**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 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**