   [HLSL] using different size RT - occlusion culling
  Hi all !I was wondering if it's possible to use two render targets of different size at the same rendering pass.I need this in my Light PrePass renderer because the first would the depth buffer, and the second an approximate depth buffer which I call Occlusion Buffer (much smaller than frame buffer) that I would use to implement occlusion culling.Can I write on both of them simultaneously ??-An alternative way to accomplish this is to set the occlusion buffer as the render target, and render a full screen quad after having set the depth buffer as the texture to read from. But this solution implies to read one more time the whole depth buffer... which I wouldn't like.Any suggestion ?Thanks !   
  If you think about it carefully, what you want doesn't make sense. How will the hardware know how to deal with several pixels being written to the same place in the small render target? (After all, you're drawing at the resolution of the big buffer, so need to discard pixels or combine them when drawing to the small one.)You need to do something like your second suggestion. That's what most games do, and it shouldn't cause a huge performance problem. In D3D9 you can use StretchRect to do it.   ;Quote:Original post by ET3DIf you think about it carefully, what you want doesn't make sense. How will the hardware know how to deal with several pixels being written to the same place in the small render target? (After all, you're drawing at the resolution of the big buffer, so need to discard pixels or combine them when drawing to the small one.)I was wondering if the GPU could automatically 'scale' the coordinate to fit them to the smaller render target. Kinda the opposite of doing "tex2D" when sampling from a texture.Anyway, it's sufficient for me to know this is impossible ;)thank you !   