Fichier rouladescr2.mp (figure 4) — Modifié le 21 Mars 2008 à 20 h 46
input geometriesyr16;
vardef roulades(expr n,m,num,deno,total)=
save $;
picture $;
pair O,A[],B[];
path cc,poly;
%numeric totalcen,totaltour
O=(0,0);
%polygone sur lequel on roule
B1=u*(5,-5);
%n=8;
for k=2 upto n:
B[k]=rotation(B1,O,(k-1)*360/n);
endfor;
B[n+1]=B1;
trace B1
for k=2 upto n:
--B[k]
endfor
--cycle withcolor bleu;
%polygone roulant
A1=B1;
A2=(num/deno)[B1,B2];
for k=3 upto m:
A[k]=rotation(A[k-2],A[k-1],(180*m-360)/m);
endfor;
trace A1
for k=2 upto m:
--A[k]
endfor
--cycle withcolor violet;
%définition des centres de rotation
pair cen[];
cen[0]=B1;
totalcen:=0;
for k=0 upto n-1:
for j=1 upto deno:
cen[deno*k+j]:=(j/deno)[B[k+1],B[k+2]];
totalcen:=totalcen+1;
endfor;
endfor;
marque_p:="plein";
for k=0 upto totalcen:
pointe(cen[k]);
endfor;
totaltour:=num*m;
totalcentre:=totalcen;
for p=1 upto totaltour:
for k=0 upto totalcen:
cen[p*totalcen+k]=cen[k];
totalcentre:=totalcentre+1;
endfor;
endfor;
%calcul et tracé de la trajectoire
pair I[];
I0=A1;
ang:=360/m;
angn:=360/n;
p:=0;
path trajectoire;
trajectoire=I0--I0;
$=image(
for k=num step num until total:
%show k;
if (k-deno*((k div deno))<num) and (k-deno*((k div deno))>0):
if (deno*((k div deno)+1)-k)=0:
%message("au revoir");
I[p+1]=rotation(I[p],cen[deno*((k div deno)+1)],3.5*angn);
trace arccercle(I[p],I[p+1],cen[deno*((k div deno)+1)]) withcolor orange;
trajectoire:=trajectoire..arccercle(I[p],I[p+1],cen[deno*((k div deno)+1)]);
p:=p+1;
else:
%message("bonjour");
I[p+1]=rotation(I[p],cen[deno*(k div deno)],angn);
I[p+2]=rotation(I[p+1],cen[k],ang);
trace arccercle(I[p],I[p+1],cen[deno*(k div deno)])--arccercle(I[p+1],I[p+2],cen[k]) withcolor orange;
trajectoire:=trajectoire..arccercle(I[p],I[p+1],cen[deno*(k div deno)])--arccercle(I[p+1],I[p+2],cen[k]);
p:=p+2;
fi;
elseif (k mod deno)=0:
%message("bien joue");
I[p+1]=rotation(I[p],cen[k],ang+angn);
if I[p+1]<>I[p]:
trace arccercle(I[p],I[p+1],cen[k]) withcolor orange;
trajectoire:=trajectoire..arccercle(I[p],I[p+1],cen[k]);
fi;
p:=p+1;
else:
%message("perdu");
I[p+1]=rotation(I[p],cen[k],ang);
trace arccercle(I[p],I[p+1],cen[k]) withcolor orange;
trajectoire:=trajectoire..arccercle(I[p],I[p+1],cen[k]);
p:=p+1;
fi;
endfor;
trajectoire:=trajectoire--cycle;
);
$
enddef;
beginfig(1);
trace roulades(3,3,1,7,6);
endfig;
beginfig(2);
trace roulades(3,3,1,7,7);
endfig;
beginfig(3);
trace roulades(3,3,1,7,8);
endfig;
beginfig(4);
trace roulades(3,3,1,7,21);
endfig;
beginfig(5);
trace roulades(3,3,1,11,33);
trace hachurage(trajectoire,60,0.3,0);
fill B3--B1--B2--cycle withcolor blanc;
trace roulades(3,3,1,11,33);
endfig;
end