Box2DX.Collision.Shape.GetVertex C# (CSharp) Метод

        public abstract Vector2 GetVertex(int index);

        internal unsafe void ReadCache(SimplexCache *cache, Shape shapeA, Transform TransformA, Shape shapeB, Transform TransformB)
        {
            Box2DXDebug.Assert(0 <= cache->Count && cache->Count <= 3);

            // Copy data from cache.
            _count = cache->Count;
            SimplexVertex **vertices = stackalloc SimplexVertex *[3];

            fixed(SimplexVertex *v1Ptr = &_v1, v2Ptr = &_v2, v3Ptr = &_v3)
            {
                vertices[0] = v1Ptr;
                vertices[1] = v2Ptr;
                vertices[2] = v3Ptr;
                for (int i = 0; i < _count; ++i)
                {
                    SimplexVertex *v = vertices[i];
                    v->indexA = cache->IndexA[i];
                    v->indexB = cache->IndexB[i];
                    Vector2 wALocal = shapeA.GetVertex(v->indexA);
                    Vector2 wBLocal = shapeB.GetVertex(v->indexB);
                    v->wA = TransformA.TransformPoint(wALocal);
                    v->wB = TransformB.TransformPoint(wBLocal);
                    v->w  = v->wB - v->wA;
                    v->a  = 0.0f;
                }

                // 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 < Common.Settings.FLT_EPSILON)
                    {
                        // Reset the simplex.
                        _count = 0;
                    }
                }

                // If the cache is empty or invalid ...
                if (_count == 0)
                {
                    SimplexVertex *v = vertices[0];
                    v->indexA = 0;
                    v->indexB = 0;
                    Vector2 wALocal = shapeA.GetVertex(0);
                    Vector2 wBLocal = shapeB.GetVertex(0);
                    v->wA  = TransformA.TransformPoint(wALocal);
                    v->wB  = TransformB.TransformPoint(wBLocal);
                    v->w   = v->wB - v->wA;
                    _count = 1;
                }
            }
        }