static DemoEntityManager::dListNode* LoadScene(DemoEntityManager* const scene, const char* const name, const dMatrix& location)
{
	char fileName[2048];
	GetWorkingFileName (name, fileName);

	DemoEntityManager::dListNode* const lastEnt = scene->GetLast();
	scene->LoadScene (fileName);
	for (DemoEntityManager::dListNode* node = lastEnt->GetNext(); node; node = node->GetNext()) {
		DemoEntity* const entity = node->GetInfo();
		dMatrix matrix (entity->GetNextMatrix() * location);
		entity->ResetMatrix(*scene, matrix);
	}
	return lastEnt->GetNext(); 
}
NewtonBody* CreateLevelMesh (DemoEntityManager* const scene, const char* const name, bool optimized)
{
	// load the scene from a ngd file format
	char fileName[2048];
	GetWorkingFileName (name, fileName);
	scene->LoadScene (fileName);

	NewtonBody* levelBody = NULL;
	NewtonWorld* const world = scene->GetNewton();
	for (DemoEntityManager::dListNode* node = scene->GetLast(); node; node = node->GetPrev()) {
		DemoEntity* const ent = node->GetInfo();
		DemoMesh* const mesh = (DemoMesh*) ent->GetMesh();
		dAssert (mesh->IsType(DemoMesh::GetRttiType()));

		if (mesh) {
			if (mesh->GetName() == "levelGeometry_mesh") {
				levelBody = CreateLevelMeshBody (world, ent, optimized);
				break;
			}
		}
	}
	return levelBody;
}
static void LoadHangingBridge (DemoEntityManager* const scene, TriggerManager* const triggerManager, NewtonCollision* const sceneCollision, const char* const name, const dMatrix& location, NewtonBody* const playGroundBody)
{
	NewtonWorld* const world = scene->GetNewton();
	DemoEntityManager::dListNode* const bridgeNodes = scene->GetLast();
	LoadScene(scene, name, location);

	// add bridge foundations
	for (DemoEntityManager::dListNode* node = bridgeNodes->GetNext(); node; node = node->GetNext()) {
		DemoEntity* const entity = node->GetInfo();
		if (entity->GetName().Find("ramp") != -1) {	
			DemoMesh* const mesh = (DemoMesh*)entity->GetMesh();
			dAssert (mesh->IsType(DemoMesh::GetRttiType()));

			NewtonCollision* const collision = NewtonCreateConvexHull(world, mesh->m_vertexCount, mesh->m_vertex, 3 * sizeof (dFloat), 0, 0, NULL);
			void* const proxy = NewtonSceneCollisionAddSubCollision (sceneCollision, collision);
			NewtonDestroyCollision (collision);

			// get the location of this tire relative to the car chassis
			dMatrix matrix (entity->GetNextMatrix());

			NewtonCollision* const bridgeCollision = NewtonSceneCollisionGetCollisionFromNode (sceneCollision, proxy);
			NewtonSceneCollisionSetSubCollisionMatrix (sceneCollision, proxy, &matrix[0][0]);	
			NewtonCollisionSetUserData(bridgeCollision, entity);
		}
	}


	// add all the planks that form the bridge
	dTree<NewtonBody*, dString> planks;
	dFloat plankMass = 30.0f;
	for (DemoEntityManager::dListNode* node = bridgeNodes->GetNext(); node; node = node->GetNext()) {
		DemoEntity* const entity = node->GetInfo();
		if (entity->GetName().Find("plank") != -1) {	
			DemoMesh* const mesh = (DemoMesh*)entity->GetMesh();
			dAssert (mesh->IsType(DemoMesh::GetRttiType()));

			// note: because the mesh matrix can have scale, for simplicity just apply the local mesh matrix to the vertex cloud
			dVector pool[128];
			const dMatrix& meshMatrix = entity->GetMeshMatrix();
			meshMatrix.TransformTriplex(&pool[0].m_x, sizeof (dVector), mesh->m_vertex, 3 * sizeof (dFloat), mesh->m_vertexCount);

			NewtonCollision* const collision = NewtonCreateConvexHull(world, mesh->m_vertexCount, &pool[0].m_x, sizeof (dVector), 0, 0, NULL);
			NewtonBody* const body = CreateSimpleBody (world, entity, plankMass, entity->GetNextMatrix(), collision, 0);
			NewtonDestroyCollision (collision);
			planks.Insert(body, entity->GetName());
		}
	}

	// connect each plant with a hinge
	// calculate the with of a plank
	dFloat plankwidth = 0.0f;
	dVector planksideDir (1.0f, 0.0f, 0.0f, 0.0f);
	{
		NewtonBody* const body0 = planks.Find("plank01")->GetInfo();
		NewtonBody* const body1 = planks.Find("plank02")->GetInfo();

		dMatrix matrix0;
		dMatrix matrix1;
		NewtonBodyGetMatrix(body0, &matrix0[0][0]);
		NewtonBodyGetMatrix(body1, &matrix1[0][0]);

		planksideDir = matrix1.m_posit - matrix0.m_posit;
		planksideDir = planksideDir.Scale (1.0f / dSqrt (planksideDir % planksideDir));

		dVector dir (matrix0.UnrotateVector(planksideDir));
		NewtonCollision* const shape = NewtonBodyGetCollision(body0);

		dVector p0;
		dVector p1;
		NewtonCollisionSupportVertex(shape, &dir[0], &p0[0]);
		dVector dir1 (dir.Scale (-1.0f));
		NewtonCollisionSupportVertex(shape, &dir1[0], &p1[0]);
		plankwidth = dAbs (0.5f * ((p1 - p0) % dir));
	}


	dTree<NewtonBody*, dString>::Iterator iter (planks);
	iter.Begin();

	dMatrix matrix0;
	NewtonBody* body0 = iter.GetNode()->GetInfo();
	NewtonBodyGetMatrix(body0, &matrix0[0][0]);

	for (iter ++; iter; iter ++) {
		NewtonBody* const body1 = iter.GetNode()->GetInfo();
		
		dMatrix matrix1;
		NewtonBodyGetMatrix(body1, &matrix1[0][0]);

		// calculate the hinge parameter form the matrix location of each plank
		dMatrix pinMatrix0 (dGetIdentityMatrix());
		pinMatrix0[0] = pinMatrix0[1] * planksideDir;
		pinMatrix0[0] = pinMatrix0[0].Scale (1.0f / dSqrt (pinMatrix0[0] % pinMatrix0[0]));
		pinMatrix0[2] = pinMatrix0[0] * pinMatrix0[1];
		pinMatrix0[0][3] = 0.0f;
		pinMatrix0[1][3] = 0.0f;
		pinMatrix0[2][3] = 0.0f;

		// calculate the pivot
		pinMatrix0[3] = matrix0.m_posit + pinMatrix0[2].Scale (plankwidth);
		pinMatrix0[3][3] = 1.0f;

		dMatrix pinMatrix1 (pinMatrix0);
		pinMatrix1[3] = matrix1.m_posit - pinMatrix1[2].Scale (plankwidth);
		pinMatrix1[3][3] = 1.0f;

		// connect these two plank by a hinge, there a wiggle space between eh hinge that give therefore use the alternate hinge constructor
		new CustomHinge (pinMatrix0, pinMatrix1, body0, body1);

		body0 = body1;
		matrix0 = matrix1;
	}

	// connect the last and first plank to the bridge base
	{
		iter.Begin();
		body0 = iter.GetNode()->GetInfo();
		NewtonBodyGetMatrix(body0, &matrix0[0][0]);

		dMatrix pinMatrix0 (dGetIdentityMatrix());
		pinMatrix0[0] = pinMatrix0[1] * planksideDir;
		pinMatrix0[0] = pinMatrix0[0].Scale (1.0f / dSqrt (pinMatrix0[0] % pinMatrix0[0]));
		pinMatrix0[2] = pinMatrix0[0] * pinMatrix0[1];
		pinMatrix0[0][3] = 0.0f;
		pinMatrix0[1][3] = 0.0f;
		pinMatrix0[2][3] = 0.0f;
		pinMatrix0[3] = matrix0.m_posit - pinMatrix0[2].Scale (plankwidth);

		new CustomHinge (pinMatrix0, body0, playGroundBody);
	}

	{
		iter.End();
		body0 = iter.GetNode()->GetInfo();
		NewtonBodyGetMatrix(body0, &matrix0[0][0]);

		dMatrix pinMatrix0 (dGetIdentityMatrix());
		pinMatrix0[0] = pinMatrix0[1] * planksideDir;
		pinMatrix0[0] = pinMatrix0[0].Scale (1.0f / dSqrt (pinMatrix0[0] % pinMatrix0[0]));
		pinMatrix0[2] = pinMatrix0[0] * pinMatrix0[1];
		pinMatrix0[0][3] = 0.0f;
		pinMatrix0[1][3] = 0.0f;
		pinMatrix0[2][3] = 0.0f;
		pinMatrix0[3] = matrix0.m_posit + pinMatrix0[2].Scale (plankwidth);

		new CustomHinge (pinMatrix0, body0, playGroundBody);
	}
}
static void LoadSlide (DemoEntityManager* const scene, TriggerManager* const triggerManager, NewtonCollision* const sceneCollision, const char* const name, const dMatrix& location, NewtonBody* const playGroundBody)
{
	NewtonWorld* const world = scene->GetNewton();
	DemoEntityManager::dListNode* const bridgeNodes = scene->GetLast();
	LoadScene(scene, name, location);

	// add bridge foundations
	for (DemoEntityManager::dListNode* node = bridgeNodes->GetNext(); node; node = node->GetNext()) {
		DemoEntity* const entity = node->GetInfo();
		if (entity->GetName().Find("ramp") != -1) {
			DemoMesh* const mesh = (DemoMesh*)entity->GetMesh();
			dAssert (mesh->IsType(DemoMesh::GetRttiType()));

			NewtonCollision* const collision = NewtonCreateConvexHull(world, mesh->m_vertexCount, mesh->m_vertex, 3 * sizeof (dFloat), 0, 0, NULL);
			void* const proxy = NewtonSceneCollisionAddSubCollision (sceneCollision, collision);
			NewtonDestroyCollision (collision);

			// get the location of this tire relative to the car chassis
			dMatrix matrix (entity->GetNextMatrix());

			NewtonCollision* const bridgeCollision = NewtonSceneCollisionGetCollisionFromNode (sceneCollision, proxy);
			NewtonSceneCollisionSetSubCollisionMatrix (sceneCollision, proxy, &matrix[0][0]);	
			NewtonCollisionSetUserData(bridgeCollision, entity);
		}
	}


	// add start triggers
	CustomTriggerController* trigger0 = NULL;
	CustomTriggerController* trigger1 = NULL;
	for (DemoEntityManager::dListNode* node = bridgeNodes->GetNext(); node;) {
		DemoEntity* const entity = node->GetInfo();
		node = node->GetNext() ;
		if (entity->GetName().Find("startTrigger") != -1) {
			DemoMesh* const mesh = (DemoMesh*)entity->GetMesh();
			dAssert (mesh->IsType(DemoMesh::GetRttiType()));

			// create a trigger to match his mesh
			NewtonCollision* const collision = NewtonCreateConvexHull(world, mesh->m_vertexCount, mesh->m_vertex, 3 * sizeof (dFloat), 0, 0, NULL);
			dMatrix matrix (entity->GetNextMatrix());
			CustomTriggerController* const controller = triggerManager->CreateTrigger(matrix, collision, NULL);
			NewtonDestroyCollision (collision);

			if (!trigger0) {
				trigger0 = controller;
			} else {
				trigger1 = controller;
			}
			// remove this entity from the scene, since we do not wan the trigger to be visible
			// to see triggers click "show collision mesh, and or "show contact points" in the main menu.
			scene->RemoveEntity(entity);
		}
	}

	// add the platform object
	for (DemoEntityManager::dListNode* node = bridgeNodes->GetNext(); node;) {
		DemoEntity* const entity = node->GetInfo();
		node = node->GetNext() ;
		if (entity->GetName().Find("platform") != -1) {
			// make a platform object
			PlaformEntityEntity* const platformEntity = new PlaformEntityEntity (scene, entity, trigger0->GetBody(), trigger1->GetBody());

			// store the platform in the trigger use data
			trigger0->SetUserData(platformEntity);
			trigger1->SetUserData(platformEntity);

			// remove this entity from the scene
			scene->RemoveEntity(entity);
		}
	}

}