internal void WriteCache(ref SimplexCache cache)
{
cache.Metric = GetMetric();
cache.Count = (ushort)Count;
for (int i = 0; i < Count; ++i)
{
cache.IndexA[i] = (byte)V[i].IndexA;
cache.IndexB[i] = (byte)V[i].IndexB;
}
}
internal void ReadCache(ref SimplexCache cache, ref DistanceProxy proxyA, ref Transform transformA, ref DistanceProxy proxyB, ref Transform transformB)
{
Debug.Assert(cache.Count <= 3);
// Copy data from cache.
Count = cache.Count;
for (int i = 0; i < Count; ++i)
{
SimplexVertex v = V[i];
v.IndexA = cache.IndexA[i];
v.IndexB = cache.IndexB[i];
Vector2 wALocal = proxyA._vertices[v.IndexA];
Vector2 wBLocal = proxyB._vertices[v.IndexB];
v.WA = MathUtils.Mul(ref transformA, wALocal);
v.WB = MathUtils.Mul(ref transformB, wBLocal);
v.W = v.WB - v.WA;
v.A = 0.0f;
V[i] = v;
}
// Compute the new simplex metric, if it is substantially different than
// old metric then flush the simplex.
if (Count > 1)
{
float metric1 = cache.Metric;
float metric2 = GetMetric();
if (metric2 < 0.5f * metric1 || 2.0f * metric1 < metric2 || metric2 < MathConstants.Epsilon)
{
// Reset the simplex.
Count = 0;
}
}
// If the cache is empty or invalid ...
if (Count == 0)
{
SimplexVertex v = V[0];
v.IndexA = 0;
v.IndexB = 0;
Vector2 wALocal = proxyA._vertices[0];
Vector2 wBLocal = proxyB._vertices[0];
v.WA = MathUtils.Mul(ref transformA, wALocal);
v.WB = MathUtils.Mul(ref transformB, wBLocal);
v.W = v.WB - v.WA;
v.A = 1.0f;
V[0] = v;
Count = 1;
}
}
