Function ReadbackImagePixels

source/graphics_platform_d3d11.cpp:138–184

// ***********************************************************************

void ReadbackImagePixels(sg_image img_id, void* pixels) {
	_sg_image_t* img = _sg_lookup_image(&_sg.pools, img_id.id);

    // create staging texture
    ID3D11Texture2D* staging_tex = NULL;
    D3D11_TEXTURE2D_DESC staging_desc = {
        .Width = (UINT)img->cmn.width,
        .Height = (UINT)img->cmn.height,
        .MipLevels = 1,
        .ArraySize = 1,
        .Format = img->d3d11.format,
        .SampleDesc = {
            .Count = 1,
            .Quality = 0,
        },
        .Usage = D3D11_USAGE_STAGING,
        .BindFlags = 0,
        .CPUAccessFlags = D3D11_CPU_ACCESS_READ,
        .MiscFlags = 0
    };
    _sg_d3d11_CreateTexture2D(_sg.d3d11.dev, &staging_desc, NULL, &staging_tex);

    // copy pixels to staging texture
	_sg.d3d11.ctx->CopySubresourceRegion(
        (ID3D11Resource*)staging_tex,
        0, 0, 0, 0,
        (ID3D11Resource*)img->d3d11.tex2d,
        0, NULL);

    // map the staging texture's data to CPU-accessible memory
    D3D11_MAPPED_SUBRESOURCE msr = {.pData = NULL};
    _sg_d3d11_Map(_sg.d3d11.ctx, (ID3D11Resource*)staging_tex, 0, D3D11_MAP_READ, 0, &msr);

    // copy the data into the desired buffer, converting pixels to the desired format at the same time
    int res = SDL_ConvertPixels(
        img->cmn.width, img->cmn.height,
        _sg_d3d11_dxgi_format_to_sdl_pixel_format(staging_desc.Format),
        msr.pData, msr.RowPitch,
        SDL_PIXELFORMAT_RGBA32,
        pixels, img->cmn.width * 4);
    _SOKOL_UNUSED(res);

    // unmap the texture
    _sg_d3d11_Unmap(_sg.d3d11.ctx, (ID3D11Resource*)staging_tex, 0);

    if(staging_tex) _sg_d3d11_Release(staging_tex);
}

// ***********************************************************************