add Runnable class to handle the processing to be done in another thread

src/main/java/ca/blarg/gdx/tilemap3d/TileMapUpdater.java

@@ -0,0 +1,55 @@
+package ca.blarg.gdx.tilemap3d;
+
+public class TileMapUpdater implements Runnable {
+	final TileMap tileMap;
+
+	boolean waitingForVboCreation;
+	TileChunk chunkNeedingVboCreation;
+	float progress;
+	boolean isRunning;
+
+	public TileMapUpdater(TileMap tileMap) {
+		this.tileMap = tileMap;
+	}
+
+	public float currentProgress() {
+		return progress;
+	}
+
+	public boolean isUpdating() {
+		return isRunning;
+	}
+
+	public TileChunk getChunkNeedingVboCreation() {
+		return chunkNeedingVboCreation;
+	}
+
+	public synchronized void signalDoneVboCreation() {
+		waitingForVboCreation = false;
+	}
+
+	@Override
+	public void run() {
+		isRunning = true;
+
+		TileChunk[] chunks = tileMap.getChunks();
+
+		for (int i = 0; i < tileMap.chunks.length; ++i) {
+			progress = (float)i / (float)(chunks.length - 1);
+
+			TileChunk chunk = chunks[i];
+			tileMap.vertexGenerator.generateVertices(chunk);
+			chunkNeedingVboCreation = chunk;
+			waitingForVboCreation = true;
+
+			// wait for the render thread to take care of VBO creation and single to us that it's done
+			while (waitingForVboCreation)
+				Thread.yield();
+
+			chunkNeedingVboCreation = null;
+		}
+
+		progress = 1.0f;
+		isRunning = false;
+	}
+}