Method Collide

DynamicsB2ContactManager.go:86–145

This is the top level collision call for the time step. Here all the narrow phase collision is processed for the world contact list.

()

// all the narrow phase collision is processed for the world
// contact list.
func (mgr *B2ContactManager) Collide() {
	// Update awake contacts.
	c := mgr.M_contactList

	for c != nil {
		fixtureA := c.GetFixtureA()
		fixtureB := c.GetFixtureB()
		indexA := c.GetChildIndexA()
		indexB := c.GetChildIndexB()
		bodyA := fixtureA.GetBody()
		bodyB := fixtureB.GetBody()

		// Is this contact flagged for filtering?
		if (c.GetFlags() & B2Contact_Flag.E_filterFlag) != 0x0000 {
			// Should these bodies collide?
			if bodyB.ShouldCollide(bodyA) == false {
				cNuke := c
				c = cNuke.GetNext()
				mgr.Destroy(cNuke)
				continue
			}

			// Check user filtering.
			if mgr.M_contactFilter != nil && mgr.M_contactFilter.ShouldCollide(fixtureA, fixtureB) == false {
				cNuke := c
				c = cNuke.GetNext()
				mgr.Destroy(cNuke)
				continue
			}

			// Clear the filtering flag.
			c.SetFlags(c.GetFlags() & ^B2Contact_Flag.E_filterFlag)
		}

		activeA := bodyA.IsAwake() && bodyA.M_type != B2BodyType.B2_staticBody
		activeB := bodyB.IsAwake() && bodyB.M_type != B2BodyType.B2_staticBody

		// At least one body must be awake and it must be dynamic or kinematic.
		if activeA == false && activeB == false {
			c = c.GetNext()
			continue
		}

		proxyIdA := fixtureA.M_proxies[indexA].ProxyId
		proxyIdB := fixtureB.M_proxies[indexB].ProxyId
		overlap := mgr.M_broadPhase.TestOverlap(proxyIdA, proxyIdB)

		// Here we destroy contacts that cease to overlap in the broad-phase.
		if overlap == false {
			cNuke := c
			c = cNuke.GetNext()
			mgr.Destroy(cNuke)
			continue
		}

		// The contact persists.
		B2ContactUpdate(c, mgr.M_contactListener)
		c = c.GetNext()