GLVIEWPORT(3G) GLVIEWPORT(3G)

NAME

glViewport - set the viewport
 

C SPECIFICATION

void glViewport( GLint x,
GLint y,
GLsizei width,
GLsizei height )
 
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PARAMETERS

x, y
Specify the lower left corner of the viewport rectangle, in pixels. 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 normalized 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:
 
xw=(xnd+1)(width2)+x
 
yw=(ynd+1)(height2)+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(3G)