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Software texture sampling off by one pixel #34

Closed GoogleCodeExporter closed 9 years ago

GoogleCodeExporter commented 9 years ago 
To reproduce problem:

1. Execute 'SimpleTexture' and 'BicubicTexture' applications compiled using
the native CUDA toolchain executing on the GPU.
2. Copy their outputs into the 'data/' directory to be used as reference
inputs for GPU Ocelot.
3. Execute SimpleTexture and BicubicTexture with emulated and LLVM devices. 

The expected output should match the reference inputs. Instead, the output
consists of images shifted by approximately one pixel.

The current reference inputs were produced by GPU Ocelot and not provided
by the CUDA toolchain. We should see this as a defect in the texture
sampling procedures used by GPU Ocelot's emulated and translated devices.

Original issue reported on code.google.com by arkerr@gmail.com on 5 Nov 2009 at 7:06

GoogleCodeExporter commented 9 years ago 
It turns out that pixels are centered dead center rather than on the edge of a 
grid.
 Realigning the implementation of texture sampling fixed this problem.

Original comment by gregory....@gatech.edu on 4 May 2010 at 1:28