Multitexturing and Texture Matrix

OpenGL OpenGL: Basic Coding
1

Hi guys!
I am so happy I managed to implement Multitexturing in Visual Basic by making a DLL from C++!!!

Is it possible to do the following? I have a floor with two textures. The first one is a snow texture, and the second one is a fog texture.

I want to apply a texture transformation to just the fog texture and scroll, it but not to the snow texture (obviously, to keep it static).

I used to achieve this effect by using two polygon layers with different textures and blending. Of course I am not expecting to go back to that now that I managed to get Multitexturing support.

Any ideas will be helpful! :slight_smile:
Thanks so much!
Rod

2

Oooh!! I just got it!..
I guess that with glActiveTextureARB(GL_TEXTURE0_ARB) you select to which texture the changes go.

Could anybody post me a link of a tutorial that explains TextEnv?

I googled and there is not so much info on that and I had seen very long a go a tutorial which showed you all the different combination of parameters of TextEnv and the results… Although I can’t find it.

The tutorial I followed contains the following but no explanation…
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB)
glTexEnvi(GL_TEXTURE_ENV, GL_RGB_SCALE_ARB, 1)

Thanks so much!
Cheers!
Rod

3

Read OpenGL specs on glTexEnv, and specs for ARB_texture_env_combine.
This is what I did. I don’t use tutorials. Specs seem difficult at first, but once you get through 2-3 specs you’ll get addicted :slight_smile:

4

use 2 texture units
then bind 2 textures in difference,
one use the org texcoord
other scroll the texcoord

glActiveTexutre(GL_TEXTURE0);
glBindTexture();
glActiveTexture(GL_TEXTURE1);
glBindTexture();

glMultTexCoord();
glMultTexCoord();
glVertex3f();/and so on/

combine color in fragment shader

5

Originally posted by k_szczech:
Specs seem difficult at first, but once you get through 2-3 specs you’ll get addicted :slight_smile:
k_szczech could you please point me as to where to get those specs? Blue book, red book, rainbow book/ ! haha

A web link would be greatly appreciated. :slight_smile:
Thanks guys!

6

Hi,

The official list of GL extensions is found here: http://www.opengl.org/registry/

Some of the newest “EXT” and “NV” ones (only implemented on NVIDIA G80 or so) are found on NVIDIA developer site: http://developer.nvidia.com/object/nvidia_opengl_specs.html

Hope this helps!