GLORTHO(3G)							   OpenGL Manual						       GLORTHO(3G)

NAME

       glOrtho - multiply the current matrix with an orthographic matrix

C SPECIFICATION

       void glOrtho(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble nearVal, GLdouble farVal);

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.

       nearVal, farVal
	   Specify the distances to the nearer and farther depth clipping planes. These values are negative if the plane is to be behind the
	   viewer.

DESCRIPTION

       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:

       2 right - left 0 0 t x 0 2 top - bottom 0 t y 0 0 -2 farVal - nearVal t z 0 0 0 1

       where t x = - right + left right - leftt y = - top + bottom top - bottomt z = - farVal + nearVal farVal - nearVal

       Typically, the matrix mode is GL_PROJECTION, and left bottom - nearVal and right top - nearVal 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).
       - farVal specifies the location of the far clipping plane. Both nearVal and farVal can be either positive or negative.

       Use glPushMatrix() and glPopMatrix() to save and restore the current matrix stack.

ERRORS

       GL_INVALID_VALUE is generated if left = right, or bottom = top, or near = far.

       GL_INVALID_OPERATION is generated if glOrtho is executed between the execution of glBegin() and the corresponding execution of glEnd().

ASSOCIATED GETS

       glGet() with argument GL_MATRIX_MODE

       glGet() with argument GL_COLOR_MATRIX

       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()

COPYRIGHT

       Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
       http://oss.sgi.com/projects/FreeB/.

AUTHORS

       opengl.org

opengl.org							    06/10/2014							       GLORTHO(3G)