Digital Equipment Corporation OpenGL man pages



  glScissor - define the scissor box

C Specification

  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.


  The glScissor	routine	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.

  The scissor test is enabled and disabled using glEnable and glDisable	with
  argument GL_SCISSOR_TEST.  While the 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, so  glScissor(0,0,1,1)	allows only the	lower left pixel in
  the window to	be modified,  and glScissor(0,0,0,0) disallows modification
  to all 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.

  GL_INVALID_OPERATION is generated if glScissor is executed between
  execution of glBegin and the corresponding execution ofglEnd.

Associated Gets

  glGet	with argument GL_SCISSOR_BOX
  glIsEnabled with argument GL_SCISSOR_TEST

See Also

  glEnable, glViewport

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Last Edited: Fri Dec 6 11:18:03 EST 1996 by AFV
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