Contains() public method

public Contains ( float x, float y ) : bool
x float
y float
return bool
Exemplo n.º 1
0
        public static List <CollisionInfo> Intersects(Body body_a, Body body_b)
        {
            List <CollisionInfo> data = new List <CollisionInfo>();

            int bApmCount = body_a.count;
            int bBpmCount = body_b.count;

            BoundingSquare boxB = body_b.aabb;

            // check all PointMasses on bodyA for collision against bodyB.  if there is a collision, return detailed info.
            CollisionInfo infoAway = new CollisionInfo();
            CollisionInfo infoSame = new CollisionInfo();

            for (int i = 0; i < bApmCount; i++)
            {
                Vector2 pt = body_a.pointmass_list[i].position;

                // early out - if this point is outside the bounding box for bodyB, skip it!
                if (!boxB.Contains(pt.X, pt.Y))
                {
                    continue;
                }

                // early out - if this point is not inside bodyB, skip it!
                if (!body_b.Contains(ref pt))
                {
                    continue;
                }

                int prevPt = (i > 0) ? i - 1 : bApmCount - 1;
                int nextPt = (i < bApmCount - 1) ? i + 1 : 0;

                Vector2 prev = body_a.pointmass_list[prevPt].position;
                Vector2 next = body_a.pointmass_list[nextPt].position;

                // now get the normal for this point. (NOT A UNIT VECTOR)
                Vector2 fromPrev = new Vector2();
                fromPrev.X = pt.X - prev.X;
                fromPrev.Y = pt.Y - prev.Y;

                Vector2 toNext = new Vector2();
                toNext.X = next.X - pt.X;
                toNext.Y = next.Y - pt.Y;

                Vector2 ptNorm = new Vector2();
                ptNorm.X = fromPrev.X + toNext.X;
                ptNorm.Y = fromPrev.Y + toNext.Y;
                VectorHelper.Perpendicular(ref ptNorm);

                // this point is inside the other body.  now check if the edges on either side intersect with and edges on bodyB.
                float closestAway = 100000.0f;
                float closestSame = 100000.0f;

                infoAway.Clear();
                infoAway.body_a      = body_a;
                infoAway.pointmass_a = body_a.pointmass_list[i];
                infoAway.body_b      = body_b;

                infoSame.Clear();
                infoSame.body_a      = body_a;
                infoSame.pointmass_a = body_a.pointmass_list[i];
                infoSame.body_b      = body_b;

                bool found = false;

                int b1 = 0;
                int b2 = 1;
                for (int j = 0; j < bBpmCount; j++)
                {
                    Vector2 hitPt;
                    Vector2 norm;
                    float   edgeD;

                    b1 = j;

                    if (j < bBpmCount - 1)
                    {
                        b2 = j + 1;
                    }
                    else
                    {
                        b2 = 0;
                    }

                    Vector2 pt1 = body_b.pointmass_list[b1].position;
                    Vector2 pt2 = body_b.pointmass_list[b2].position;

                    // quick test of distance to each point on the edge, if both are greater than current mins, we can skip!
                    float distToA = ((pt1.X - pt.X) * (pt1.X - pt.X)) + ((pt1.Y - pt.Y) * (pt1.Y - pt.Y));
                    float distToB = ((pt2.X - pt.X) * (pt2.X - pt.X)) + ((pt2.Y - pt.Y) * (pt2.Y - pt.Y));


                    if ((distToA > closestAway) && (distToA > closestSame) && (distToB > closestAway) && (distToB > closestSame))
                    {
                        continue;
                    }

                    // test against this edge.
                    float dist = body_b.GetClosestPointOnEdgeSquared(pt, j, out hitPt, out norm, out edgeD);

                    // only perform the check if the normal for this edge is facing AWAY from the point normal.
                    float dot;
                    Vector2.Dot(ref ptNorm, ref norm, out dot);
                    if (dot <= 0f)
                    {
                        if (dist < closestAway)
                        {
                            closestAway            = dist;
                            infoAway.pointmass_b   = body_b.pointmass_list[b1];
                            infoAway.pointmass_c   = body_b.pointmass_list[b2];
                            infoAway.edge_distance = edgeD;
                            infoAway.point         = hitPt;
                            infoAway.normal        = norm;
                            infoAway.penetration   = dist;
                            found = true;
                        }
                    }
                    else
                    {
                        if (dist < closestSame)
                        {
                            closestSame            = dist;
                            infoSame.pointmass_b   = body_b.pointmass_list[b1];
                            infoSame.pointmass_c   = body_b.pointmass_list[b2];
                            infoSame.edge_distance = edgeD;
                            infoSame.point         = hitPt;
                            infoSame.normal        = norm;
                            infoSame.penetration   = dist;
                        }
                    }
                }

                // we've checked all edges on BodyB.
                if ((found) && (closestAway > 0.3f) && (closestSame < closestAway))
                {
                    infoSame.penetration = (float)Math.Sqrt(infoSame.penetration);
                    data.Add(infoSame);
                }
                else
                {
                    infoAway.penetration = (float)Math.Sqrt(infoAway.penetration);
                    data.Add(infoAway);
                }
            }

            return(data);
        }