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