_glViewport - mkilgore/QB64pe GitHub Wiki

_glViewport: set the viewport

QB64:SUB _glViewport (BYVAL x AS LONG, BYVAL y AS LONG, BYVAL width AS LONG, BYVAL height AS LONG)

C/C++: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.

_glViewport specifies the affine transformation of x and y from normalized device coordinates to window coordinates. Let (x_nd, y_nd) be normalized device coordinates. Then the window coordinates (x_w, y_w) 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.

_GL_INVALID_VALUE is generated if either width or height is negative.

_glGet with argument _GL_VIEWPORT

_glGet with argument _GL_MAX_VIEWPORT_DIMS

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 https://spdx.org/licenses/SGI-B-2.0.html.

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