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
Fix bug that AnimatedMeshSceneNode ignored ReadOnlyMaterials flag when checking materials for transparent render passes.
Make IVideoDriver::getMaterialRenderer const.
Fix bugs in COctreeSceneNode, CMeshSceneNode and CAnimatedMeshSceneNode where check for transparency in OnRegisterSceneNode() and in render() where no longer identical (those got added after Irrlicht 1.8).
Some notes for future:
- Maybe we should have a getRenderPass instead of just needsTransparentRenderPass, but this way the code didn't need so much changes and behaves (aside from fixes) pretty much as before.
- Still wondering if the default implementation in CNullDriver::needsTransparentRenderPass should always return false when SMaterial.ZWriteEnable is set to EZW_ON.
This might be nicer with another material flag. Thought then we might want a material enum to choose the renderpass and that's more work.
And we get some recursion as needsTransparentRenderPass might want to check result of getWriteZBuffer which calls needsTransparentRenderPass, so we might need a second function or an additional flag there.
But return false when SMaterial.ZWriteEnable == EZW_ON could still be done as EZW_ON is a new flag so existing behavior shouldn't break. I just don't know right now if having an extra render pass for transparent nodes might still make sense even when zbuffer is not written or if that's really the only reason to do that. Any feedback anyone?
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6033 dfc29bdd-3216-0410-991c-e03cc46cb475
