29 lines
896 B
Plaintext
29 lines
896 B
Plaintext
1 rem MTU 80 Column 3D HAT Program
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2 REM Micro, the 6502 magazine, may 1981 page 2
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3 REM http://archive.6502.org/publications/micro/micro_36_may_1981.pdf
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4 rem https://archive.org/details/creativecomputing-1981-05/page/n67
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10 HGR2 : HCOLOR=3
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20 P=140 : Q=100 : rem original was 160 but 140 is centered on Apple II
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30 XP=120:XR=1.5*3.1415927
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40 YP=56:YR=1:ZP=64
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50 XF=XR/XP:YF=YP/YR:ZF=XR/ZP
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60 FOR ZI=-Q TO Q-1
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70 IF ZI<-ZP OR ZI>ZP GOTO 150
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80 ZT=ZI*XP/ZP:ZZ=ZI
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90 XL=INT(.5+SQR(XP*XP-ZT*ZT))
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100 FOR XI=-XL TO XL
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110 XT=SQR(XI*XI+ZT*ZT)*XF:XX=XI
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120 YY=(SIN(XT)+.4*SIN(3*XT))*YF
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130 GOSUB 170
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140 NEXT XI
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150 NEXT ZI
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160 END
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170 X1=XX+ZZ+P
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180 Y1=YY-ZZ+Q
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181 IF Y1<1 THEN Y1=1 : REM MUST BE 1 OR ERROR IN 210
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182 IF Y1>191 THEN Y1=191
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183 IF X1<0 THEN X1=0
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184 IF X1>279 THEN X1=279
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190 HCOLOR=3:HPLOT X1,191-Y1
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210 HCOLOR=0:HPLOT X1,191-(Y1-1) TO X1,191-0
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220 RETURN |