Have Texture2Ds want alphamaps.

If I call `terrainData.GetAlphamapTexture()` I get a `Texture2D`. How would I then load that back into terrainData? `SetAlphamaps` requires a float[,,].

 

Ok, figured it out. I was specifically having a problem with the CTS splat maps being in a texture on the material's shader. (Or in the CTS component.) This will pull those splat maps and write them to the terrain data. Geez, took me 6 hours... At least it's done.

Code (CSharp):

1.         private void DoExport()
2.         {
3. #if UNITY_EDITOR
4.             var sceneName = SceneManager.GetActiveScene().name;
5.             var timeText = DateTime.Now.ToString("HHmmss");
6.             var path = "Assets/Scenes/" + sceneName + "/TerrainData-" + timeText + ".asset";
7.             Debug.Log("Saving to: " + path);
8.  
9.             var terrain = GetComponent<Terrain>();
10.             var terrainData = terrain.terrainData;
11.  
12.             // Write the CTS splat map to the terrainData!
13.             var splats = GenerateCtsAlphamap(terrainData);
14.  
15.             UnityEditor.AssetDatabase.CreateAsset(terrainData, path);
16.  
17.             // It is necessary to re-set and save. Unity issue?
18.             terrainData.SetAlphamaps(0, 0, splats);
19.             UnityEditor.AssetDatabase.SaveAssets();
20. #endif
21.         }
22.  
23.         private float[,,] GenerateCtsAlphamap(TerrainData terrainData)
24.         {
25.             var cts = GetComponent<CompleteTerrainShader>();
26.             var splatList = new[] {cts.Splat1, cts.Splat2, cts.Splat3, cts.Splat4};
27.  
28.             // Ensure we have the correct size array.
29.             var myMap = terrainData.GetAlphamaps(0, 0, terrainData.alphamapWidth, terrainData.alphamapHeight);
30.  
31.             // When we have a second splat. Two splats of 4 layers = 8.
32.             // var myMap = new float[terrainData.alphamapWidth, terrainData.alphamapHeight, 8];
33.             var layerCount = myMap.GetLength(2);
34.  
35.             for (var splatId = 0; splatId < 4; splatId++)
36.             {
37.                 var tex = splatList[splatId];
38.                 if (tex == null) continue;
39.  
40.                 var colors = splatList[splatId].GetPixels();
41.                 for (var x = 0; x < terrainData.alphamapWidth; x++)
42.                 {
43.                     for (var y = 0; y < terrainData.alphamapHeight; y++)
44.                     {
45.                         // First splat will go in slots 0, 1, 2, 3
46.                         // Second splat will go in slots 4, 5, 6, 7
47.                         // Texture is 513, vs alphamap is 512. This is ok, ignore the 513th element.
48.                         // RGBA (Assume height and width are equal.)
49.                         myMap[x, y, splatId * 4 + 0] = colors[x * splatList[splatId].width + y].r;
50.                         if (layerCount <= splatId * 4 + 1) continue;
51.                         myMap[x, y, splatId * 4 + 1] = colors[x * splatList[splatId].width + y].g;
52.                         if (layerCount <= splatId * 4 + 2) continue;
53.                         myMap[x, y, splatId * 4 + 2] = colors[x * splatList[splatId].width + y].b;
54.                         // Sometimes there are 7 layers, so we have no where to place the 8th layer.
55.                         if (layerCount <= splatId * 4 + 3) continue;
56.                         myMap[x, y, splatId * 4 + 3] = colors[x * splatList[splatId].width + y].a;
57.                     }
58.                 }
59.             }
60.  
61.             return myMap;
62.         }
63.