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 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 , y ) be normalized
nd nd
device coordinates. Then the window coordinates (x , y ) are computed as
w w
follows:
(_____)
x = (x + 1) + x
w nd ( 2 )
(______)
y = (y + 1) + y
w nd ( 2 )
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.
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glViewport(3G) OpenGL Reference glViewport(3G)ASSOCIATED GETS
glGet with argument GL_VIEWPORT
glGet with argument GL_MAX_VIEWPORT_DIMS
SEE ALSO
glDepthRange
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