电子游戏AI编辑本段回目录
长期以来我都在为电子游戏开发中的AI氛围所缺乏的进步现状而感到悲哀。在新千年初的那几年AI曾经是个大胆而光明，并且令人兴奋的话题。《虚幻竞技》、《盗贼》、《黑与白》、《光晕》等游戏就因其AI而表现出机智而富有创新的特点，它们提供了那些可用团队合作来超越玩家的敌人，以及会追捕玩家的警卫，还有可以模仿玩家的猴子。
这种现象一直持续到2005年左右，《FEAR》成为最后一款我对其AI念念不忘的游戏。之后情况就开始变化了，再后来就没有什么变化了。潜行AI也有数年时间沿袭了同样的路径，射击AI在2006年以后就止步不前了，你最后一次玩一款涉及AI模拟的游戏是什么时候？
videogameai1(from bit-tech)
直到最近我才总结出自己的观点，游戏AI停滞不前了。这很糟糕，我们必须做点什么来改变。但我最近看了一些关于这个话题的内容，并寻找一些有趣的项目，这促使我改变了自己的立场。现在我不知道究竟何为AI了。此外，我认为自己的困境与游戏行业所遭遇的问题并没有多大区别。
这个问题始于“AI”的含义。当我想起AI时，脑中形成的就是一个机器人的画面，或者类似于GLaDOS这种感性的电脑。除了它们都是用电脑创造而成的这个事实之外，科技AI与游戏AI并没有什么太多共性。科技AI的终极目标是形成与人类相似的感知智能，而游戏AI只需呈现一些游戏所需要的智能而已，它可以在必要的情况下通过脚本、寻径或者即兴技术来实现。
这种合并概念很快出现了一些问题。人们在评价游戏时很容易根据智能状况来评判其AI。但我们极容易制作一个超人类智慧的游戏AI，在多数情况下这却并不会让游戏更棒。理想情况下，你对大部分游戏，尤其是射击游戏或战略游戏的需求就是，让AI的智能跟人类同一个水平。它必须能够制定聪明的决策，犯一些合理的错误。
videogameai2(from bit-tech)
但这也不正是我们所谓的与游戏AI截然不同的科技AI的目标吗？
不，科技AI的目标是知觉。它可以像我们所希望的那样智慧，但从智能角度来讲，这种AI必须能够回应和应对特定环境。游戏AI则只需要在游戏框架内发挥像人类一样的行为就可以了，相比之下，这是一项要求较低的任务。所以FPS要求其AI射击玩家，但不能每次都准确命中玩家。另一项重要能力就是地图导航，使用掩体，以及制定一些战略决策，例如翼侧包围等。它并不需要具有同情心，或者做出道德选择，甚至是感受到任何东西。但《模拟人生》这类游戏中的AI就不同了，其中的AI要能够回应生理需求以及情绪，这正是游戏的重要元素。
videogameai3(from bit-tech)
这似乎就是定义了游戏AI与科技AI区别之处的游戏题材所加诸于其中的限制。电子游戏AI更小，更特殊，这正是它看起来更为广泛而没有明确方向的原因。
也许我们没有看到AI朝自己所期望的方向发展是因为，在AI发展应该决定题材的时候，却让游戏题材决定了AI的发展。也许，要实现电子游戏AI的真正发展，我们有必要采用一个统一的方法。
为理解这一点，让我们考虑另一个在过去十年取得了巨大进步的游戏开发领域——图像。图像发展是由照片真实感这一终极目标所驱动的。现在，无论你是否认同照片真实感是一个可靠的追求目标这一说法，都必须承认主流发行商对此的普遍追求推动了游戏渲染可信环境、角色等方面的迅速发展。这跟开发者所制作的游戏类型无关，它的假设前提就是玩家都想看到更棒画质的游戏。
但另一方面，AI却从未真正获得相同的关注，从来没有推动其本身的发展。它的发展往往取决于特定游戏的需求。这真令人遗憾，因为当个体开发者试验新型AI技术时，其结果可能十分惊人。因为Looking Glass Studios采用了“消极”和“积极”这两种默认的AI行为，以及介于这两者间的第三种“警戒”状态（游戏邦注：AI搜查玩家所在地，但它很清楚后者所在区域），行业也由此诞生了潜行游戏题材。
现在你可能会以《孤岛惊魂》这类游戏为例，证明AI行为的最近发展。但这些游戏最终所做的不过是结合过去已经存在数年的不同类型AI脚本而已。如果我们想看到自己所玩游戏的真正变化，就必须探索新颖或者极少被使用的AI类型。无论如何，AI必须处于开发者关注的前沿。
好消息就是，已经有一些即将问世的游戏将AI放在了首位。其一是Simon Roth的《Maia》，它让玩家建设和维护一个外星殖民地。该游戏受到经典Bullfrog管理游戏，尤其是《地下城守护者》的启发，采用了自动化殖民者，而你只能间接操控而非直接控制其行动。除此之外，Roth还计算让游戏中采用一个更为粒状的AI模拟系统，殖民者会受到环境影响表现出不同的情绪和情感状态，并且这些情绪还会影响到他们的行为。
videogameai5(from bit-tech)
第二款游戏就是《Clockwork Empires》，它和《Maia》一样是款克隆模拟游戏，但发生于美洲殖民地。它采用了可让玩家直接控制的自动化殖民者，但其自动化方法略有不同。殖民者有不同的人格特征，这又会影响到他们对待彼此的行为。他们还会交换想法和保存记忆。最值得一提的是，如果你让殖民者无所事事，他们就会很无聊并且会暗中培养一项兴趣，而这会让他们做出对殖民地的一些不虔诚的恐怖之事，从而破坏殖民地。但这个系统也可以通过其他更小的方式表现出来，例如殖民者如何参战，他们如何应对损失等等。
这两款游戏都还处于开发阶段，所以我们还需要一些时日才能看到它们是否能实现自己的愿景。但至少从理论上来讲，《Maia》和《Clockwork Empires》都采用了极少被游戏所用的即兴AI，其AI可以通过玩家对它的反应进行“学习”。《黑与白》中的Creature就是这方面的一个著名典型，这正是为何它存在问题，但我还是对其偏爱有加的原因。但这个AI还有其他值得关注的层面。其中一个典型就是XCOM式的游戏，它不是让你直接控制战士行为，而是让你在战役开始前给他们训练一定的战术，然后再将他们送上战场自发参战。
videogameai6(from bit-tech)
虽然《Maia》和《Clockwork Empires》所采用的更为大胆的试验的确令人兴奋，但它们并不能代表AI发展的整体趋势。这两者仍在为特定游戏创造特定AI，其AI是游戏中的主要系统而不是一个二级或三级考虑内容。
另外，AI的重要性在未来数年只会有增无减，并且成为主流开发者的一个关注点。VR头碗等技术让游戏更具沉浸感，而巨大的开放世界和美观的图像也越来越普遍，那些坚持使用具有信服力的AI行为来保持这种沉浸感的工作室将获得更多关注。最终，游戏AI不再作弊，而是学会应对开发者所创造的世界。（本文为游戏邦/gamerboom.com编译，作者：Rick Lane）
What the hell is videogame AI anyway?
by Rick Lane
Dearest readers of bit-tech! Come hither and listen to my whispered words, as I am a troubled soul. For a long time now I have lamented the lack of progress made in the AI sphere of game development. In the years surrounding the millennium AI was bold and bright and exciting. Games like Unreal Tournament, Thief, Black and White and Halo were doing clever and innovative things with artificial intelligence, providing enemies that could use teamwork to outmanoeuvre us, guards that would hunt us, and a big daft monkey that could learn from us.
This continued until around 2005, with FEAR being the last game I can recall with truly memorable AI. Then something changed, and after that nothing changed. Stealth AI has patrolled the same pathways for years, shooter AI crouched behind a wall circa 2006 and decided to make a home there, and when was the last time you played a game that involved the AI learning anything?
What the hell is videogame AI anyway?
Until very recently this was more or less the sum of my position. Game AI has stagnated. This is bad. We need to do something. Yet I’ve been reading a little more about the subject lately, and looking into a couple of interesting projects, and this has resulted in my altering my stance. Now I’m unsure what video game AI is at all. What’s more, I think my own dilemma is not altogether dissimilar from the problems the games industry is encountering.
The problem begins with the very meaning of the term “AI”. When I think of an AI, I picture an android, or a sentient computer like GLaDOS (which, ironically as a game AI is about as intelligent as a shoe). Aside from the fact that they’re both created using computers, a technological AI bears little in common with a game AI. The ultimate goal of technological AI is to give it an equal level of sentient intelligence as a human being. Game AI only needs to appear as intelligent as the game in question requires it to, and it can do this by any means necessary, be it through scripting, pathfinding, or more emergent techniques.
Immediately this conflation of concept causes problems. When criticising games it is tempting to judge AI based on its intelligence. But it’s very easy to make a game AI super-humanly intelligent, and in most cases that isn’t going to make the game better. Ideally, what you want in the majority of games, certainly games like shooters or strategy games, is for the AI to be humanly stupid. It needs to be capable of making clever decisions and reasonable mistakes.
What the hell is videogame AI anyway?
But hang on, isn’t that also the goal of technological AI, which we just said was completely different from game AI?
No, the goal of technological AI is sentience. It can be as smart as we dare make it, but regardless of the level of intelligence, the AI needs to be capable of reacting to and coping with any given environment. Game AI, on the other hand, only needs to act human within the confines of the game, which by comparison is a far less demanding task. So an FPS needs its AI to shoot at the player, but not hit them with pinpoint accuracy every time. Other important capabilities are navigation of the map, use of cover, and possibly some tactical decision making, such as flanking and covering fire. It doesn’t need to be capable of empathy, or making moral choices, or even feeling anything. This is very different from a game like The Sims, where the AI’s ability to demonstrate and respond to physical needs and emotional moods are vital components of the game.
What the hell is videogame AI anyway?
Hence, it appears to be the limitations imposed by gaming genres which defines the difference between game AI and technological AI. The goals of video game AI are smaller, more specific, which is why it seems to be such a broad church with no real direction.
Only, maybe it shouldn’t be. Perhaps the reason we don’t see game AI developing as we would like is because genre is defining AI development when AI development should be defining genre. Maybe, for video game AI to really progress, a unified approach is necessary.
To understand this, let’s consider another area of game development which has made huge leaps in the last ten years – graphics. Historically, graphics development has been driven by the ultimate goal of photo-realism. Now, regardless of whether or not you think photo-realism is a valid target to shoot toward or not, the universal desire of mainstream publishers to push further toward this objective has resulted in a rapid advancement in games’ ability to render convincing environments, characters, and so on. It never really mattered what kinds of games were being made, it was just assumed that players would want their games to have better graphics.
What the hell is videogame AI anyway?
AI, on the other hand, has never really received the same attention, never been pushed forward for its own sake. Instead its development has always been based on the needs of individual games. This is a shame, because when individual developers have experimented with new AI techniques, the consequences can be enormous. The entire stealth genre exists because Looking Glass Studios took the two default AI behaviours of “passive” and “aggressive” and sandwiched between them a third state of “alert”, where the AI searches for the players presence but it’s actively aware of their location.
Now you might be tempted to point to a game like Far Cry as an example of more recent evolutions of AI behaviour. But ultimately all these games do is combine different types of AI scripts that have existed for years. If we’re to see radical changes in terms of the games we play, we need to explore new or at the very least rarely used types of AI. Either way, AI needs to be at the forefront of the developer’s mind.
The good news is, there are a couple of games on the horizon which are prioritising AI. The first is Simon Roth’s Maia, which tasks you with building and maintaining a colony on a hostile alien planet. Inspired by the classic Bullfrog management games, particularly Dungeon Keeper, Maia features autonomous colonists whose actions you can only indirectly manipulate rather than directly control. In addition, Roth plans for Maia to have a far more granular AI simulation than its inspiration. Colonists will have different moods and emotional states which are affected by their environment and can affect their behaviour.
What the hell is videogame AI anyway?
The second game in question is Clockwork Empires, which like Maia is a colony simulator, except set in colonial America. Again, it feature autonomous colonists who you cannot control directly, but it’s approach to that autonomy is slightly different. Colonists have different personality traits which affect their behaviour with other colonists. They can also exchange ideas and preserve memories. The ultimate extension of this is that, if you leave your colonists with too little to do, they can become bored and will develop an interest in the occult, which can lead to them unleashing some ungodly terror onto the colony, leading to its destruction. But this system can also express itself in other, smaller ways, how colonists react in battle, how they cope with loss, so on and so forth.
Both games are still heavily in development, so it’ll be some time before we see whether they can deliver on their promises. But in theory at least, both Maia and Clockwork Empires lean toward emergent AI that is rarely used in games, where the AI can “learn” through player response to its actions. The Creature in Black and White is the most famous example of this, and why, despite its problems, I have an enduring fondness for that game. But there are other prospects for this AI as well. A typical example would be an XCOM-style game where, instead of controlling your soldiers’ actions directly, you train them in certain tactics before a battle, and then send them out to fight autonomously.
What the hell is videogame AI anyway?
Although the more experimental approaches of Maia and Clockwork Empires are exciting, they don’t represent a unified push in AI development. Both games are still creating specific AI for specific games, it’s just that AI is very much the primary system in those games rather than a secondary or tertiary consideration.
What’s more, the importance of AI is only going to grow in the coming years, certainly as a focus of mainstream developers. As tech like VR headsets make games more immersive, while huge open worlds and pretty visuals become more and more commonplace, it will be those studios that can keep that level of immersion consistent using convincing AI behaviours which will garner the most attention. Eventually, game AI will have to stop cheating, and learn to cope with the worlds developers create. （source：bit-tech）
