How do I get the current size of a matrix stack in OpenGL?

Question

How do I get the current size of a matrix stack (GL_MODELVIEW, GL_PROJECTION, GL_TEXTURE) in OpenGL?

I want this so that I can do some error checking to ensure that in certain parts of the code I can check that the matrix stacks have been left in the original condition.

Answer 1

Try:

  GLint depth;
  glGetIntegerv (GL_MODELVIEW_STACK_DEPTH, &depth);

The enums for the other stacks are:

  GL_MODELVIEW_STACK_DEPTH       
  GL_PROJECTION_STACK_DEPTH      
  GL_TEXTURE_STACK_DEPTH         

If you use multi-texturing, you have more than one texture matrix stack to query. To do so, set the current texture-unit via glActiveTexture();.