- multiply the current matrix with an orthographic matrix



C SPECIFICATION


PARAMETERS

       _param1, _param2 Specify  the coordinates for the left and
                        right vertical clipping planes.

       _param3, _param4 Specify the coordinates  for  the  bottom
                        and top horizontal clipping planes.

       _param5, _param6 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  paral-
       lel  projection.  The current matrix (see glMatrixMode) is
       multiplied by this matrix and the result replaces the cur-
       rent  matrix, as if glMultMatrix were called with the fol-
       lowing matrix as its argument:











































                 0            _e_q_n_p_a_r_a_m____e_q_n_p_a_r_a_m__           0           ty









       (                                                                    )









                 0                     0            _e_q_n_p_a_r_a_m____e_q_n_p_a_r_a_m__ tz


















left  and upper right corners of the window, respectively, assum-
ing that the eye is located at (0, 0, 0).  -_param6 specifies the
location of the far clipping plane.  Both _param5 and _param6 can
be either positive or negative.


Use glPushMatrix and glPopMatrix to save and restore the current

matrix stack.


ERRORS

       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



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