Difference between revisions of "GLAPI/glViewport"

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Core in version 4.5 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 (xnd, ynd) be normalized device coordinates. Then the window coordinates (xw, yw) 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 with argument GL_MAX_VIEWPORT_DIMS.

Errors

GL_INVALID_VALUE is generated if either width​ or height​ is negative.

Associated Gets

with argument GL_VIEWPORT

with argument GL_MAX_VIEWPORT_DIMS

Copyright

Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see http://oss.sgi.com/projects/FreeB/.