GLAPI/glScissor

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glScissor
Core in version 4.4

glScissor: define the scissor box

Function Definition

 void glScissor(GLint x​, GLint y​, GLsizei width​, GLsizei height​);
x, y
Specify the lower left corner of the scissor box. Initially (0, 0).
width, height
Specify the width and height of the scissor box. When a GL context is first attached to a window, width​ and height​ are set to the dimensions of that window.

Description

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 test is initially disabled. While the 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.

Errors

GL_INVALID_VALUE​ is generated if either width​ or height​ is negative.

Associated Gets

glGet with argument GL_SCISSOR_BOX​

glIsEnabled with argument GL_SCISSOR_TEST​

See Also

glEnable(GL_SCISSOR_TEST), glScissorArray, glScissorIndexed, glViewport

Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.