Platinumoxicity on 21/11/2009 at 10:00
The guards should also be fun to run from.
The guards usually guard a well-known place right? They know each hallway and room in the building.So, the guards should know "good escape paths" -so that when in pursuit, they don't just go to alert level 1 after the player has been out of their line of sight for 10 seconds, but they continue on the "good escape path" until they see something or just give up.
This way, the player can run into a room, open the door leading out of it and hide in the shadows. The guards assume that the door is open because the thief just went through it and continue the pursuit on the assumed escape path. Now the player can sneak out.
Chade on 21/11/2009 at 11:36
Indeed. It is important that the player can have fun even when he is hiding from a searching guard, or running away. I think having guards respond to the environment when pursuing a player is a fantastic idea.
I think there are a lot of things which could be done to improve the game experience once the player starts to screw up. I don't care that much about the issue as a player, but I think that if I was a developer, I would be spending a lot of time thinking about this issue. More on that later ...
The Shroud on 21/11/2009 at 16:20
Much agreed. Just about all of the ideas in this thread are good ones, honestly. As was stated earlier, one of the most important things they need to change is the way in which guards pursue you when you're running away. Right now, if guards are chasing you and you manage to dart out of their line of sight for a brief moment and hide while unobserved, they will still magically home in on your position - no matter how clever your hiding place may be. The old dash-round-the-corner-and-hide-beside-the-doorframe trick doesn't work because the guards aren't actually heading toward where they think you went - they're heading for you, no matter where you are or whether you're out of their sight for the moment. The only way to deceive them is to stay out of their line of sight for a certain amount of time - at which point they'll stop chasing you and start searching around for you rather stupidly, even if there's only one direction you possibly could have gone. This instantly reminds the player that they're in a game and breaks immersion.
So what needs to change is the method by which guards track the player. If the player ever leaves their lines of sight, even for one moment, they should proceed to the location where the player was last seen:
"He went that way!"
If they catch sight of the player again (either before reaching the player's last seen location or after arriving there), pursuit should resume normally:
"There he is!"
If, upon arriving at the player's last seen area, the player is still nowhere in sight, they should continue running in the same direction until they come to a fork or crossroads, or anywhere that presents more than one possible path (like an adjoining hallway, an empty and well-lit room with more than one exit, or a dark area where the player could potentially be hiding). Once faced with this problem, they should enter search-mode:
"You check that way, I'll check this way."
After the guard(s) have searched an entire room or hall (i.e. they have checked every visible area and scanned every shadow dark enough to conceal the player), they should not keep revisiting the same spots and corners over and over again, circling stupidly as if expecting the player to spontaneously appear where they've already looked. They should remember where they've searched and progress onward from there:
"Not in here."
"You check that way, I'll check this way."
If the guard(s) have finished searching a room and that room has only one exit (other than the one through which they originally entered), then they should invariably choose to proceed that way (even if the player has long since sneaked back out the room's entrance while their backs were turned searching around the room):
"Not in here."
"He must have gone this way, come on."
If a guard reaches a dead end, but there are still un-searched routes to check, he should backtrack and proceed to the next un-checked path:
"Well, so much for this way." ... "Must have gone that other route."
Only if the guard(s) reach a dead end and they've already searched every possible path should they double back and re-search previously searched areas:
"Well, so much for this way."
"He's around here somewhere. We must have missed something, let's go back and search again."
Or, if the guard(s) are lazier (for instance, on Normal difficulty, or in a less tightly run place like Bafford's or Rumford's) and they've completed one search without success, they can give up:
"Damn. Can't find him anywhere."
"Let's just forget it. I don't get paid enough for this. He's probably long gone by now anyway."
Platinumoxicity on 22/11/2009 at 18:36
I believe that we'll be positively surprised by the AI in Thief 4, because the last working model of AI in Thief was seen almost 10 years ago, in Thief 2. The AI in TDS took a step backwards in almost every level and all of the AI bugs seen in T2 were replicated in TDS instead of being solved so that doesn't count.
Eigenface on 23/11/2009 at 02:36
I love undead. My favorite parts of Thief 1 were the scary parts. If I had my way, all of Thief 4 would be like that.
Condemned: Criminal Origins isn't a stealth game, but it does have a lot of scary parts with innovative AI behavior. For example, it has an abandoned department store with both real mannequins and enemies disguised as mannequins, who stand still, and then try to sneak up on you when you aren't looking - the "living statues" mentioned in this thread. Condemned also has enemies that won't attack you face to face; whenever you turn toward them, they turn away and run off into the darkness, and attempt to circle around and attack you from behind. Many enemies will retreat and hide behind something, and then surprise attack when you get close.
A lot of games, particularly first-person shooters but also the Cradle from Thief 3, have areas with no enemies, which build tension with a combination of foreboding atmosphere and false positives, that is, phantom sounds and apparitions. You feel like you're going to be attacked at any moment, and that's so much scarier than actually being attacked. The fear of the unknown is worse than coming face to face with the threat. However, these empty areas are often bereft of replay value, and sometimes half way through your first pass you realize there is no real threat. In my opinion, there needs to be a credible threat, that is, you need to know you really could be attacked at any moment.
The scariest game would have a mixture of the known and the unknown. I don't mean like F.E.A.R. which alternates back and forth between battles with enemies and supernatural scenes. I mean a thorough intermixing of real enemies with false positives. It has to be somewhat randomized - if the real enemies always appear at the same places, it won't be scary on the second pass.
Imagine fumbling around with a torch in the woods in the dead of night, and you think you see something scampering away in the shadows at the edge of your torch's range. It could have been an enemy which is now out there stalking you in the dark, it could have been a phantom enemy that will simply fade away when it's out of range, or it could have been a real enemy that will remain out of range and not bother you, unless you follow it and reveal it again, in which case it will attack. Of course, you don't even know these are the possibilities - you just think you saw something. And right when you start to think you know what you're up against, you also start to see (think you see) a new kind of enemy with different behavior, some ghostly apparition floating above...
Eigenface on 23/11/2009 at 04:20
Quote Posted by "hikikomori-san"
Also, here is another "technical" idea for implementing AI vision (I'm a graphics programmer, unemployed yet though). First, preliminary testing is done to determine which AI entities are looking in the direction of Garrett or anything affected by his presence. Then for each of those (should be rather a small number of such entities, probably no more than 3), the scene is rendered from their point of view with simplistic shaders (but proper lighting) into a small render target (say, 64x64), but without Garrett in it. Then Garrett is rendered, and the image with Garrett in it is compared with the one without, and the number of pixels by which they differ and the amount of difference is calculated, and based on that, it can be determined whether the AI entities can see Garrett or not. So, if a small number of pixels only differ (typically when Garrett is away from the AI entity, or when a small part of him is visible from behind whatever cover he's behind), or when the amount (intensity) of the difference is small (typically when Garrett is well hidden into the shadows or blends well with the background), the AI will not see him.
That's a great idea, and I think it has the potential work really well in a lot of situations. However, the concept of camouflage totally breaks it, right? If a man in camo is crouched in front of a bush, you're going to see lots of pixels that are different than if he wasn't there, but that won't do you any good, because you'll mistake the green splotches on his clothes for leaves on the bush. It's not enough for you to see him - you have to be able to identify him as a man and not part of the background. In reality, you have no automatic way to separate the background from what you're looking for. The worst case is a black wall with a white silhouette shape of a man painted on it, and a man in black cloths stands in front of the white shape and covers it up. By your method he's 100% visible, but in reality he's very hard to see.
Bakerman on 23/11/2009 at 08:31
Quote Posted by hikikomori-san
Also, here is another "technical" idea for implementing AI vision (I'm a graphics programmer, unemployed yet though). First, preliminary testing is done to determine which AI entities are looking in the direction of Garrett or anything affected by his presence. Then for each of those (should be rather a small number of such entities, probably no more than 3), the scene is rendered from their point of view with simplistic shaders (but proper lighting) into a small render target (say, 64x64), but without Garrett in it.
I had a similar idea with my first forays into AI, except the idea was basically to ray-trace the entire scene from the AI's perspective and use the depth buffer to reason for things like pathfinding. Obviously way too expensive, but I just found out that Killzone 2 does something similar. At each pathfinding waypoint, they pre-render a cube-map of depth values, which the AIs at those points can use to reason with for locomotion.
Quote Posted by Eigenface
It has to be somewhat randomized - if the real enemies always appear at the same places, it won't be scary on the second pass.
Nobody ever said a truer word. I'm replaying STALKER, and when I was venturing through the Agroprom tunnels, the parts that scared my pants off the first time round (the bloodsucker, particularly, and the creepy noises and stuff - and the controller at the end) were pretty routine this time. Without the fear of the unknown, and with faith that I knew every monster in the area and how I needed to take them down, it was a pretty simple linear FPS romp (albeit with fantastic atmosphere and that great STALKER gunplay).
Bouregard on 23/11/2009 at 14:57
Easy things without making Garret powerless:
1. Guards are able to wake other guards.
2. Per default only 20% of all guards are awake at the start of the map. However if the player triggers an all out alarm those sleeping 80% will take up patrols and/or reinforce old guards. Could be even tricky.
(The main objective for example could force an alarm, however the player can lock the door of the barracks with ... say the key of the watchofficer and presto you get some really angry guards in the barracks that can't chase you. It's also an increased difficult, cause as soon as you trigger an alarm they would not go back to sleep. So even earlier pacified areas can now be full of guards again.)
3. Guards with random patrolroutes. Each guard has a patrolnet. At each point the guard will randomly choose a new way. Makes it hard to wait for an opportunity.
4. The elite guard:
Is nearly silent so the player will not hear him half across the map. Preferably has it's back to walls to prevent backstabbing/clubbing and moves that way. If faced with an unseen enemy it will try to get into a corner to protect it's back and slowly scan the surroundings.
If the elite sees the player it will not mindlessly chase after him, but will try to scream for help while staying alive/conscious as long as possible. If enough friends arrive it will attack.
5. Hidden guards:
Think of it: a archer in a dark tower across the courtyard. If you enter a not dark place in the courtyard you will be filled with arrows (firearrows for added light and damage)
Or a guard that is hidden behind the opened door, absolutly silent to check whoever enters, and if you're not suposed to be here stabs you.
Platinumoxicity on 23/11/2009 at 16:24
Quote Posted by Bouregard
5. Hidden guards:
Think of it: a archer in a dark tower across the courtyard. If you enter a not dark place in the courtyard you will be filled with arrows (firearrows for added light and damage)
I think that would be a bit harsh, except in a situation where the enemy forces have already been alerted to your presence. Ambushing guards wouldn't make any sense in a random calm evening in the castle.
My old ideas:
-City watch elite units, fast movers that work in groups, use ranged weapons as well as short swords, and clear rooms using flashbombs and heavy riot shields. They can enter with ropes from elevated positions, bust down doors and communicate silently using hand signals. They would only be a special enemy that Garrett has to face when a job at some rival criminal installation (Gambling den?) goes horribly wrong and he has to evade the police siege.
-Pagan scouts, unarmed but very fast and alert. The pagans are guerillas that use ambush tactics by leading the enemy to a suitable place using the scout. The pagans are weak and outnumbered in metropolitan areas, so they don't engage in direct combat, but strike, flee and hide.
-Hive-minded strange creatures, get seen by one, and every single one of them knows exactly where you are, as long as one of them knows. You have to escape very quickly or take the alerted one out immediately to avoid being surrounded from all sides.
-Enemies that kill you with one hit. Don't get seen. Or if you do, run like hell.
-Indestructible, invulnerable enemies. You need to change your tactics. If you're sure you need to get rid of one of them in some way, you need to trick it to go to a place where you can lock it up and prevent it from getting out. :)
-Partially invisible enemies. You can only see their eyes, or their shadow.
