glPushMatrix(3G)

NAME
     glPushMatrix, glPopMatrix - push and pop the current matrix stack


C SPECIFICATION
     void glPushMatrix( void )


C SPECIFICATION
     void glPopMatrix( void )


DESCRIPTION
     There is a stack of matrices for each of the matrix modes.  In
     GL_MODELVIEW mode, the stack depth is at least 32.  In the other modes,
     GL_COLOR, const(PROJECTION), and GL_TEXTURE, the depth is at least 2.
     The current matrix in any mode is the matrix on the top of the stack for
     that mode.

     glPushMatrix pushes the current matrix stack down by one, duplicating the
     current matrix.  That is, after a glPushMatrix call, the matrix on top of
     the stack is identical to the one below it.

     glPopMatrix pops the current matrix stack, replacing the current matrix
     with the one below it on the stack.

     Initially, each of the stacks contains one matrix, an identity matrix.

     It is an error to push a full matrix stack, or to pop a matrix stack that
     contains only a single matrix.  In either case, the error flag is set and
     no other change is made to GL state.

ERRORS
     GL_STACK_OVERFLOW is generated if glPushMatrix is called while the
     current matrix stack is full.

     GL_STACK_UNDERFLOW is generated if glPopMatrix is called while the
     current matrix stack contains only a single matrix.

     GL_INVALID_OPERATION is generated if glPushMatrix or glPopMatrix is
     executed between the execution of glBegin and the corresponding execution
     of glEnd.

ASSOCIATED GETS
     glGet with argument GL_MATRIX_MODE
     glGet with argument GL_COLOR_MATRIX
     glGet with argument GL_MODELVIEW_MATRIX
     glGet with argument GL_PROJECTION_MATRIX
     glGet with argument GL_TEXTURE_MATRIX
     glGet with argument GL_COLOR_STACK_DEPTH
     glGet with argument GL_MODELVIEW_STACK_DEPTH
     glGet with argument GL_PROJECTION_STACK_DEPTH
     glGet with argument GL_TEXTURE_STACK_DEPTH
     glGet with argument GL_MAX_MODELVIEW_STACK_DEPTH
     glGet with argument GL_MAX_PROJECTION_STACK_DEPTH
     glGet with argument GL_MAX_TEXTURE_STACK_DEPTH


SEE ALSO
     glFrustum, glLoadIdentity, glLoadMatrix, glMatrixMode, glMultMatrix,
     glOrtho, glRotate, glScale, glTranslate, glViewport