVS", "vs_5_1");
 	gGeometryShader.CompileFromFile(L"Res/Shader/gs.hlsl", "MainGS", "gs_5_1");
 	gPixelShader.CompileFromFile(L"Res/Shader/gs.hlsl", "MainPS", "ps_5_1");
-	ID3D12PipelineState* pso = CreatePSO(rootSignature, gVertexShader.GetBytecode(), gPixelShader.GetBytecode(), gGeometryShader.GetBytecode());
+	ID3D12PipelineState* pso = CreatePSO(rootSignature, gVertexShader.GetD3D12Bytecode(), gPixelShader.GetD3D12Bytecode(), gGeometryShader.GetD3D12Bytecode());
 
 	gConstantBuffer.Initialize(gD3D12Device.GetDevice(), 65536, D3D12_RESOURCE_STATE_GENERIC_READ, D3D12_HEAP_TYPE_UPLOAD);
 	DirectX::XMMATRIX projectionMatrix = DirectX::XMMatrixPerspectiveFovLH(