GLVIEWPORT()GLVIEWPORT()NAMEglViewport - set the viewport
C SPECIFICATION
void glViewport( GLint x,
GLint y,
GLsizei width,
GLsizei height )
delim $$
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.
DESCRIPTIONglViewport specifies the affine transformation of $x$ and $y$ from nor‐
malized device coordinates to window coordinates. Let ($x sub nd$, $y
sub nd$) be normalized device coordinates. Then the window coordinates
($x sub w$, $y sub w$) are computed as follows:
x sub w ~=~ ( x sub nd + 1 ) left ( "width" over 2 right ) ~+~ "x"
y sub w ~=~ ( y sub nd + 1 ) left ( "height" over 2 right ) ~+~ "y"
Viewport width and height are silently clamped to a range that depends on theimplementation. To query this range, call glGet with argument GL_MAX_VIEW‐
PORT_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
GLVIEWPORT()