OSX and GL2.1 and 64bit

[bilgili]

Because of the integer texture sampler restrictions we can not use the same code path, we are using with the current GL4 renderer. The sampling of integer textures are supported from 1.30 and on.

For GL2.1 to work textures should be in normalized form and, this means substantial amount of code change in TexturePool, Renderer and the fragment shader.

[eile]

I'm not fully understanding: By integer and normalized do you mean GL_TEXTURE_RECTANGLE and GL_TEXTURE_2D 'addressing', or do the GL2 texture values need to be normalized? I.e., what does the integer in integer textures refer to, and what does the normalized form refer to?

[bilgili]

Simply Sampler3D in the shaders cannot be used with integer textures, where now we are using absolute values of the data as textures with the latest changes so that we can use transfer functions as they are. I recommend you reading the glTexImage3D texture formats. The textures are normalized when you put into GPU memory or not. We are putting them as they are.

[hernando]

Try adding

#extension GL_EXT_gpu_shader4 : enable

in the GLSL shaders using integer texture samplers.