(OpenGL) Pushing "old" matrix onto stack - c

Question

I'm currently trying to get to know the basics with the means of OpenGL.
At the time I try to render a Floating Cube with a Pyramid beneath it. I want the Cube to rotate on Input (which is already working) and the Pyramid to stay where it's supposed to be.
After figuring out the use of Push- and PopMatrix I managed to rotate only the cube.
My Problem is, that the Cube stops rotating as soon as I let go of the key.
The player.X and Player.Z aren't reset at that point (checked that).
So my guess is that PushMatrix puts some kind of standard matrix onto the stack, then rotates it and displays it. Because of 1 * x always equalling x there is no rotation.
So the question is:
How do I manage to push the "old" matrix onto the stack, rather than the new one?
glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
glPushMatrix();
glRotatef( -(player->Z), 1.0f, 0.0f, 0.0f );
glRotatef( -(player->X), 0.0f, 1.0f, 0.0f );
glBegin( GL_QUADS );
//Draw Cube
glEnd();
glPopMatrix( );
glBegin( GL_TRIANGLES );
//Draw Pyramid
glEnd();
glFlush();
SwapBuffers (hDC);

Answer 1

glPushMatrix() does not push a 'standard' matrix onto the stack, it pushes the current matrix. Hopefully you've initialised the matrix at some point with a glLoadIdentity(), and possibly some initial transforms to set up the view, and so this is what will be pushed.
You should not generally keep updating that matrix from frame to frame, as errors will eventually accumulate.
Instead, update your rotation values in some update loop, rather than in the key-down routine.
Also, note that this method of rendering with GL is considered deprecated. The recommended approach is to use the programmable pipeline, which involves creating your own matrices (amongst other changes).
(if you desperately want to keep a persistent transform while also pushing and popping to render other things, it is possible to read the current matrix with a glGet(), store it somewhere, and then perform a glLoadMatrix() to restore it again later... but don't do that for this.)