有时候,我们需要查看depth/stencil buffer的内容,比如上一章中,我们要查看stencil buffer,看看我们设置的stencil值是否起作用,这时就要输出depth/stencil buffer内容,但这些内容在gpu中,我们并不能直接查看,需要通过纹理copy,资源映射的方式,拷贝到system memory中才可以直接查看。
下面是输出depth/stencil buffer的代码,最终结果被输出到一个csv文件中,便于用excel 查看。该函数我加在了D3DClass类中:
bool D3DClass::SaveDepthStencilBuffer()
{
D3D11_TEXTURE2D_DESC dsDesc, destTexDesc;
ID3D11Texture2D* destTex;
HRESULT result;
if(m_depthStencilBuffer)
{
m_depthStencilBuffer->GetDesc(&dsDesc);
// 使目的和源的描述一致
memcpy(&destTexDesc,&dsDesc,sizeof(destTexDesc));
destTexDesc.Usage = D3D11_USAGE_STAGING;
destTexDesc.BindFlags = 0;
destTexDesc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
result = m_device->CreateTexture2D(&destTexDesc, 0, &destTex);
if(FAILED(result))
{
HR(result);
return false;
}
//depthBufferDesc.Format = DXGI_FORMAT_D24_UNORM_S8_UINT;
m_deviceContext->CopyResource(destTex, m_depthStencilBuffer);
D3D11_MAPPED_SUBRESOURCE mappedResource;
result = m_deviceContext->Map(destTex, 0, D3D11_MAP_READ, 0, &mappedResource);
if(FAILED(result))
{
return false;
}
FILE *fp = fopen("depth-stencil.csv","w");
const UINT WIDTH = destTexDesc.Width ;
const UINT HEIGHT = destTexDesc.Height;
//映射为32位的dword
DWORD* pTexels = (DWORD*)mappedResource.pData;
for( UINT row = 0; row < HEIGHT; row++ )
{
UINT rowStart = row * mappedResource.RowPitch/sizeof(pTexels[0]);
for( UINT col = 0; col < WIDTH; col++ )
{
fprintf(fp,"%08x,",pTexels[rowStart + col]);
}
fprintf(fp,"\n");
}
fclose(fp);
m_deviceContext->Unmap(destTex, 0);
}
return true;
}
在GraphicClass类的Render函数中,调用该函数,我们就可以得到depth/stencil buffer的内容了。
本文参考了http://www.cppblog.com/GameAcademe/articles/DirectX11.html这篇blog。