GLSCISSOR(3gl)GLSCISSOR(3gl)NAMEglScissor - 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 con‐
text 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 com‐
mands. 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
GLSCISSOR(3gl)
