GameTime.java

import org.lwjgl.Sys;


public class GameTime {

    /**
     * time at last frame
     */
    private static long lastFrame;

    /**
     * frames per second
     */
    private static int fps, frames;

    /**
     * last fps time
     */
    private static long lastFPS;

    private static int delta;

    /**
     * initialize delta time and frame time
     */
    public static void init() {
        updateDelta();
        lastFPS = getTime();
    }

    /**
     *  update delta timer and FPS counter. Call once per loop.
     */
    public static void update() {
        updateDelta();
        updateFPS();
    }

    /**
     * returns current FPS value
     * @return: fps
     */
    public static int getFPS() {
        return fps;
    }


    /**
     * Get the accurate system time
     * @return: Zeit
     */
    public static long getTime() {
        return (Sys.getTime() * 1000) / Sys.getTimerResolution();
    }


    /**
     * return the delta value for this frame
     * @return: delta
     */
    public static int getDelta() {
        return delta;
    }


    /**
     * Calculate how many milliseconds have passed since last frame and update delta
     */
    private static void updateDelta() {
        long time = getTime();
        delta = (int) (time - lastFrame);
        lastFrame = time;
    }


    /**
     * increment or reset FPS counter
     */
    private static void updateFPS() {
        if (getTime() - lastFPS > 1000) {
            fps = frames;
            frames = 0;
            lastFPS += 1000;
        }
        frames++;
    }


}