glViewport

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 (x_nd, y_nd) be normalized device coordinates. The window coordinates (x_w, y_w) 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.

**  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.

glBegin, glDepthRange