# Difference between revisions of "GLAPI/glViewport"

From OpenGL.org

< GLAPI

(4.0 API.) |
(Math equations.) |
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== Description == | == Description == | ||

− | '''glViewport''' specifies the affine transformation of | + | '''glViewport''' specifies the affine transformation of ''x'' and ''y'' from normalized device coordinates to window coordinates. Let (x<sub>nd</sub>, y<sub>nd</sub>) be normalized device coordinates. Then the window coordinates (x<sub>w</sub>, y<sub>w</sub>) are computed as follows: |

− | < | + | <math>x_w = (x_{nd} + 1)\left ( \tfrac{width}{2} \right) + x</math> |

− | < | + | <math>y_w = (y_{nd} + 1)\left ( \tfrac{height}{2} \right) + y</math> |

Viewport width and height are silently clamped to a range that depends on the implementation. To query this range, call [[GLAPI/glGet|glGet]] with argument {{code|GL_MAX_VIEWPORT_DIMS}}. | Viewport width and height are silently clamped to a range that depends on the implementation. To query this range, call [[GLAPI/glGet|glGet]] with argument {{code|GL_MAX_VIEWPORT_DIMS}}. |

## Revision as of 18:32, 31 January 2012

Core in version | 4.5 | |
---|---|---|

Core since version | 1.0 |

**glViewport:** set the viewport

## Function Definition

voidglViewport(GLintx, GLinty, GLsizeiwidth, GLsizeiheight);

- 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:

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

## 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/.