[Solved] 1) 3D lines 2) About meshes

[Piter]

Hello all,

I have a couple of problems:

1) 3D lines don't seem to be drawn properly. At the beginning they are, but when I move the camera their positions aren't correct. I think it's not something I've done wrong, because the positions where the lines should be drawn in are static.

2) I have a problem with meshes. I need to have a lot of small meshes for a map, but the perfomance is really poor. I've taken a look to the MeshCombiner, but I can't use it for my project. Therefore, the question is: can I have multiple meshes with the same mesh data (so the perfomance is good)? If so, if I wanted to change the color of a node, could I do the following?

Code: Select all

smgr->getMeshManipulator()->setVertexColors(...)

I've tried using that, but every node gets painted, not only the one I specified.

Thank you for any help you can provide.

[CuteAlien]

1. Do you reset the transformation before you start to draw? (See: http://irrlicht.sourceforge.net/docu/cl ... 3a4eebb5e6)
2. Scenenodes can share the mesh and overwrite materials. But vertex-colors are part of the mesh - so if you want to modify those you have to copy the mesh. At least when using the fixed function pipeline. Depending on what exactly you try to do you might be able to use shaders instead and change certain colors from there.

[jiangcaiyang]

The first question seems like what I posted in another thread:
http://irrlicht.sourceforge.net/forum/v ... =4&t=49330
I've resolved in this way: the problem is when drawing 3D line as a scene node, you probably forget to set material, or set material count to zero. This is not the correct behaviour, the result is somthing that z-order get messed up. So let getMaterialCount() method returns 1 and getMaterial() method returns a dummy material.

[Piter]

1. Do you reset the transformation before you start to draw? (See: http://irrlicht.sourceforge.net/docu/cl ... 3a4eebb5e6)

That was exactly what I was missing. Many thanks. Thank you jiangcaiyang too for your response.

2. Scenenodes can share the mesh and overwrite materials.

Could you explain how can two nodes share a mesh?

[CuteAlien]

SceneNodes share the mesh by default when they are using the same one (you pass it as a parameter when creating scenenodes).

[Piter]

If when I painted the mesh of a node, all of them got painted, then that means they were sharing the mesh, right? In that case, I don't know why I am getting bad FPS (like 10-16) with a 14*10 map. In the future, it should be something like 1000*1000 or even bigger. Isn't Irrlicht using some kind of clipping/culling automatically? I really need a fix for this.

[CuteAlien]

You can use clipping, but if it's a static mesh then the better optimization is making the mesh static (http://irrlicht.sourceforge.net/docu/cl ... 8599043dfe).
And if you have lots of nodes it will certainly get slower. Depends certainly also on the polygon numbers. One way to optimize is to merge meshes into a single mesh. CMeshCombiner and CBatchingMesh from here are good for something like that for example: http://sourceforge.net/p/irrext/code/HE ... ene/IMesh/

[hendu]

Another minecraft clone? 1 million draw calls is simply not possible, you will need to batch in some way. One node = at least one draw call, even if mesh data is shared.

Sharing the mesh data only saves memory.

[Piter]

It's not a minecraft clone, but the maps are made of cubes.
Thanks for the provided solutions, I really appreciate your help. I didn't want to use external tools, but now I'll consider it.

[kklouzal]

May I suggest PolyVox http://www.volumesoffun.com/phpBB3/

[Piter]

Thanks for your input, kklouzal.

By the way, I've found this thread (http://irrlicht.sourceforge.net/forum/v ... hp?t=42065) and the user seemed to find a way to do it. But I can't figure out the code he could have written. Any idea is welcome...

[mongoose7]

He said he removes inner vertices and uses one draw call. The code would write itself.

[Piter]

I've ended up using the CMeshCombiner, which works really really well. Congratulations to the author.

And thank you all. Problems solved