Forums » Help » Patrolling Enemy entity

I'm trying to create patrolling enemies like in the Mario games, but can;t figure out how to get the entity to turn around after a certain distance, moving forward and back on itself.

Any ideas? Thanks

Rather than a certain distance, it might be easier to think of it as "after a certain amount of time"... Create a timer

var timer = new ig.Timer();

and change directions after a certain amount of time has elapsed...

// Change direction after 5 seconds...
if(timer.delta() >= 5) { changeDirection(); }

Ah right, makes sense thanks. I am guessing "changeDirection();" is a method I would have to implement? It isn't a standard method with ImpactJS is it?

Do you know if there is a way to check whether the entity has either hit a wall or come to the edge of a platform, and then turn around?

Theres a lot of simple good instructions in this project:
https://github.com/gamecook/super-jetroid-starter-kit

Also the two books that are featured on the site have a lot of good information and supporting the authors keeps them helping out the community.

handleMovementTrace: function (res) {
                this.parent(res);
                // collision with a wall? return!
                if (res.collision.x) {
                    this.flip = !this.flip;
                }
            }

Quote from Jon123
I am guessing "changeDirection();" is a method I would have to implement?

Correct.

@stillen, that's amazing! Thanks a lot, hopefully I can take the relevant code from that to get my game working.

@joncom, thanks for the timer idea too, I can use that for ground entities.