Changing ID3D11Texture2D with DirectCompute

Question

I do video editing. I want to try using DirectCompute, but there are difficulties with the start.

Can anyone help with a simple example? There is an ID3D11Texture2D texture in the format DXGI_FORMAT_R8G8B8A8_UNORM or DXGI_FORMAT_R16G16B16A16_FLOAT. It needs to be processed with a DirectCompute shader. It is necessary to invert all color values and write the result to the same texture. Is this even possible?

Answer 1

The best thing to is proceed by trail and error. But this requires the getting VS graphics Diagnostics working https://docs.microsoft.com/en-us/visualstudio/debugger/graphics/getting-started-with-visual-studio-graphics-diagnostics?view=vs-2022 . In visual studio menu >debug >Graphics >Start Graphics Degugging

It will show you the state of the input textures/buffers and output textures/buffers (after the shader call).

Just write write to the texture with float4(1, 0, 0, 1);and look in the debugger to see if you get blue or red (with DXGI_FORMAT_R8G8B8A8_UNORM it will be red).

Here's some hlsl code you can play around with.

RWTexture2D<unorm float4> ReadWriteTexture: register(u0); // Bind with UAV
Texture2D<unorm float4> ReadOnlyTexture: register(t0); // Bind with SRV

[numthreads(TEXTURE_WIDTH, 1, 1)]
void main(uint3 pos : SV_DispatchThreadID)
{
    float4 rgba = readWriteTexture[uint2(pos.x, pos.y)] ;
    //float4 rgba = readOnlyTexture[uint2(pos.x, pos.y)] ;
    float red = 1 - rgba.x;
    float green = 1 - rgba.y;
    float blue = 1 - rgba.z;
    readWriteTexture[uint2(pos.x, pos.y)] = float4(red, green, blue, 1); 
}

You will need to bind a Unordered access view to the compute pipeline it order to write to the texture.

deviceContext->CSSetUnorderedAccessViews(...);
deviceContext->Dispatch(1, TEXTURE_HEIGHT, 1);