Ortho
The Ortho function multiplies the current matrix by an orthographic matrix.
Ortho( left, right, bottom, top, near, far );
Arguments
left, right
The coordinates for the left and right vertical clipping planes.
bottom, top
The coordinates for the bottom and top horizontal clipping planes.
near, far
The distances to the nearer and farther depth clipping planes. These distances are negative if the plane is to be behind the viewer.
Remarks
The Ortho function describes a perspective matrix that produces a parallel projection. The (left, bottom, - near) and (right, top, - near) parameters specify the points on the near clipping plane that are mapped to the lower-left and upper-right corners of the window, respectively, assuming that the eye is located at (0, 0, 0). The -far parameter specifies the location of the far clipping plane. Both near and far can be either positive or negative. The corresponding matrix is
where
The current matrix is multiplied by this matrix with the result replacing the current matrix. That is, if M is the current matrix and O is the ortho matrix, then M is replaced with M · O.
Use PushMatrix and PopMatrix to save and restore the current matrix stack.
Note: Do not call Ortho between a call to Begin and the corresponding call to End.
See Also