Active Texture

OpenGL OpenGL: Basic Coding
1

quoting the glActiveTexture man-page

glActiveTexture selects which texture unit subsequent texture state calls will affect.

Could somebody tell me which functions are related to the Active Texture?

The only function I’m sure it’s related to the AT is glTexParameter, but I can’t see any changes in the common rendering operations when I use glActiveTexture in my code.

Thanks

2

This function is used to make the texture accessible in GLSL shaders. So you activate your texture to unit (for example unit 0), then you bind the texture with glBindTexture which will bind it to that texture unit. The glBindTexture is the subsequent texture state call the documentation is talking about. In GLSL you can then sample texture unit 0 with a sampler.

You wouldn’t see anything different unless you wrote your own shader.

3

I write my own shaders… :stuck_out_tongue:
but my first shaders used just one texture, so the glActiveTexture call is not so important.

Now I’ve read some chapters from a couple of books (the Orange Book and Beginning OpenLG game programming) and I have a better knowledge of the matter.

glActiveTexture selects a specific Texture Unit and it’s the main function you need to use MultiTexturing.

However thanks to Budric for his reply. :wink: