import UnityEngine;
import UnityEditor;
import System.Collections;
import System.IO;
 
class HeightmapExportPNG extends EditorWindow
{
    static var terraindata : TerrainData;
   
    @MenuItem ("Terrain/Export Height Map as PNG")
    static function Init () {
        terraindata = null;
        var terrain : Terrain = null;
       
        if ( Selection.activeGameObject )
            terrain = Selection.activeGameObject.GetComponent( Terrain );
 
        if (!terrain) {
            terrain = Terrain.activeTerrain;
        }
        if (terrain) {
            terraindata = terrain.terrainData;
        }
        if (terraindata == null) {
            EditorUtility.DisplayDialog("No terrain selected", "Please select a terrain.", "Cancel");
            return;
        }
       
        //// get the terrain heights into an array and apply them to a texture2D
        var myBytes : byte[];
        var myIndex : int = 0;
        var rawHeights = new Array(0.0,0.0);
        var duplicateHeightMap = new Texture2D(terraindata.heightmapWidth, terraindata.heightmapHeight, TextureFormat.ARGB32, false);
        rawHeights = terraindata.GetHeights(0, 0, terraindata.heightmapWidth, terraindata.heightmapHeight);
 
        /// run through the array row by row
        for (y=0; y < duplicateHeightMap.height; ++y)
        {
            for (x=0; x < duplicateHeightMap.width; ++x)
            {
                /// for wach pixel set RGB to the same so it's gray
                var data = rawHeights[myIndex]; 
                var color = Vector4(data, data,data, 1.0);
                duplicateHeightMap.SetPixel (x, y, color);
                myIndex++;
            }
        }
        // Apply all SetPixel calls
        duplicateHeightMap.Apply();
 
        /// make it a PNG and save it to the Assets folder
        myBytes = duplicateHeightMap.EncodeToPNG();
        var filename : String = "DupeHeightMap.png";
        File.WriteAllBytes(Application.dataPath + "/" + filename, myBytes);
        EditorUtility.DisplayDialog("Heightmap Duplicated", "Saved as PNG in Assets/ as: " + filename, "");
    }
    }