glOrtho
NAME
glOrtho -- multiply the current matrix by an orthographic matrix
C SPECIFICATION
void glOrtho(GLdouble left,
GLdouble right,
GLdouble bottom,
GLdouble top,
GLdouble near,
GLdouble far)
PARAMETERS
- 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 distances are negative if the plane is to be behind the viewer.
DESCRIPTION
glOrtho describes a matrix that produces a parallel projection.
(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. 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
glPushMatrix and
glPopMatrix
to save and restore the current matrix stack.
ERRORS
GL_INVALID_OPERATION is generated if glOrtho is called between
a call to glBegin and the corresponding
call to glEnd.
ASSOCIATED GETS
glGet with argument
GL_MATRIX_MODE
glGet with argument
GL_MODELVIEW_MATRIX
glGet with argument
GL_PROJECTION_MATRIX
glGet with argument
GL_TEXTURE_MATRIX
SEE ALSO
glFrustum,
glMatrixMode,
glMultMatrix,
glPushMatrix,
glViewport
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© 1995 Uwe Behrens. All rights reserved.