function update() {
    // This depends upon pointerOrigin (Phaser.Point) being defined. You'll also need to update 'player' to match your specific needs.
    if (this.game.input.activePointer.isDown) {
        if (this.pointerOrigin) {
            this.player.position.x += this.game.input.activePointer.position.x - this.pointerOrigin.x;
            this.player.position.y += this.game.input.activePointer.position.y - this.pointerOrigin.y;
        }
        // Keep track of where the pointer has been so we can use it for the next update cycle.
        this.pointerOrigin = this.game.input.activePointer.position.clone();
    }
    else {
        this.pointerOrigin = null;
    }
}