The glViewport function sets the viewport.
void glViewport( GLint x, GLint y, GLsizei width, GLsizei height );
- 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.
The glViewport function specifies the affine transformation of x and y from normalized device coordinates to window coordinates. Let (xnd, ynd) be normalized device coordinates. The window coordinates (xw, yw) are then computed as follows:
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
The following are the error codes generated and their conditions.
|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.|
Windows NT/2000: Requires Windows NT 3.5 or later.
Windows 95/98: Requires Windows 95 or later. Available as a redistributable for Windows 95.
Header: Declared in Gl.h.
Library: Use Opengl32.lib.