glViewport(3G) OpenGL Reference 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 default is (0,0).
width, height
Specify the width and height, respectively, 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 , y ) be normalized
nd nd
device coordinates. Then the window coordinates (x , y ) are computed as
w w
follows:
x = (x +1)*(width / 2) + x
w nd
y = (y +1)*(height / 2) + y
w nd
Viewport width and height are silently clamped to a range that depends on
the implementation. This range is queried by calling glGet with argument
GLMAXVIEWPORTDIMS.
ERRORS
GLINVALIDVALUE is generated if either width or height is negative.
GLINVALIDOPERATION is generated if glViewport is executed between the
execution of glBegin and the corresponding execution of glEnd.
ASSOCIATED GETS
glGet with argument GLVIEWPORT
glGet with argument GLMAXVIEWPORTDIMS
SEE ALSO
glDepthRange
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