CODEWITHSUNDEEP
c++directx
Martin85
Martin85

Reputation: 308

OMSetRenderTargets renders only first provided target

I'm trying to render to multiple ID3D11RenderTargetView simultaneously. But it seems that only the first target is being rendered:

  ID3D11RenderTargetView* targets [ 2 ] = { _backbuffer
                                          , _renderToTextureRTV
                                          };

  _devcon->OMSetRenderTargets( 2, targets, nullptr );

Depending on which parameter I specify first in my targets array, will be rendered. The other render target view will not be rendered.

I create my IDXGISwapChain with D3D11_CREATE_DEVICE_DEBUG flag and cannot see any error messages related to this function.

I can reproduce the same problem if I specify nullptr as first targets element. In this case the second element will not be rendered. But if I specify nullptr as the second element, the first element will be rendered correctly.

Why does OMSetRenderTargets seem to only evaluate the first targets element?

Edit:

What I'm actually trying to achieve is to render to the backbuffer and to a texture simultaneously. I need to render to a texture, as I want to be able to access the pixel values from the CPU.

I want to render to a 16 bit unsigned image, so I use DXGI_FORMAT_R16G16B16A16_UNORM for the texture. For the backbuffer, I need to use a different format suitable for screen display, so I use DXGI_FORMAT_R16G16B16A16_FLOAT.

For performance reasons, I do not want to element-wise convert between the two and this is the reason why I have two render targets.

Upvotes: 0

Views: 802

Answers (1)

Mrfence
Mrfence

Reputation: 370

Is your pixel shader similar to this one? You need to manually set which render target the pixel shader outputs to:

struct Output 
{
  float4 target0 : SV_Target0;
  float4 target1 : SV_Target1;
};

Output PixelShader(float4 pos : SV_Position)
{
  Output output;

  output.target0 = float4(1.0, 0, 0, 0); //Output to the first rendertarget
  output.target1 = float4(0, 1.0, 0, 0); //Output to the second rendertarget

  return output;
}

Upvotes: 2

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