add constent buffer for rotation

StudyDx/App.cpp

@@ -25,6 +25,6 @@ void App::DoFrame()
 {
 	const float c = sin(timer.Peek()) / 2.0f + 0.5f;
 	wnd.Gfx().ClearBuffer(c, c, 1.0f);
-	wnd.Gfx().DrawTestTriangle();
+	wnd.Gfx().DrawTestTriangle( timer.Peek() );
 	wnd.Gfx().EndFrame();
 }
\ No newline at end of file

StudyDx/Graphics.cpp

@@ -102,7 +102,7 @@ void Graphics::ClearBuffer(float red, float green, float blue) noexcept
 	pContext->ClearRenderTargetView(pTarget.Get(), color);
 }
 
-void Graphics::DrawTestTriangle()
+void Graphics::DrawTestTriangle(float angle)
 {
 	namespace wrl = Microsoft::WRL;
 	HRESULT hr;
@@ -176,6 +176,40 @@ void Graphics::DrawTestTriangle()
 	// Bind index buffer to pipeline
 	pContext->IASetIndexBuffer(pIndexBuffer.Get(), DXGI_FORMAT_R16_UINT, 0u);
 
+	// Create constant buffer for transformation matrix
+	struct ConstantBuffer
+	{
+		struct
+		{
+			float element[4][4];
+		} transformation;
+	};
+
+	const float heightWidthRatio = 0.3f / 0.4f;
+	const ConstantBuffer cb =
+	{
+		{
+			heightWidthRatio * std::cos(angle),		-std::sin(angle),	0.0f,	0.0f,
+			heightWidthRatio * std::sin(angle),		std::cos(angle),	0.0f,	0.0f,
+			0.0f,									0.0f,				1.0f,	0.0f,
+			0.0f,									0.0f,				0.0f,	1.0f,
+		}
+	};
+	wrl::ComPtr<ID3D11Buffer> pConstantBuffer;
+	D3D11_BUFFER_DESC cbd = {};
+	cbd.BindFlags = D3D11_BIND_CONSTANT_BUFFER;
+	cbd.Usage = D3D11_USAGE_DYNAMIC;
+	cbd.CPUAccessFlags = D3D11_CPU_ACCESS_WRITE;
+	cbd.MiscFlags = 0u;
+	cbd.ByteWidth = sizeof(cb);
+	cbd.StructureByteStride = 0u;
+	D3D11_SUBRESOURCE_DATA csd = {};
+	csd.pSysMem = &cb;
+	GFX_THROW_INFO(pDevice->CreateBuffer(&cbd, &csd, &pConstantBuffer));
+
+	// Bind constant buffer to vertex
+	pContext->VSSetConstantBuffers(0u, 1u, pConstantBuffer.GetAddressOf());
+
 	// create pixel shader
 	wrl::ComPtr<ID3D11PixelShader> pPixelShader;
 	wrl::ComPtr<ID3DBlob> pBlob;

StudyDx/Graphics.h

@@ -53,7 +53,7 @@ public:
 	void EndFrame();
 	// 刷新RGB
 	void ClearBuffer(float red, float green, float blue) noexcept;
-    void DrawTestTriangle();
+    void DrawTestTriangle(float angle);
 private:
     #ifndef NDEBUG
     DxgiInfoManager infoManager;

StudyDx/VertexShader.hlsl

@@ -4,10 +4,15 @@ struct VSOut
 	float4 pos : SV_Position;
 };
 
+cbuffer CBuf
+{
+	row_major matrix transform;
+};
+
 VSOut main( float2 pos : Position, float3 color : Color )
 {
 	VSOut vso;
-	vso.pos = float4(pos.x, pos.y, 0.0f, 1.0f);
+	vso.pos = mul( float4(pos.x, pos.y, 0.0f, 1.0f), transform );
 	vso.color = color;
 
 	return vso;