Problem with flickering triangles (dynamic mesh)

Unity Engine
1

I am writing a simple heightmap-based terrain engine for use with Unity iPhone. I have written a Chunk2D class that generates the vertices/triangles for a section of heights from my global heightmap. Everything seems to be working pretty well when the landscape is fairly smooth, but the second I start to get sharp edges the triangles start to flicker.

I have uploaded an example of the problem here: http://emerganz.com/terraintest/WebPlayer.html

Here is the part of my chunk class where I generate the geometry:

// vdx, vdy = number of vertices in X and Y of the grid
public void Generate() {
        float z;
    
        int i=0;
        int t=0;
        
        for(int x=0; x<vdx; x++) {
            for(int y=0; y<vdy; y++) {
                // Generate vertices
                z = (heights[x,y] + heights[x,y+1] + heights[x,y+1] + heights[x+1,y+1]) / 4;
                
                vertices[i].x = offsetX + x * scaleX;
                vertices[i].y = offsetZ + z * scaleZ;
                vertices[i].z = offsetY + y * scaleY;
                
                uvs[i].x = x * scaleU;
                uvs[i].y = y * scaleV;
                
                // Generate triangles
                if((x>0)  (y>0)) {
                    triangles[t++] = i - vdx - 1;
                    triangles[t++] = i;
                    triangles[t++] = i - 1;
                    
                    triangles[t++] = i - vdx - 1;
                    triangles[t++] = i - vdx;
                    triangles[t++] = i;
                }
                i++;
            }
        }
    }

Here’s the code from my simple test scene where I create the mesh:

    private void GenerateMesh() {
        chunk = new Chunk2D(dx, dy, heightMap, typeMap);
        
        Mesh mesh = new Mesh();
        
        MeshFilter meshFilter = GetComponent<MeshFilter>();
        meshFilter.mesh = mesh;
        
        mesh.vertices = chunk.vertices;
        mesh.uv = chunk.uvs;
        mesh.triangles = chunk.triangles;
        
        mesh.RecalculateNormals();
    }

I’m pretty much at a loss here - only 2 options I can imagine would be:

a) Calculating normals myself could help?

b) Angles > 45 degrees cannot be smoothed. Giving each triangle its own set of vertices might work?

I haven’t decided if I want a smooth or a sharp look on the triangles in the landscape - preferably I’d like to make it a configurable option.

2

Just as a test, turn shadows off, see if its that as I recently had some flickering issues which were down to the shadow distance.

3

Duh - thanks. That fixed the flickering. :slight_smile:

(not like shadows work on iPhone anyways)