GLAPI/glViewport: Difference between revisions
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== Function Definition == | == Function Definition == | ||
void '''glViewport'''(GLint | void '''glViewport'''(GLint {{param|x}}, GLint {{param|y}}, GLsizei {{param|width}}, GLsizei {{param|height}}); | ||
; x, y | ; x, y | ||
: Specify the lower left corner of the viewport rectangle, in pixels. The initial value is (0,0). | : Specify the lower left corner of the viewport rectangle, in pixels. The initial value is (0,0). | ||
; width, height | ; width, height | ||
: Specify the width and height of the viewport. When a GL context is first attached to a window, | : Specify the width and height of the viewport. When a GL context is first attached to a window, {{param|width}} and {{param|height}} are set to the dimensions of that window. | ||
== 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: | ||
{{glapi viewport equations}} | |||
Viewport width and height are silently clamped to a range that depends on the implementation. To query this range, call {{apifunc|glGet}} with argument {{enum|GL_MAX_VIEWPORT_DIMS}}. | |||
Viewport width and height are silently clamped to a range that depends on the implementation. To query this range, call | |||
== Errors == | == Errors == | ||
{{ | {{enum|GL_INVALID_VALUE}} is generated if either {{param|width}} or {{param|height}} is negative. | ||
== Associated Gets == | == Associated Gets == | ||
{{apifunc|glGet}} with argument {{enum|GL_VIEWPORT}} | |||
{{apifunc|glGet}} with argument {{enum|GL_MAX_VIEWPORT_DIMS}} | |||
== See Also == | == See Also == | ||
{{apifunc|glDepthRange}}, {{apifunc|glViewportArray}}, {{apifunc|glViewportIndexed}} | |||
== Copyright == | == Copyright == | ||
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see [ | Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see [https://khronos.org/registry/OpenGL-Refpages/LICENSES/LicenseRef-FreeB.txt LicenseRef-FreeB]. | ||
[[Category:API Reference | [[Category:Core API Ref Viewport and Clipping|Viewport]] | ||
[[Category:Core API Reference|Viewport]] | |||
Latest revision as of 21:53, 5 February 2021
| 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
glDepthRange, glViewportArray, glViewportIndexed
Copyright
Copyright © 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see LicenseRef-FreeB.