> My last question, but I think Vincoof has answered :
> how many textures can be used for multitexturing ?
That depends on your hardware. You can count at least on two texture units for almost any kind of current hardware.
Better hardware like GeForce3/4 can support 4 texture units, Radeon8500 can support 6 texture units.

> Should 3 textures be used with rgb chanels of a 4th texture
> indicating the percentage of the blending ?
> r -> % of 1st texture
> g -> % of 2nd texture
> b -> % of 3rd texture
No you can't do it with texture combiners. At best you could use the alpha channel of each image like Corrail described nicely once again.

[edit: what Corrail proposed can be done in a single texture stage in fact]

glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_TEXTURE_ENV_COMBINE);glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COMBINE, GL_INTERPOLATE_ARB);glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE0_ARB);glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_TEXTURE1_ARB);glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB, GL_TEXTURE0_ARB);glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB_ARB, GL_SRC_COLOR);glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, GL_SRC_COLOR);glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_RGB_ARB, GL_SRC_ALPHA);

[edited by - vincoof on October 25, 2003 7:59:39 AM]

quote:Original post by Corrail
Yeah, this might be faster than my version! :-)
But you still need 2 Texture Units...

Yes obviously
But with this you have a free texture stage that can perform post-texturing color operations, which happen to be handy in many effects such as brightening/darkening, color masks, inversion, etc