gc.setTargetFrameRate(Constants.FRAME_RATE);
gc.setVSync(true);
worldCenterX = gc.getWidth() / 2;
worldCenterY = gc.getHeight() / 2;
world = new World();
world.setIterations(Constants.ITERATIONS);
world.setGravity(-10);
terrainy = new ImageBuffer(Constants.MAX_WIDTH, Constants.MAX_HEIGHT*2);