NAME
	  fglPushMatrix, fglPopMatrix -	push and pop the current
	  matrix stack


     FORTRAN SPECIFICATION
	  SUBROUTINE fglPushMatrix( )


     FORTRAN SPECIFICATION
	  SUBROUTINE fglPopMatrix( )


     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 two	modes, GL_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.

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

	  fglPopMatrix 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 fglPushMatrix is called
	  while	the current matrix stack is full.

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

	  GL_INVALID_OPERATION is generated if fglPushMatrix or
	  fglPopMatrix is executed between the execution of fglBegin
	  and the corresponding	execution of fglEnd.

     ASSOCIATED	GETS
	  fglGet with argument GL_MATRIX_MODE
	  fglGet with argument GL_MODELVIEW_MATRIX
	  fglGet with argument GL_PROJECTION_MATRIX
	  fglGet with argument GL_TEXTURE_MATRIX
	  fglGet with argument GL_MODELVIEW_STACK_DEPTH
	  fglGet with argument GL_PROJECTION_STACK_DEPTH
	  fglGet with argument GL_TEXTURE_STACK_DEPTH
	  fglGet with argument GL_MAX_MODELVIEW_STACK_DEPTH
	  fglGet with argument GL_MAX_PROJECTION_STACK_DEPTH
	  fglGet with argument GL_MAX_TEXTURE_STACK_DEPTH

     SEE ALSO
	  fglFrustum, fglLoadIdentity, fglLoadMatrix, fglMatrixMode,
	  fglMultMatrix, fglOrtho, fglRotate, fglScale,	fglTranslate,
	  fglViewport