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arcm:: using hyperbolic trigonometry instead of binary search

This commit is contained in:
Zeno Rogue 2020-04-29 15:09:02 +02:00
parent 97c9be0dde
commit dc3eeba73c
1 changed files with 17 additions and 19 deletions
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36
archimedean.cpp
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@ -402,29 +402,27 @@ void archimedean_tiling::compute_geometry() {
ld alpha_total = 0;
for(int i=0; i<N; i++) {
ld crmin = 0, crmax = sphere ? M_PI/2 : 10;
ld el = 0;
for(int q=0; q<100; q++) {
circumradius[i] = (crmin + crmax) / 2;
hyperpoint p1 = xpush0(circumradius[i]);
hyperpoint p2 = spin(2 * M_PI / faces[i]) * p1;
inradius[i] = hdist0(mid(p1, p2));
el = hdist(p1, p2);
if(el > edgelength) crmax = circumradius[i];
else crmin = circumradius[i];
}
if(el < edgelength - 1e-3) alpha_total += 100; // could not make an edge that long
hyperpoint h = xpush(edgelength/2) * xspinpush0(M_PI/2, inradius[i]);
ld a = atan2(-h[1], h[0]);
if(a < 0) a += 2 * M_PI;
ld gamma = M_PI / faces[i];
auto& c = circumradius[i];
c = asin_auto(sin_auto(edgelength/2) / sin(gamma));
inradius[i] = hdist0(mid(xpush0(circumradius[i]), xspinpush0(2*gamma, circumradius[i])));
hyperpoint h = xpush(c) * spin(M_PI - 2*gamma) * xpush0(c);
ld a = atan2(h);
cyclefix(a, 0);
if(a < 0) a = -a;
alphas[i] = a;
// printf(" H = %s alp = %f\n", display(h), (float) atan2(-h[1], h[0]));
alpha_total += alphas[i];
}
// printf("el = %f alpha = %f\n", float(edgelength), float(alpha_total));
if(sphere ^ (alpha_total > M_PI)) elmin = edgelength;
if(debugflags & DF_GEOM)
println(hlog, "edgelength = ", edgelength, " angles = ", alphas, " inradius = ", inradius, " circumradius = ", circumradius);
if(isnan(alpha_total)) elmax = edgelength;
else if(sphere ^ (alpha_total > M_PI)) elmin = edgelength;
else elmax = edgelength;
if(euclid) break;
}