NAME
fglScissor - define the scissor box
FORTRAN SPECIFICATION
SUBROUTINE fglScissor( INTEGER*4 x,
INTEGER*4 y,
INTEGER*4 width,
INTEGER*4 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
fglScissor 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 fglEnable and
fglDisable 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.
GL_INVALID_OPERATION is generated if fglScissor is executed
between the execution of fglBegin and the corresponding
execution of fglEnd.
ASSOCIATED GETS
fglGet with argument GL_SCISSOR_BOX
fglIsEnabled with argument GL_SCISSOR_TEST
SEE ALSO
fglEnable, fglViewport