So far SceneManager always sorted Nodes per render stage.
Now we allow sorting per mesh-buffer per render stage by creating a new node for each mesh-buffer.
It's only supported for CMeshSceneNode so far.
This allows to enable better transparency sorting for meshes which have transparent buffers.
Previously those always got rendered in the order in which they got added and ignored mesh-buffer bounding-boxes, but just used the bbox of the full mesh. Now they can use the bbox for each meshbuffer which can sometimes avoid render errors.
Also depending on the scene this can be quite a bit faster because it can help reduce texture changes. We sort solid nodes per texture, but only per node. So nodes with several textures had a texture switch between rendering each meshbuffer. And those are rather expensive in Irrlicht right now (and we support no bindless textures yet...)
Lastly it's now also used to buffer the render-stage. Checking this twice (once in registering the node and once in render) constantly showed up in the profiler. Which was a bit surprising really, but anyway - now it's gone.
I tried to keep it working for all cases we had before (all kind of situations, like when people may want to call render() outside the SceneManager). But not (yet) supporting the case of changing the meshbuffers (adding or removing some) without calling setMesh() again. Reason is that this wasn't well supported before either (node materials never updated). So for now I just assume people will call setMesh() again when they change the mesh.
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6483 dfc29bdd-3216-0410-991c-e03cc46cb475
Allows to find out which class a meshbuffer has.
I used the same kind of style as ISceneNode::getType. So using four CC codes and virtual functions (instead of type variable).
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6330 dfc29bdd-3216-0410-991c-e03cc46cb475
