glPushMatrix.3gl







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 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.



  glPushMatrix pushes the current matrix stack down by one, duplicating	the

  current matrix.  That	is, after a glPushMatrix call, the matrix on the 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_MODELVIEW_MATRIX

  glGet	with argument GL_PROJECTION_MATRIX

  glGet	with argument GL_TEXTURE_MATRIX

  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






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Last Edited: Mon, May 22, 1995

AFV