好几个月，我是这个项目唯一的全职员工，这大大拖延了开发进度。好在有其他员工帮助我，Ron Millar、Stu Rose等人也参与了项目的设计。几位美工在自己的项目间歇时也抽时间贡献了一些原画。
那时，我们还在开发16位的主机游戏《The Lost Vikings 2》（游戏邦注：这是一款横版“跑跳”益智游戏，但这个续作叫好不叫座）、《黑色荆棘》（横版“跑跳”游戏，主角拿枪当武器）、《正义联盟》（《街头霸王》的翻版，以DC漫画世界为背景）和《超人归来》（横版格斗游戏，是DC漫画世界系列的同名游戏）。
使用这个策略的最佳案例大约就是Valve Software；联合创始人Gabe Newell用他在微软工作时获得的收入资助《半条命》的开发，因此很大程度上控制了游戏的发布时间安排—-只有在游戏达到高品质时才可以发布，而不是像Sierra Entertainment（该游戏的发行商）所期望的那样匆匆忙忙做出一款能达到一季度收益目标的产品。更重要的是，Gabe提供的必要资金为Valve争取到《半条命》的在线销售权；那时候数字下载正在成为游戏销售的可行策略，并且最终缔造了该工作室后来的巨大成功。
我工作过的公司——当时名叫Silicon and Synapse，也是自行出资开发《魔兽争霸》和另一个叫作《Games People Play》的项目（它包含在机场书店里经常可以找到的填写益智游戏、串串字等供滞留旅客消遣的文字游戏）。
无论如何，制作《Games People Play》最终被证明是失策，因为开发休闲娱乐产品令程序员们斗志全无，所以这个项目始终没有进度，后来就被取消了。或者也许它也不算是错误，因为《魔兽争霸》和《Games People Play》的组合打动了当时世界上第二大教育软件公司Davidson & Associates，所以Silicon & Synapse被它收购了。
Davidson & Associates,是由Jan Davidson创立的，后来她的丈夫Bob也加入。这是一家从事教育软件开发的公司，《Math Blaster》是其成功的奠基之作。在这款游戏中，玩家通过回答数学问题来炸毁小行星，以免自己的飞船被撞坏。《Math Blaster》是寓教于乐的典范，它为该公司赢得了不少荣誉。
另外，作为一款教育游戏，《Math Blaster》如果使用得当确实有一些价值，但我经常看到它被误用。我上中学时，给我们的校报写文章的记者班的同学和矫正教育班的同学共用一个电脑房，我和我的记者小伙伴们惊恐地发现，十二年级的矫正教育班的同学居然用计算器玩《Math Blaster》！当小行星显示数学算式“3 + 5”和“2 * 3”时，这些学生会飞快地把算式输入计算器，然后把计算器输出的答案打出来，使飞船击毁这些小行星。确实，他们正在学习，毕竟他们比他们的老师更聪明，但考虑到他们马上就要工作了，我不敢说他们充分利用了课堂时间。
在上进的领导层的良好管理下，Davidson & Associates的业务拓展到游戏制造（制作和包装零售游戏）、游戏销售（把游戏分配给零售商和中间商）和面向学校的教材销售。他们看到进入娱乐行业的机遇，但他们自己制作娱乐产品的早期经验告诉他们，收购一个有经验的游戏开发工作室来继续开发他们的游戏更合理，因为他们自己的员工对早教的了解远多于刀剑和魔法。
所以，阻碍《魔兽争霸》开发团队成长的资金流问题一下子就因公司被收购而解决了；有了新东家的雄厚财力的支持，Silicon & Synapse（游戏邦注：被收购后更名为“暴雪”）得以专注于自己的项目开发而不是跟其他游戏发行商争抢那一点儿利润。新东家其实也很边缘，甚至在1993年制作了两款广受欢迎的游戏，为该公司赢利了“年度Nintendo游戏开发者”的荣誉，他们并不收取任何版税。
加州理工大学的毕业生Jesse McReynolds已经完成在本地网络中发送IPX包的低级网络库。这些代码是根据《毁灭战士》的源代码（是id software公司的John Carmack公开的）在编写的。虽然IPX中间层只是几百条C代码语句，但它是连接网卡驱动的代码的一部分，而网卡驱动保证在一个游戏客户端生成的信息被发送到另一个客户端。
Bob Fitch是加州州立大学的硕士，他开发了让玩家能够创建和加入多人游戏的最初的“glue screen”用户界面屏幕。我的办公室就在Bob旁边，非常方便，因为我们要密切合作，把他的游戏加入或创建逻辑整合到我的游戏事件循环中。
作为在开发《魔兽争霸》以前已经玩过许多许多策略游戏的人，我很清楚那个时代的电脑AI的缺陷。虽然我与许多电脑AI对抗过，偶尔失败，多数获胜，但我从来没有被AI吓倒过，甚至在玩Chris Crawford制作的《Eastern Front》时面临俄国的疯狂进攻时。我用朋友的Atari 800玩那款游戏，一直玩到存有游戏的磁带老得不能读取时。
所以说，《魔兽争霸》的第一场比赛是平局，但同时，它又是游戏开发团队的伟大胜利。不久后，办公室里的其他团队的成员也开始玩多人模式，发现它就像“Blue Sky”——《绝命毒师》里的主人公Walter White所研制的冰毒纯晶体脱氧麻黄碱：一旦玩过一次《魔兽争霸》的多人模式，就会觉得其他游戏都不好玩了。即使游戏还是经常出现漏洞，但我们知道我们正在做一件大事。
The making of Warcraft part 3
by Patrick Wyatt
The first-ever multiplayer game of Warcraft was a crushing victory, an abject defeat, and a tie, all at once. Wait, how is that possible? Well, therein lies a tale. This tale grew organically during the writing to include game AI, the economics of the game business, fog of war and more. Read on if you have lots of free time!
After six months of development that started in September 1993, Warcraft: Orcs vs. Humans, the first product in what would eventually become the Warcraft series, was finally turning into a game instead of an extended tech-demo.
For several months I was the only full-time employee on the project, which limited the rate of development. I was fortunate to be assisted by other staff members, including Ron Millar, Stu Rose, and others, who did design work on the project. And several artists contributed prototype artwork when they found time in between milestones on other projects.
The team was thinly staffed because the development of Warcraft was self-funded by the company from revenues received for developing titles for game publishers like Interplay and SunSoft, and the company coffers were not deep.
At that time we were developing four 16-bit console titles: The Lost Vikings 2 (the sequel to our critically-acclaimed but low-selling, side-scrolling “run-and-jump” puzzle game), Blackthorne (a side-scrolling “run-and-jump” game where the lead character gets busy with a shotgun), Justice League Task Force (a Street Fighter clone set in the DC Comics universe), and Death and Return of Superman (a side-scrolling beat-em-up based on the DC universe comic series of the same name).
With the money received for developing these games and other odd jobs the company was able to pay initial development costs.
Game development economics
For most of the history of the game industry, independent game development studios — which is to say studios that weren’t owned by a retail game publishing company — usually funded their projects by signing contracts with those publishing companies. Publishers would “advance” money for the development of the project. In addition to advances for development, publishers were responsible for publicity, marketing, manufacturing, retail distribution, customer support and so forth.
Back in the early 90′s there were many more retail game-publishers than exist today, but the increasing cost of game development and especially of game publishing led to massive industry consolidation due to bankruptcies and acquisitions, so when you think of a retail game publisher today you’ll probably think of Activision-Blizzard, EA or Ubisoft instead of the myriad mid-sized companies that existed twenty years ago.
As in all industries, the terms of contracts are drawn up to be heavily in the favor of the people with the money. This is the other golden rule: “he who has the money makes the rules”. While in theory these agreements are structured so that the game developer is rewarded when a game sells well, as in the record and movie industries publishers capture the vast majority of profits, with developers receiving enough money to survive to sign another agreement — if they’re lucky.
When I mentioned “advances” paid by the publisher, the more correct term is “advances against royalties”, where the developer if effectively receiving a forgivable loan to be repaid from royalties for game sales. It sounds great: develop a game, get paid for each copy sold. But the mechanics work out such that the vast majority of game titles never earn enough money to recoup (pay for) the advances. Since development studios often had to give up the rights to their title and sequels, these agreements are often thinly disguised work-for-hire agreements.
To aim for better deal terms, a common strategy employed by development studios was to self-fund an initial game prototype, then use the prototype to “pitch” a development deal to publishers. The longer a developer was able to self-fund game creation the better the eventual contract terms.
Perhaps the best example of this strategy is Valve Software, where Gabe Newell used the wealth he earned at Microsoft to fund the development of Half Life and thereby gain a measure of control over the launch schedule for the game — releasing the game only when it was a high-quality product instead of rushing it out the door to meet quarterly revenue goals as Sierra Entertainment (the game’s publisher) desired. More importantly, Gabe’s financial wherewithal enabled Valve to obtain ownership of the online distribution rights for Half Life just as digital downloads were becoming a viable strategy for selling games, and led to that studio’s later — vast — successes.
The downside to self-funding a prototype is the risk that the developer takes in the event that the game project is not signed by a publisher — oftentimes resulting in the death of the studio.
The company I worked for — at that time named Silicon and Synapse — was self-funding Warcraft, along with another project called Games People Play, which would include crossword puzzles, boggle and similar games found on the shelves at airport bookstores to entertain stranded travelers.
By developing two games that targeted radically different audiences the company owners hoped to create multiple sources of revenue that would be more economically stable compared to betting all the company’s prospects on the core entertainment market (that is, “hard core” gamers like you ‘n me).
Of course spreading bets across diverse game genres also has risks, inasmuch as a company brand can be diluted by creating products that don’t meet the desires its audiences. One of the great strengths of the Blizzard brand today is that users will buy its games sight-unseen because they believe in the company’s vision and reputation. That reputation would have been more difficult to establish had the company released both lower-budget casual titles and high-budget AAA+ games, as did Sierra Entertainment, which is now out of business after repeated struggles to find an audience.
In any event, creating Games People Play turned out to be a misstep because developing a casual entertainment product was so demoralizing for the lead programmer that the project never matured and was later canceled. Or perhaps it wasn’t a mistake, because the combination of Warcraft and Games People Play convinced Davidson & Associates, at that time the second largest educational software company in the world, to purchase Silicon & Synapse.
Our new overlords
Davidson & Associates, started by Jan Davidson and later joined by her husband Bob, was a diversified educational software company whose growth was predicated on the success of a title named Math Blaster, in which a player answers math problems to blow up incoming asteroids before they destroy the player’s ship. It was a clever conjunction of education and entertainment, and the company reaped massive rewards from its release.
Aside: As an educational title Math Blaster may have had some value when used properly, but I had occasion to see it used in folly. My high school journalism class would write articles for our school newspaper in a computer room shared with the remedial education class; my fellow journalism students and I watched in horror as remedial twelfth graders played Math Blaster using calculators. As asteroids containing expressions like “3 + 5″ and “2 * 3″ approached those students would rapidly punch the equations into calculators then enter the results to destroy those asteroids. Arguably they were learning something, considering they outsmarted their teachers, but I’m not sure it was the best use of their time given their rapidly approaching entry into the work-force.
With good stewardship and aggressive leadership Davidson & Associates expanded into game manufacturing (creating & packing the retail box), game distribution (shipping boxes to retailers and intermediate distributors), and direct-to-school learning-materials distribution. They saw an opportunity to expand into the entertainment business, but their early efforts at creating entertainment titles internally convinced them that it would make better sense to purchase an experienced game development studio rather than continuing to develop their own games with a staff more knowledgeable about early learning than swords & sorcery.
And so at a stroke the cash-flow problems that prevented the growth of the Warcraft development team were solved by the company’s acquisition; with the deep pockets of Davidson backing the effort it was now possible for Silicon & Synapse (renamed Blizzard in the aftermath of the sale) to focus on its own titles instead of pursuing marginally-profitable deals with other game publishers. And they were very marginal — even creating two top-rated games in 1993, which led to the company being named “Nintendo Developer of the Year”, the company didn’t receive any royalties.
With a stack of cash from the acquisition to hire new employees and enable existing staff to jump on board the project, the development of Warcraft accelerated dramatically.
The design “process”
The approach to designing and building games at Blizzard during its early years could best be described as “organic”. It was a chaotic process that occurred during formal design meetings but more frequently during impromptu hallway gatherings or over meals.
Some features came from design documents, whereas others were added by individual programmers at whim. Some game art was planned, scheduled and executed methodically, whereas other work was created late at night because an artist had a great idea or simply wanted to try something different. Other elements were similarly ad-libbed; the story and lore for Warcraft came together only in the last several months prior to launch.
While the process was unpredictable, the results were spectacular. Because the team was comprised of computer game fanatics, our games evolved over the course of their development to become something that gamers would want to play and play and play. And Warcraft, our first original game for the IBM PC, exemplified the best (and sometimes the worst) of that process, ultimately resulting in a game that — at least for its day — was exemplary.
How the Warcraft unit-creation system came about
As biologists know the process of evolution has false starts where entire branches of the evolutionary tree are wiped out, and so it was with our development efforts. Because we didn’t have spec to measure against, we instead experimented and culled the things that didn’t work. I’d like to say that this was a measured, conscious process in each case, but many times it arose from accidents, arguments, and personality conflicts.
One event I remember in particular was related to the creation of game units. During the early phase of development, units were conjured into existence using “cheat” commands typed into the console because there was no other user-interface mechanism to build them. As we considered how best to create units, various ideas were proposed.
Ron Millar, an artist who did much of the ideation and design for early Blizzard games proposed that players would build farm-houses, and — as in the game Populous — those farms would periodically spawn basic worker units, known as (Human) peasants and (Orc) peons. The player would be able to use those units directly for gold-mining, lumber-harvesting and building-construction, but they wouldn’t be much good as fighters.
Those “peons” not otherwise occupied could be directed by the player to attend military training in barracks, where they’d disappear from the map for a while and eventually emerge as skilled combatants. Other training areas would be used for the creation of more advanced military units like catapult teams and wizards.
The idea was not fully “fleshed out”, which was one of the common flaws of our design process: the end result of the design process lacked the formality to document how an idea should be implemented. So the idea was kicked around and argued back and forth through the informal design team (that is, most of the company) before we started coding (programming) the implementation.
Before we started working on the code Ron left to attend a trade show (probably Winter CES — the Consumer Electronics Show), along with Allen Adham, the company’s president. And during their absence an event occurred which set the direction for the entire Warcraft series, an event that I call the “Warcraft design coup”.
Stu Rose, another early artist/designer to join the company (employee #6, I believe), came late one afternoon to my office to make a case for a different approach. Stu felt that the unit creation mechanism Ron proposed had too many as-yet-unsolved implementation complexities, and moreover that it was antithetical to the type of control we should be giving players in a Real-Time Strategy (RTS) game.
In this new RTS genre the demands on players were much greater than in other genres and players’ attention could not be focused in one place for long because of the many competing demands: plan the build/upgrade tree, drive economic activity, create units, place buildings, scout the map, oversee combat and micromanage individual unit skills. In an RTS the most limited resource is player attention so adding to the cognitive burden with an indirect unit creation mechanism would add to the attention deficit and increase the game’s difficulty.
To build “grunts”, the basic fighting unit, it would be necessary to corral idle peasants or those working on lower priority tasks to give them training, unnecessarily (in Stu’s view) adding to the game’s difficulty.
I was a ready audience for his proposal as I had similar (though less well thought out) concerns and didn’t feel that unit creation was an area where we needed to make bold changes. Dune II, the game from which the design of Warcraft was derived, had a far simpler mechanism for unit creation: just click a button on the user-interface panel of a factory building and the unit would pop out a short time later. It wasn’t novel — the idea was copied from even earlier games — but it just worked.
Stu argued that we should take this approach, and in lieu of more debate just get it done now, so over the next couple of days and late nights I banged out the game and user-interface code necessary to implement unit creation, and the design decision became fait accompli. By the time Ron and Allen returned the game was marginally playable in single-player mode, excepting that the enemy-computer AI was still months away from being developed.
Warcraft was now an actual game that was simple to play and — more importantly — fun. We never looked back.
The first multiplayer game of Warcraft
In June 1994, after ten months of development, the game engine was nearly ready for multiplayer. It was with a growing sense of excitement that I integrated the code changes that would make it possible to play the first-ever multiplayer game of Warcraft. While I had been busy building the core game logic (event loop, unit-dispatcher, path-finding, tactical unit-AI, status bar, in-game user-interface, high-level network code) to play, other programmers had been working on related components required to create a multiplayer game.
Jesse McReynolds, a graduate of Caltech, had finished coding a low-level network library to send IPX packets over a local-area network. The code was written based on knowledge gleaned from the source code of Quake Doom, which had been recently was later open-sourced by John Carmack at id software. While the IPX interface layer was only several hundred lines of C code, it was the portion of the code that interfaced with the network-card driver to ensure that messages created on one game client would be sent to the other player.
And Bob Fitch, who was earning his master’s degree from Cal State Fullerton, developed the initial “glue screens” that enabled players to create and join multiplayer games. My office was next to Bob’s, which was mighty convenient since it was necessary for us to collaborate closely to integrate his game join-or-create logic to my game-event loop.
After incorporating the changes I compiled the game client and copied it to a network drive while Bob raced back to his office to join the game. In what was a minor miracle, the code we’d written actually worked and we were able to start playing the very first multiplayer game of Warcraft.
As we started the game I felt a greater sense of excitement than I’d ever known playing any other game. Part of the thrill was in knowing that I had helped to write the code, but even more so were two factors that created a sense of terror: playing against a human opponent instead of a mere computer AI, and more especially, not knowing what he was up to because of the fog of war.
The fog of war
A small village surrounded by the fog of war; what’s out there?!?
One of the ideas drawn from earlier games was that of hiding enemy units from sight of the opposing player. A black graphic overlay hid areas of the game map unless a friendly unit explored the area, which is designed to mimic the imperfect information known by a general about enemy operations and troop movements during real battles.
Empire, a multiplayer turn-based strategy game written almost seventeen years before by the brilliant Walter Bright (creator the “D” programming language), used fog of war for that same purpose. Once an area of the map was “discovered” (uncovered) it would remain visible forever afterwards, so an important consideration when playing was to explore enough of the map early in the game so as to receive advance warning of enemy troop movements before their incursions could cause damage to critical infrastructure or economic capability.
The psychological terror created by not knowing what the enemy is doing has been the demise of many generals throughout history, and adding this element to the RTS genre is a great way to add to the excitement (and fear) level. Thank Walter and the folks at Westwood who created Dune II for their savvy!
As many gamers know, computer-controlled “Artificial Intelligence” (AI) players in strategy games are often weak. It’s common for human players to discover exploits that the computer AI is not programmed to defend against that can be used destroy the AI with little difficulty, so computer AI players usually rely upon a numeric troop advantage, positional advantage, or “asymmetric rules” in order to give players a good challenge.
In most Warcraft missions the enemy computer players are given entire cities and armies to start with when battling human players. Moreover, Warcraft contains several asymmetric rules which make it easier for the AI player to compete, though these rules would perhaps be called outright cheating by most players.
One rule we created to help the computer AI was to reduce the amount of gold removed from gold mines to prevent them from being mined-out. When a human player’s workers emerge from a gold mine those workers remove 100 units of ore from the mine and deliver it back to the player’s town hall on each trip, and eventually the gold mine is exhausted by these mining efforts. However, when an AI-controlled worker makes the same trip, the worker only remove 8 units of ore from the mine, while still delivering 100 units into the AI treasury.
This asymmetric rule actually makes the game more fun in two respects: it prevents humans from “turtling”, which is to say building an unassailable defense and using their superior strategic skills to overcome the computer AI. Turtling is a doomed strategy against computer AIs because the human player’s gold-mines will run dry long before those of the computer.
Secondarily, when the human player eventually does destroy the computer encampment there will still be gold left for the player to harvest, which makes the game run faster and is more fun than grinding out a victory with limited resources.
Most players are aware of a more serious violation of the spirit of fair competition: the computer AI cheats because it can see through the fog of war; the AI knows exactly what the player is doing from moment to moment. In practice this wasn’t a huge advantage for the computer and merely served to prevent it from appearing completely stupid.
Interestingly, with the long popularity of StarCraft (over 14 years since launch and still played), a group of AI programmers has risen to the challenge of building non-cheating AIs. Aided by a library called BWAPI, these programmers write code that can inject commands directly into the StarCraft engine to play the game. Programmers enter their AIs in competitions with each other to determine the victor. While these BWAPI AI players are good, the best of them are handily beaten by skilled human opponents.
Playing against a human
As a person who had played many (many many) strategy games before developing Warcraft, I was well aware of the limitations of computer AIs of that era. While I had battled against many computer AIs, sometimes losing, many times winning, I was never scared by AI intelligence, even when battling the terrible Russian offensive in the game Eastern Front by Chris Crawford, which I played on a friend’s Atari 800 until eventually the audio cassette tape (!) that contained the game was so old it could no longer be read.
These games were fun, exciting, and most certainly challenging, but not scary. But something changed when I played the first multiplayer game of Warcraft.
The knowledge that I was competing against an able human player — not just in terms of skill and strategy, but also in terms of speed of command — but was prevented from seeing his actions by the fog of war was both electrifying and terrifying. In my entire career I have never felt as excited about a single game as I was during that first experience playing Warcraft, where it was impossible to know whether I was winning or losing.
As a massive adrenaline rush spiked in my bloodstream, I did my best to efficiently harvest gold and lumber, build farms and barracks, develop an offensive capability, explore the map, and — most importantly — crush Bob’s armies before he could do the same to mine.
This was no test-game to verify the functionality of the engine; I know he felt the same desire to claim bragging rights over who won the first-ever multiplayer game of Warcraft. Moreover, when we had played Doom together at Blizzard, I had won some renown because, after a particularly fierce game Bob had become so angry at me for killing him so frequently with a rocket launcher that he had vowed never to play me again. I knew he’d be looking for payback.
As our armies met in battle, we redoubled our efforts to build more units and threw them into the fray. Once I discovered his encampment and attacked, I felt more hopeful. Bob’s strategy seemed disorganized and it appeared I would be able to crush his forces, but I wanted to leave nothing to chance so I continued at a frenzied pace, attacking his units and buildings wherever I could find them.
And then … crash:
Bad news bears – DOS4GW lets us know Warcraft crashed
As any programmer knows, the likelihood of new code working properly the first time is close to zero, and so it should be no surprise that the game crashed. The game’s graphics scrolled off the top of the monitor and were replaced with the blocky text of the DOS4GW “crash screen” so familiar to gamers in the era before Windows gaming. Now we have the far more sophisticated Windows Error Reporting dialog which enables the player to submit the crash report, though occasionally players see the dreaded “blue screen of death” which is remarkably similar to those of old.
After the crash I leaped up from my chair and ran into Bob’s office, yelling “That was awesooooommmme!” immediately followed by “… and I was kicking your ass!” So I was surprised to hear Bob’s immediate rebuttal: to the contrary, he had been destroying me.
It took a few minutes for our jangled nerves to return to normal but in short order we determined that not only did we have a crash bug but also a game-state synchronization problem, which I termed a “sync bug”: the two computers were showing entirely different battles that, while they started identically, diverged into two entirely different universes.
Someone who hasn’t worked on programming network code might assume that the two Warcraft game clients would send the entire game state back and forth each turn as the game is played. That is, each turn the computers would send the positions and actions for every game unit. In a slow-paced game with only a few board positions, like Chess or Checkers, this would certainly be possible but in a game like Warcraft, with up to 600 units in action at once, it was impossible to send that volume of information over the network.
We anticipated that many gamers would play Warcraft with 2400 baud modems, which could only transmit a few hundred characters per second. Younger gamers who never used a modem should take the time to read up on the technology, which was little removed from smoke signals, and only slightly more advanced than banging rocks together. Remember, this was before Amazon, Google and Netflix — we’re talking the dark ages, man.
Having previously “ported” Battle Chess from DOS to Windows, I was familiar with how multiplayer games could communicate using modems. I knew that because of the limited bandwidth available via a modem it would have been impossible to send the entire game state over the network, so my solution was to send only each player’s commands and have both players execute those commands simultaneously.
I knew that this solution would work because computers are great at doing exactly what they’re told. Unfortunately it turned out that many times we humans who program them are not so good at telling computers exactly the right thing to do, and that is a major source of bugs. When two computers are supposed to be doing the same thing, but disagree because of a bug, well, that’s a problem.
A sync bug arises when the two computers simulating the game each choose different answers to the same question, and from there diverge further and further over time. As in time-travel movies like Back to the Future, small changes made by the time-traveler while in the past lead to entirely different futures; so it was that games of Warcraft would similarly diverge. On my computer my Elvish Human archer would see your Orcish peon and attack, whereas on your computer the peon would fail to notice the attack and wander off to harvest lumber. With no mechanism to discover or rectify these types of disagreements, our two games would soon be entirely different.
So it was that the first game of Warcraft was a draw, but at the same time it was a giant win for the game team — it was hella fun! Other team members in the office played multiplayer soon afterwards and discovered it was like Blue Sky, the pure crystal meth manufactured by Walter White in Breaking Bad. Once people got a taste for multiplayer Warcraft, nothing else was as good. Even with regular game crashes, we knew we were on to something big.
All we needed to do was get the game done.
Tragically, we soon made an even worse discovery: not only did we have numerous sync bugs, but there were also many different causes for those sync bugs. If all the sync bugs were for similar reasons we could have endeavored to fix the singular root cause. Instead it turned out there were numerous different types of problems, each of which caused a different type of sync bug, and each which therefore necessitated its own fix.
Why do sync bugs happen
When developing Warcraft I had designed a solution to minimize the amount of data that needed to be transmitted over the network by only sending the commands that each player initiated, like “select unit 5″, “move to 650, 1224″, and “attack unit 53″. Many programmers have independently designed this same system; it’s an obvious solution to the problem of trying to synchronize two computers without sending the entire game state between them every single game turn.
Aside: These days there are probably several patents retroactively trying to claim credit for this approach. Over time I’ve come to believe that software should not be patentable; most any idea in software is something that a moderately experienced programmer could invent, and the definition of patents requires that patents be non-obvious. Nuff said.
I hadn’t yet implemented a mechanism to verify synchronization between the two computers, so any bug in the game code that caused those computers to make different choices would cause the game to “bifurcate” – that is, split it into two loosely-coupled universes that would continue to communicate but diverge with increasing rapidity over time.
Creating systems designed to detect de-synchronization issues was clearly the next task on my long list of things to do to ship the game!
In for the long haul
You know the ending to this story: Warcraft eventually shipped only five months later. It seemed an eternity because we worked so many hours each day, encountered so many obstacles, overcame so many challenges, and created something we cared for so passionately. I’ll continue to explore those remaining months in future blog articles, but so much was packed into that time that it’s impossible to squeeze those recollections into this already too long post!(source:codeofhonor)