Animate a pendulum: Difference between revisions

==={{header|Applesoft BASIC}}===

{{trans|Commodore BASIC}}

Two shapes are used to draw and undraw the pendulum. Undrawing and drawing is done on the page that is not being displayed to make the animation flicker free. Animation code is compacted and hoisted to the beginning of the program. Variables are defined for all non-zero values.

<lang gwbasic> 0 ON NOT T GOTO 9: FOR Q = 0 TO T STEP 0:BX = PX + L * S * SIN (F):BY = PY - L * S * COS (F): HCOLOR= 0: FOR I = 0 TO N(P): DRAW T + (I = N(P)) AT X(P,I),Y(P,I): NEXT I:N(P) = 0: HCOLOR= C

1 FOR X = PX TO BX STEP (BX - PX) / Z:Y = PY + (X - PX) * (BY - PY) / (BX - PX): DRAW T AT X,Y:X(P,N(P)) = X:Y(P,N(P)) = Y:N(P) = N(P) + 1: NEXT X

2 HCOLOR= T: DRAW B AT BX,BY:X(P,N(P)) = BX:Y(P,N(P)) = BY:A = PEEK (R + P):P = NOT P: POKE U,W + W * P:A = G * SIN (F) / L / H:V = V + A / Z:F = F + V: NEXT Q

9 DIM N(1),X(1,11),Y(1,11): FOR P = 32 TO 64 STEP 32: POKE 230,P: HCOLOR= 0: HPLOT 0,0: CALL 62454: NEXT :R = 49236:P = ( PEEK (R) + PEEK (49234) + PEEK (49239) + PEEK (49232)) * 0 + 1

10 S$ = CHR$ (2) + CHR$ (0) + CHR$ (6) + CHR$ (0) + CHR$ (8) + CHR$ (0) + "-" + CHR$ (0) + ".%'?>..%" + CHR$ (0): PRINT MID$ ( STR$ ( FRE (0)) + S$,1,0);: POKE 236, PEEK (131): POKE 237, PEEK (132)

15 S = PEEK (236) + PEEK (237) * 256: POKE 232, PEEK (S + 1): POKE 233, PEEK (S + 2): SCALE= 1: ROT= 0

20 T = 1

25 F = 3.1415926535 / 2: REM THETA

30 G = 9.81

35 L = 0.5

40 V = 0: REM SPEED

45 PX = 140

50 PY = 80

55 S = 20

60 Z = 10

65 C = 3

70 B = 2

75 U = 230

80 W = 32

85 H = 50

90 GOTO</lang>