Arcade Physics: Race Game with boost and slow zones

[Ironcheese]

Hello everyone,

i am having a hard time implementing the physics for a race like game where you can drive over "boosting" and "slowing" zones. The player can control in which lane the vehicle drives (left, mid, right).

On the track there are different zones/areas. Boosting Zones should accelerate the vehicle and "Slowing" zones should really punish the player with very slow speed and a massive drag. The game is played in portrait mode with the vehicle going up. The camera is fixed on the vehicle.

The lane switching is working and right now I am using tweens for that.

My problem is the "natural" feeling for the acceleration / deceleration. I tried tweening the amount of pixels the y coordinate gets manipulated, I tried working with acceleration and velocity. Nothing of that "feels" right.
The Zones fire events when ever the vehicle enters and leaves them. I am stuck at the physics part. What should I manipulate? Acceleration? Velocity? Drag? Friction?

Inside my State:

/**
 * handle Vehicle entering a zone!
 *
 * @param obstacle
 */
handleVehicleZoneEnter(event) {
    if (event.zone instanceof SlowingZone) {
        this.vehicle.speedEffect = 'SLOWED';
    }

    if (event.zone instanceof BoostingZone) {
        this.vehicle.speedEffect = 'BOOSTED';
    }
}

/**
 * handle vehicle zone leave
 * @param event
 */
handleVehicleZoneLeave(event) {
    if (event.zone instanceof SlowingZone) {
        this.vehicle.speedEffect = 'NONE';
    }

    if (event.zone instanceof BoostingZone) {
        this.vehicle.speedEffect = 'NONE';
    }
}

Inside my vehicle Object:

    // This gets called on every frame as long as the vehicle hasnt reached the end of the track
    adjustSpeed() {
        let minSpeed    = 30;
        let normalSpeed = 500;
        let maxSpeed    = 3000;

        switch (this.speedEffect) {
            case 'SLOWED' :
                    this.body.drag.y = 500;
                    this.body.friction.y = 500;
                break;
            case 'BOOSTED' :
                    this.body.acceleration.y = -500;
                break;
            default :
                    this.body.drag.y = 100;
                    this.body.friction.y = 100;

                break;
        }
    }

 

Thanks.

[samme]

It will work with drag and acceleration (remove friction). I think in the default case you would set drag.y = 0 and apply a small acceleration up or down (if necessary) to return to normal velocity.

Another approach is to tween the velocity when the car enters or leaves the zone:

function boost () {
  this.game.add.tween(this.body.velocity)
    .to({y: -maxSpeed}, DURATION, EASE, true);
}

function slow () {
  this.game.add.tween(this.body.velocity)
    .to({y: -minSpeed}, DURATION, EASE, true);
}

function normal () {
  this.game.add.tween(this.body.velocity)
    .to({y: -normal}, DURATION, EASE, true);
}

It's precise and you can choose the duration and easing function.

[Ironcheese]

Thanks samme,

I will try this tomorrow.