Method SolveTOI

engine/source/Box2D/Dynamics/b2World.cpp:577–895

Find TOI contacts and solve them.

// Find TOI contacts and solve them.
void b2World::SolveTOI(const b2TimeStep& step)
{
	b2Island island(2 * b2_maxTOIContacts, b2_maxTOIContacts, 0, &m_stackAllocator, m_contactManager.m_contactListener);

	if (m_stepComplete)
	{
		for (b2Body* b = m_bodyList; b; b = b->m_next)
		{
			b->m_flags &= ~b2Body::e_islandFlag;
			b->m_sweep.alpha0 = 0.0f;
		}

		for (b2Contact* c = m_contactManager.m_contactList; c; c = c->m_next)
		{
			// Invalidate TOI
			c->m_flags &= ~(b2Contact::e_toiFlag | b2Contact::e_islandFlag);
			c->m_toiCount = 0;
			c->m_toi = 1.0f;
		}
	}

	// Find TOI events and solve them.
	for (;;)
	{
		// Find the first TOI.
		b2Contact* minContact = NULL;
		float32 minAlpha = 1.0f;

		for (b2Contact* c = m_contactManager.m_contactList; c; c = c->m_next)
		{
			// Is this contact disabled?
			if (c->IsEnabled() == false)
			{
				continue;
			}

			// Prevent excessive sub-stepping.
			if (c->m_toiCount > b2_maxSubSteps)
			{
				continue;
			}

			float32 alpha = 1.0f;
			if (c->m_flags & b2Contact::e_toiFlag)
			{
				// This contact has a valid cached TOI.
				alpha = c->m_toi;
			}
			else
			{
				b2Fixture* fA = c->GetFixtureA();
				b2Fixture* fB = c->GetFixtureB();

				// Is there a sensor?
				if (fA->IsSensor() || fB->IsSensor())
				{
					continue;
				}