d3d11如何使用着色器

在D3D11中，使用着色器主要涉及以下几个步骤[^1]：

1. **创建着色器资源**: 编写并编译着色器代码（通常使用High-Level Shading Language (HLSL)），然后创建对应的Shader Object (SO) 或者 Shader Bytecode。

ID3DBlob* vertexShaderBlob;
D3DCompileFromFile("vertex.hlsl", nullptr, nullptr, "VS_main", "vs_5_0", D3DCOMPILE_DEBUG, 0, &vertexShaderBlob, nullptr);
ID3DBlob* pixelShaderBlob;
D3DCompileFromFile("pixel.hlsl", nullptr, nullptr, "PS_main", "ps_5_0", D3DCOMPILE_DEBUG, 0, &pixelShaderBlob, nullptr);
ID3D11VertexShader* vertexShader;
ID3D11PixelShader* pixelShader;
device->CreateVertexShader(vertexShaderBlob->GetBufferPointer(), vertexShaderBlob->GetBufferSize(), nullptr, &vertexShader);
device->CreatePixelShader(pixelShaderBlob->GetBufferPointer(), pixelShaderBlob->GetBufferSize(), nullptr, &pixelShader);

2. **设置管线状态**: 创建Pipeline State Object (PSO)，将着色器与管线配置绑定在一起。

D3D11_INPUT_ELEMENT_DESC layout[] = {{"position", 0, DXGI_FORMAT_R32G32B32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0}};
D3D11_PASS desc[] = {
    {D3D11 Pass::DepthStencilDesc(D3D11_DEFAULT, 0), {}},
    {D3D11 Pass::BlendStateDesc(D3D11_DEFAULT, D3D11_DEFAULT), {}}
};
ID3D11VertexShader* vs = ...; // previously created
ID3D11PixelShader* ps = ...; // previously created
device->CreateBlendState(..., &blendState);
device->CreateInputLayout(layout, _countof(layout), vertexShader->GetByteCodePointer(), vertexShader->GetByteCodeLength(), &inputLayout);
D3D11_SAMPLER_DESC sampDesc = {};
device->CreateSamplerState(&sampDesc, &samplerState);
D3D11_DEPTH_STENCIL_DESC depthDesc = {D3D11_DEFAULT};
device->CreateDepthStencilState(&depthDesc, &depthStencilState);

PSOCreateInfo psoCI;
psoCI.pVertexShader = vs;
psoCI.pPixelShader = ps;
psoCI.pInputLayout = inputLayout;
psoCI.pRasterizerState = NULL;
psoCI.pDepthStencilState = depthStencilState;
psoCI.pBlendState = blendState;
psoCI.SampleDesc = D3D11_DEFAULT_SAMPLE_DESC;
psoCI.PrimitiveTopologyType = D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST;
device->CreateGraphicsPipelineState(&psoCI, &pipelineState);

3. **设置顶点输入**: 设置几何描述符视图，指定顶点缓冲区的位置和格式。

D3D11_MAPPED_SUBRESOURCE mappedResource;
deviceContext->Map(vertexBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource);
// 填充顶点数据到内存...
deviceContext->Unmap(vertexBuffer, 0);
IASetVertexBuffers(deviceContext, 0, 1, &vertexBuffer, &stride, &offset);
IASetInputLayout(deviceContext, inputLayout);

4. **绘制**: 执行管线状态和绘制命令来让GPU执行着色器。

deviceContext->VSSetShader(pipelineState->VS, vertexShader, NULL);
deviceContext->PSSetShader(pipelineState->PS, pixelShader, NULL);
deviceContext->Draw(3, 0); // 假设有3个顶点

这些只是基本的流程，实际应用可能还需要处理更复杂的特性，如纹理采样、算术运算、光照等。着色器的具体功能取决于你想要在图形上实现什么样的效果。记得，着色器编程需要对数学和光影原理有一定了解。