Difference between revisions of "GLAPI/glViewport"

From OpenGL Wiki
Jump to: navigation, search
m (Bot: Adding better formatting.)
m (Bot: Adding better formatting.)
Line 35: Line 35:
== See Also ==
== See Also ==
{{apifunc|glDepthRange}}, {{apifunc|glViewportArray}}, {{apifunc|glViewportIndexed}}
== Copyright ==
== Copyright ==

Latest revision as of 01:57, 27 September 2012

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.


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 glGet with argument GL_MAX_VIEWPORT_DIMS.


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 © 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/.