Project290.Physics.Collision.DistanceProxy.GetVertex C# (CSharp) Method

        public Vector2 GetVertex(int index)
        {
            Debug.Assert(0 <= index && index < Vertices.Count);
            return Vertices[index];
        }

        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.GetVertex(v.IndexA);
                Vector2 wBLocal = proxyB.GetVertex(v.IndexB);
                v.WA = MathUtils.Multiply(ref transformA, wALocal);
                v.WB = MathUtils.Multiply(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 < Settings.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.GetVertex(0);
                Vector2 wBLocal = proxyB.GetVertex(0);
                v.WA  = MathUtils.Multiply(ref transformA, wALocal);
                v.WB  = MathUtils.Multiply(ref transformB, wBLocal);
                v.W   = v.WB - v.WA;
                V[0]  = v;
                Count = 1;
            }
        }