Dragon curve: Difference between revisions

=={{header|Commodore BASIC}}==

{{trans|BASIC256}}

The values of <code>SIN</code> and <code>COS</code> for multiplies of <code>PI / 4</code> are remembered in arrays, so that the program may run (a little) faster.

{{works with|Commodore BASIC|3.5}}

<lang basic>

10 REM DRAGON CURVE

20 REM SIN, COS IN ARRAYS FOR PI/4 MULTIPL.

30 DIM S(7),C(7)

40 QPI=ATN(1)

50 FOR I=0 TO 7

60 S(I)=SIN(I*QPI)

70 C(I)=COS(I*QPI)

80 NEXT I

90 LEVEL=15

100 INSIZE=128:REM 2^WHOLE_NUM (LOOKS BETTER)

110 X=112

120 Y=70

130 SQ=SQR(2)

140 ROTQPI=0:ITER=0:RQ=1

150 DIM R(LEVEL)

160 GRAPHIC 2,1

170 GOSUB 190

180 END

190 REM DRAGON

200 IF ROTQPI<0 THEN ROTQPI=ROTQPI+8:GOTO 220

210 IF ROTQPI>7 THEN ROTQPI=ROTQPI-8

220 IF LEVEL>1 THEN GO TO 290

230 YN=S(ROTQPI)*INSIZE+Y

240 XN=C(ROTQPI)*INSIZE+X

250 DRAW ,X,Y TO XN,YN

260 ITER=ITER+1

270 X=XN:Y=YN

280 RETURN

290 INSIZE=INSIZE*SQ/2

300 ROTQPI=ROTQPI+RQ

310 IF ROTQPI<0 THEN ROTQPI=ROTQPI+8:GOTO 330

320 IF ROTQPI>7 THEN ROTQPI=ROTQPI-8

330 LEVEL=LEVEL-1

340 R(LEVEL)=RQ:RQ=1

350 GOSUB 190

360 ROTQPI=ROTQPI-R(LEVEL)*2

370 IF ROTQPI<0 THEN ROTQPI=ROTQPI+8:GOTO 390

380 IF ROTQPI>7 THEN ROTQPI=ROTQPI-8

390 RQ=-1

400 GOSUB 190

410 RQ=R(LEVEL)

420 ROTQPI=ROTQPI+RQ

430 IF ROTQPI<0 THEN ROTQPI=ROTQPI+8:GOTO 450

440 IF ROTQPI>7 THEN ROTQPI=ROTQPI-8

450 LEVEL=LEVEL+1

460 INSIZE=INSIZE*SQ

470 RETURN

</lang>