What changed with SetTriangleStrip to SetTriangles with the Unity 5 update?

Questions & Answers
1

I am updating a project that is running on Unity 3.5.7f6 to 5.1.0f3. The one aspect of this project I cannot seem to figure out is with the mesh I create in code for the game dirt. This project heavily relies on dirt simulation, that is why the mesh is created and managed via C#.

The issue I am having with the ground at this moment is the mesh creation. When porting this project over to Unity 5, I was given the error that SetTriangleStrip was obsolete and I got the error Type UnityEngine.Mesh’ does not contain a definition for SetTriangleStrip. So I changed it to SetTriangles and the compile error was gone. But something had broken my mesh. Below I have pictures to show what the ground mesh should look like as well as a broken version.

49368-workingdirt.png

This is what the ground should look like. A simple triangular plane.

49369-brokendirt1sided.png

This second image is what I get when I update the project to Unity 5 and change SetTriangleStrip to SetTriangles.

If I create and add a 2 sided material, I get a similar result to the 2nd image, except that there are 2 triangles that form diamond shapes. There are still large empty holes where other missing triangles should be.

Does SetTriangles work very differently from SetTriangleStrip? I have looked for more in depth documentation and have not found anything very useful. One guess I have is that SetTriangles has changed the winding order of the verticies I am passing in. Here is a small snippet of code so you can see what I mean.

  private GameObject CreatePatch()
  {
    GameObject patch = new GameObject();
    patch.AddComponent<MeshRenderer>();
    patch.AddComponent<MeshFilter>();

    patch.GetComponent<MeshRenderer>().sharedMaterial = DirtMaterial;

    patch.transform.parent = Parent.transform;

    Mesh mesh = new Mesh();

    mesh.vertices = GeneratePatchVertices();
    mesh.uv = GeneratePatchUVs();
    mesh.normals = GeneratePatchNormals();
    mesh.tangents = GeneratePatchTangents();
    mesh.SetTriangles(GeneratePatchTriangleStrip(), 0);

    DynamicMesh dynamicMesh = patch.AddComponent<DynamicMesh>();
    dynamicMesh.Mesh = mesh;

    patch.GetComponent<MeshFilter>().sharedMesh = mesh;

    return patch;
  }

Any help would be very appreciated.

2

A triangle strip is a special way to provide vertices to avoid repeating them. If you’re using SetTriangles instead of SetTriangleStrip you’ll need to reorganize the vertices generated by your GeneratePatchTriangleStrip function.

This other answer may help you out.

3

Use SeTriangles instead of SetTriangleStrip and GetTriangle instead of GetTriangleStrip