5 ms·

Bunnyhopping from the Programmer's Perspective

73 points by Artemis2 12y ago

krat0sprakhar 12y ago
Haha! This is awesome! Reminds me of the good days of CS 1.6 when newbs would to be totally flabbergasted on seeing others bunnyhopping. The best times were when a sniper would get knifed by some bunnyhopper! :D Thanks for sharing :)
- hedwall 12y ago
  If I remember correctly so was bunnyjumping fixed in version 1.5, which also started a mod of CS called classic 1.3 or something like that.
  - deleted 12y ago
    [deleted]
  - benihana 12y ago
    It was 'fixed' in 1.3 but was still possible in 1.5 and 1.6, just much harder
TwoBit 12y ago
So games intentionally program support for bunnyhopping, or us it a math logic bug.
- scarlson 12y ago
  Both. It was originally a bug, has since turned into a feature.
  - sirclueless 12y ago
    Talking of other CS "bugs" that have turned into features, anyone who's never seen "surfing" should check that out. Basically, you take the same air-strafing principles from this article, add a little bunny-hopping, and another "feature" of counterstrike where if you land on a steep enough slope you won't take falling damage or apply friction. Give this to some insane map makers and the end result is an incredibly skill-intensive obstacle course of sorts at tremendously high speeds. Here's a good example of what I'm talking about: https://www.youtube.com/watch?v=o0Xv00yJhjs https://www.youtube.com/watch?v=o0Xv00yJhjs There's a really dedicated community behind this stuff, you can find 64-man servers full of people playing this type of map in CS:GO and CS:Source.
    - nawitus 12y ago
      Here's an interesting bug/technique in HL2 called 'Accelerated Back Hopping' https://www.youtube.com/watch?v=NV-AWxqYAgc&t=41m43s https://www.youtube.com/watch?v=NV-AWxqYAgc&t=41m43s It's used in speedruns, but I believe is fixed these days. Apprently if you're bunnyhopping backwards, the game tries to limit the speed, but since you're going backwards the player ends up accelerating essentially indefinitely.
  - bitwize 12y ago
    See also: skiing in Tribes, or the entire notion of combos in VS fighting games.
jsprogrammer 12y ago
Cross-posting my comment from reddit (had the article first): Asheron's Call had a similar bug, although it took a while to be discovered. There was a buried feature that allowed you to turn/rotate, your character by clicking your mouse on the screen in certain locations. Your rotation speed was controlled by how far from the origin the mouse was located and ramped up to a capped rotation speed after a certain distance. The closer you were to the origin, the slower your rotation speed. The game came out around 1998 when most people were playing on 800x600 or maybe 1024x768 screens and since the possible rotation speeds you could achieve were directly related to the pixel width of the viewport, there was effectively a limit to the slowness of your rotation. Fast forward half a decade and people are playing on dual 1600x1200 screens and you can now turn reeeally slow if you get your cursor in the right position (and enabled the rarely used feature). Well, you could combine this slow rotation with strafe-running to make your velocity vector scale out many multiples of your normal run speed. In-game, other people viewed you as essentially teleporting (game had slow updates and basic client-side prediction) huge distances at a time. Not too long after this exploit was found, they introduced a new game client (for other reasons) that didn't have the mouse turn feature (I don't think anyone ever really used it in the previous ~7 years), so it was no longer possible to use. My friend and I had some fun nights on the PK server being able to just 'disappear' from a fight at will.
- jsprogrammer 12y ago
  Hmm, looks like something ate my line breaks and editing/deleting isn't working...
  - louhike 12y ago
    You have to double them.
    - jsprogrammer 12y ago
      I tried that...about 10 times...
Morphling 12y ago
Not bunnyhopping, but similar idea a game called Gunz: The Duel had many animation glitches where you could cancel animation lock with higher priority move. The action would execute, but the animation would be cut in short with a shorter animation which allowed you to perform a new longer animation move. Commonly it was called kStyle or "korean style" in west since the game was korean and koreans came up with the bug. It made the game everyone was doing it flying through the map with swords swinging wildly it was a lot of fun and definitely raised the skill ceiling and someone how it didn't seem nearly as cheaty as the bunnyhopper in articles video.
- simonlc 12y ago
  That sounds like how certain types of combos work in games like Street Fighter.
yelnatz 12y ago
Source video for the gif: https://www.youtube.com/watch?v=KYEyIGLRqW0&t=47 https://www.youtube.com/watch?v=KYEyIGLRqW0&t=47 It really shows how much of an advantage it was if you knew how to bunny hop.
- bko 12y ago
  Here is another video showing a fuller explanation of bunny hopping and going into the history a bit https://www.youtube.com/watch?v=n1HowpVX-hU https://www.youtube.com/watch?v=n1HowpVX-hU
JoachimSchipper 12y ago
Isn't this... just a bug? Good on the players for finding it, of course; and I can even see the community agreeing to let everyone exploit bunnyhopping - but intentionally programming in this behaviour seems really odd to me.
- clarry 12y ago
  It is now considered a feature, and there are entire maps & games built with a focus on trick jumping. It's a fun thing to learn and it really opens up new possibilities, even in maps that weren't specifically designed with trick jumping in mind. For most games, it increases the skill cap, thus adding depth... I am so used to bunny hopping that I feel handicapped in any FPS that doesn't let me do it. If I ever get my FPS project going, it'll sure as heck have this feature.
  - ryanlol 12y ago
    Not exactly true, valve "fixed" the phoon style bunnyhopping after the vide on in the article surfaced (even though it had been in the game for years). There still exists a version of bunnyhopping in the game but using it for speed gain on longer distances is very difficult.
  - vehementi 12y ago
    I really wish people perceived the bar to be higher than "well, it doesn't totally break the game, and it adds to the skill cap, so ship it!" for keeping any bug/feature in. Literally anything that can impair you adds to the skill cap because it's another thing you have to learn to use/avoid. We must also answer questions like "Is it credibility-destroyingly stupid to have players flying around at high speed in a semi-realistic military shooter" and "is this even fun" and "what effect does this have on the intended balance & map design". I don't know the answers for CS but in general I often see criticism of the status quo in games met with with knee-jerk "this increases the skill cap, learn to play" responses.
    - reubenmorais 12y ago
      Realistic military shooters are niche. The average player wants fun, not believable. I personally attribute most of Counter-Strike's success to its completely unrealistic movement/weapon handling, creating a game that is arcade-y: you can replicate movements with almost 100% accuracy which means with enough practice you can master the game in incredible ways. This means the replay value is almost infinite: see for example, how the 1.6 competitive scene has used the same 15 original bomb defuse maps for more than a decade without it getting stale.
agumonkey 12y ago
Ha, I thought it was a `Skater Bunnyhop from the Physicist Perspective` article. Interesting nonetheless.
Paul_S 12y ago
I think it's extremely telling how people react to it. Some will get annoyed and demand for this to be disabled because others have the advantage on them. Others will try and learn to do it to get that advantage on other people. I wonder if you could use this to perform a similar test to the marshmallow experiment (http://en.wikipedia.org/wiki/Stanford_marshmallow_experiment http://en.wikipedia.org/wiki/Stanford_marshmallow_experiment).
neckro23 12y ago
The good old-fashioned rocket jump is another example of this. Quake 1 had a feature where if a player took damage, they'd get pushed in the direction the damage came from. This was originally intended to serve as a visual indicator. Of course, this meant that if you aimed the rocket launcher at your feet, and jumped and fired simultaneously, the damage kick + the jump would launch you a good distance upward. This became a popular enough technique that it was retained in the Quake sequels, and even imitated in games like Half-Life (the Gauss Gun would push you backwards, allowing a "rocket jump" of sorts)...
- _neil 12y ago
  This was also a common tactic in Tribes, which also had jet packs and 'skiing' (basically bunny hopping downhill while building up momentum). The game had vehicles, but after people figured out skiing, the vehicles were basically abandoned. In the later years of the game, people even figured out disc jumping in midair off of their own grenade. Edit: here's a quick Tribes 1 video where a guy skis around the enemy base, team kills his own flag carrier, catches the flag in midair, and disc jumps home to cap it. http://youtu.be/HF_htZRhbiQ http://youtu.be/HF_htZRhbiQ

73 points by Artemis2 12y ago

Haha! This is awesome! Reminds me of the good days of CS 1.6 when newbs would to be totally flabbergasted on seeing others bunnyhopping. The best times were when a sniper would get knifed by some bunnyhopper! :D Thanks for sharing :)

hedwall 12y ago
If I remember correctly so was bunnyjumping fixed in version 1.5, which also started a mod of CS called classic 1.3 or something like that.
- deleted 12y ago
  [deleted]
- benihana 12y ago
  It was 'fixed' in 1.3 but was still possible in 1.5 and 1.6, just much harder

TwoBit 12y ago

So games intentionally program support for bunnyhopping, or us it a math logic bug.

scarlson 12y ago
Both. It was originally a bug, has since turned into a feature.
- sirclueless 12y ago
  Talking of other CS "bugs" that have turned into features, anyone who's never seen "surfing" should check that out. Basically, you take the same air-strafing principles from this article, add a little bunny-hopping, and another "feature" of counterstrike where if you land on a steep enough slope you won't take falling damage or apply friction. Give this to some insane map makers and the end result is an incredibly skill-intensive obstacle course of sorts at tremendously high speeds. Here's a good example of what I'm talking about: https://www.youtube.com/watch?v=o0Xv00yJhjs https://www.youtube.com/watch?v=o0Xv00yJhjs There's a really dedicated community behind this stuff, you can find 64-man servers full of people playing this type of map in CS:GO and CS:Source.
  - nawitus 12y ago
    Here's an interesting bug/technique in HL2 called 'Accelerated Back Hopping' https://www.youtube.com/watch?v=NV-AWxqYAgc&t=41m43s https://www.youtube.com/watch?v=NV-AWxqYAgc&t=41m43s It's used in speedruns, but I believe is fixed these days. Apprently if you're bunnyhopping backwards, the game tries to limit the speed, but since you're going backwards the player ends up accelerating essentially indefinitely.
- bitwize 12y ago
  See also: skiing in Tribes, or the entire notion of combos in VS fighting games.

jsprogrammer 12y ago

Cross-posting my comment from reddit (had the article first): Asheron's Call had a similar bug, although it took a while to be discovered. There was a buried feature that allowed you to turn/rotate, your character by clicking your mouse on the screen in certain locations. Your rotation speed was controlled by how far from the origin the mouse was located and ramped up to a capped rotation speed after a certain distance. The closer you were to the origin, the slower your rotation speed. The game came out around 1998 when most people were playing on 800x600 or maybe 1024x768 screens and since the possible rotation speeds you could achieve were directly related to the pixel width of the viewport, there was effectively a limit to the slowness of your rotation. Fast forward half a decade and people are playing on dual 1600x1200 screens and you can now turn reeeally slow if you get your cursor in the right position (and enabled the rarely used feature). Well, you could combine this slow rotation with strafe-running to make your velocity vector scale out many multiples of your normal run speed. In-game, other people viewed you as essentially teleporting (game had slow updates and basic client-side prediction) huge distances at a time. Not too long after this exploit was found, they introduced a new game client (for other reasons) that didn't have the mouse turn feature (I don't think anyone ever really used it in the previous ~7 years), so it was no longer possible to use. My friend and I had some fun nights on the PK server being able to just 'disappear' from a fight at will.

jsprogrammer 12y ago
Hmm, looks like something ate my line breaks and editing/deleting isn't working...
- louhike 12y ago
  You have to double them.
  - jsprogrammer 12y ago
    I tried that...about 10 times...

Morphling 12y ago

Not bunnyhopping, but similar idea a game called Gunz: The Duel had many animation glitches where you could cancel animation lock with higher priority move. The action would execute, but the animation would be cut in short with a shorter animation which allowed you to perform a new longer animation move. Commonly it was called kStyle or "korean style" in west since the game was korean and koreans came up with the bug. It made the game everyone was doing it flying through the map with swords swinging wildly it was a lot of fun and definitely raised the skill ceiling and someone how it didn't seem nearly as cheaty as the bunnyhopper in articles video.

simonlc 12y ago
That sounds like how certain types of combos work in games like Street Fighter.

yelnatz 12y ago

Source video for the gif: https://www.youtube.com/watch?v=KYEyIGLRqW0&t=47 https://www.youtube.com/watch?v=KYEyIGLRqW0&t=47 It really shows how much of an advantage it was if you knew how to bunny hop.

bko 12y ago
Here is another video showing a fuller explanation of bunny hopping and going into the history a bit https://www.youtube.com/watch?v=n1HowpVX-hU https://www.youtube.com/watch?v=n1HowpVX-hU

JoachimSchipper 12y ago

Isn't this... just a bug? Good on the players for finding it, of course; and I can even see the community agreeing to let everyone exploit bunnyhopping - but intentionally programming in this behaviour seems really odd to me.

clarry 12y ago
It is now considered a feature, and there are entire maps & games built with a focus on trick jumping. It's a fun thing to learn and it really opens up new possibilities, even in maps that weren't specifically designed with trick jumping in mind. For most games, it increases the skill cap, thus adding depth... I am so used to bunny hopping that I feel handicapped in any FPS that doesn't let me do it. If I ever get my FPS project going, it'll sure as heck have this feature.
- ryanlol 12y ago
  Not exactly true, valve "fixed" the phoon style bunnyhopping after the vide on in the article surfaced (even though it had been in the game for years). There still exists a version of bunnyhopping in the game but using it for speed gain on longer distances is very difficult.
- vehementi 12y ago
  I really wish people perceived the bar to be higher than "well, it doesn't totally break the game, and it adds to the skill cap, so ship it!" for keeping any bug/feature in. Literally anything that can impair you adds to the skill cap because it's another thing you have to learn to use/avoid. We must also answer questions like "Is it credibility-destroyingly stupid to have players flying around at high speed in a semi-realistic military shooter" and "is this even fun" and "what effect does this have on the intended balance & map design". I don't know the answers for CS but in general I often see criticism of the status quo in games met with with knee-jerk "this increases the skill cap, learn to play" responses.
  - reubenmorais 12y ago
    Realistic military shooters are niche. The average player wants fun, not believable. I personally attribute most of Counter-Strike's success to its completely unrealistic movement/weapon handling, creating a game that is arcade-y: you can replicate movements with almost 100% accuracy which means with enough practice you can master the game in incredible ways. This means the replay value is almost infinite: see for example, how the 1.6 competitive scene has used the same 15 original bomb defuse maps for more than a decade without it getting stale.

agumonkey 12y ago

Ha, I thought it was a `Skater Bunnyhop from the Physicist Perspective` article. Interesting nonetheless.

Paul_S 12y ago

I think it's extremely telling how people react to it. Some will get annoyed and demand for this to be disabled because others have the advantage on them. Others will try and learn to do it to get that advantage on other people. I wonder if you could use this to perform a similar test to the marshmallow experiment (http://en.wikipedia.org/wiki/Stanford_marshmallow_experiment http://en.wikipedia.org/wiki/Stanford_marshmallow_experiment).

neckro23 12y ago

The good old-fashioned rocket jump is another example of this. Quake 1 had a feature where if a player took damage, they'd get pushed in the direction the damage came from. This was originally intended to serve as a visual indicator. Of course, this meant that if you aimed the rocket launcher at your feet, and jumped and fired simultaneously, the damage kick + the jump would launch you a good distance upward. This became a popular enough technique that it was retained in the Quake sequels, and even imitated in games like Half-Life (the Gauss Gun would push you backwards, allowing a "rocket jump" of sorts)...

_neil 12y ago
This was also a common tactic in Tribes, which also had jet packs and 'skiing' (basically bunny hopping downhill while building up momentum). The game had vehicles, but after people figured out skiing, the vehicles were basically abandoned. In the later years of the game, people even figured out disc jumping in midair off of their own grenade. Edit: here's a quick Tribes 1 video where a guy skis around the enemy base, team kills his own flag carrier, catches the flag in midair, and disc jumps home to cap it. http://youtu.be/HF_htZRhbiQ http://youtu.be/HF_htZRhbiQ