GlViewport
_glViewport: set the viewport
Contents
Syntax
SUB _glViewport (BYVAL x AS LONG, BYVAL y AS LONG, BYVAL width AS LONG, BYVAL height AS LONG) 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 (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:
Template:Glapi viewport equations
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.
Use With:
_glGet with argument _GL_VIEWPORT
_glGet with argument _GL_MAX_VIEWPORT_DIMS
See also
SUB _GL _glDepthRange, _glViewportArray, _glViewportIndexed
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/.
