[ Previous |
Next |
Contents |
Glossary |
Home |
Search ]

*OpenGL 1.1 for AIX: Reference Manual*

## glPushMatrix or glPopMatrix Subroutine

### Purpose

Pushes and pops the current matrix stack.

### Library

OpenGL C bindings library: **libGL.a**

### C Syntax

**void** **glPushMatrix(**void**)**

**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.

The **glPushMatrix** subroutine 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.

The **glPopMatrix** subroutine 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.

### Error Codes

**GL_STACK_OVERFLOW** |
The **glPushMatrix** subroutine is called while the current matrix stack is full. |

**GL_STACK_UNDERFLOW** |
The **glPopMatrix** subroutine is called while the current matrix stack contains only a single matrix. |

**GL_INVALID_OPERATION** |
The **glPushMatrix** subroutine is called between a call to **glBegin** and the corresponding call to **glEnd**. |

### Associated Gets

Associated gets for the **glPushMatrix** or **glPopMatrix** subroutine are as follows. (See the **glGet** subroutine for more information.)

**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**.

### Files

**/usr/include/GL/gl.h** |
Contains C language constants, variable type definitions, and ANSI function prototypes for OpenGL. |

### Related Information

The **glBegin** or **glEnd** subroutine, **glFrustum** subroutine, **glLoadIdentity** subroutine, **glLoadMatrix** subroutine, **glMatrixMode** subroutine, **glMultMatrix** subroutine, **glOrtho** subroutine, **glRotate** subroutine, **glScale** subroutine, **glTranslate** subroutine, **glViewport** subroutine.

OpenGL Overview.

[ Previous |
Next |
Contents |
Glossary |
Home |
Search ]