glScissor(3) glScissor(3)
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 con-
text 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 coor-
dinates. The first two arguments, x and y, specify the lower left cor-
ner 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 win-
dow.
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(3), glViewport(3)
glScissor(3)
Mac OS X 10.6 - Generated Thu Sep 17 20:20:28 CDT 2009