GLAPI/glViewport

glViewport

Core in version		4.6
Core since version		1.0

glViewport: set the viewport

Function Definition

 void glViewport(GLint x​, GLint y​, GLsizei width​, GLsizei height​);

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_nd, y_nd) be normalized device coordinates. Then the window coordinates (x_w, y_w) are computed as follows:

$x_{w}=(x_{nd}+1)\left({\tfrac {width}{2}}\right)+x$

$y_{w}=(y_{nd}+1)\left({\tfrac {height}{2}}\right)+y$

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.

Associated Gets

glGet with argument GL_VIEWPORT

glGet with argument GL_MAX_VIEWPORT_DIMS

See Also

glDepthRange, glViewportArray, glViewportIndexed

Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see LicenseRef-FreeB.