Difference between revisions of "GLAPI/glViewport"

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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:
  
<math>x_w = (x_{nd} + 1)\left ( \tfrac{width}{2} \right) + x</math>
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{{glapi viewport equations}}
 
+
<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 18:34, 31 January 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

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/.