glViewport(3) glViewport(3)
NAME
glViewport - set the viewport
C SPECIFICATION
void glViewport( GLint x,
GLint y,
GLsizei width,
GLsizei height )
PARAMETERS
x, y Specify the lower left corner of the viewport rectangle, in pix-
els. The initial value is (0,0).
width, height
Specify the width and height of the viewport. When a GL context
is first attached to a window, width and height are set to the
dimensions of that window.
DESCRIPTION
glViewport specifies the affine transformation of x and y from normal-
ized device coordinates to window coordinates. Let (xnd, ynd) be nor-
malized device coordinates. Then the window coordinates (xw, yw) are
computed as follows:
xw = (xnd+1) (width/2) + x
yw = (ynd+1) (height/2) + y
Viewport width and height are silently clamped to a range that depends
on the implementation. To query this range, call glGet with argument
GL_MAX_VIEWPORT_DIMS.
ERRORS
GL_INVALID_VALUE is generated if either width or height is negative.
GL_INVALID_OPERATION is generated if glViewport is executed between the
execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GL_VIEWPORT
glGet with argument GL_MAX_VIEWPORT_DIMS
SEE ALSO
glDepthRange(3)
glViewport(3)
Mac OS X 10.6 - Generated Thu Sep 17 20:20:31 CDT 2009