you can use VPOS to get your screen coordinates:

Code:
float4 PShader(in float4 vScreenPos : VPOS, ...) : COLOR0
{
   float2 TexcoordScreen = (vScreenPos.xy + 0.5) / vecViewPort.xy;

   ...
}
x and y of the VPOS-register represent the coordinate of the pixel (1 unit = 1 pixel!)
the '+ 0.5' is needed to sample from the center of the pixel because the top-left pixel's coordinates are (0, 0) not (0.5, 0.5)
finally, dividing by vecViewPort.xy transforms the coordinates to the [0 - 1] range which is needed (edit: you can also use '* vecViewPort.zw')

Last edited by Kartoffel; 09/12/16 11:10.
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