glScissor(3G) OpenGL Reference 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
glScissor 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 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
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.
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glScissor(3G) OpenGL Reference glScissor(3G)ASSOCIATED GETS
glGet with argument GL_SCISSOR_BOX
glIsEnabled with argument GL_SCISSOR_TEST
SEE ALSO
glEnable, glViewport
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