The StarCraft path-finding hack
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The StarCraft path-finding hack
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Re: The StarCraft path-finding hack
#2> Some bugs were related to the development process itself. The Protoss Carrier regularly lagged behind other units because it had its own way of doing … everything. At some point in time the code for the Carrier was branched from the main game code and had diverged beyond any hope of re-integration. Consequently any time a feature was added for other units, it had to be re-implemented for the Carrier. And any time a bug was fixed for other units, a similar bug would later be found in the Carrier code too, only more devious and difficult to fix.
I guess it's comforting to know that even elite development teams also struggle with code design. I wonder how far off the branch the Carrier unit was that required it to have its own reimplemented features...and what kind of features needed to be reimplemented for it? (story-game events, path-finding?)
Re: The StarCraft path-finding hack
#3The Protoss Carrier regularly lagged behind other units because it had its own way of doing … everything.
The Carrier should have been scrapped entirely and replaced with a different air unit. Even to the latest upgrades of Starcraft I, the AI simply couldn't deal with the carrier effectively--they would always attack the interceptors first. This made using the carrier a cheap game-breaking trick against the computer.
Re: The StarCraft path-finding hack
#4I always thought that the fact that workers don't jam was one of the coolest little details of the game that made it so awesome! I never would have thought that it was basically an ugly, last-resort bugfix :)
Re: The StarCraft path-finding hack
#5One of the reasons Starcraft is interesting as an e-sport is because bugs like this have kept the game in racial balance for over a decade.
For example, the game was not designed to give mutalisks the ability to stack on top of each other. However, at some point in the early 2000s, it was discovered that when 11 mutalisks were grouped with 1 overlord, the mutas tended to stack: http://www.youtube.com/watch?v=NfqQYJzq7o0 . This meant that an attacking player could deal the damage of 11 units while only exposing the surface area of 1 of them. Using this technique, a pro gamer named July won the 3 OSL tournaments: http://wiki.teamliquid.net/starcraft/July .
With respect to the path-finding behavior described in the article, there is a funny aspect the author doesn't mention: mining workers still collide with buildings while mining, just not other workers. This lead to a technique known as the manner pylon: http://www.youtube.com/watch?v=EmS2ghQyAYI . If a protoss player builds a pylon in their opponent's mineral line with great timing, they can trap their opponent's workers between the minerals and the pylon. This renders the workers useless until the pylon is killed.
In Starcraft-speak, "manner" means being respectful (such as saying "good game" when you lose). The manner pylon got it's name because it is so incredibly annoying to deal with, it will cause anyone to lose their manners.
For those of you who might be familiar with Starcraft, but not the competitive scene, you should know that pro players are executing these techniques at a rate of hundreds of APM (actions per minute): https://www.youtube.com/watch?v=Z4UTDudShDY
Re: The StarCraft path-finding hack
#6The Protoss Carrier regularly lagged behind other units because it had its own way of doing … everything. The Carrier should have been scrapped entirely and replaced with a different air unit. Even to the latest upgrades of Starcraft I, the AI simply couldn't deal with the carrier effectively--they would always attack the interceptors first. This made using the carrier a cheap game-breaking trick against the computer…
...and made it one of the most interesting units in multiplayer. In programmer-land, where all abstractions should be pure and elegant, the carrier (as implemented in SC1) may be abhorrent, but this is irrelevant because the customers (i.e. the players) loved it.
Some of the quirky behavior of the SC1 carrier was even re-implemented into the upcoming SC2 expansion at the behest of fans. Why? Because it made the unit fun.
Re: The StarCraft path-finding hack
#7I always thought that the fact that workers don't jam was one of the coolest little details of the game that made it so awesome! I never would have thought that it was basically an ugly, last-resort bugfix :)
It's become such an important part of the gameplay that it's funny to think it was just a fix.
Re: The StarCraft path-finding hack
#8> Some bugs were related to the development process itself. The Protoss Carrier regularly lagged behind other units because it had its own way of doing … everything. At some point in time the code for the Carrier was branched from the main game code and had diverged beyond any hope of re-integration. Consequently any time a feature was added for other units, it had to be re-implemented for the Carrier. And any time a…
I think it's because of the way the unit works. The carrier itself doesn't actually attack anything. It produces and spawns interceptors which are independent and targetable(but not capable of taking orders) units, which then go out and attack the carrier's target.
The unit, by itself, is closer to a building than an actual unit, because the player has to manually queue up interceptor production, which has a resource cost and takes time.
Since it does spawn the interceptors to attack, there are a lot of behaviors that it shows that other units don't. For one, the maximum range to a target where it can start to attack is fixed, like most units. At that range or lower, the carrier will launch it's interceptors, which will attack the target. However, there is also a longer "leash" range, where the carrier can move away from the target, after the interceptors have been launched, and they will keep attacking the target until the carrier goes out of the range, at which point the interceptors will go back to the carrier that spawned it. An explanation of this behavior can be found here: http://www.youtube.com/watch?v=1Rqx8s2qKXM
Also, when the carrier dies, all interceptors that it has launched die.
Re: The StarCraft path-finding hack
#9> Some bugs were related to the development process itself. The Protoss Carrier regularly lagged behind other units because it had its own way of doing … everything. At some point in time the code for the Carrier was branched from the main game code and had diverged beyond any hope of re-integration. Consequently any time a feature was added for other units, it had to be re-implemented for the Carrier. And any time a…
It functioned in a significantly different way from other units. They had to include the unit building mechanisms from factory buildings (for producing interceptors), and instead of having its own direct attacks it controlled a small fleet of child units with their own weapons.
The engine wouldn't have been particularly flexible about that kind of thing, as almost every other unit has either a direct "shoot guns at the target" attack or no attack at all. The two exceptions to this were the Protoss carrier (air) and reaver (ground). Reavers would have been a bit simpler because their projectiles just find a path to the target and blow up; there's no need for swarming behavior, returning to the carrier to recharge, etc.
Re: The StarCraft path-finding hack
#10One of the reasons Starcraft is interesting as an e-sport is because bugs like this have kept the game in racial balance for over a decade. For example, the game was not designed to give mutalisks the ability to stack on top of each other. However, at some point in the early 2000s, it was discovered that when 11 mutalisks were grouped with 1 overlord, the mutas tended to stack: http://www.youtube.com/watch?v=NfqQYJzq…
There were all kinds of discoveries like that. I remember when the reaver drop was invented by someone out of MIT. Can't remember his handle but he was one of the top players pre-brood war.
Edit: Found him, Zileas aka Tom Cadwell. Brings back the memories.