' ***** Déplacement de 2 cercles
 
    SCREEN 12: WINDOW SCREEN (1, 1)-(640, 480)
    CLS : L.Ecr% = 640: H.Ecr% = 480
    LINE (9, 9)-(631, 471), 11, B
    PAINT (5, 5), 10, 11
 
' ***** Départ du cercle n° 1
    R1% = 30: D.X1% = 1: D.Y1% = 1
    X.C1% = 150: Y.C1% = 150
    Xold1% = X.C1%: Yold1% = Y.C1%
    CIRCLE (X.C1%, Y.C1%), R1%, 14
    CIRCLE (X.C1%, Y.C1%), R1% - 2, 14
    K1% = 1
' ***** Départ du cercle n° 2
    R2% = 50: D.X2% = 1: D.Y2% = 1
    X.C2% = 330: Y.C2% = 330
    Xold2% = X.C2%: Yold2% = Y.C2%
    CIRCLE (X.C2%, Y.C2%), R2%, 12
    CIRCLE (X.C2%, Y.C2%), R2% - 2, 12
    K2% = 1
 
DO
    Debut! = TIMER
' ***** Cercle N° 1
    X.C1% = X.C1% + D.X1% * K1%: Y.C1% = Y.C1% + D.Y1% * K1%
    CIRCLE (Xold1%, Yold1%), R1%, 0
    CIRCLE (Xold1%, Yold1%), R1% - 1, 0
    CIRCLE (Xold1%, Yold1%), R1% - 2, 0
    IF (X.C1% >= L.Ecr% - R1% - 11) OR (X.C1% <= R1% + 11) THEN
        D.X1% = -D.X1%
    END IF
    IF (Y.C1% >= H.Ecr% - R1% - 11) OR (Y.C1% <= R1% + 11) THEN
        D.Y1% = -D.Y1%
    END IF
    CIRCLE (X.C1%, Y.C1%), R1%, 14
    CIRCLE (X.C1%, Y.C1%), R1% - 1, 14
    CIRCLE (X.C1%, Y.C1%), R1% - 2, 14
    Xold1% = X.C1%: Yold1% = Y.C1%
    
' ***** Cercle N° 2
    X.C2% = X.C2% + D.X2% * K2%: Y.C2% = Y.C2% + D.Y2% * K2%
    CIRCLE (Xold2%, Yold2%), R2%, 0
    CIRCLE (Xold2%, Yold2%), R2% - 1, 0
    CIRCLE (Xold2%, Yold2%), R2% - 2, 0
    IF (X.C2% >= L.Ecr% - R2% - 11) OR (X.C2% <= R2% + 11) THEN
        D.X2% = -D.X2%
    END IF
    IF (Y.C2% >= H.Ecr% - R2% - 11) OR (Y.C2% <= R2% + 11) THEN
        D.Y2% = -D.Y2%
    END IF
    CIRCLE (X.C2%, Y.C2%), R2%, 12
    CIRCLE (X.C2%, Y.C2%), R2% - 1, 12
    CIRCLE (X.C2%, Y.C2%), R2% - 2, 12
    Xold2% = X.C2%: Yold2% = Y.C2%
' ***** Test de rencontre
    IF (R1% + R2%) ^ 2 >= (Y.C1% - Y.C2%) ^ 2 + (X.C1% - X.C2%) ^ 2 THEN
        BEEP
CEPABON: ' **** Changement des sens de déplacement
        RANDOMIZE TIMER * 100
        Cas% = INT(RND * 19) + 1
        SELECT CASE Cas%
            CASE 1:  D.X1% = -D.X1%: D.Y1% = -D.Y1% ')
                     D.X2% = -D.X2%: D.Y2% = -D.Y2%          ') Inversions de toutes directions
            CASE 2:  D.X1% = -D.X1%: D.X2% = -D.X2% ' Inversions de direction horizontale
            CASE 3:  D.Y1% = -D.Y1%: D.Y2% = -D.Y2% ' Inversions de direction verticale
            CASE 4:  D.X1% = -D.X1%                                  ' Inversion de direction horizontale Cercle 1
            CASE 5:  D.Y1% = -D.Y1%                                  ' etc
            CASE 6:  D.X2% = -D.X2%
            CASE 7:  D.Y2% = -D.Y2%
            CASE 8:  D.X1% = 0: K1% = 1
            CASE 9:  D.Y1% = 0: K1% = 1
            CASE 10: D.X2% = 0: K2% = 1
            CASE 11: D.Y2% = 0: K2% = 1
            CASE 12: D.X1% = 1
            CASE 13: D.X1% = -1
            CASE 14: D.Y1% = 1
            CASE 15: D.Y1% = -1
            CASE 16: D.X2% = 1
            CASE 17: D.X2% = -1
            CASE 18: D.Y2% = 1
            CASE 19: D.Y2% = -1
            CASE 20: K1% = RND(99) + 1 ' **** Modif de la vitesse de d‚placement
            CASE 21: K2% = RND(99) + 1
            ' ***** D'autres possibilités pourraient être envisagées ....
        END SELECT
        Niou.C1% = X.C1% + D.X1%
        Niou.Y1% = Y.C1% + D.Y1%
        Niou.C2% = X.C2% + D.X2%
        Niou.Y2% = Y.C2% + D.Y2%
        IF (R1% + R2%) ^ 2 >= (Niou.Y1% - Niou.Y2%) ^ 2 + (Niou.C1% - Niou.C2%) ^ 2 THEN
            GOTO CEPABON
        END IF
    END IF
    'DO
    'LOOP UNTIL TIMER >= Debut! + .000001 'OR TIMER < Debut!
    ' !!!!! Ce temporisateur ne MARCHE PAS !!!!! POURQUOI ?????
    ' ***** Je le supprime car il ralentit trop .....
LOOP UNTIL INKEY$ = CHR$(27)