creates array of edges from array of mesh triangles

MeshTrianglesToEdges.cs

int2[] ToEdges ( int[] triangles )
{
	var edges = new Dictionary<ulong,int2>();
	for( int i=0 ; i<triangles.Length ; i+=3 )
	{
		int a = triangles[i];
		int b = triangles[i+1];
		int c = triangles[i+2];
		ulong hash;
		
		hash = (ulong)math.max(a,b)*(ulong)1e6 + (ulong)math.min(a,b);
		if( !edges.ContainsKey(hash) )
			edges.Add( hash , new int2(a,b) );
		
		hash = (ulong)math.max(b,c)*(ulong)1e6 + (ulong)math.min(b,c);
		if( !edges.ContainsKey(hash) )
			edges.Add( hash , new int2(b,c) );

		hash = (ulong)math.max(c,a)*(ulong)1e6 + (ulong)math.min(c,a);
		if( !edges.ContainsKey(hash) )
			edges.Add( hash , new int2(c,a) );
	}
	var results = new int2[ edges.Count ];
	edges.Values.CopyTo( results , 0 );
	return results;
}