NAME

glViewport - set the viewport

C SPECIFICATION

void glViewport( GLint x,

	GLint y,
	GLsizei width,
	GLsizei height )

PARAMETERS

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_{nd}

y_{nd}

) be normalized device coordinates. Then the window coordinates (

x_{w}

y_{w}

) are computed as follows:

$x_{w} = (x_{nd} + 1) (\frac{width}{2}) + x$

$y_{w} = (y_{nd} + 1) (\frac{height}{2}) + y$

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.

GL_INVALID_OPERATION is generated if glViewport is executed between the execution of glBegin and the corresponding execution of glEnd.

ASSOCIATED GETS