fglScissor(3G) OpenGL Reference fglScissor(3G)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.
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fglScissor(3G) OpenGL Reference fglScissor(3G)ASSOCIATED GETS
fglGet with argument GL_SCISSOR_BOX
fglIsEnabled with argument GL_SCISSOR_TEST
SEE ALSO
fglEnable, fglViewport
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