NAME

ortho, ortho2 − define an orthographic projection transformation

SPECIFICATION

C
ortho(left, right, bottom, top, near, far)
Coord left, right, bottom, top, near,

ortho2(left, right, bottom, top)
Coord left, right, bottom, top;

FORTRAN
subroutine ortho(left, right, bottom, top, near, far)
real left, right, bottom, top, near, far

subroutine ortho2(left, right, bottom, top)
real left, right, bottom, top

Pascal
procedure ortho(left, right, bottom, top, near,
far: Coord);

procedure ortho2(left, right, bottom, top: Coord);

DESCRIPTION

ortho specifies a box-shaped enclosure in the eye coordinate system that is mapped to the viewport.  left, right, bottom, top are the x and y clipping planes.  near and far are distances along the line of sight from the eye space origin, and can be negative.  The z clipping planes are at −near and −far. 

ortho2 defines a 2-D clipping rectangle.  When you use ortho2 with 3-D world coordinates, the z values are not transformed.  When ortho2 is specified, objects with z values outside the range -1≤z≤1 are clipped out. 

Both ortho and ortho2 load a matrix onto the transformation stack, overwriting what was there. 

SEE ALSO

perspective, window Programming Guide, Section 4.3, Projection Transformations
 

Version 3.6  —  December 20, 1987