Paging module - how to make it stream things other than terrain? colliders?

[slapin]

Hi, all!
I have set up paging terrain and it works very well now. Also I update it with my sun/moon system parameters and it even updates dynamically which is super cool. Now my appetite grows and I want to add buildings and trees and possibly grass to the terrain. So I ask how to handle objects with paging?
Adding to that I will need colliders, have anybody joined Ogre's terrain system with Bullet heightmap collider? Or trimesh collider?
Another thing is of course roads. But that is for another topic.

[paroj]

did you see viewtopic.php?t=58756?

[slapin]

No, thanks a bunch for the find!

[slapin]

did you see viewtopic.php?t=58756?

Looks like at time when prepareProceduralPage is running no terrain exists,
so the code

Code: Select all

	class DummyPageProvider : public Ogre::PageProvider {
	public:
		DummyPageProvider(btDynamicsWorld *world)
			: Ogre::PageProvider()
			, mBtWorld(world)
		{
		}
		std::unordered_map<Ogre::PageID, btRigidBody *> body;
		btDynamicsWorld *mBtWorld;
		bool prepareProceduralPage(Ogre::Page *page,
					   Ogre::PagedWorldSection *section)
		{
			Ogre::TerrainGroup *pGroup =
				((Ogre::TerrainPagedWorldSection *)section)
					->getTerrainGroup();
			long x, y;
			pGroup->unpackIndex(page->getID(), &x, &y);
			Ogre::Terrain *pTerrain = pGroup->getTerrain(x, y);
			if (!pTerrain)
				return true;
			float *terrainHeightData = pTerrain->getHeightData();
			Ogre::Vector3 terrainPosition = pTerrain->getPosition();

		float *pDataConvert = new float[pTerrain->getSize() *
						pTerrain->getSize()];
		for (int i = 0; i < pTerrain->getSize(); i++)
			memcpy(pDataConvert + pTerrain->getSize() *
						      i, // source
			       terrainHeightData +
				       pTerrain->getSize() *
					       (pTerrain->getSize() -
						i - 1), // target
			       sizeof(float) *
				       (pTerrain->getSize()) // size
			);

		float metersBetweenVertices =
			pTerrain->getWorldSize() /
			(pTerrain->getSize() -
			 1); //edit: fixed 0 -> 1 on 2010-08-13
		btVector3 localScaling(metersBetweenVertices, 1,
				       metersBetweenVertices);

		btHeightfieldTerrainShape *groundShape =
			new btHeightfieldTerrainShape(
				pTerrain->getSize(),
				pTerrain->getSize(), pDataConvert,
				1 /*ignore*/, pTerrain->getMinHeight(),
				pTerrain->getMaxHeight(), 1, PHY_FLOAT,
				true);

		groundShape->setUseDiamondSubdivision(true);
		groundShape->setLocalScaling(localScaling);

		btRigidBody *groundBody = new btRigidBody(
			0, new btDefaultMotionState(), groundShape);

		groundBody->getWorldTransform().setOrigin(btVector3(
			terrainPosition.x,
			terrainPosition.y + (pTerrain->getMaxHeight() -
					     pTerrain->getMinHeight()) /
						    2,
			terrainPosition.z));

		groundBody->getWorldTransform().setRotation(
			btQuaternion(Ogre::Quaternion::IDENTITY.x,
				     Ogre::Quaternion::IDENTITY.y,
				     Ogre::Quaternion::IDENTITY.z,
				     Ogre::Quaternion::IDENTITY.w));

		mBtWorld->addRigidBody(groundBody);
		body[page->getID()] = groundBody;

		return true;
	}
	bool loadProceduralPage(Ogre::Page *page,
				Ogre::PagedWorldSection *section)
	{
		return true;
	}
	bool unloadProceduralPage(Ogre::Page *page,
				  Ogre::PagedWorldSection *section)
	{
		return true;
	}
	bool unprepareProceduralPage(Ogre::Page *page,
				     Ogre::PagedWorldSection *section)
	{
		return true;
	}
};

doesn't work and can't work. My other tries with definers work but consume all of the CPU.
The below code works but is super expensive too. Need some task/workqueue system
for this to work properly.

Code: Select all

	std::unordered_set<long> col_terrains;
	std::unordered_map<long, btRigidBody *> col_bodies;
	void create_colliders()
	{
		btDynamicsWorld *world = mDynWorld->getBtWorld();
		std::unordered_set<long> new_terrains;
		Ogre::TerrainGroup::TerrainSlotMap slots =
			mTerrainGroup->getTerrainSlots();
		auto slot_it = slots.begin();
		while (slot_it != slots.end()) {
			Ogre::Terrain *terrain = slot_it->second->instance;
			long x = slot_it->second->x;
			long y = slot_it->second->y;
			long key = y * 1024 + y;
			std::cout << "x: " << x << "\n";
			std::cout << "y: " << y << "\n";
			if (!terrain) {
				slot_it++;
				continue;
			}
			if (new_terrains.find(key) != new_terrains.end()) {
				slot_it++;
				continue;
			}
			if (col_terrains.find(key) != col_terrains.end()) {
				slot_it++;
				continue;
			}
			new_terrains.insert(key);
			col_terrains.insert(key);
			btRigidBody *body = createHeightfieldShape(
				terrain->getSize(), terrain->getHeightData(),
				terrain->getMinHeight(),
				terrain->getMaxHeight(), terrain->getPosition(),
				terrain->getWorldSize() /
					(terrain->getSize() - 1),
				world);
			OgreAssert(body, "Could not allocate body");
			col_bodies[key] = body;
			std::cout << "adding terrain body: " << terrain << " "
				  << col_bodies[key] << "\n";
			slot_it++;
		}
		auto col_it = col_terrains.begin();
		std::list<long> rm_bodies;
		while (col_it != col_terrains.end()) {
			std::cout
				<< "checking: terrain still exists: " << *col_it
				<< "\n";
			/* no terrain */
			if (new_terrains.find(*col_it) == new_terrains.end()) {
				std::cout << "was removed: "
					  << col_bodies[*col_it] << " "
					  << *col_it << "\n";
				rm_bodies.push_back(*col_it);
				/* free shapes and bodies */
			}
			col_it++;
		}
		while (!rm_bodies.empty()) {
			long key = rm_bodies.front();
			rm_bodies.pop_front();
			btRigidBody *body = col_bodies[key];
			OgreAssert(body, "No body :(");
			btCollisionShape *shape = body->getCollisionShape();
			col_terrains.erase(key);
			mDynWorld->getBtWorld()->removeRigidBody(body);
			delete shape;
			delete body;
		}