I’m trying to write a High Dynamic Range application that utilises floating point textures attached to FBOs. Ideally I want quick access to important information in the FBO attached texture (like the min, avg, and max) so I can perform a range of selectable effects from tone-mapping to auto-exposure.
For the average I’ve settled for using the high level mipmaps as a quick approximation. The minimum and maximum values have been a little less trivial to obtain. I wanted to keep reading the texture from the graphics card as a last resort and I can’t figure out how to use gl[Get]Minmax on the FBO or texture.
Is it possible to easily find the minumum and maximum of a texture (attached to an FBO if that makes a difference) and to have the values in their full dynamic range? (ie. not clamped [0,1] or [0,255]…)
Thanks for the help,