• Log InLog In
  • Register
Liquid`
Team Liquid Liquipedia
EDT 03:56
CEST 09:56
KST 16:56
  • Home
  • Forum
  • Calendar
  • Streams
  • Liquipedia
  • Features
  • Store
  • EPT
  • TL+
  • StarCraft 2
  • Brood War
  • Smash
  • Heroes
  • Counter-Strike
  • Overwatch
  • Liquibet
  • Fantasy StarCraft
  • TLPD
  • StarCraft 2
  • Brood War
  • Blogs
Forum Sidebar
Events/Features
News
Featured News
[ASL21] Ro24 Preview Pt2: News Flash10[ASL21] Ro24 Preview Pt1: New Chaos0Team Liquid Map Contest #22 - Presented by Monster Energy18ByuL: The Forgotten Master of ZvT30Behind the Blue - Team Liquid History Book20
Community News
Weekly Cups (March 23-29): herO takes triple6Aligulac acquired by REPLAYMAN.com/Stego Research8Weekly Cups (March 16-22): herO doubles, Cure surprises3Blizzard Classic Cup @ BlizzCon 2026 - $100k prize pool51Weekly Cups (March 9-15): herO, Clem, ByuN win4
StarCraft 2
General
Rongyi Cup S3 - Preview & Info Team Liquid Map Contest #22 - Presented by Monster Energy Blizzard Classic Cup @ BlizzCon 2026 - $100k prize pool What mix of new & old maps do you want in the next ladder pool? (SC2) Aligulac acquired by REPLAYMAN.com/Stego Research
Tourneys
RSL Season 4 announced for March-April Sparkling Tuna Cup - Weekly Open Tournament StarCraft Evolution League (SC Evo Biweekly) WardiTV Mondays World University TeamLeague (500$+) | Signups Open
Strategy
Custom Maps
[M] (2) Frigid Storage Publishing has been re-enabled! [Feb 24th 2026]
External Content
The PondCast: SC2 News & Results Mutation # 520 Moving Fees Mutation # 519 Inner Power Mutation # 518 Radiation Zone
Brood War
General
Pros React To: JaeDong vs Queen so ive been playing broodwar for a week straight. BSL 22 Map Contest — Submissions OPEN to March 10 Klaucher discontinued / in-game color settings BGH Auto Balance -> http://bghmmr.eu/
Tourneys
[Megathread] Daily Proleagues [ASL21] Ro24 Group E [ASL21] Ro24 Group F Azhi's Colosseum - Foreign KCM
Strategy
What's the deal with APM & what's its true value Fighting Spirit mining rates Simple Questions, Simple Answers
Other Games
General Games
Stormgate/Frost Giant Megathread Starcraft Tabletop Miniature Game Nintendo Switch Thread General RTS Discussion Thread Darkest Dungeon
Dota 2
The Story of Wings Gaming Official 'what is Dota anymore' discussion
League of Legends
G2 just beat GenG in First stand
Heroes of the Storm
Simple Questions, Simple Answers Heroes of the Storm 2.0
Hearthstone
Deck construction bug Heroes of StarCraft mini-set
TL Mafia
Mafia Game Mode Feedback/Ideas TL Mafia Community Thread Five o'clock TL Mafia
Community
General
US Politics Mega-thread Russo-Ukrainian War Thread The Chess Thread NASA and the Private Sector Things Aren’t Peaceful in Palestine
Fan Clubs
The IdrA Fan Club
Media & Entertainment
[Manga] One Piece [Req][Books] Good Fantasy/SciFi books Movie Discussion!
Sports
2024 - 2026 Football Thread Formula 1 Discussion Cricket [SPORT] Tokyo Olympics 2021 Thread General nutrition recommendations
World Cup 2022
Tech Support
[G] How to Block Livestream Ads
TL Community
The Automated Ban List
Blogs
Broowar part 2
qwaykee
China Uses Video Games to Sh…
TrAiDoS
Funny Nicknames
LUCKY_NOOB
Iranian anarchists: organize…
XenOsky
FS++
Kraekkling
ASL S21 English Commentary…
namkraft
Electronics
mantequilla
Customize Sidebar...

Website Feedback

Closed Threads



Active: 15858 users

BWAPI, and an inside look into StarCraft's code - Page 2

Forum Index > BW General
Post a Reply
Prev 1 2 All
Sonko
Profile Joined February 2019
154 Posts
October 27 2019 09:24 GMT
#21
Really enjoyed your series on molesting crabs and such, looking forward to your newest deep dive!


Thank you! Hovercrabs cannot be molested enough!
A site about brood war AI: www.makingcomputerdothings.com
Peeano
Profile Blog Joined March 2009
Netherlands5354 Posts
October 27 2019 13:35 GMT
#22
When I issue attack move command on a group of medics and marines, the medics will act the same as if I ordered the heal move command.
I always assumed it was because heal also has the hotkey a (by default). If I change the attack move hotkey from A to Z and issue attack move via Z Medic/Marine in the same group will make the medics respond the same.

My conclusion is they have coded attack move on medics to work the same as the heal command. Because other non-attacking units receive the attack move command just move instead.

If you select a group of carriers and build interceptors, all carriers will build interceptors. The same way a group of reavers will all build scarabs. Or all tanks will siege, etc.

Can you easily decipher from the code if all these special actions are specifically unique?
I'm basically asking if there is any combination where you can have 2 (or more) different units listen to same assigned hotkey the way medic marine do.

I've tried to set scarab building and interceptors to the same hotkey. In hopes that I can order a group of carriers and reavers to both build interceptors and scarabs respectively, but it doesn't work.
And I've been wondering if it is ever possible to combine 2 commands in one hotkey? For example burrow and siege mode or mael strom and psionic storm? I'm curious but too lazy to test all combinations.
Imagine being able to cast ensare and plague with just 1 click, or storm and mael strom...

Can you see how the area plague hits is defined in code? Because from my experience it seems like the aoe is slightly skewed to the right of where you click instead of being centered and ever since I wondered if it may be a small number mistake in coding.
FBH #1!
Sonko
Profile Joined February 2019
154 Posts
October 27 2019 17:32 GMT
#23
Hi Peeano,

I was considering answering your questions one by one, but truth to be told, all of these are to be covered in later articles, so just stay tuned. If you have some coding background, you can take a look in the source files of openBW here:

https://github.com/OpenBW/openbw/blob/master/bwgame.h
A site about brood war AI: www.makingcomputerdothings.com
ThunderJunk
Profile Joined December 2015
United States726 Posts
October 27 2019 20:49 GMT
#24
Wow, what an excellent series of articles. Thank you so much for sharing.

I had no idea that all ranged attacks have a 1/256 miss chance by default!
I am free because I know that I alone am morally responsible for everything I do.
[UoN]Sentinel
Profile Blog Joined November 2009
United States11320 Posts
Last Edited: 2019-10-27 21:56:41
October 27 2019 21:45 GMT
#25
Btw you reference an appendix often, is this posted anywhere on the site? I'm assuming it's lifted from the forthcoming book where you do have an appendix, but there's a few things I'd like to check if you already have it up.

Also nitpick about this section:


Second, an addition to the Energy segment of unit abilities:

The starting energy of a unit is the quarter of the maximum energy of the unit type (rounded up), so upgrades affect it. The exception is the Protoss Shield Battery, with the starting energy of 100.

Dark Archon is another exception. They always start with 50 energy even with Argus Talisman researched.
Нас зовет дух отцов, память старых бойцов, дух Москвы и твердыня Полтавы
Sonko
Profile Joined February 2019
154 Posts
October 28 2019 08:35 GMT
#26
Hi,

Btw you reference an appendix often, is this posted anywhere on the site? I'm assuming it's lifted from the forthcoming book where you do have an appendix, but there's a few things I'd like to check if you already have it up.


Not yet. What are you curious about? Maybe I can look it up for you. Also, I'm considering adding stat blocks and weapon statistics to the untits' description - a little bit redundant, but maybe it would look good.

Dark Archon energy: Thanks for the find, I will add that!
A site about brood war AI: www.makingcomputerdothings.com
Freakling
Profile Joined October 2012
Germany1533 Posts
October 30 2019 00:13 GMT
#27
This is very interesting:
[image loading]

Particularly because ScmDraft does not implement this correctly yet. Gotta ask SI about it.

Anyway, I looked it up, and the function to calculate distances looks like this in OpenBW:
	int xy_length(xy vec) const {
unsigned int x = std::abs(vec.x);
unsigned int y = std::abs(vec.y);
if (x < y) std::swap(x, y);
if (x / 4 < y) x = x - x / 16 + y * 3 / 8 - x / 64 + y * 3 / 256;
return x;
}

It's easy to see how this would give you a dodecagonal structure like depicted above, although I haven't figured out how they came up with this particular approximation yet. Also gotta wonder why they did not just use simple Euclidian distance (I know that square roots are computationally bad, but there is little need to ever calculate and actual distance, only thing of interest is usually to check whether something is within a certain range, which can be done using only squares).
Anyway, this is certainly an interesting piece of code that you should discuss in some detail when you talk about distances.
aqrit
Profile Joined January 2016
13 Posts
Last Edited: 2019-10-30 22:49:21
October 30 2019 22:42 GMT
#28
(a*a + b*b) costs up to 80 cycles in "ye olden times" (warcraft 2 era)
LG)Sabbath
Profile Blog Joined July 2005
Argentina3024 Posts
October 30 2019 23:22 GMT
#29
Also aren't all these division operations optimizable by using bit shifting?

PS. does anyone know if there's any info about the save game file formats (single or multiplayer) anywhere? I have not found anything on google at all
https://www.twitch.tv/argsabbath/
Sonko
Profile Joined February 2019
154 Posts
November 02 2019 10:34 GMT
#30
so gotta wonder why they did not just use simple Euclidian distance


In uniform grids, that is usually not the best approximation.Generally, the Manhattan distance is considered to be best.
Here is a link that explains the what and why:
http://theory.stanford.edu/~amitp/GameProgramming/Heuristics.html#heuristics-for-grid-maps

Also aren't all these division operations optimizable by using bit shifting?


In the openBW code, there are often bitshifts. But that's a decompiled reverse-engineered version. Functionally identical, but I'm not sure that these things are exactly the same. They probably are, though.

PS. does anyone know if there's any info about the save game file formats (single or multiplayer) anywhere? I have not found anything on google at all


Yeah, surprisingly little information. I'm not there yet.
A site about brood war AI: www.makingcomputerdothings.com
Sonko
Profile Joined February 2019
154 Posts
Last Edited: 2019-11-04 13:12:52
November 04 2019 13:12 GMT
#31
Hi everyone, I updated the article a bit. Some ranges were not entirely correct, and rephrased some things to be more clear.
https://makingcomputerdothings.com/brood-war-api-the-comprehensive-guide-movement-modifiers-and-terran-units/

Maybe the most interesting thing is the firebat attack pattern - I created an image that showcases how the Firebat hits work.
(with iscript source)
[image loading]
A site about brood war AI: www.makingcomputerdothings.com
Sonko
Profile Joined February 2019
154 Posts
November 13 2019 17:51 GMT
#32
I have updated and reworked some stuff since - and updated the Firebat image to be more clear.
But in bigger news here is the next part:
Brood War API – The Comprehensive Guide: Terran units continued, and some Zerg ones

Enjoy!
A site about brood war AI: www.makingcomputerdothings.com
2Pacalypse-
Profile Joined October 2006
Croatia9530 Posts
November 14 2019 02:04 GMT
#33
Awesome! Really cool stuff dude.

One small suggestion: drop "BWAPI" from the name of the articles. Seems like most (all?) of these articles are describing the internals of BW itself and don't have much to do with BWAPI, so it might just cause confusion. If there are some articles that talk about BWAPI, then it'd be good to recognize those as such.
Moderator"We're a community of geniuses because we've found how to extract 95% of the feeling of doing something amazing without actually doing anything." - Chill
Sonko
Profile Joined February 2019
154 Posts
November 14 2019 09:35 GMT
#34
One small suggestion: drop "BWAPI" from the name of the articles. Seems like most (all?) of these articles are describing the internals of BW itself and don't have much to do with BWAPI, so it might just cause confusion. If there are some articles that talk about BWAPI, then it'd be good to recognize those as such.


In the long run, this is a part of the BWAPI book - this chapter just got a little bit longer than I anticipated
A site about brood war AI: www.makingcomputerdothings.com
2Pacalypse-
Profile Joined October 2006
Croatia9530 Posts
November 14 2019 13:58 GMT
#35
On November 14 2019 18:35 Sonko wrote:
Show nested quote +
One small suggestion: drop "BWAPI" from the name of the articles. Seems like most (all?) of these articles are describing the internals of BW itself and don't have much to do with BWAPI, so it might just cause confusion. If there are some articles that talk about BWAPI, then it'd be good to recognize those as such.


In the long run, this is a part of the BWAPI book - this chapter just got a little bit longer than I anticipated

It might be a good idea to be able to quickly sort BWAPI articles from non-BWAPI articles, so that people who are only interested in BW internals and not so much in BWAPI itself, could quickly find what they're looking for ^^.
Moderator"We're a community of geniuses because we've found how to extract 95% of the feeling of doing something amazing without actually doing anything." - Chill
Sonko
Profile Joined February 2019
154 Posts
November 14 2019 14:16 GMT
#36
By the way, I lied a lot. Here are some corrections, or rather, clarifications - just as an example
I made these corrections in the article as well. I'm constantly revising, rephrasing, and verifying all of this - not without help, of course.
When upgraded, the Vulture is the fastest unit in the game.
- technically, only the unit with the fastest average top speed among the controllable units. Nukes, scarabs, and interceptors are faster, for example.

(Spider mines) After being laid, it is invisible in the ground (like burrowed units)

They actually take some time to become invisible.

Added this section to the spider mine damage section:
"It fires a stationary bullet when 30 distance away from the target, then gets destroyed 9 frames later. Since this is splash damage, this explains why running away from mines can reduce the damage taken. (See Combat and Damage for more details)"

The tank's turret and base are handled as two separate units in the game code, but that has no bearing on gameplay.


That was a blatant lie. Corrected it to:

This allows the turret to face an enemy unit, while the body moves in a different direction. So when stopping and attacking, the unit does not need to change facing, effectively making it a bit more effective at hit and rtun attacks.

Also with Goliaths:
The turret can turn away from the direction of the body, but has a limit of 32 angle units, so in practice this works more like an increased fire arc.



the Valkyrie fires 8 rockets, and cannot move until all of them are fired.


It can, it just cannot be interrupted during this.

Larva timing is further clarfiied to this. (Imagine digging this out)
Each Hatchery has a larva_timer variable, which is set to 37 when a larva is spawned. This gets decreased every 9 frames, but that timer is randomized every 150 frames. So this timer is subject to 2 or 3 randomizations. This means that as long the larva count is never max, larva will spawn every 328-361 frames, otherwise this number will vary between 319-360.


I also added this to the Spore Colony:
Since it’s a building, the detection range is 7 tiles, or 7*32 pixels, which is not the same as the unit’s sight range)
but spore colony does not


It's of course, a matter of how precise I want to be exactly. At some point, it's a pointless exercise, but I feel I'm far from it.

Kudos if you have noticed any of these while reading the article :D

A site about brood war AI: www.makingcomputerdothings.com
Sonko
Profile Joined February 2019
154 Posts
November 14 2019 14:16 GMT
#37

It might be a good idea to be able to quickly sort BWAPI articles from non-BWAPI articles, so that people who are only interested in BW internals and not so much in BWAPI itself, could quickly find what they're looking for ^^.


Okay, you have a point, I'll add some clarifying label.
A site about brood war AI: www.makingcomputerdothings.com
2Pacalypse-
Profile Joined October 2006
Croatia9530 Posts
November 14 2019 14:35 GMT
#38
Another small suggestion: you should update the original post of this thread to include all of the newer articles as well.
Moderator"We're a community of geniuses because we've found how to extract 95% of the feeling of doing something amazing without actually doing anything." - Chill
Sonko
Profile Joined February 2019
154 Posts
November 14 2019 14:46 GMT
#39
Another small suggestion: you should update the original post of this thread to include all of the newer articles as well.


Thanks, I wasn't aware I can do that. Added the new articles!
A site about brood war AI: www.makingcomputerdothings.com
Xeofreestyler
Profile Blog Joined June 2005
Belgium6775 Posts
November 14 2019 19:59 GMT
#40
This is AWESOME. Thank you!
Graphics
Prev 1 2 All
Please log in or register to reply.
Live Events Refresh
Next event in 2h 4m
[ Submit Event ]
Live Streams
Refresh
StarCraft 2
SortOf 76
StarCraft: Brood War
910 856
Pusan 306
ggaemo 146
Larva 91
Nal_rA 89
Killer 74
ToSsGirL 39
Bale 17
League of Legends
JimRising 598
Counter-Strike
shoxiejesuss439
Heroes of the Storm
Khaldor145
Other Games
summit1g12874
WinterStarcraft497
ceh9458
crisheroes65
Organizations
Counter-Strike
PGL3683
Other Games
BasetradeTV185
StarCraft 2
Blizzard YouTube
StarCraft: Brood War
BSLTrovo
sctven
[ Show 12 non-featured ]
StarCraft 2
• LUISG 13
• AfreecaTV YouTube
• intothetv
• Kozan
• IndyKCrew
• LaughNgamezSOOP
• Migwel
• sooper7s
StarCraft: Brood War
• BSLYoutube
• STPLYoutube
• ZZZeroYoutube
League of Legends
• Stunt490
Upcoming Events
Afreeca Starleague
2h 4m
Wardi Open
3h 4m
Replay Cast
16h 4m
Sparkling Tuna Cup
1d 2h
PiGosaur Cup
1d 16h
Kung Fu Cup
2 days
The PondCast
3 days
Replay Cast
3 days
Replay Cast
4 days
CranKy Ducklings
5 days
[ Show More ]
BSL
5 days
Replay Cast
5 days
Sparkling Tuna Cup
6 days
BSL
6 days
Replay Cast
6 days
Liquipedia Results

Completed

CSL Elite League 2026
RSL Revival: Season 4
NationLESS Cup

Ongoing

BSL Season 22
ASL Season 21
CSL Season 20: Qualifier 2
CSL 2026 SPRING (S20)
StarCraft2 Community Team League 2026 Spring
Nations Cup 2026
PGL Bucharest 2026
Stake Ranked Episode 1
BLAST Open Spring 2026
ESL Pro League S23 Finals
ESL Pro League S23 Stage 1&2
PGL Cluj-Napoca 2026
IEM Kraków 2026
BLAST Bounty Winter 2026

Upcoming

Escore Tournament S2: W2
IPSL Spring 2026
Escore Tournament S2: W3
Acropolis #4
BSL 22 Non-Korean Championship
CSLAN 4
Kung Fu Cup 2026 Grand Finals
HSC XXIX
uThermal 2v2 2026 Main Event
RSL Revival: Season 5
IEM Cologne Major 2026
Stake Ranked Episode 2
CS Asia Championships 2026
Asian Champions League 2026
IEM Atlanta 2026
PGL Astana 2026
BLAST Rivals Spring 2026
CCT Season 3 Global Finals
IEM Rio 2026
TLPD

1. ByuN
2. TY
3. Dark
4. Solar
5. Stats
6. Nerchio
7. sOs
8. soO
9. INnoVation
10. Elazer
1. Rain
2. Flash
3. EffOrt
4. Last
5. Bisu
6. Soulkey
7. Mini
8. Sharp
Sidebar Settings...

Advertising | Privacy Policy | Terms Of Use | Contact Us

Original banner artwork: Jim Warren
The contents of this webpage are copyright © 2026 TLnet. All Rights Reserved.