private bool IsSelfCollision(Vector ph, Vector ch, double w, Snake sk, out double it)
{
double thr = sk.TurningRadius * Math.PI; // half
double curlen = 0;
int i = 0;
for (; i < sk.Body.Count - 1; i++)
{
double len = (sk.Body[i] - sk.Body[i + 1]).Length;
if (curlen + len >= thr)
{
break;
}
curlen += len;
}
for (; i < sk.Body.Count - 1; i++)
{
double s, t, distsq;
distsq = IntersectionSolver.ClosestSegSeg(ph, ch, sk.Body[i], sk.Body[i + 1], out s, out t);
double len = (sk.Body[i] - sk.Body[i + 1]).Length;
it = curlen + t * len;
double plen = it / sk.Length;
double tw = MathHelper.Map(plen, sk.WidthBeginPercentage, sk.WidthEndPercentage) * sk.Width;
double ttw = tw + w;
if (it >= thr && distsq <= ttw * ttw)
{
return(true);
}
curlen += len;
}
it = 0;
return(false);
}
private bool IsHeadCollision(Vector ph, Vector ch, double w, Snake sk, out double it)
{
double curlen = 0;
for (int i = 0; i < sk.Body.Count - 1; i++)
{
double s, t, distsq;
distsq = IntersectionSolver.ClosestSegSeg(ph, ch, sk.Body[i], sk.Body[i + 1], out s, out t);
double len = (sk.Body[i] - sk.Body[i + 1]).Length;
it = curlen + t * len;
double plen = it / sk.Length;
double tw = MathHelper.Map(plen, sk.WidthBeginPercentage, sk.WidthEndPercentage) * sk.Width;
double ttw = tw + w;
if (distsq <= ttw * ttw)
{
return(true);
}
curlen += len;
}
it = 0;
return(false);
}
