I hope I post it in the right forum.
I've played with procedural generation of Perlin Noise in fragment shaders using RenderMonkey to develop those shaders. The problem is that when using a big integer array in fragment shader (512 int entries) framerate is very low (single digit). I've changed array to texture and now some strange lines appeared. Additionally my shader causes RenderMonkey to fail when using nVidia card.
First version (using int array):
Further versions (using textures):
Anyone have a clue what could be wrong? My shader is based on: http://http.developer.nvidia.com/GPUGems2/gpugems2_chapter26.html and Ken Perlin examples.
I don't know how RenderMonkey is now since it has reached end of life and AMD no longer supports RenderMonkey.
If you write your own opengl program, you will get the warning message like "Large size of this xxx shader may cause slow execution". It means that the big array causes the scratch buffer using, the poor performance may be expected. We strong recommend you to using other ways like uniform array, texture buffer and so on.
If you still have problems when running your program NOT using RenderMonkey, please tell me.
Sorry for the inconvenience.