glScissor
- define the scissor box
void glScissor(GLint x, GLint y, GLsizei width, GLsizei height)
x
, y
Specify the lower left corner of the scissor box, in pixels. The initial value is (0, 0).
width
, height
Specify the width and height of the scissor box. When a GL context is first attached to a surface (e.g. window), width
and height
are set to the dimensions of that surface.
glScissor
defines a rectangle, called the scissor box, in window coordinates. The first two arguments, x
and y
, specify the lower left corner of the box. width
and height
specify the width and height of the box.
To enable and disable the scissor test, call glEnable
and glDisable
with argument GL_SCISSOR_TEST
. The scissor test is initially disabled. While scissor test is enabled, only pixels that lie within the scissor box can be modified by drawing commands. Window coordinates have integer values at the shared corners of frame buffer pixels. glScissor
(0, 0, 1, 1) allows modification of only the lower left pixel in the window, and glScissor
(0, 0, 0, 0) doesn't allow modification of any pixels in the window.
When the scissor test is disabled, it is as though the scissor box includes the entire window.
GL_INVALID_VALUE
is generated if either width
or height
is negative.
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/.