What is the proper way to implement multi threading while using a gameLoop

Question

I'm working on a game where I move a car image based on keyboard input. Currently I'm using this game loop:

private void runGameLoop() {
        window.setVisible();
        isRunning = true;
        final double FRAMES_PER_SECOND = 60;
        double timePerUpdate = 1000000000 / FRAMES_PER_SECOND;
        double timeFromLastUpdate = 0;
        long now;
        long last = System.nanoTime();
        while (isRunning) {
            now = System.nanoTime();
            timeFromLastUpdate += (now - last) / timePerUpdate;
            last = now;
            if(timeFromLastUpdate >= 1) {
                tick();
                render();
                timeFromLastUpdate--;
            }
        }
    }

The tick method updates the car image location, and the render method will render the image(with the new location) on screen. I want to have the calculations for the new image location on a separate thread, because at the moment the calculations are taking to long and causing a rendering lag. Is there a way to use multi threading while still implementing a game loop? Thanks in advance.

Answer 1

Perhpas you can do something similar to what Android does. In Android there is the mainthread which would be like your game loop. It has a Handler for runnables that are posted from background/concurrent threads to the mainthread.

So at every loop cycle the mainthread executes any runnables posted feom background threads.

Note, that the calculations should not be done in the runnables (which are executed in mainthread), only passing the results/updating stuff should be done in the runnables.