[solved] Some sort of clipping problem.

[bitplane]

I gave agamemnus a code snippet and some advice on IRC. It basically boils down to a bit of compositing:

1) Background pass: draw the sea in the skybox pass with z-writes disabled, followed by all the ground nodes as usual.
2) Foreground pass: draw the sea as a skybox with colour writes disabled but z-write on, followed by boats and other units.

This should prevent ordering problems where the sea swallows up the land, yet allow boats to be partially occluded by the sea.

[agamemnus]

Yeah, so the realization was that putting the ("solid") nodes in some specific order into the scene doesn't matter... what matters is how close each node is to the camera. When I add and start moving the ship nodes, Irrlicht re-sorts nodes and the order they are drawn in. It somehow recalculates the sea node with a very fast but inaccurate distance algorithm so that it isn't always the first node (because it's not farthest to the camera), and that is why I get these seemingly random "area" node disappearances (they are actually just hidden by the sea node).

Bitplane's code looks good, but I am going to make some slight modifications and I will post my full code later on.

[agamemnus]

Ok, here it is.

Code: Select all

class CCustomPassNode : public scene::ISceneNode {
	video::SMaterial material;
 irr::scene::IMeshBuffer *meshBuffer;
	E_SCENE_NODE_RENDER_PASS renderPass;

public:
       CCustomPassNode(scene::ISceneNode* parent, scene::ISceneManager* mgr, s32 id, IMeshBuffer *mb, E_SCENE_NODE_RENDER_PASS pass)
                : scene::ISceneNode(parent, mgr, id), meshBuffer(mb), renderPass(pass) { 
                 material = meshBuffer->getMaterial();
	}
	virtual void OnRegisterSceneNode() {

  if (IsVisible) SceneManager->registerNodeForRendering (this, renderPass);
		ISceneNode::OnRegisterSceneNode();
	}

	virtual void render()	{
		driver->setMaterial(material);
		driver->setTransform(video::ETS_WORLD, AbsoluteTransformation);
		driver->drawMeshBuffer(meshBuffer);
	}

	virtual const core::aabbox3d<f32>& getBoundingBox() const {
		return meshBuffer->getBoundingBox();
	}

	virtual u32 getMaterialCount() const {
		return 1;
	}

	virtual video::SMaterial& getMaterial(u32 i) {
		return material;
	}	
};

// .....

void * DLL_EXPORT IrrAddCustomPassMeshToScene (IAnimatedMesh* mesh, u32 passEnum, s32 id = 0) {
 return (new CCustomPassNode(smgr->getRootSceneNode(), smgr, id, mesh->getMesh(0)->getMeshBuffer(0), (irr::scene::E_SCENE_NODE_RENDER_PASS)passEnum));
}

void DLL_EXPORT IrrRemoveCustomPassMeshFromScene (u32* node) {
 ((CCustomPassNode*)node)->drop();
}

The current mesh I am passing is just two triangles, making a rectangle -- one material.

I would like to add three modifications, though:

1) Make it work for multiple materials.
2) Make it work for actually dynamic meshes.
3) Add a way to record the addition and removal/deletion of nodes into a global data structure so that I can cleanly automatically drop the custom nodes in my cleanup function.

Edit: I realized the roads are going to flicker too (in and out of areas). Not sure what I am going to do about this, but now that I am more clear on how it works, I am confident I will find a solution.