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   bazzargh@hachyderm.io's status on Saturday, 24-Feb-2024 22:12:14 JST bazzargh

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   • BBC Micro Bot :mastodon:
   • groff

   @bbcmicrobot @geoffl I had a sign flipped 🤦 also fixed the z-offset, shading looks much better now I think.

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     bazzargh@hachyderm.io's status on Saturday, 24-Feb-2024 22:12:15 JST bazzargh

     in reply to

     • BBC Micro Bot :mastodon:
     • groff

     @bbcmicrobot @geoffl Messing with the maths, which I probably got wrong-I see I left in an unnecessary if abs(K)<abs(X). At each value of x from -(R+r) to (R+r) and each value of K=(R+rcosv) I get the 4 points on the surface and plot them. Seems to have enough density to avoid bleed, but the shading looks wrong to me, I think I have incorrect Z-values in there

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     bazzargh@hachyderm.io's status on Saturday, 24-Feb-2024 22:12:17 JST bazzargh

     in reply to

     • groff

     @geoffl #bbcmicrobot 🚀 MODE0
     R=100
     r=22:G=R+r
     FORW=0TO450STEP93
     S=SINRAD(W+33)
     C=COSRAD(W+33)
     FORX%=0TOG:F=X%:IFF<R-r:F=R-r
     FORI=0TO60:K=F+I*(G-F)/60
     IFABS(K)<ABS(X%)GOTO160
     Z%=S*SQR(r*r-(K-R)*(K-R))
     Y%=C*SQR(K*K-X%*X%)
     FORM%=-1TO1STEP2:FORN%=-1TO1STEP2:FORO%=-1TO1STEP2
     A%=M%*X%+W*1.5:B%=N%*Y%+O%*Z%+256:J%=(7*(A% MOD4)+5*(B% MOD4))MOD16
     IF(N%*Y%*S/C+O%*Z%*C/S)+300>35*J%:PLOT69,2*A%,2*B%
     NEXT,,
     NEXT,,

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     BBC Micro Bot :mastodon: (bbcmicrobot@mastodon.me.uk)'s status on Saturday, 24-Feb-2024 22:12:17 JST BBC Micro Bot :mastodon:

     in reply to

     I ran @bazzargh's program and got this.
     Source: https://bbcmic.ro/?t=9qOzN #bbcbasic

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     groff (geoffl@mastodon.me.uk)'s status on Saturday, 24-Feb-2024 22:12:19 JST groff

     in reply to

     @bazzargh #bbcmicrobot 🚀
     MO.0:DIMS(720),D(7,7):F.I=0TO720:S(I)=SINRADI:N.
     FORI=0TO7:FORJ=0TO7
     D(I,J)=(I DIV4*2+J DIV4*3)MOD4+(I DIV 2 MOD 2*2+J DIV2 MOD2*3)MOD4*4+(I MOD2*2+J MOD2*3)MOD4*16
     N.,
     W=48:R=14
     F.A=0TO360S.64
     T=((2+(A DIV64))*80)MOD360
     F.U=0TO-(A>0)*180+179
     F.V=0TO89
     B=W+R*S(4*V)
     X=(A+B*S(U))*2
     Y=INT(B*S(U+90))
     Z=R*S(4*V+90)
     M=Y*S(T+90)+Z*S(T)
     N=Y*S(T)-Z*S(T+90)+R*3
     C=1/16:IFN>0:C=C+N/R*.2
     G=((INTM*4)+512)MOD8
     H=(ABSX*2)MOD8
     IFC*16>D(G,H) PLOT69,2*INTX,512+4*INTM
     N.,,

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     groff (geoffl@mastodon.me.uk)'s status on Saturday, 24-Feb-2024 22:12:20 JST groff

     • BBC Micro Bot :mastodon:

     @bbcmicrobot pre-calculating the SIN table from 0 to 720 degrees saves 129,600 MOD360 commands being executed.