glOrtho — multiply the current matrix with an orthographic matrix
void glOrthof( | GLfloat left, |
GLfloat right, | |
GLfloat bottom, | |
GLfloat top, | |
GLfloat near, | |
GLfloat far) ; |
void glOrthox( | GLfixed left, |
GLfixed right, | |
GLfixed bottom, | |
GLfixed top, | |
GLfixed near, | |
GLfixed far) ; |
left
,
right
Specify the coordinates for the left and right vertical clipping planes.
bottom
,
top
Specify the coordinates for the bottom and top horizontal clipping planes.
near
,
far
Specify the distances to the nearer and farther depth clipping planes. These values are negative if the plane is to be behind the viewer.
glOrtho
describes a transformation that produces a parallel projection.
The current matrix (see
glMatrixMode)
is multiplied by this matrix and the result replaces the
current matrix, as if
glMultMatrix
were called with the following matrix as its argument:
where
Typically, the matrix mode is
GL_PROJECTION
, and
(left
, bottom
,
-near
) and
(right
, top
,
-near
)
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).
-far
specifies the location of the far clipping plane. Both
near
and far
can be either positive or negative.
Use glPushMatrix and glPopMatrix to save and restore the current matrix stack.
Copyright © 2003-2004 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see https://khronos.org/registry/OpenGL-Refpages/LICENSES/LicenseRef-FreeB.txt.