C PROJ      SOURCE    CHAT      05/01/13    02:32:14     5004
C  SOURCE  MARTINEZ
      SUBROUTINE PROJ (P0,M0,M1,M2,M3,DIM2)
C
C     Projection de M0 sur le plan M1,M2,M3 -> P0
C
C
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8 (A-H,O-Z)
      REAL*8 P0(3),M0(3),M1(3),M2(3),M3(3)
      REAL*8 AP(3,3),YP(3),XP(3)
      LOGICAL DIM2,DETNUL
C
      A1=M2(1)-M1(1)
      A2=M2(2)-M1(2)
      A3=M2(3)-M1(3)
      B1=M3(1)-M1(1)
      B2=M3(2)-M1(2)
      B3=M3(3)-M1(3)
      C1=A2*B3-A3*B2
      C2=A3*B1-A1*B3
      C3=A1*B2-A2*B1
C
      AP(1,1)=A1
      AP(1,2)=A2
      AP(1,3)=A3
      AP(2,1)=B1
      AP(2,2)=B2
      AP(2,3)=B3
      AP(3,1)=C1
      AP(3,2)=C2
      AP(3,3)=C3
C
      YP(1)=A1*M0(1)+A2*M0(2)+A3*M0(3)
      YP(2)=B1*M0(1)+B2*M0(2)+B3*M0(3)
      YP(3)=C1*M0(1)+C2*M0(2)+C3*M0(3)
C
C
C       > 1ERE EQUATION : M1M2.M0P0 = 0
C       > 2EME EQUATION : M1M3.M0P0 = 0
C       > 3EME EQUATION : DET(M1M2,M1M3,M1P0) = 0
C
C
      CALL EQPAR3(XP,AP,YP,DETNUL)
C
      IF (DETNUL.EQV..FALSE.) THEN
         P0(1)=XP(1)
         P0(2)=XP(2)
         P0(3)=XP(3)
         DIM2=.TRUE.
      ELSE
         P0(1)=0.D0
         P0(1)=0.D0
         P0(1)=0.D0
         DIM2=.FALSE.
      ENDIF
C
C     P0(1)=M0(1)
C     P0(2)=M0(2)
C     P0(3)=M0(3)
      RETURN
      END