glViewport — set the viewport
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 and from normalized device coordinates to window coordinates. Let be normalized device coordinates. Then the window coordinates are computed as follows:
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.
GL_INVALID_OPERATION
is generated if glViewport
is executed between the execution of glBegin and the corresponding execution of glEnd.
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