Esempio n. 1
0
    size_t collide(CircleShape &circle, BoxShape &box, float dt, Contact *pxContacts, size_t numMaxContacts)
    {
        dt, pxContacts, numMaxContacts;
        const Point2f &p1 = circle.body.getPosition();
        const Point2f &p2 = box.body.getPosition();

        // work in the box's coordinate system
        const Point2f kDiff = p1 - p2;

        // compute squared distance and closest point on box
        float fSqrDistance = 0.0f, fDelta;
        Point2f kClosest(kDiff * box.GetDir(0), kDiff * box.GetDir(1));
        const Point2f &extents = box.GetExtents();
        if (kClosest.x < -extents.x)
        {
            fDelta = kClosest.x + extents.x;
            fSqrDistance += fDelta*fDelta;
            kClosest.x = -extents.x;
        }
        else if (kClosest.x > extents.x)
        {
            fDelta = kClosest.x - extents.x;
            fSqrDistance += fDelta*fDelta;
            kClosest.x = extents.x;
        }
        if (kClosest.y < -extents.y)
        {
            fDelta = kClosest.y + extents.y;
            fSqrDistance += fDelta*fDelta;
            kClosest.y = -extents.y;
        }
        else if (kClosest.y > extents.y)
        {
            fDelta = kClosest.y - extents.y;
            fSqrDistance += fDelta*fDelta;
            kClosest.y = extents.y;
        }
        if (fSqrDistance > circle.GetRadius() * circle.GetRadius())
        {
            return 0;
        }
        Point2f d = p2 + kClosest - p1;
        d.Normalize();

        pxContacts[0] = Contact(p1 + d * circle.GetRadius(), p2 + kClosest, &circle.body, &box.body);
        return 1;
    }
Esempio n. 2
0
    size_t collide(BoxShape &box1, BoxShape &box2, float dt, Contact *pxContacts, size_t numMaxContacts)
    {
        dt;

        Point2f xAxis [4];
        float  fDepth[4];

        xAxis[0] = box1.GetDir(0);
        if (!IntervalIntersect(xAxis[0], box1, box2, fDepth[0])) return 0;

        xAxis[1] = box1.GetDir(1);
        if (!IntervalIntersect(xAxis[1], box1, box2, fDepth[1])) return 0;

        xAxis[2] = box2.GetDir(0);
        if (!IntervalIntersect(xAxis[2], box1, box2, fDepth[2])) return 0;

        xAxis[3] = box2.GetDir(1);
        if (!IntervalIntersect(xAxis[3], box1, box2, fDepth[3])) return 0;

        float dcoll;
        Point2f Ncoll;
        if (!FindCollisionPlane(xAxis, fDepth, Ncoll, dcoll)) return 0;

        Point2f D = box1.body.getPosition() - box2.body.getPosition();

        if (D * Ncoll < 0.0f)
            Ncoll *= -1.0f;

        Point2f xPoints0[4];
        Point2f xPoints1[4];
        size_t numPoints0;
        size_t numPoints1;

        numPoints0 = box1.FindSupportPoints( Ncoll, xPoints0);
        numPoints1 = box2.FindSupportPoints(-Ncoll, xPoints1);

        if (!ConvertSupportPointsToContacts(box1, box2, Ncoll, xPoints0, numPoints0, xPoints1, numPoints1, pxContacts, numMaxContacts))
            return 0;
        return numMaxContacts;
    }