gpu-based histogram


    Feb 21 2006 | 6:32 pm
    Is there any way to access the histogram or min/max functions included in the gl_arb_imaging extension that is a part of opengl? This would require rasterization, but it might still be faster than going back to a jit.matrix to perform the histogram analysis on the CPU.
    Can this be accessed through glslang through jit.gl.slab? Through an external? Thanks in advance.
    -=jack turner

    • Feb 21 2006 | 7:00 pm
      On Feb 21, 2006, at 10:32 AM, Jack Turner wrote:
      > Is there any way to access the histogram or min/max functions included > in the gl_arb_imaging extension that is a part of opengl? This would > require rasterization, but it might still be faster than going back to > a jit.matrix to perform the histogram analysis on the CPU.
      We don't currently expose any of the imaging extensions in Jitter, though a third party extern in theory should be capable of doing this if the card supports
      > Can this be accessed through glslang through jit.gl.slab?
      This is something of a tricky thing to implement inside a pixel shader. It would need to be multi-pass as a histogram in its typical implementation is a "scatter" algorithm rather than a "gather" algorithm (the latter being a requirement for stream processing). However, with multiple passes you can implement a gather algorithm, though it will be tricky to accomplish.
      -Joshua
    • Feb 22 2006 | 4:04 am
      this is a great idea... it would add a lot of value to jitter's GPU processing. i'm imagining an on-the-fly autolevels effect. very nice!
      i'm officially making a feature request, since i don't currently have the proper coding chops. :)
      -jlm