glViewport
[New
- Windows 95, OEM Service Release 2]
The glViewport
function sets the viewport.
void glViewport(
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GLint x, |
|
|
GLint y, |
|
|
GLsizei width, |
|
|
GLsizei height |
|
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); |
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Parameters
x,
y
The
lower-left corner of the viewport rectangle, in pixels. The default is (0,0).
width,
height
The width and
height, respectively, of the viewport. When an OpenGL context is first
attached to a window, width and height are set to the dimensions
of that window.
Remarks
The glViewport
function specifies the affine transformation of x and y from
normalized device coordinates to window coordinates. Let (x (nd) , y (nd) ) be normalized device coordinates. The window
coordinates (x (w) , y (w) ) are then computed as follows:
{bml bm63.BMP}
Viewport
width and height are silently clamped to a range that depends on the
implementation. This range is queried by calling glGet with argument
GL_MAX_VIEWPORT_DIMS.
The following
functions retrieve information related to glViewport:
glGet
with argument GL_VIEWPORT
glGet with
argument GL_MAX_VIEWPORT_DIMS
Error Codes
The following
are the error codes generated and their conditions.
|
Error
Code |
Condition |
|
GL_INVALID_VALUE
|
Either width
or height was negative. |
|
GL_INVALID_OPERATION
|
glViewport was called between a call to glBegin and the
corresponding call to glEnd. |
See Also