glScissor(3G)

NAME
     glScissor - define the scissor box


C SPECIFICATION
     void glScissor( GLint x,
                     GLint y,
                     GLsizei width,
                     GLsizei height )


PARAMETERS
     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
     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.

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

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

ASSOCIATED GETS
     glGet with argument GL_SCISSOR_BOX
     glIsEnabled with argument GL_SCISSOR_TEST


SEE ALSO
     glEnable, glViewport