Why are texture UV map changed for all cubes?

Question

I am trying to change and resize textures put on faces of bilt-in cube in Unity. Without any problems I managed to put different image on every face with this code:

void Start()
{
    Mesh mesh = GetComponent<MeshFilter>().mesh;
    Vector2[] UVs = new Vector2[mesh.vertices.Length];
    // Front
    UVs[0] = new Vector2(0.0f, 0.0f);
    UVs[1] = new Vector2(0.333f, 0.0f);
    UVs[2] = new Vector2(0.0f, 0.333f);
    UVs[3] = new Vector2(0.333f, 0.333f);
    // Top
    UVs[4] = new Vector2(0.334f, 0.333f);
    UVs[5] = new Vector2(0.666f, 0.333f);
    UVs[8] = new Vector2(0.334f, 0.0f);
    UVs[9] = new Vector2(0.666f, 0.0f);
    // Back
    UVs[6] = new Vector2(1.0f, 0.0f);
    UVs[7] = new Vector2(0.667f, 0.0f);
    UVs[10] = new Vector2(1.0f, 0.333f);
    UVs[11] = new Vector2(0.667f, 0.333f);
    // Bottom
    UVs[12] = new Vector2(0.0f, 0.334f);
    UVs[13] = new Vector2(0.0f, 0.666f);
    UVs[14] = new Vector2(0.333f, 0.666f);
    UVs[15] = new Vector2(0.333f, 0.334f);
    // Left
    UVs[16] = new Vector2(0.334f, 0.334f);
    UVs[17] = new Vector2(0.334f, 0.666f);
    UVs[18] = new Vector2(0.666f, 0.666f);
    UVs[19] = new Vector2(0.666f, 0.334f);
    // Right        
    UVs[20] = new Vector2(0.667f, 0.334f);
    UVs[21] = new Vector2(0.667f, 0.666f);
    UVs[22] = new Vector2(1.0f, 0.666f);
    UVs[23] = new Vector2(1.0f, 0.334f);
    mesh.uv = UVs;
    GetComponent<MeshFilter>().mesh = mesh
     }

This works, but it uses only texture (texture atlas??) attached to the cube/shader. I wonder if it is possible to use two different texture sets so for example I have 4 faces with the parts of the texture 1, and 2 faces with parts of texture 2. Or maybe it is possible to generate texture atlas by code using 6 different textures? Can PackTexture() method be used for that?

Klamore74 · Answer 1 · 2016-03-26T17:43:46.497

To use more textures you need a separate submesh. With separate subMesh Unity allow to attach other material and other texture.

Look at

http://docs.unity3d.com/ScriptReference/Mesh.SetTriangles.html

For example create a script with this code and attach it to a GameObject with a cube.

void Awake () 
{
    Mesh currentMesh = this.GetComponent<MeshFilter>().mesh;

    int[] submesh0 = new int[]{0,2,3,0,3,1,8,4,5,8,5,9,10,6,7,10,7,11,12,13,14,12,14,15};
    int[] submesh1 = new int[]{16,17,18,16,18,19, 20,21,22,20,22,23};

    currentMesh.subMeshCount=2;

    currentMesh.SetTriangles(submesh0,0);
    currentMesh.SetTriangles(submesh1,1);
}

After the awake, attach two material to cube and it uses for 4 face a material, for other 2 the other.

Please note that this is not the best way to this. Using two material break unity optimization and need two separate draw calls (more expensive).

Hi. Thanks, but if I will have two submeshes attached to cube, one having six cube faces texture and secon also having different six faces texture, will I be able to use four faces from first texture and two faces from second texture? — Łukasz Motyczka, Mar 25 '16 at 16:04
Hi, I solved my problem with using Texture2D.PackTextures, and then by setting UVs for every opf packed textures. Thanks anyway :) — Łukasz Motyczka, Mar 26 '16 at 17:59

Why are texture UV map changed for all cubes?

1 Answers1