GLVIEWPORT(3G)

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 (xnd, ynd) be normalized device coordinates. Then the window coordinates (xw, yw) are computed as follows:
xw = (xnd+1) (width/2) + x
yw = (ynd+1) (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
glGet with argument GL_VIEWPORT
glGet with argument GL_MAX_VIEWPORT_DIMS

SEE ALSO
glDepthRange