I find projects like this really fun, but when it comes to being a game I am seeing a lot of problems.
- renderer and physics aren't synced in any way, physics shouldn't be tied to frame rate, but running as 2 separate threads with no synchronization means you might read garbage at some points if you render while the physics thread is updating.
- physics using this_thread::sleep_for is not accurate and can sleep for longer than the specified time, assuming the period to be 1/60 isn't correct. The delta time needs to be measured.
- using VK_PRESENT_MODE_FIFO_KHR or VK_PRESENT_MODE_MAILBOX_KHR force vsync, but vsync can be anything. With the physics system being locked to 60, you'll notice a stutter on non-mulitiple vsyncs like 144hz. There aren't many solutions I know for this, but the main ones I know of are interpolation and extrapolation of the physics state based on the framerate. I would bump the physics update rate to 120hz to match rocket league and then experiment from there.
- Using both Eigen and GLM is overkill in this case, both are slow, but if sticking with one I would use switch solely glm.
- More of a nitpick, but I would separate out all the code at least between rendering and physics to their own independent files. The vulkan api on it's own adds a lot of clutter, moving that to it's own file should make the project easier to navigate and explorer.
There are more things, like how hard coded that shaders are, but I assume the vulkan renderer will be improved past just being from the vulkan-tutorial, so advice for that can't really be given till the renderer has been updated.
P.S. Sorry if any of this sounds harsh, it's not my intention. I've just done a lot of work involving games, game engines and renderers. And I'm seeing a lot of the problems I made when I first started. I wish you the best of luck with your project.
Thanks a lot for the feedback! I built it in ~2 weeks and it's really just a prototype at this stage. Some of the points I did on purpose to finish a prototype quickly (Eigen + GLM, one file, not syncing renderer and physics, hardcoding shaders etc.). But some things I didn't know - thanks for that :)
I played so much Rocket League before it went free-to-play. Seeing this repo made me watch some youtube videos, and remember what a great game it is. It's been tweaked and polished until it feels perfect. I think getting an open source version of the game to that level would require a lot of work, so I wish you well.
It's a great game - unfortunately the insane and obnoxious way they do ranked ladder means the experience is often miserable if you want to play competitively.
Could you elaborate? I play the game, but I don’t play much of anything else with ranks so I’m curious what ladder means here and the alternative examples.
I could write an essay on this (played since 2015) so I'm sorry if this is overly wordy and I hope it makes sense.
A long time ago they had a pretty basic MMR/matchmaking system that was being gamed pretty badly by smurfs. So, in an attempt to deal with smurfs, Epic made a really opaque blackbox "internal" MMR, that determines what kind of teammates you get. The reason this exists is because everyone tends to get lumped into "chokepoint" ranks - Diamond 3/low champ, C3/GC, and from there I think there's another one closer to SSL but I've only been a GC1 before so I can't comment on that experience. The reason for this is you can have a 60+% winrate in diamond and never leave diamond. That results in tons of players being in a rank they clearly do not belong in - very ironically creating an unintentional smurf problem they were trying to addresss in the first place - and this is exacerbated by a draconian rank decay/reset every season which only lasts a quarter. So, it's not entirely uncommon to see players with a GC tournament tag from the previous season (means they won a GC tournament, which means they almost certainly are SSL players) in low champ or even diamond. This is made even WORSE by the way that placement games work every season - pros have worked out it's almost always better to just sit out the first few weeks of a season before doing your placements, because you may accidentally get a really high "internal" mmr (the only purpose of these placements) by beating other smurfs in a low rank ladder.
As a result, epic has tried to balance this idiotic mess by pairing these types of players with lower "true" ranks. So, often when I am in high diamond/low champ I will have a literal carried platinum player with me every single time against another team with a guy who also has a higher "true" MMR and whatever "low" MMR player the matchmaking has decided he also gets paired with. I solo queue though, so this effect is basically a miserable experience trying to climb, as it's much more difficult for me to climb out of a low rank than other players closer to their "true" rank. And I have to repeat this process every 12 fucking weeks.
when I play casual, within 10 games the matchmaking immediately puts me in high champ lobbies. So, they know how to match make fairly, clearly - there's simply no mechanism in ranked to quickly rank someone up who very obviously should not be in the rank. It should not be possible to win 15 games in a row and stay in the same rank - every other game addresses this by quickly ranking up people on win streaks. For whatever reason, epic does not, and for this reason and all of what I listed above, the experience is absolutely miserable.
If it helps anyone else-
The term 'smurf' is used in gaming to describe a player in an online game that creates a new account to play against lower-ranked players, however, it can be used as an all-around term for describing a player who uses an alternate account or multiple accounts.
The etymology I've heard is that it comes from Warcraft 2, where some top players made Smurf-themed alt-accounts after everyone started dodging them. That may be apocryphal.
yea, sorry, these are common terms in that community I didn't explain, thank you. When I'm using it here it mostly means "someone who is intentionally playing in a rank they don't belong in"
> when I play casual, within 10 games the matchmaking immediately puts me in high champ lobbies. So, they know how to match make fairly, clearly - there's simply no mechanism in ranked to quickly rank someone up who very obviously should not be in the rank. It should not be possible to win 15 games in a row and stay in the same rank - every other game addresses this by quickly ranking up people on win streaks. For whatever reason, epic does not, and for this reason and all of what I listed above, the experience is absolutely miserable.
Adding to this note, the blizzard card game Hearthstone has had the same notorious problem for as long as I've known (havent played in a few years no idea if it changed, I doubt it). They started to mess around with bonus mechanisms for win streaks, but largely before legend ranks (which worked with a much more sane ranking system) you would never be put in a higher rank if you went 50-0 vs going 200-150 - the game viewed that as exactly the same. The result was the same as with rocket league - huge rank choke points in which people were stuck for weeks playing players far above their own rank. Frustrating for both sides, and the only reasoning I can put behind it is they want you to spend more time grinding, and that's the only way they can think to do it.
One thing that has always bugged me, and that I've never seen discussed, is that when I play solo they'll pair me up with two other solo players and then match us up against a 3 player clan!
Even if we all have the same rank, they're not at all considering the advantage of 3 players who play well as a team, and in the clan case... probably practice and play together a lot. Especially at the lower ranks, but sometimes in the mid-high ranks, a well organized team can demolish a random group of slightly higher ranked players who haven't established a playbook.
At times when the servers are saturated with players, I think they should only match parties with other parties of the same size. For example, parties of two would only be matched against other parties of two and then each party would get solo player(s) to reach the team size of a given match. Parties of three would only play against other parties of three, etc. I understand there are times of low liquidity and such matchmaking would be impossible, and that's fine... I'd rather play than not, but when liquidity is high then I'd rather wait an extra 15-30 seconds for teams and parties to be more balanced.
What do you think about party size aware match making?
> What do you think about party size aware match making?
I'm heavily in favor of what you said, and yea, back in the day when psyonix owned it there was a mode called "solo standard" which was 3v3 but you couldn't join with a team. It was awesome, people who did well in that mode tended to be extremely good teammates - you kinda had to to succeed. As a result it was usually much less toxic. Epic killed that mode almost immediately and it made me super upset.
Yea I have a whole rant about this too - it probably costs them very little to keep these mods alive. I don't know their backend at all, or their engines - maybe some minor engineering effort they deemed wasn't worth it per patch so they axed it. At least that's what they claim by saying it was removed for lack of popularity. Which is a little gas-lighty because they can completely control the flow of traffic into these modes via incentives. Personally, every mode they've removed except solo standard I haven't cared about much, but I always laugh when they do it because it cannot possibly cost them that much to maintain. Just terrible management and it suggests they have a tiny skeleton team with little bandwidth or deep knowledge of how to maintain it. They don't really introduce any updates except cosmetics, and almost never server code. And everyone's happy with that - the community's deepest fear from the outset was that they'd mess with server code or the physics engines, which remain much the same as the day the game came out - which is a good thing.
The game is unique and important enough, for whatever reason, as an e-sport that I think it should be preserved in some form and I think to epic's credit so far they've mostly preserved what was there. These things however are quite frustrating.
I completely agree. I almost forgot about Football too, that's one of the best game modes and it's only around for 1-2 weeks/year. I get that they're probably licensing the NFL brands for that time period, but they could still offer the game mode void of any NFL branding at other times of the year.
Thanks! I'll keep it way simpler than RL - especially the graphics as you can see. But we can make the physics and multiplayer great, since we build everything from scratch.
Same here, maps like bzmatchball or passtheflag came to mind. Whoever makes a more modern, still free, simple and equally fun, version of bzflag will probably win a good number of players among people from under 20 to over 50. Not that bz isn't fun as it is today, but I miss the much bigger community it had many years ago.
Very very cool. Let's make a real game out of it. No steam no gigabyte large assets. Just that cool game. Maybe use some ai to generate some assets with stability ai / stable diffusion an let's get a lot of people on board. That could be a fantastic project.
And it is very funny. I used to play it sometimes and then I told a friend about it, he then introduced me to rocket league which I didn't knew at the time.
Looks just like Rocket League! Seriously though, this is awesome and the single source file makes it much easier to poke around the source without cloning. Thanks for sharing!
I seriously, seriously think that in the future (possibly far future) various eSports will all be derived from a few open-source base games.
The ability of game developers to leverage licensing, contracts with orgs, etc. to lock down a competitive ecosystem with exclusivity results in inability for a "free market" to develop around running events and broadcasts. Rocket League and League of Legends come to mind here, where the competitive scene is almost exclusively eSports content produced by the developer itself and doing all sorts of tricks to establish lock-in.
If we look at how traditional sports work, it's much more organic. Leagues have the ability to negotiate their own game rules, TV rights, oversight, and more. Leagues compete with each other for viewership, because viewers naturally want to watch the best games (or their local games) and viewership drives revenue via sponsorships and TV licensing. Game developer lock-in prevents this economy from developing, prevents the competitive nature of leagues from working on improving the game from a viewership perspective, and the closed-source nature of the game prevents the game from being able to "move on" from bad rules, bad communities, bad design, etc.
Many (most? all?) of these online competitive games have toxic online communities and in-game interactions. The game developers don't have the money to develop exhaustive anti-abuse mechanisms, or to pay a large support staff to sift through reports, so lots of times the best you get is a simple heuristic. And these companies are not financially incentivized to ban bad actors. In fact, they're incentivized to ban _as few as possible_ without damaging the player base. Players will quit over toxic interactions and cheaters, but cheaters and toxic players can also be the most reliable spenders in a game, so there's to reason to ban any more of them than absolutely necessary.
But with an open-source game, communities can self-organize and self-moderate. If I play on a local soccer team and they're all racist or homophobic, I'll find a new team or a new league. But at present there's no "find a new Rocket League".
So I think open-source games will have a big impact on the competitive online game industry. I think the resulting ecosystem has a lot more sustainability and player stickiness than current games do in light of the aforementioned toxicity and anti-competitive patterns, so there is much more money to be made than game developers are making currently.
Alternatively, the "sport" in esports is the genre (FPS, Moba, Fighting, etc), and the "leagues" are the individual games. Yes, the specific rules and mechanics of each game are vastly different even within the same genre, and strategies will be different, but skills like leadership, reaction time, hand-eye-coordination, etc will be used similarly across all games. Even with an open source game, it's likely each league will want to make changes to the base game anyways.
Maybe an open source game could work for smaller "leagues" that don't have the resources to develop an entire game from scratch (and assuming there's even a demand for a small league like that), but even then forking/building atop an open source game is still a lot more work than just using an existing commercial game that has more flexible multiplayer options (and so long as there aren't licensing issues)
> The game developers don't have the money to develop exhaustive anti-abuse mechanisms, or to pay a large support staff to sift through reports, so lots of times the best you get is a simple heuristic. And these companies are not financially incentivized to ban bad actors. In fact, they're incentivized to ban _as few as possible_ without damaging the player base.
I can promise you this is not true. Major publishers absolutely try to curb toxic behavior and are heavily invested in doing so.
I’m interested in learning more about this. Obviously this is something I care about and want to be well-read in when presenting a case. I do know in League of Legends that there’s a lot more care and attention put into it, and frankly I suspect that it’s because they have the money to do so and because they care deeply about the game still being relevant in 1 & 2 decades from now. The same can be said of Fortnite, possibly because of their closer integration with app stores as well and the sensitivity of having a younger audience.
Anecdotally, I think it can’t be said of Rocket League at all. It seems strongly to be profit-driven and moderation-light, and I think most games that size and smaller are operating the same way.
I’d love to hear where/why I’m wrong and what public information there is on the subject.
I don't think "open-source" means much of anything here. You can freely copy game design and make your own knockoffs. That's why half of the video gaming market is Doom-derived.
Anybody can make a football league, and anyone can make a MOBA. But to make the next League of Legends or the NFL, you need a ton of marketing money, and you need to pay to attract the top player talent. The actual money you pay the developers is not the lion's share of the spend. By the reports I can find, Overwatch cost about $50M to make, but they spent over $900M on advertising/marketing/tournaments/etc.
Let’s say that you want to be a tournament organizer and do tournament streams of an esport. You are going to use sponsorships and ad revenue to drive your profit, and you have a sponsor providing the prize pool.
You won’t be able to feature current league teams that are contractually obligated to participate in developer-endorsed events only, because the developer has all the leverage in being able to provide a larger prize pool for their official championship league (that is marketing budget for their game, funded by the game itself), so esports organizations are going to be locked-in to that contract.
The barrier to entry for you as an organizer is now to either pay a licensing fee to the developer for the privilege of being endorsed and allowing their contracted organizations to participate, which has a huge impact on your profitability… or to make your own fucking video game.
The open source aspect gives you:
- an existing player base
- ability to provide your own game rules
- ability to use exclusive visuals/assets
- ability to avoid licensing fees destroying your profitability
And if your organization goes under, the game lives on. If another organization goes under, you have opportunities to capture more of your market. You have the ability to improve your viewership by funding improvement of the game.
And, by the way, if you suck, somebody who can do it better will come along and take your money, which is actually good for the viewer and the player, which is much better than the way current games/leagues deteriorate.
Hard disagree. With the exception of 1v1 fighting games, centralized/official servers are _required_ for esports to even work. Peer-to-peer communication models and self-hosted client-server games both are filled with cheaters. How would players ever feel comfortable competing on community/self-hosted server?
"Esports" games require absolutely massive communities (e.g., marketing) and no open-source game has even come close to the scale required to sustain an esport.
Servers can be community-run and centralized per league/community. See TF2 (more decentralized) and FaceIt (Counter-Strike) for examples of self-moderating communities than can exist outside of the developer-centralized model.
At no point do I assume P2P to be a requirement or even beneficial in this scenario.
TF2 is overrun with bots right now to the point that the game is unplayable and the surviving community has been screaming at Valve about this for years.
As for FaceIt, that came about from the existing CS community. After 15+ years of the game being out. You can't just build something like that in a vacuum.
The whole point is that "esports" depends on centralized servers and somebody footing the bill for that. Even in fighting games that are P2P, there's still the matchmaking lobbies.
And you could say "well, there's FightCade!"...but a) that's illegal and b) I've never seen more than 150 people in a FightCade lobby and it's usually around 10-30. Esports games have > 10^4 concurrent players.
I’m optimistic that as the opportunities come along, players will take them.
Your argument sounds to me analogous to “everybody will just use Twitter/X because why would somebody want to pay to host a Mastodon instance with no participants.”
The reality is that some (but not all) people do genuinely have grief with the centralized platform (moderation, censorship, toxicity), do have the ability to pay for something better (or freeload off people who do care), and are thus willing to make a change with there’s sufficiently low resistance.
The reason this is possible at all is because people that did care in a very small minority made the decentralized platform for free while everybody else was oblivious. It doesn’t get built overnight and usage doesn’t convert overnight, but when the solution exists it can then be viable.
I do think open source games are a fair ways off, but I find it impossible to believe that people will work for decades for free on open source social media because they enjoy it, but the same will never be true of games.
It’s an eventuality, and it is one that changes dynamics for the end-consumer.
> TF2 is overrun with bots right now to the point that the game is unplayable and the surviving community has been screaming at Valve about this for years.
Perfect example. With the existence of a sufficiently-close open-source base, the community would have self-organized TF2 out of existence with a functional replacement. This just isn’t possible today, but when it is possible there will be no turning back.
> "Esports" games require absolutely massive communities (e.g., marketing) and no open-source game has even come close to the scale required to sustain an esport.
If by "sustain an esport" you mean as a profitable enterprise, then probably not. Is that the best metric though? Open source games can become popular enough for competitive scenes to emerge; Warsow is an example of this.
Popular enough for competitive play but not enough to get corporate sponsors seems fine to me. It's probably not healthy to be promoting the idea (to kids particularly) that playing video games can be a profitable career.
No I mean "sustain an esport" the same as I would mean "sustain a sport".
For it to be an actual contest it needs an actual sample size of players. Sports need spectators and narratives that generate interest.
Nobody gives a damn about Warsow the same way nobody gave a damn about Ferret-Legging.
It's not a sport if its players are limited to "you and your mates from round the way", that's just a game. Sports are meant to expose the limits of human potential.
Warsow's popularity fell off but it was there for a while. You can't reasonably expect every game to stay popular forever, not be the most popular around. It's not like every ball sport other than football/soccer is a failure just because "nobody cares about it" relative to that.
When a game is not popular anymore some developers just turn off their servers destroying the multiplayer. That won't happen with decentralized open source servers.
Cheating is a community problem, not a technical issue. Esports would have organizations managing things requiring players to sign up and be vetted. The community/organization would handle cheating.
> The game developers don't have the money to develop exhaustive anti-abuse mechanisms, or to pay a large support staff to sift through reports, so lots of times the best you get is a simple heuristic.
And neither do open-source projects. The majority of people looking to play video games do not want to be the ones moderating. They'll take the path of least resistance and let companies do it for them.
> If I play on a local soccer team and they're all racist or homophobic, I'll find a new team or a new league. But at present there's no "find a new Rocket League".
You don't need to find a new game though, you can find a new league. Except for maybe battle royale games, most games still allow private matches. Make a private match and invite the people you want to play with. Organize a league yourself. It'll be easier than building your own game, and you'll run into the same problems with an open-source game: how do you convince people to play your league rather than the official easy matchmaking? Rather than the official huge playerbase game?
For certain there will be de facto community centers in open source games, but the fact that a group _can_ self-organize, self-fund, and self-moderate means that communities _will_.
Mastodon is I think a good example of this in social media.
A game example is Team Fortress 2, where community-run servers coexist with matchmaking servers. Some of these are buy-in communities, some of them are freemium ad-ridden servers, some are just small friend groups. And they can pose an alternative to official matchmaking on merit and exist just fine. Oh, and they can remove cheaters and bots themselves.
This is a good example to your last point: when the de-facto league has cheaters, bots, or lack of moderation, people will flock to alternatives en masse, but the alternative has to exist for it to work. This isn't a "problem" with the open-source game, it's the main feature. It's the bridged gap between "building your own game" and "the official huge playerbase game" -- they're almost the same out-of-the-box, so neither the building nor convincing is insurmountable, they're surface-level.
Some very interesting thoughts here. Imo open source software is mostly higher quality than proprietary one.
And apparently the industry is not so interested in Linux. Proton from Valve is interesting but crashes on my machine all the time. So I guess we have to build ourselves and have some fun in the process.
Traditional sports are totally dominated by individual companies.
There may be some street baseball games here and there, or independent baseball leagues, but the MLB has the viewership, the money to buy all the players, the sponsors, the stadiums, etc. In many ways they have a monopoly on the sport, including a unique exemption from various antitrust laws handed down by the supreme court.
I like open source and open source games, I played many hours of Armagetron Advanced back in the day. But organized competition usually needs an organization to back and, well, organize.
I get your point, but I'm not sure loss leader is quite the way to describe it. I think of it as a marketing/promo expense like any other. Are user conferences loss leaders?
Also, RL is free-to-play nowadays. They're banking on in-app purchases, not sales of video games.
I think online matchmaking has absolutely destroyed people's ability to feel like they're good at any game.
Like you'll never be a big fish in a small pond. If you played as much as you currently do but could only play with people local to you, you'd be the best person you know at this thing. And that's a really good feeling. But you'll never get that feeling, because you should really be grinding past whatever plat 3 is in order to not suck.
Conversely you'll never be a small fish in a big pond. If you could only play with people local to you and they all played much more than you, you'd be the worse person you know at this thing. And that's a really bad feeling. That gets people to quit games.
The big fish eat all the small fish until the big fish are the only ones left.
I have a triple-digit-hour play time and I could barely get out of Bronze. I can't really explain why, but my brain just doesn't mesh with it, skill-wise. It's still a lot of fun though (otherwise I wouldn't have spent so long playing it!). In fact, being so bad at it somehow made it more enjoyable - it's not often I allow myself to be bad at something.
I'd rank myself as "unusually good" at Mario Kart, which is obviously a very different game, but it surprises me that I have such a wide skill gap between the two games.
I'm decent at Rocket League and sit between Plat III and Diamond I. It seems our metrics are slightly different :) I've found these ranks are the natural breaking point between what I could classify as "sweaty" players and "casuals." I've never been interested in going much further.
It's very weird seeing RL discussed on HN - worlds are colliding! But, yes, this is good advice. Also consider playing 1v1. I'm Diamond I-II there. It's a lot of fun, and probably the only mode where turning off the chat doesn't put you at a disadvantage.
I heard Comm, a pro, once say that he wished he had his 14 year old fingers back...think he was 17 at a time. To me, a 40 year old playing with KBM, I feel like I just can't bend my brain around all of the 3d possibilities. I just don't have any intuition for rolling my car while it accelerates towards the front...and then you add in the complexity of the camera and, yeah, I suck.
Part of the problem is rolling vs. yawing. Most players have something along the lines of LB mapped to powerslide + air roll. So when flying, they have to think (actively or otherwise) about when to roll vs. when to release LB so that the left stick X axis will yaw instead. This is, in my experience, very difficult to actually do.
There's a control config I tried and greatly enjoyed that addresses this. I want to get back into it but I haven't yet felt like dealing with the adjustment period again. This works best if you have a controller with mappable paddles.
Left stick X: Ground steer and air steer (yaw)
Left stick Y: Pitch
Right stick X: Air roll
Right stick Y: Ground throttle
And then jump/boost/powerslide go on triggers/bumpers/paddles as desired.
Being able to simultaneously yaw and roll feels quite nice once you get used to it and allows for some surprisingly intuitive recoveries, wall jumps, etc. "Tornado spinning" is now as simple as pushing the sticks in opposite directions. Other interesting results can be had from the various other combinations of stick directions.
This does require you to no longer use the button pad for anything, so if you use ballcam toggle while playing, or need to peek at the scoreboard a lot, or need a thumb free for real-time quickchats, or whatever, then I hope you have a lot of extra paddles
I've only just started trying to do aerials, really, and I find myself getting vertigo from it haha. I'm also 40. It's so disorienting. None of the camera settings feel "right".
It takes some playing around with and is highly subjective. Best method I found was to just try camera configs used by pros or recommended by others and see what feels good. My current:
The rest aren't relevant for me because swivel speed is about looking with the right stick and transition speed is about switching to/from ball cam, and I leave ball cam on.
Of these, I believe the most important (by which I mean tangibly relevant to control quality/feel) are distance, stiffness, and, to some degree, height+angle. Shake and FOV are also important, but those are the only good values for those settings.
I used to play with max distance because it felt better for visibility, but I found some people saying 270/280 works much better for them for precise ball control and accurate strikes, and that does seem to be the case. Stiffness is the other setting that will make the most difference in feel: Lower values let the camera's distance from your car rubber-band further in relation to your speed. It might seem as if maxing this out would be ideal, because why wouldn't you want the camera to follow your movement as closely as possible, and why would you want the camera to lag behind you when you go faster and disorient you when you're trying to aerial? But I'm not so sure. I've tried stiffness at 1 (max) and I don't remember why, but apparently it didn't work for me, because I lowered it to 0.75, which I guess I found acceptable enough not to have changed it. I've just come across some people saying a stiffness of around 0.35 is counterintuitively great as it turns out that moving the car without instantly moving the camera helps a lot with car control for some reason, so I'm about to test run that value myself and see about it.
I also used to run with stiffness maxed out and I think it contributed to the motion sickness feeling. There's definitely a tradeoff in all of these values.
This... is a Rocket League clone, yeah, in the loosest sense of the word. I don't think the author's deeply involved in political wheelings and dealings around Epic's past actions and trying to whitewash something they did.
People make side projects all the time that port "missing" software to new platforms, regardless of the reason that software is missing from that platform. There's a good chance OP didn't even know about the Epic backstory here.
I also feel bad about this engagement. I don't think there's actually any conflicting arguments here, just misunderstandings. I don't understand why people keep projecting wierd meanings onto the word mitigation.
It's only natural to think about rocket league for linux in a submission about rocket league for linux (now with the HN title reworded). Mentioning that this rocket league for linux is not a full replacement for rocket league for linux in a thread about linux rocket league is hardly ragebait and supremely on-topic. Unlike everything else in this sub-thread.
- renderer and physics aren't synced in any way, physics shouldn't be tied to frame rate, but running as 2 separate threads with no synchronization means you might read garbage at some points if you render while the physics thread is updating.
- physics using this_thread::sleep_for is not accurate and can sleep for longer than the specified time, assuming the period to be 1/60 isn't correct. The delta time needs to be measured.
- using VK_PRESENT_MODE_FIFO_KHR or VK_PRESENT_MODE_MAILBOX_KHR force vsync, but vsync can be anything. With the physics system being locked to 60, you'll notice a stutter on non-mulitiple vsyncs like 144hz. There aren't many solutions I know for this, but the main ones I know of are interpolation and extrapolation of the physics state based on the framerate. I would bump the physics update rate to 120hz to match rocket league and then experiment from there.
- Using both Eigen and GLM is overkill in this case, both are slow, but if sticking with one I would use switch solely glm.
- More of a nitpick, but I would separate out all the code at least between rendering and physics to their own independent files. The vulkan api on it's own adds a lot of clutter, moving that to it's own file should make the project easier to navigate and explorer.
There are more things, like how hard coded that shaders are, but I assume the vulkan renderer will be improved past just being from the vulkan-tutorial, so advice for that can't really be given till the renderer has been updated.
P.S. Sorry if any of this sounds harsh, it's not my intention. I've just done a lot of work involving games, game engines and renderers. And I'm seeing a lot of the problems I made when I first started. I wish you the best of luck with your project.