text: C Copyright(C) 1999-2020 National Technology & Engineering Solutions
  C of Sandia, LLC (NTESS).  Under the terms of Contract DE-NA0003525 with
  C NTESS, the U.S. Government retains certain rights in this software.
  C
  C See packages/seacas/LICENSE for details
  
  C=======================================================================
        SUBROUTINE MP3PG(NV,XV,YV,ZV,NO,XVO,YVO,ZVO)
        COMMON /MAP/MODEL(4,4),VIEW(4,4),PROJ(4,4),CPNEAR,CPFAR,VWPORT(4),
       *       MVP(4,4),VP(4,4),CPLINE(2,2,10),CPPLAN(2,3,10),PEYE(3),
       *       PLOOK(3),ETWIST,NCPLIN,NCPLAN,TMAT1(4,4),TMAT2(4,4),
       *       TMAT3(4,4),TVEC1(4),TVEC2(4),TVEC3(4),TVEC4(4),TARR1(32),
       *       TARR2(32),TARR3(32),TARR4(32),TARR5(32),TARR6(32),
       *       TARR7(32),TARR8(32)
        REAL MODEL,MVP
        LOGICAL NOCLIP
        DIMENSION C1(3),C2(3),XV(NV),YV(NV),ZV(NV),XVO(NO),YVO(NO),ZVO(NO)
        dimension mask(1)
  
        VCX = (VWPORT(1)+VWPORT(2))/2.
        VSX = (VWPORT(2)-VWPORT(1))/2.
        VCY = (VWPORT(3)+VWPORT(4))/2.
        VSY = (VWPORT(4)-VWPORT(3))/2.
        NOCLIP = (NCPLAN.EQ.0)
        NOSAVE = NO
        NO = 0
        MASK(1) = -1
        IF (NOCLIP) THEN
           CALL MPMUL3(NV,XV,YV,ZV,MVP,TARR1,TARR2,TARR3,TARR4)
  
        ELSE
           CALL MPMUL3(NV,XV,YV,ZV,MODEL,TARR1,TARR2,TARR3,TARR4)
           DO 2220 I = 1,NCPLAN
              C1(1) = CPPLAN(1,1,I)
              C1(2) = CPPLAN(1,2,I)
              C1(3) = CPPLAN(1,3,I)
              C2(1) = CPPLAN(2,1,I)
              C2(2) = CPPLAN(2,2,I)
              C2(3) = CPPLAN(2,3,I)
              CALL PLTCP3(NV,MASK,TARR1,TARR2,TARR3,C1,C2)
              IF (MASK(1).NE.-1) THEN
                 GO TO 2220
  
              END IF
  
   2220    CONTINUE
           CALL MPMUL4(NV,MASK(1),TARR1,TARR2,TARR3,TARR4,VP,TARR1,TARR2,
       *               TARR3,TARR4)
        END IF
  
        CALL PLTZCP(CPNEAR,CPFAR,NV,MASK,TARR4)
        IF (MASK(1).NE.-1) THEN
           RETURN
  
        END IF
  
        DO 2240 I = 1,NV
           TARR1(I) = (TARR1(I)/TARR4(I))*VSX + VCX
           TARR2(I) = (TARR2(I)/TARR4(I))*VSY + VCY
           TARR3(I) = TARR3(I)/TARR4(I)
   2240 CONTINUE
        C1(1) = VWPORT(1)
        C1(2) = VWPORT(3)
        C2(1) = VWPORT(2)
        C2(2) = VWPORT(4)
        NO = NOSAVE
        CALL PLTVWG(C1,C2,NV,TARR1,TARR2,TARR3,NO,XVO,YVO,ZVO)
        RETURN
  
        END
  