III. Artificial Intelligence


Since Atomic Sam is based around interesting combat scenarios, the primary function of the game s AI is to support these conflicts, providing the player with a compelling challenge. The AI will also be essential for imbuing the friends Atomic Sam encounters with some semblance of life, making them seem like more than just automatons.

Enemy AI

Many of the adversaries Sam faces will be robots. As such, the AI for these adversaries can be quite simple-minded while still being believable. Indeed, the simple-mindedness of some of his opponents will allow Sam to set traps for them using the interactive environments found in the levels. Not all robots will be simpletons, however. As the game progresses and the levels ramp up in difficulty, the robots will become more and more intelligent and thereby more and more challenging. Still later in the game, the player will fight human adversaries such as the Merciless Mercenaries. These human opponents will need to appear as intelligent in their combat decisions as a real-world human might be.

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Player Detection

Different AI agents will have differing abilities to detect and track the player, which will in turn affect how much of a challenge they present to the player. Some robots will only be able to see in a very narrow cone in front of them, while others will have full 360-degree vision. Also, the distance of detection can vary from adversary to adversary; some can only see Sam when he is close to them, others can see him before Sam can see them. Some of the robots may have super-vision, which allows them to see through walls and to always find Sam, regardless of how he may be hiding.

Some robots will also have very short memories. If Sam manages to run behind these robots, fully out of their field of vision, they may forget entirely about Sam and will return to an idle state. Other robots, once locked on to Sam s position, will never lose him. The player will need to figure out how well an adversary can detect Sam and use that to his advantage.

Motion

All adversaries will move in believable ways, employing a simple physics system to give the appearance that Sam s world is a realistic one. However, the feel of Sam s gameplay is one of a console action game, and hence does not need to rely too heavily on truly authentic motion systems. Indeed, the retro-future setting of Atomic Sam with its fantastic, implausible flying machines suggests a world that does not adhere to the laws of physics too closely.

Flying

Many of the adversaries Sam fights will be airborne , and it will be important to convey a sense of believable flight for these creatures . The type of flight motion involved will vary significantly depending on what type of flying equipment that enemy uses. An enemy kept aloft by a blimp will only be able to make slow turns and will not be able to move up or down very quickly. A creature with wings and propellers will be able to make turns, but will need to be able to bank to do so. Sam is the only character in the game who will have a rocket-pack, and this pack grants him a significant amount of maneuverability, something which will prove to be a great advantage over many of the adversaries he will face. Again, the flight model used by these creatures does not need to be truly authentic, but must be believable enough that the player gets a sense that the enemies Sam is fighting are truly flying.

Pathfinding

Detecting Sam is only the first part of the challenge for the robots. Once they have found Sam, the simpler robots may be too stupid to actually reach him. Pathfinding ability will vary significantly from the dumbest robot to the smartest. The dumbest robots will use a beeline technique and will be unable to maneuver around objects that get in their way. Somewhat smarter robots will be able to navigate around objects that they run into, but can still get hung up on corners. The smartest robots and the humans will always be able to navigate to the player, including opening doors and pushing obstacles out of the way as necessary. The player will need to exploit the deficiencies in the robots pathfinding in order to succeed in the game.

Taking Damage

Many of the robots and other adversaries Sam faces will be incapacitated by a single hit from one of Sam s projectiles . Other, larger robots may take multiple hits before they are actually incapacitated. For instance, an electrical robot with heavy shielding may be able to survive three hits from water balloons before finally short-circuiting . Of course, different projectiles will have different effectiveness on different enemies, and some robots or enemies may be completely immune to certain attacks. See the Projectiles section under Game Elements for more information about the projectiles.

Combat Attacks

The AI agents in Atomic Sam will have a variety of attacks they can use to try to incapacitate young Sam. Many of the enemies will have multiple attacks to choose from in a given situation; for instance, an NPC may have a melee, close-range attack, and several projectile, long-range attacks. The NPCs will be able to pick which attack is most effective, or, when several attacks may be equally effective, will pick one at random or cycle through them in series.

Evading

The projectiles thrown by Sam travel at a slow speed, and as a result some of the smarter enemies will be able to dodge out of the way of incoming attacks. Of course, the AI agents will not be so good at dodging that the player never has a chance of hitting them, but just enough to provide an interesting challenge for the player.

Special Actions

To keep the challenges fresh and interesting to the player, there will be a variety of special behaviors that only the more advanced robots and human adversaries use. These will appear later in the game, and will force the player to adapt to them in order to succeed.

Taking Hostages

The battles the player fights with his enemies will often take place in inhabited communities, with non- hostile characters walking around to provide color . Some of the smarter AI agents will know to grab some of these NPCs and hold them as hostages. Sam will now need to avoid hitting these hostages with his projectiles. If the player flies Sam up close to these hostages and presses the Action key, he will be able to snatch them away and fly them to safety.

Internal Repair Arms

As some of the robots take damage from Sam s projectile attacks, the more sophisticated robots will be able to repair themselves . A common way for this to work is that a special repair arm can spring from a compartment on the robot. This arm can then bend around the robot s body to weld broken parts back together. The effect is more cartoonish than realistic, but conveys the sense that the robot is repairing itself. Some robots may first retreat to a relatively safe location, such as around a corner or far from Sam. Other robots will be able to multi-task by having the repair arm work on them while continuing to fight Sam.

Collaboration

Some of the enemies, in particular the Merciless Mercenaries, will know how to work together. Many of the robots will be singular in their purpose (attack Sam) and will know nothing of the other robots that may simultaneously attack Sam. But the significantly more intelligent Mercenaries will know that working collaboratively will be much more effective in defeating Sam. For instance, while one Mercenary keeps Sam busy with attacks from the front, others may swing around to the flank and attack Sam from there. Of course, having the enemies work together will allow the enemies to provide a much greater challenge for the player.

Trash Talking

While Sam fights these adversaries, he will hear them making derogatory comments about him, suggesting he can never win against their superior numbers : Admit defeat, human! , Your success is statistically unlikely , and Steel is stronger than flesh! Relent! Not all of the robots are able to speak English, and some may utter beeps and squawks as their means of communication. Others may be so cruel as to taunt Sam that he will never see his parents again.

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Falling into Traps

A big part of the game mechanics in Atomic Sam is the player using the environment to his advantage by triggering various traps and contraptions that will help to defeat the robots Sam faces. The AI will actually facilitate the player using the traps effectively, in part through the robots lack of intelligence. In addition, designers will be able to set up these adversaries to have a tendency to maneuver into areas where the player will be able to incapacitate them if she is clever. For instance, if there is an empty oil drum set on a lever that the player can activate, the robots will have a tendency to fly by the potential trajectory of that oil drum.

Non-Combatant Agents

The various areas Sam travels to are places where the people of Sam s world live and work. As such, the areas will not only be inhabited by the enemies sent to capture Sam, but also by normal citizens. These citizens will not be very smart, and their inclusion in the levels is not in order to create the impression of a real environment. These citizens are mostly there for color, while also creating targets that Sam must be careful not to accidentally hit with his projectiles.

Fleeing

Often, at the first sign of trouble, these citizens will run away, trying to find cover away from the battles between Sam and the robots. Of course, the mere existence of flying robots or a boy with a rocket-pack will not be anything too exciting to the jaded people of the future; it is only when the fighting starts that the citizens will realize the dangerous situation they are in. The level designers will be able to set up paths for these citizens to walk along and positions they will try to flee to for safety.

Talking To and Helping Sam

Of course, certain citizens will be willing to talk to Sam, and may share information about the area Sam is currently navigating. Others may even be willing to give Sam objects, or to make improvements to Sam s rocket-pack. Citizens who will be able to help Sam will have a tendency to wave to Sam as he flies by, differentiating them from the citizens who are merely there to add color and variety to the game environment.

Friends

One of the most complicated pieces of AI that will be needed for Atomic Sam is that which will control the friends he meets throughout the game. These agents need to be able to follow along with Sam and provide him with help in key locations without ever getting lost or stuck. Making a teammate AI that can support the player without seeming stupid or canned will be quite a challenge, but will have a significant payoff in terms of gameplay.

Invincible

The friends that follow Sam through the levels will not be able to be killed or captured by the robots and other hostile creatures found in the levels. First, the enemy creatures will have a tendency to attack Sam instead of the friends, since indeed it is Sam that they have been sent to subdue. Second, the friend AI agents will be able to defend against any attack that does happen to come their way. Similarly, if Sam should happen to throw a projectile at a friend, the friend will easily be able to bat it out of the way, saying something to the effect of You ve got to be careful with those things! The logistics in terms of the friend AI being defeated and what this does to the gameplay is simply too complex to deal with. It may be useful, however, for the friends to be temporarily stunned, only to return to full helpfulness within a few seconds.

Following Sam

The most important task these friend AI agents must be able to performis to follow the player around the levels. This means the friends will have to be able to flawlessly follow the player through the potentially complex 3D environments that make up the Atomic Sam game-world. If the player ever turns around to find that a friend got stuck a distance back on some sort of structure, the gaming experience will be ruined.

The NPC will not necessarily be right on top of Sam at all times. Indeed, the flying friends will be able to fly in and out of frame, giving the player the sense that they are always nearby without actually being on the screen constantly. Sometimes the friends will be just in front of Sam, sometimes just behind him, but always close by.

Guarding Sam s Back

These friends will play a crucial role in the gameplay by pointing out enemies that may be attacking Sam from a given direction that Sam has not seen: Watch out, Sam, it s coming up behind you! In some cases, the AI agents will be able to use their own attacks or projectiles to help defeat an enemy before it gets too close to Sam, though in any given situation the agents will be far less successful than Sam. It is important that the player will still have to fight robots on his own and will not be able to just sit back and let the friends take care of everything for him.

Providing Advice

Similarly, the friends in Atomic Sam will be able to provide the player with advice about different enemies as they arrive : That one looks like trouble! or I don t think water balloons will work on that one! In certain situations in the levels, the friends will be able to point out secret areas or show Sam a cache of projectiles he might otherwise have overlooked. The player will be able to navigate Sam close to a given friend and then press the Action key, to which the friend will always provide an answer.

Sometimes the answers will not be useful: I m glad I met you, Sam or You really showed that last robot! Other times, having Sam talk to the friend will provoke them to provide a hint: Take the fork to the left; that will get us there faster or The best way to take care of these climbing robots is to throw something sticky at them. Do you have anything like that?

Storytelling

In addition to the snippets of advice the friends can provide, they will also be key in communicating elements of the story to the player. When Sam reaches a certain part of a level, friends may start talking about the history of the area or about their own past. This provides additional story content to the game in a non cut-scene format, since Sam is still navigating the world while hearing about the story. The friends will be smart enough to only talk in safe situations when Sam is not actively being threatened by an enemy.




Game Design Theory and Practice
Game Design: Theory and Practice (2nd Edition) (Wordware Game Developers Library)
ISBN: 1556229127
EAN: 2147483647
Year: 2005
Pages: 189

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