2003-2004 Silicon Graphics, Inc.
glPushMatrix 3G
glPushMatrix glPopMatrix push and pop the current matrix stack

## C Specification

void `glPushMatrix` void `glPopMatrix`

## Description

There is a stack of matrices for each of the matrix modes. In `GL_MODELVIEW` mode, the stack depth is at least 16. In the other 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 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.

## Notes

Each texture unit has its own texture matrix stack. Use glActiveTexture to select the desired texture matrix stack.

## 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.

## Associated Gets

glGet with argument `GL_MAX_MODELVIEW_STACK_DEPTH`

glGet with argument `GL_MAX_PROJECTION_STACK_DEPTH`

glGet with argument `GL_MAX_TEXTURE_STACK_DEPTH`

glGet with argument `GL_MAX_TEXTURE_UNITS`

## See Also

glActiveTexture, glFrustum, glGet, glLoadIdentity, glLoadMatrix, glMatrixMode, glMultMatrix, glOrtho, glRotate, glScale, glTranslate, glViewport

## Copyright

Copyright 2003-2004 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.