After playing minecraft...

Sadly, CombineMeshes don't work for meshCollider(
I can't create liquid and grass (

 

I made some logic improvement to code posted by alezzz in this thread. Vertex displacement now. I think i should apply displacement not for all block types (eg bricks)

 

Why don't you use an atlas instead of bothering with tons of submeshes and mandatory optimizations coming with it ? but your mesh collider can't be the same than your rendered mesh so I don't really see the problem with your combine mesh stuff, it's supposed to be 2 seperate things.
your displacement look nice but you are still missing lightning , or there is a weird glitch, I don't know.
Differentiate block type for displacement sound heavy since you'll have to add a lot of checks for each vertex to avoid gaps, basically 3 additional by vertex to know if an adjacent cell can't move + the current one.

I would have liked more thought on chunk data structure.

 

Why don't you use an atlas instead of bothering with tons of submeshes and mandatory optimizations coming with it
eg different shader for material

My mesh collider problem:
What i do now:
generate geometry -> combine into 1 mesh -> assing to mesh filter -> render - mesh count equals to chunks count

If i want to have some submesh without collider (eg grass or liquid sumbesh) i should creating one more mesh for collider.
And mesh count in 2 times more than chunks count - uses more memory, but it's not problem, problem is destroing it after.
It can be avoided by using CombineMeshes for MeshCollider, but it's impossible


Sorry for my ugly english

 

Can anyone tell me what the best way to overlay a cracked texture on a block is? I know you can create a temporary box around whatever block you're breaking, but is there a way to put the damaged texture onto the mesh?

 

Add over damaged side(or block) texture with alpha cutout shader

 

I figured out that i have a lot of draw calls due to using Transparent\Cutout soft edge for glasses. There is stats from editor and game

With cutout shader



Without




Guys, what shader do you use for glass?

 

Do you mean instantiate a new gameobject on the block's position with the damaged texture? Because what I want to know if there is a way to put the damaged texture onto the mesh of the chunk itself.

 

I think there is a way to add textute_2 over texture_1.
Or you can write shader with 2 texture - block texture (eg grass) and damage texture.

 

But how could you tell the shader use one set of uv coords for texture 1 and another set for texture 2?

 

Use submeshes

 

What kind of a performance hit would this incur? And what about z-fighting?

 

The z-fighting would depend on how far you put the crack-texture submesh from the terrain submesh and possibly the shader. It's up to you.

 

I spend 4 hours creating water block with wave and nothing. How do you creating liquid wave: Shader? Script ?

 

https://dl.dropboxusercontent.com/u/17783172/Farm Me Now/Farm Me Now.html

In that I had just used a submesh with Unity's water shaders. I had to fiddle with the shader settings until the waves only waved up and down, then I made them not as rough (you can't really see them at all at this point). The collisions remain the same as if it were any other shader/material though. My thinking would be that you if you are using MeshColliders for everything then you could try to build a seperate water mesh and assign it to a different GameObject somehow. Maybe have an object parented to the chunk's GameObject that is only there for holding water mesh.

 

Or just do something like this

HasCollider return true for collide-able block type such as liquid(lava, water), grass bilboard.
But with this an implementation meshes will be 2 times more: one render mesh, 1 collider mesh => little more RAM using. As with the separate gameobject for water)

Code (csharp):

1.     public void BuildMesh(Chunk chunk)
2.     {
3.         if (chunk == null)
4.             throw new ArgumentNullException("chunk");
5.  
6.         MeshFilter meshFilter = gameObject.GetComponent<MeshFilter>();
7.         MeshCollider meshCollider = gameObject.GetComponent<MeshCollider>();
8.  
9.         List<CombineInstance> draw = new List<CombineInstance>(8);
10.         List<CombineInstance> collider = new List<CombineInstance>(8);
11.  
12.         for (int i = 0; i < 6; ++i)
13.         {
14.             Geometry geometry = chunk.Geometry[i + 1];
15.             CombineInstance instance = new CombineInstance
16.             {
17.                 mesh = geometry.ConvertToUnityMesh(),
18.                 subMeshIndex = 0,
19.             };
20.  
21.             if (geometry.HasCollider)
22.                 collider.Add(instance);
23.             draw.Add(instance);
24.         }
25.  
26.         UnityEngine.Object.Destroy(meshFilter.mesh);
27.         UnityEngine.Object.Destroy(meshCollider.sharedMesh);
28.  
29.         Mesh mesh = new Mesh();
30.         mesh.CombineMeshes(draw.ToArray(), false, false);
31.  
32.         meshFilter.sharedMesh = null;
33.         meshFilter.sharedMesh = mesh;
34.  
35.         mesh = new Mesh();
36.         mesh.CombineMeshes(collider.ToArray(), false, false);
37.  
38.         meshCollider.sharedMesh = null;
39.         meshCollider.sharedMesh = mesh;
40.  
41.         Debug.LogError(collider.Count);
42.         for (int i = 0; i < draw.Count; ++i)
43.         {
44.             UnityEngine.Object.Destroy(draw[i].mesh);
45.         }
46.         draw.Clear();
47.  
48.         for (int i = 0; i < collider.Count; ++i)
49.         {
50.             UnityEngine.Object.Destroy(collider[i].mesh);
51.         }
52.         collider.Clear();
53.  
54.         //UnityEngine.Object.Destroy(mesh);
55.  
56.         for (int i = 0; i < 6; ++i)
57.         {
58.             PoolGeometry.AddObject(chunk.Geometry[i]);
59.         }
60.  
61.         chunk.SwitchJob(Job.Finish);
62.     }

 

"Another rendering optimization that you can do is merge triangle faces for neighbour blocks that share the same block type or block colour. This optimization is a little more involved because you have to come up with a looping algorithm that will check each block neighbour in sequence and merge any faces which share common properties. This can become quite complex depending on the type of algorithm you use. And in some cases you might not get the most optimum face merge output. This is an area for further investigation."

Has anyone do this?

 

That's exactly what I've been doing the past for weeks/months. My new problem though is that I have to account for blocks that have been rotated. The uvs will be rotated and won't be able to share the same faces unless it's next to another block that is rotated similarly.

Edit:
Look what I found http://unitycoder.com/blog/2012/10/18/voxel-resources-engines-for-unity/
They've got a list of voxel related projects, one of them being InfiChunk (my terrain generator)(also just noticed Free Terrain 3 on the list at #10).

 

I figured out a way using shaders to show a cracked texture on the side. This only works with vertex lighting, a texture atlas, the cracks use uv2, and needs the mesh to be updated everytime a block is damaged but it works well enough for what I wanted.

Code (csharp):

1.  
2. Shader "Vertex Colored" {    Properties {
3.          //_Color ("Main Color", Color) = (1,1,1,1)
4.          _MainTex ("Base (RGBA)", 2D) = "white" {}
5.     }
6.  
7.  
8.     SubShader {
9.         Pass {
10.             BindChannels {
11.                 Bind "Color", Color
12.                 Bind "texcoord", texcoord0
13.             }
14.            
15.             SetTexture [_MainTex] {
16.                 Combine texture * primary//, texture * primary
17.             }
18.         }
19.         Pass{
20.             BindChannels{
21.                 Bind "texcoord1", texcoord0
22.             }
23.             AlphaTest Equal 1
24.             //ZWrite off
25.             SetTexture [_MainTex]{
26.                 combine texture
27.             }
28.         }
29.     }
30.    
31.     Fallback " VertexLit", 1
32. }
33.  

 

WOW! great find!

 

screen shot please? would be appreciated

 

I spend 1 hour for implementing circular array described in this post http://forum.unity3d.com/threads/63...craft/page75?p=1179343&viewfull=1#post1179343

Time in ms to generate 32*32 meshes, 16*16*64 block per chunk

Old: 752ms
New unoptimized: 650ms

I hope that optimized version spend less than 0.5 secons)

add: optimized 583ms
add: optimized v2.0: 515ms

 

I do this in block story. It is tricky, because in order to get an atlas to work with this, you need to write your own shader that will repeat a texture when a triangle spawns several blocks. It also has the issue that it can produce artifacts at the edges of blocks because of floating point precision errors in the vertex shader, since now adjacent triangles may not have the same length.

There is absolutely no way block story would work in mobile without this optimization.

 

Thanks for the tip on mobile. Your 'Block Engine Demystified' articles was a great read, and has been a great help!

 

After some tests i figured out, that i have problem with circular array.
http://forum.unity3d.com/threads/63...craft/page75?p=1179343&viewfull=1#post1179343

I thought alezzzzz use shift by 10 coz width of him world is 32 (chunk block width) * 32 (chunks in width count) = 1024 == 1 << 10
I replace 10 by 9, coz width of my world is 16 (chunk block width) * 32 (chunks in width count) = 512 = 1 << 9, but this change lead to error. Using shift by 10 help me to avoid this problem, but use in 4 times more RAM for array.
Old: 370mb
New (1 << 9): 350mb
New (1 << 10): 505mb



solved

 

I have a questions for you: how you save chunk to file? How long does the saving and loading for one chunk in ms??? And what dimension of your chunk?

 

I just do a dump of the data from memory. Data in memory can be stored compressed or uncompressed, depending on how recently it has been accessed. If it's compressed then I use RLE for 'cubic' style data and DEFLATE for smooth (Marching Cubes) data.

Unfortunately I haven't timed this but I do need to profile at some point.

I make a distinction between the size of a chunk which is stored on disk/memory, and the size of the meshes which are generated from the data. Conceptually there is no reason why these need to be the same (though it may be easier if they are).

In disk/memory I store the data in a chunk of 64x64x64 for cubic data and 32x32x32 for density data. The density data is bigger per voxel which is why the chunk size is smaller.

For generating the meshes I find it depends on the size of the scene and the target hardware, to balance batch count against extraction time. On my desktop I find I can regenerate 64x64x64 meshes in real time, whereas my laptop can only manage 16x16x16 meshes in real time.

 

I thought of how to implement a Oclussion Culling system. Just need to build list of visible chunks using player position and camera view direction, and after just set not active all chunks that not present in this list.

 

I thought I would share our project with everyone here. And if you are a talented programmer with a passion for voxel technology we could use another coder to help.

http://7daystodie.com/

Edit: I tried embedding a youtube video but it didn't work for some reason, what am I doing wrong?

 

A working occlusion culling system would be the holy grail of voxel engines. I have not come up with anything that would work fast enough. I think it is doable if your terrain is octree based, but that has a lot of performance issues in other areas.

 

@Joel Huenink - I remember seeing your game when it launched on Kickstarter, looks like a nice project.

 

Thanks!

 

Same, looks like a really good project to be on. Hopefully you guys do well with the kickstarter since you have a nice prototype to show the community. I think with time it will definitely become a polished product if you guys can get the funding you are seeking.

-Dane

 

Are you guys aware that dynamic shadows are now available in Unity Free? They're a great solution for lighting voxel-based worlds. Much easier than baking shadows into the mesh (though not so cheap to render of course).

 

Isn't not very expensive?

 

No, dynamic shadows are now free! See the Unity 4.2 release notes.

It's hard shadows only and for just a single directional light, but still a big step forward

 

No, no, i'm about GPU and CPU usage

 

Ah, sorry! Of course that's what you meant

Yes, there is some cost to real-time shadows, but I have not profiled it so I don't know how significant it is. I didn't notice any performance impact on my desktop but that is a fairly powerful machine.

For real-time shadows you basically have to render the scene twice (once is into the shadowmap), so this is some extra work for both the CPU and the GPU. You also have the overhead of reading from and comparing to the shadowmap when doing the main render, so this is some extra work for the GPU.

At some point I'll try it on my laptop to see how it performs there...

 

Realtime shadows is working out great for me so far, but ive yet to try this in a larger world and see what the performance hit is. In a smaller level though, its marginal it seems. No performance loss that I can tell.

 

Finaly i reduce memory usage of my game to 300mb for 32*32 chunks, each chunk store 16*16*64 blocks. Without tangents and normals.
With normals: 330 - 340mb

2 weeks ago, the game required more than 1 gigabyte. 330mb is not a chapel.

 

I think i can reduce memory usage by using 1 submesh per shader, instead 1 submesh per material

 

But what about if you're using, let's say, two materials with the diffuse shader. One uses a grass texture and the other uses a dirt texture. How will it account for the two different textures?

 

Texture atlas

"I think i can reduce memory usage by using 1 submesh per shader, instead 1 submesh per material "

After tests i figured out that it is not

 

1 submesh per material: 330mb cold start
1 submesh per shader (unoptimized) 640mb cold start
1 submesh per shader (optimized) 630mb cold start

 

why would the size double when you merge your submeshes, it don't make any sense...

 

Lovely post!

Just wanted to share a video of the "voxel engine" we created in unity for a game project! Ask away if you want to know anything

 

Just dropping in to let anyone interested know that I am writing quite a large tutorial series on Voxels in Unity, found in my sig or here : http://forum.unity3d.com/threads/192954-CoreDev-Creating-Voxelised-Worlds-(Like-Minecraft!)

 

Nice work

Will help a lot of people.

 

I really like the concept you got going here and it looks really fun! How long have you guys been working on this project and when are you looking to finish/release it?

-Dane