GLAPI/glViewport: Difference between revisions
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'''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: | '''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: | ||
{{glapi viewport equations}} | |||
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 22:34, 31 January 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.
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 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/.