Burger Time Enemy AI

[davidbrit2]

Has anybody thoroughly dissected the enemy AI in Burger Time (as has been done for Pac-Man)? It seems like most of the time, they proceed straight ahead, and will make a 90-degree turn whenever it becomes possible, preferring whichever direction will move them toward Peter Pepper. But it seems like the enemies will ignore corners often enough that there must be something else going on, perhaps with behavior varying by enemy type. Anybody figured it out?

[Jumpman1981]

I had a quick play, and I noticed a few things about the enemy movements:

 

All enemies move in the same way - they all directly chase Peter, but they never pass a stairwell that can get them to the platform he's on

The only real difference is how quickly they make their next move; The eggs are sharper than the hot dogs, and the pickles are sharper than the eggs. 

 

[davidbrit2]

1 minute ago, Jumpman1981 said:

I had a quick play, and I noticed a few things about the enemy movements:

 

All enemies move in the same way - they all directly chase Peter, but they never pass a stairwell that can get them to the platform he's on

The only real difference is how quickly they make their next move; The eggs are sharper than the hot dogs, and the pickles are sharper than the eggs. 

 

 

Yeah, if Peter is at a very obvious oblique angle to an enemy, the enemy will pretty much always get on/off a ladder at every opportunity, opting for whichever direction brings them closer to Peter.

 

Where things get a bit unpredictable is when Peter is standing on the same floor or ladder as one of the enemies while its heading toward him. Sometimes they will pass by any turns and head straight for him, and occasionally they will make a turn that will actually take them further away.

 

It's probably something really simple like the way the ghosts in Pac-Man choose their target squares, but I've never been able to figure it out.

[mr_me]

When on the same plank a hotdog will always go up ladders and the egg will always go down ladders.

[Deteacher]

Understanding how the enemies move makes it pretty easy to group them all together (with the help of a few peppers.)  Then you can rack up SERIOUS points for getting them all on a bun and sending them for a ride.

 

 

[davidbrit2]

2 minutes ago, Deteacher said:

Understanding how the enemies move makes it pretty easy to group them all together (with the help of a few peppers.)  Then you can rack up SERIOUS points for getting them all on a bun and sending them for a ride.

 

 

 

It appears that when an enemy reaches an intersection, it checks Peter's position along the axis perpendicular to the direction the enemy was traveling. So if the enemy is walking horizontally along a platform, the game checks if Peter is above or below that enemy. If he is, the enemy turns 90 degrees and heads in that direction (if possible). The same logic applies for climbing - and stepping off - ladders.

 

But when Peter's position along that axis is the same, e.g. standing on the same platform the enemy is walking along, there seem to be some exceptions. At 0:26 in the video, one of the three hot dogs goes up the ladder as the trio passes by. What causes that? Is there simply a degree of randomness like the barrels in Donkey Kong?

 

The decision process at intersections might be something like this:

 

1. Is Peter's position along the perpendicular axis different from the enemy, and does the ladder/platform proceed in that direction? If so, turn 90 degrees and head that way.

2. Is Peter's position along the perpendicular axis equal to the enemy? If so, randomly make a 90-degree turn approximately 1/3 of the time, and ignore the turn 2/3 of the time.

3. Is it no longer possible to keep traveling in the same direction (end of ladder/platform)? Randomly (?) turn 90-degrees from among the available choices.

 

Time to fire up MAME and experiment a little.

[negative1]

On 12/28/2019 at 8:31 AM, Deteacher said:

Understanding how the enemies move makes it pretty easy to group them all together (with the help of a few peppers.)  Then you can rack up SERIOUS points for getting them all on a bun and sending them for a ride.

 

that video doesn't explain anything, yes it shows you to group the enemies.

 

the problem remains as to how.

 

there is definitely a pac-man like logic to the enemies, and their distance to the player,

and when the sprites overlap, they behave the same.

 

later

-1

[mr_me]

The key is to not be on the same horizontal plank or vertical ladder as the enemies when they come to an intersection.  That way they all turn in the same direction.  If you're on the same plank or ladder, some will turn one way and others go the other.