You're just about to escape and a dozen enemies spawns in front of you. You lose / die, reload, go a completely different direction, and still the enemies spawn in front of you, as if they telepathically know your every move. In truth, you realize that the game just has your vector and x,y,z. So you wish for a pox on the game designer's house and get some cheats... How to avoid this very lame situation without insanely unrealistic AI requirements? I'm a big fan of rulesets that manage the player's expectations. The above situation is only fair if the enemy IS telepathically gifted, or you have a bug / tracking device somewhere on you. In fact, when you see it happening, it should move you to say, "they must have bugged me" instead of "this *$&##! game is cheating!" Spawining is a VERY useful AI management technique, especially when you want hordes of enemies. Without it you have to pathfind and run AI loops every entities in real-time even when they're not onscreen. That's processing power you lose to draw graphics or otherwise manage other intensive game tasks, like 3D sound. So it's not going away for awhile. Do you think these general rules, established clearly (somehow) to the player would manage expectations: 1) AI can't respawn in a closed off zone unless the game's enemies have some sort of cloaking / teleporting / hiding ability. The map designer has to take note of logically closed off areas, such as a cave with only one entrance (that you're guarding) or a base with a door that you've sealed. 2) AI generally have clustering points. This could be base camps or guard houses in an FPS, or police stations in a GTA style game. 3) In normal situations, AI are more likely to spawn the closer you get to these cluster points. (You are more likely to find police cars coming and going from a station NEAR the station, for example) 4) Whenever the player or any other game entities do things to excite the AI, the cluster point will move or break into pieces based on a time-distance calculation. So if you start some panic somewhere in a city or set off an explosion in a base, the AI is more likely (but not guaranteed) to clump around that location, depending on how bad the threat is. 5) AI patrol zones and/or routes are somehow always obtainable in some in-game context (like in Freelancer). This sets your expectations for what to expect where and may move you to think the game more fair as long as it adheres to its own rules. (I guess not having this is okay but it makes learning the map trial and error based.) 6) AI is not allowed to spawn exactly on your vector or use your x,y,z unless you're in site of another AI and a spawn would be statistically likely. The map designer could set up chokepoints, for example, around bridges in a GTA or Driver style game. If you saw the cops there, you couldn't whine because you'd KNOW these were chokepoints. So you'd have to put more thought into planning your escape route? Comments? Am I on crack with this one?

that a good start

it would also be nice if

7)even if you didnt keep track of indavidual sprites you kept a list of where they could spawn(in a area about twice the size of the screen area), Ex your alone in a closed off ally, once you get to the streen one of your prusuers sees you, you run back into the ally to find 50 more pusuers waiting for you in the ally that was empty half a second ago.

-another possability
you could also try having all the sprites already existing but to save proccesing power have them remain inactive till they get onscreen and if they get excited they move by following preset track rather than pathfinding until there onscreen

Seems to make sense, can't think of how many times some guy with an uber BFG9000 spawns on top of me and insta-gibs me, boy that pisses me off. XD

The game could also keep track of how many AI's are within a spawning zone, which could effect the odds of that AI spawning. This way the player could reduce the likelihood of enemy units spawning within the area by killing a bunch of them off. So, the police precinct could have 50 police officers, if the player starts killing them off GTA style, then it would reduce the likelihood of police officers spawning around the precinct because there are less of them to patrol the area. This could give the player a way to impact the environment more effectively than fighting limitless numbers of enemies, and would probably be more effective in a free-roaming environment.

There could be some kind of warning, something like a helicopter hovering abowe the spawning spot for a few seconds and showing some people dropping from it. Then it does not feel as much spawning as it actually is. In the police station example player could hear the police cars before seeing them, or maybe there could be a police radio which gives a warning to the player. This gives the player an opportunity to turn back and avoid the fight, or at least be prepared for it.

You should be able to watch the patrols for a while and be able to pick up on their pattern. so you can make it through with out a patrol spawning on you.

Would it be possible to have "phantom" spawn units wandering around the map? Instead of tracking the movements of individual units or generating them arbitrarily, could you have a "cloud" of heightened probability of encounter that would wander around the map on set paths or according to some tracking algorithm, dealing with blocked passages or shut doors appropriately? That way, the CPU isn't bogged down with the behavior of sixteen four-man patrol teams, but their location would be represented fairly well. If the camera points at one of these "phantoms" and there's nothing obscuring it, then the unit would spawn and begin behaving according to appropriate algorithms. When it left the screen or the immediate vicinity, it would return to its abstract form and resume its patrol. If a character alerts one of the ghost units, it would materialize and respond.

Think of it as a sort of abstract hibernation for in-game units--a mini-map representation of enemy locations. You don't have to deal with the pathfinding and behavior of a whole team of humans, you just have to keep track of the vector and status of a single point. It's like a compression technique. You trigger an alarm, and six "team tokens" are dispatched from the barracks. They travel at an appropriate speed, are impeded properly by traps or roadblocks, and when they finally get to the player's character, they expand into actual enemy units and engage.

Quote:

Original post by Kaze 7)even if you didnt keep track of indavidual sprites you kept a list of where they could spawn(in a area about twice the size of the screen area), Ex your alone in a closed off ally, once you get to the streen one of your prusuers sees you, you run back into the ally to find 50 more pusuers waiting for you in the ally that was empty half a second ago.

Hmm... right, there needs to be something about closing off/bottlenecking areas so that the AI doesn't spawn where it couldn't practically get through.

Quote:

-another possability you could also try having all the sprites already existing but to save proccesing power have them remain inactive till they get onscreen and if they get excited they move by following preset track rather than pathfinding until there onscreen

This leads to "lure 'em to their doom one-by-one" gameplay, which can be enjoyable but is certainly no real tactical challenge.

Quote:

Original post by Gyrthok The game could also keep track of how many AI's are within a spawning zone, which could effect the odds of that AI spawning. This way the player could reduce the likelihood of enemy units spawning within the area by killing a bunch of them off.

I think this works for resource limited factions but shouldn't really apply to entities like the military or police. If you wipe out every mobster in New York, it may be awhile before there are more mobsters. But if you wipe out every cop, the military is going to drop the hammer on you, and they're for all intents and purposes infinite.

Quote:

Original post by Ubik There could be some kind of warning, something like a helicopter hovering abowe the spawning spot for a few seconds and showing some people dropping from it. Then it does not feel as much spawning as it actually is. In the police station example player could hear the police cars before seeing them, or maybe there could be a police radio which gives a warning to the player. This gives the player an opportunity to turn back and avoid the fight, or at least be prepared for it.

This reminds me of some of the scenarios in the Half-Life games with Ospreys dropping marines. It's a good reminder that spawning is perfectly acceptable when its in context, even though you know its spawning.

Quote:

Original post by Iron Chef Carnage Would it be possible to have "phantom" spawn units wandering around the map?

This is an intriguing idea. Needs a lot more research but it does sound promising. One thing that it would need, though (depending on your level of detail) is a different set of movement rules for the phantom mob or you may run into immersion breaking improbabilities like an entire battalion sneaking up on you ("nobody noticed the tanks?!?!?!"). This also implies that the units are uniform in capability, under the theory that "if one could make it, all could make it." So no mixing tanks and special forces then having them climb an escarpment.

One potentially amusing, potentially exploitable problem I see, though it may only apply to really complicated pathing or large groups: There'd be a difference between actual and abstract pathing such that units would probably take longer and have more problems observed than as a single unit abstracted. But it's certainly better than nothing.

I think what I'd like to see is maybe some sort of mix of spawning and phantom pathing. Spawn to skip over the really tough areas or when the group is so far away it wouldn't matter; then phantom path when it counts, such as when near the player or dealing with something the player has invested strategic thought into, like trapping a base.