2d texture always black in compute shader - Directx 11

Question

I am learning directx11 programming and setting up a basic compute shader. My first objective is to just check if compute shader is able to write anything to a 2D texture resource. Relevant code snippets are below:

1. Buffer creation

   ID3D11Texture2D* ColoredTriangleDemo::create_render_target(ID3D11Device1* Direct3DDevice, int width, int height){
   ID3D11Texture2D* renderTarget;
   D3D11_TEXTURE2D_DESC renderTargetDesc;
   ZeroMemory(&renderTargetDesc, sizeof(renderTargetDesc));
   renderTargetDesc.BindFlags = D3D11_BIND_UNORDERED_ACCESS | D3D11_BIND_SHADER_RESOURCE;
   renderTargetDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
   renderTargetDesc.Height = height;
   renderTargetDesc.Width = width;
   renderTargetDesc.ArraySize = 1;
   renderTargetDesc.MipLevels = 1;
   renderTargetDesc.SampleDesc.Count = 1;
   renderTargetDesc.SampleDesc.Quality = 0;
   renderTargetDesc.Usage = D3D11_USAGE_DEFAULT;
   
   HRESULT rt = Direct3DDevice->CreateTexture2D(&renderTargetDesc, NULL, &renderTarget);
   if (FAILED(rt)){
       std::cout << "Error! Render target creation failed for compute shader " << rt << std::endl;
       exit;
   }
   
   //Create UAV for Compute shader
   D3D11_UNORDERED_ACCESS_VIEW_DESC uavCS;
   ZeroMemory(&uavCS, sizeof(uavCS));
   uavCS.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
   uavCS.ViewDimension = D3D11_UAV_DIMENSION_TEXTURE2D;
   uavCS.Texture2D.MipSlice = 0;
   HRESULT uav = Direct3DDevice->CreateUnorderedAccessView(renderTarget, &uavCS, &mUAVCS);
   if (FAILED(uav)){
       std::cout << "Error! UAV Creation failed for CS " << uav << std::endl;
       exit;
   }
   return renderTarget;
   }
   

2. Compute shader HLSL code- For now it just writes something to check if the entire setup is working or not

   struct vertexData{
   float4 position;
   float2 texcoord;
   float3 normal;
   int    materialID;
   };
   
   StructuredBuffer<vertexData> vData : register(t0);
   RWTexture2D<float4>          color : register(t1);
   
   cbuffer bufferSize : register(b0){
       int n_input_elements;
       int n_output_x;
       int n_output_y;
       int dummy;
   }
   
   [numthreads (1, 1, 1)]
   void main(uint3 dispatchThreadID : SV_DispatchThreadID){
       for (int i = 0; i < 1000; ++i){
           for (int j = 0; j < 1000; ++j){
               float2 loc = float2(float(i)/1000.f, float(j)/1000.f);
               color[loc.xy] = (i*j) % 2 ? float4(0.5f, 0.6f, 0.7f, 1.f) : float4(0.7f, 0.6f, 0.5f, 1.f);
           }
       }
   }
   

3. Rendering code in draw method

   ID3D11DeviceContext* direct3DDeviceContext = mGame->Direct3DDeviceContext();
   direct3DDeviceContext->CSSetShader(mComputeShader, nullptr, 0);
   direct3DDeviceContext->CSSetShaderResources(0, 1, &mSRVCS_I);
   direct3DDeviceContext->CSSetUnorderedAccessViews(0, 1, &mUAVCS, NULL);
   
   //Dispatch
   direct3DDeviceContext->Dispatch(1, 1, 1);
   
   Sleep(20);      //Sleep for 100 ms
   

But when I see the 2D texture color in visual studio graphics debugger, I get the default green screen. Is there something I have missed here?

Thanks

Answer 1

I found the error. In ComputeShader code, I was indexing the RWTexture2d (color) using float, while it should have been accessed with uint2.

So indexing color[loc.xy], loc should be int not float which fixed the problem.