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View Full Version : dynamic windowing (contrast/brightness/gamma) in16bit luminance 3d texture



plushy
09-13-2006, 05:23 AM
I'm trying to get dynamic windowing (change of contrast) in 3d texture composed from 16bit gray pixels. Is it posibbly at all ? Using color table or GLSL ? I've got a contrast changes by interpolation with gray using Accum buffer, but the problem that this contrast works on resuilting framebuffer with 8bit per color and I need to apply contrast on 16bit.

Klaus
09-14-2006, 02:26 AM
It is possible in GLSL using a color table stored in a texture and a dependent texture lookup (use gray value as texture coordinate for lookup into the color table). Alternatively, you can use a procedural windowing function in GLSL.

Note that the maximum dimensions for textures are 4096 (NVIDIA). So if you use the color table texture approach you have to stack up your 1D table into a 2D texture and do some math to fetch the right values during rendering.

For simple windowing i would use a procedural approach (procedural ramp).

- Klaus

plushy
09-19-2006, 03:41 AM
Thank you very much. The strange thin is that I found no any sample or even refernce about contrast/brightness etc on full range 16bit raw data using opengl.