Why is there a glMatrixMode in OpenGL?

Question

I just don\'t understand what OpenGL\'s glMatrixMode is for.

As far as I can see, when glMatrixMode(GL_MODELVIEW) is called, it is followed by

Answer 1

You can use glRotate and glTranslate for projection matrices as well.

Also: OpenGL supports transforms of textures and colors. If you active this feature you can for example modify the texture coordinates of an object without rewriting the texture coordinates each frame (slow).

This is a very useful feature if you want to scroll a texture across an object. All you have to do for this is to draw the textured object, set the matrix mode to GL_TEXTURE and call glTranslate to set the offset into the texture.