C SPECIFICATION

       void GLAPIENTRY glFrustum( GLdouble left,
                                  GLdouble righ )

PARAMETERS

       left, righ 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 near and far depth clipping
                  planes.  Both distances must be positive.

DESCRIPTION

       glFrustum describes a perspective matrix that  produces  a  perspective
       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:








                       _<I>r_e<I>i_q<I>g_n<I>h_p_a<I>l_r<I>e_a<I>f_m<I>t__           0           A  0



















                            0      _e_q_n_p_<I>a_<I>r_e<I>a_q<I>m_n_p_a_r<I>e_a<I>q_m<I>n_<I>p_a_r_a_m__ B  0





                            0                0           C  D



















                            0                0           -1 0


                                     A=r<I>r_i<I>i_g<I>g_h<I>h__l<I>l_e<I>e_f<I>f_t<I>t_


                               B=_e<I>e_q<I>q_n<I>n_p<I>p_a<I>a_r<I>r_a<I>a_m<I>m____e<I>e_q<I>q_n<I>n_p<I>p_a<I>a_r<I>r_a<I>a_m<I>m__


                              C=-_e<I>e_q<I>q_n<I>n_p<I>p_a<I>a_r<I>r_a<I>a_m<I>m____e<I>e_q<I>q_n<I>n_p<I>p_a<I>a_r<I>r_a<I>a_m<I>m__


                              D=-_<I>e_e<I>q_q<I>n_n<I>p_p<I>a_a<I>r_r<I>a_a<I>m_m___e<I>e_q<I>q_n<I>n_p<I>p_a<I>a_r<I>r_a<I>a_m<I>m__



       Typically,  the  matrix  mode  is  GL_PROJECTION,  and  (left, _param3,
       -_param5) and (righ, _param4,  -_param5) specify the points on the near
       clipping  plane  that are mapped to the lower left and upper right cor-
       ners of the window, assuming that the eye is  located  at  (0,  0,  0).
       -_param6  specifies  the  location  of  the  far  clipping plane.  Both
       _param5 and _param6 must be positive.

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

       GL_INVALID_OPERATION  is generated if glFrustum is executed between the
       execution of glBegin and the corresponding execution of glEnd.

       glGet with argument GL_MATRIX_MODE
       glGet with argument GL_MODELVIEW_MATRIX
       glGet with argument GL_PROJECTION_MATRIX
       glGet with argument GL_TEXTURE_MATRIX
       glGet with argument GL_COLOR_MATRIX

       glOrtho, glMatrixMode, glMultMatrix, glPushMatrix, glViewport



                                                                 GLFRUSTUM(3G)