Read pixel data from R32_UINT texture format

Question

im trying to implement ID value on geometry

so i use MRT, first render target is color texture and second render target is R32_UINT format and store unsigned int value

this is how my pixel shader works.

color for first render target and id for second one

struct PS_OUT
{
    float4 color : SV_TARGET0;
    uint id : SV_TARGET1;
};
....
...
..
.

output.color = tex[0].Sample(splr, tc * tilingFactor) * color;
output.id = 100;
return output;

and there is issue that is accessing id value from texture

i made same 2DTexture with second rendertarget and based on mouse position i coppied one pixel from texture that is second rendertarget (x,y is mouse position)

D3D11_TEXTURE2D_DESC textureDesc;
    textureDesc.Width = 1;
    textureDesc.Height = 1;
    textureDesc.MipLevels = 1;
    textureDesc.ArraySize = 1;
    textureDesc.Format = (DXGI_FORMAT_R32_UINT);
    textureDesc.SampleDesc.Count = 1;
    textureDesc.SampleDesc.Quality = 0;
    textureDesc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
    textureDesc.Usage = D3D11_USAGE_STAGING;
    textureDesc.BindFlags = 0;
    textureDesc.MiscFlags = 0;

gfx.GetDevice()->CreateTexture2D(&textureDesc, nullptr, &pTexTemp);

D3D11_BOX srcBox;
srcBox.left = x;
srcBox.right = x + 1;
srcBox.bottom = y + 1;
srcBox.top = y;
srcBox.front = 0;
srcBox.back = 1;
gfx.GetContext()->CopySubresourceRegion(pTexTemp.Get(), 0, 0, 0, 0, pTexSource.Get(), 0, &srcBox);

D3D11_MAPPED_SUBRESOURCE msr = {};
gfx.GetContext()->Map(pTexTemp.Get(), 0, D3D11_MAP::D3D11_MAP_READ, 0, &msr);
    if (x >= 0 && x <= m_width && y >= 0 && y <= m_height)
    {

        uint32_t* data = reinterpret_cast<uint32_t*>(msr.pData);
    }
gfx.GetContext()->Unmap(pTexTemp.Get(), 0);

and through map,unmap i accessed a value and cast it unsigned int *

but i got the weird value. for test i assigned 100 at the rendertarget

i got the 4294967295 which is max value on unsigned int when i drag mouse to empty space i get 0 . (becauce there is nothing)

how can i read unsigned int value from texture? is there any problem in my code?

p.s i tried CopyResource method not copy one pixel data but result was same

I don't see anything wrong with your procedure here. All the values and parameters seem correct. Can you ensure that your render target is properly filled using e.g. renderdoc or visual studio graphics debugger? Did you enable debug layer? Can you show your code where you are creating your render targets and setting them with OMSetRenderTargets? — mateeeeeee
@zezanjee oops.. there is mistake in my pixelshader code there is if branch but i i didnt assign value because of that max value assigned second rendertarget :( thank you for reply ^.^ — Green Herb

Green Herb Green Herb · Accepted Answer · 2021-02-02T06:31:25

my code is correct.. but in my pixel shader there is

PS_OUT main(float2 tc: Texcoord, float4 color : Color, float texIndex : v_TexIndex, float tilingFactor : v_TilingFactor)
{
    int index = (int)texIndex;
    PS_OUT output;
    [unroll]
    for (int i = 0; i < 32; ++i)
    {
        **if (index == 0)**
        {
            output.color = tex[0].Sample(splr, tc * tilingFactor) * color;
            return output;
        }
        **if (i == index)**
        {
            output.color =  tex[i].Sample(splr, tc * tilingFactor) * color;
            return output;
        }   
    }
    
    output.color = tex[0].Sample(splr, tc * tilingFactor) * color;
    output.id = 100;
    return output;
}

i didnt assign value at branch because of that i got max unsined int value :(

Read pixel data from R32_UINT texture format

1 Answers