Vec2 ScallopedSector::sample(RNG &rng)
{
float angle = calcAngleForArea(area*rng.getFloatL(), rng);
float d1 = distToCurve(angle, 0);
float d2 = distToCurve(angle, 1);
float d = sqrt(d1*d1 + (d2*d2 - d1*d1)*rng.getFloat());
return Vec2(P.x + cos(angle)*d, P.y + sin(angle)*d);
}
float ScallopedSector::calcAngleForArea(float area, RNG &rng)
{
float lo = a1, hi = a2, cur = lo + (hi-lo)*rng.getFloat();
for (int i=0; i<10; i++) {
if (calcAreaToAngle(cur)<area) {
lo = cur;
cur = (cur + hi)*.5f;
} else {
hi = cur;
cur = (lo + cur)*.5f;
}
}
return cur;
}