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 MPD2VC(N,X0,Y0,X1,Y1)
      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(2),C2(2),X0(*),Y0(*),X1(*),Y1(*)
      INTEGER 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 = (NCPLIN.EQ.0)
      J = 0
   10 CONTINUE
      IF ((J.LT.N)) THEN
          JN = MIN(N-J,32)
          J1 = J
          J = J + JN
          MASK(1) = -1
          IF (NOCLIP) THEN
              CALL MPMUL2(JN,X0(1+J1),Y0(1+J1),MVP,TARR1,TARR2,TARR3,
     +                    TARR4)
              CALL MPMUL2(JN,X1(1+J1),Y1(1+J1),MVP,TARR5,TARR6,TARR7,
     +                    TARR8)

          ELSE

              CALL MPMUL2(JN,X0(1+J1),Y0(1+J1),MODEL,TARR1,TARR2,TARR3,
     +                    TARR4)
              CALL MPMUL2(JN,X1(1+J1),Y1(1+J1),MODEL,TARR5,TARR6,TARR7,
     +                    TARR8)
              DO 20 K = 1,NCPLIN
                  C1(1) = CPLINE(1,1,K)
                  C1(2) = CPLINE(1,2,K)
                  C2(1) = CPLINE(2,1,K)
                  C2(2) = CPLINE(2,2,K)
                  CALL PLTCV2(JN,MASK,TARR1,TARR2,TARR5,TARR6,TARR1,
     +                        TARR2,TARR5,TARR6,C1,C2)
   20         CONTINUE
              CALL MPMUL4(JN,MASK(1),TARR1,TARR2,TARR3,TARR4,VP,TARR1,
     +                    TARR2,TARR3,TARR4)
              CALL MPMUL4(JN,MASK(1),TARR5,TARR6,TARR7,TARR8,VP,TARR5,
     +                    TARR6,TARR7,TARR8)
          END IF

          DO 30 I = 1,JN
              TARR1(I) = (TARR1(I)/TARR4(I))*VSX + VCX
              TARR2(I) = (TARR2(I)/TARR4(I))*VSY + VCY
              TARR5(I) = (TARR5(I)/TARR8(I))*VSX + VCX
              TARR6(I) = (TARR6(I)/TARR8(I))*VSY + VCY
   30     CONTINUE
          C1(1) = VWPORT(1)
          C1(2) = VWPORT(3)
          C2(1) = VWPORT(2)
          C2(2) = VWPORT(4)
          CALL PLTVWV(C1,C2,JN,MASK,TARR1,TARR2,TARR5,TARR6)
          CALL PLTVCM(JN,MASK,TARR1,TARR2,TARR5,TARR6)
          GO TO 10

      END IF
      END