Difference between revisions of "GLAPI/glViewport"

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== Function Definition ==
 
== Function Definition ==
  
   void '''glViewport'''(GLint ''x'', GLint ''y'', GLsizei ''width'', GLsizei ''height'');
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   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, ''width'' and ''height'' are set to the dimensions of that window.
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: 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 <!--Missing Equation--> and <!--Missing Equation--> from normalized device coordinates to window coordinates. Let <!--Missing Equation--> be normalized device coordinates. Then the window coordinates <!--Missing Equation--> are computed as follows:
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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:
  
<!--Missing Equation-->
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{{glapi viewport equations}}
  
<!--Missing Equation-->
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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}}.
 
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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}}.
+
  
 
== Errors ==
 
== Errors ==
  
{{code|GL_INVALID_VALUE}} is generated if either ''width'' or ''height'' is negative.
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{{enum|GL_INVALID_VALUE}} is generated if either {{param|width}} or {{param|height}} is negative.
  
 
== Associated Gets ==
 
== Associated Gets ==
  
[[GLAPI/glGet|glGet]] with argument {{code|GL_VIEWPORT}}
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{{apifunc|glGet}} with argument {{enum|GL_VIEWPORT}}
  
[[GLAPI/glGet|glGet]] with argument {{code|GL_MAX_VIEWPORT_DIMS}}
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{{apifunc|glGet}} with argument {{enum|GL_MAX_VIEWPORT_DIMS}}
  
 
== See Also ==
 
== See Also ==
  
[[GLAPI/glDepthRange|glDepthRange]]
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{{apifunc|glDepthRange}}, {{apifunc|glViewportArray}}, {{apifunc|glViewportIndexed}}
  
 
== Copyright ==
 
== Copyright ==
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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/ http://oss.sgi.com/projects/FreeB/].
 
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/ http://oss.sgi.com/projects/FreeB/].
  
[[Category:API Reference 4|Viewport]]
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[[Category:Core API Ref Viewport and Clipping|Viewport]]
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[[Category:Core API Reference|Viewport]]

Latest revision as of 21:57, 26 September 2012

glViewport
Core in version 4.5
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 http://oss.sgi.com/projects/FreeB/.