Index: binaries/data/mods/public/maps/random/rmgen/RandomMap.js
===================================================================
--- binaries/data/mods/public/maps/random/rmgen/RandomMap.js	(revision 21929)
+++ binaries/data/mods/public/maps/random/rmgen/RandomMap.js	(working copy)
@@ -457,21 +457,18 @@
  */
 RandomMap.prototype.exportTerrainTextures = function()
 {
-	let tileIndex = new Uint16Array(Math.square(this.size));
-	let tilePriority = new Uint16Array(Math.square(this.size));
+	// Use one u16 array. 8 bits for each
+	let tileData = new Uint16Array(Math.square(this.size));
 
 	for (let x = 0; x < this.size; ++x)
 		for (let z = 0; z < this.size; ++z)
 		{
 			// TODO: For now just use the texture's index as priority, might want to do this another way
-			tileIndex[z * this.size + x] = this.texture[x][z];
-			tilePriority[z * this.size + x] = this.texture[x][z];
+			let val = (this.texture[x][z] << 8) | this.texture[x][z];
+			tileData[z * this.size + x] = val;
 		}
 
-	return {
-		"index": tileIndex,
-		"priority": tilePriority
-	};
+	return tileData;
 };
 
 RandomMap.prototype.ExportMap = function()
Index: source/graphics/MapReader.cpp
===================================================================
--- source/graphics/MapReader.cpp	(revision 21929)
+++ source/graphics/MapReader.cpp	(working copy)
@@ -1309,16 +1309,11 @@
 	// build tile data
 	m_Tiles.resize(SQR(size));
 
-	JS::RootedValue tileData(cx);
-	GET_TERRAIN_PROPERTY(m_MapData, tileData, &tileData)
-
 	// parse tile data object into flat arrays
-	std::vector<u16> tileIndex;
-	std::vector<u16> tilePriority;
-	GET_TERRAIN_PROPERTY(tileData, index, tileIndex);
-	GET_TERRAIN_PROPERTY(tileData, priority, tilePriority);
+	std::vector<u16> tileDatas;
+	GET_TERRAIN_PROPERTY(m_MapData, tileData, tileDatas);
 
-	ENSURE(SQR(size) == tileIndex.size() && SQR(size) == tilePriority.size());
+	ENSURE(SQR(size) == tileDatas.size());
 
 	// reorder by patches and store
 	for (size_t x = 0; x < size; ++x)
@@ -1329,11 +1324,12 @@
 		{
 			size_t patchY = y / PATCH_SIZE;
 			size_t offY = y % PATCH_SIZE;
+			u16 tileDataValue = tileDatas[y*size + x];
 
 			STileDesc tile;
-			tile.m_Tex1Index = tileIndex[y*size + x];
+			tile.m_Tex1Index = (tileDataValue >> 8) & 255;
 			tile.m_Tex2Index = 0xFFFF;
-			tile.m_Priority = tilePriority[y*size + x];
+			tile.m_Priority = tileDataValue & 255;
 
 			m_Tiles[(patchY * m_PatchesPerSide + patchX) * SQR(PATCH_SIZE) + (offY * PATCH_SIZE + offX)] = tile;
 		}