Terrain Generating and multithreading

Got a question. I am working on a Voxel Engine for a game I'm working on. I have the voxel engine running good. I've created a Visual Node editor for generating the voxel terrain and I just over night multithreaded everything I possibly could. It's running pretty smoothly. I am now adding new ways of generating the terrain and wanted to add in Height map support. I then remembered I can't call any Unity API methods from threads other then the main thread. So I am now unable to call the get pixel method on the height map. What is the best way to add in Height map support with out using Unity's built in methods?

 

I came up with the following which seems to work but is it the best way or is there a better way that I'm over looking?

Code (CSharp):

1. using System;
2. using System.Collections.Generic;
3. using System.Linq;
4. using System.Text;
5. using UnityEngine;
6.  
7. namespace LibNoise.Generator
8. {
9.     class Heightmap : ModuleBase
10.     {
11.         private Texture2D heightmap;
12.  
13.         Dictionary<Vector2, Color> pixels = new Dictionary<Vector2, Color>();
14.         private float width;
15.         private float height;
16.         private Vector2 Scale;
17.  
18.         public Heightmap(Texture2D h)
19.             : base(0)
20.         {
21.             if (h != null)
22.             {
23.                 Scale = new Vector2(500, 500);
24.                 heightmap = h;
25.  
26.                 for (int x = 0; x < heightmap.width; x++)
27.                 {
28.                     for (int z = 0; z < heightmap.height; z++)
29.                     {
30.                         pixels.Add(new Vector2(x, z), heightmap.GetPixel(x, z));
31.                     }
32.                 }
33.  
34.                 width = heightmap.width;
35.                 height = heightmap.height;
36.             }
37.         }
38.  
39.         public override double GetValue(double x, double y, double z)
40.         {
41.             int _x = Mathf.FloorToInt((float)x / Scale.x * width);
42.             int _z = Mathf.FloorToInt((float)z / Scale.y * height);
43.  
44.             Vector2 pos = new Vector2(_x, _z);
45.  
46.             if (pixels.ContainsKey(pos))
47.                 return pixels[pos].grayscale;
48.  
49.             return 0;
50.         }
51.     }
52. }