glViewport

Name

glViewport — set the viewport

C Specification

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

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 $x nd y nd$ be normalized device coordinates. Then the window coordinates $x w y w$ are computed as follows:

$x w = x nd + 1 ⁢ width 2 + x$

$y w = y nd + 1 ⁢ height 2 + y$

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

Think you can improve this page? Edit this page on GitHub.