Thoughts on Modern C++ and Game Dev
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I find reading C++ "standards" papers onerous and feel like they're written in a way that's deliberately inaccessible. I don't much like the idea of going to CppCon -- even if my company funded it, which maybe they would, I feel like I'd be marginalized for not using template metaprogramming, not knowing the new hotness by heart, and generally being a proponent of C-with-classes. I just feel like so much of the C++ "standards" work feels like it's led by academics who think the concerns of working programmers like me are beneath them.
Is there a way I can "get involved" and does my voice have any value?
Videos of all CppCon talks from the last several years are freely available on YouTube and if you took the time to watch them you'd see that many of them are by working programmers and not academics, quite a few of them in the games industry. You'd also learn that the committee is quite focused on simplifying the use of the language and on finding more usable ways to get the benefits of template metaprogramming. You would also find explanations of many features that are more accessible than standards papers and occasional explanations of why standardese is the way it is - nobody, even the most academic speakers, claims to find the standard the most accessible way to learn about a new feature.
In a way it isn't fair. Most users of most programming languages don't know the language very well. So the views of these programmers are important.
If someone wants to represent the 'average' programmer then the best way to do it would be to educate themselves on the language and the current state of standardization and then participate as an advocate for those programmers.
It seems that the people who are supposed to be speaking for the regular programmers aren't doing a particularly good job.
I agree with this. The people at CppCon are very smart, very informed, and very very pro-C++. It's silly to think that such a person (people on the committee, no less), would be a good spokesperson for your everyday programmer.
However, that's certainly not the main problem keeping C++ complexity high. Even though the committee genuinely wants improvement in this area, there is too much fear of breaking legacy code, and too many early design mistakes to overcome on the path back to a simpler C++.
I'm not personally that interested in making it my mission to help educate people who don't want to be educated but perhaps it would be a valuable way for someone to get involved. People complaining on the basis of wrong information or misunderstandings aren't likely to be taken terribly seriously though.
I'm not part of the standards committee nor do I represent the C++ community as a whole. I personally am not particularly interested in trying to educate people who don't want to be educated. That doesn't say anything about whether I or anyone else in the C++ community is interested in the opinions of regular C++ programmers.
Here are the C++ subjects of interest to me:
* geometric primitives. Not having basic geometry by now is insane.
* concurrency, I think the API as it is is good, but some of the APIs around atomics (mostly the difference between compare_exchange_weak and compare_exchange_strong) are not clear, I have had to explain those to coworkers before. Why can't we have something called test_and_set like on atomic_flag that's an OK default? Also, while I perfectly understand why that's the case, atomics have deleted copy constructors and that tends to generate compiler errors. I don't get why compilers can't just generate default constructors that don't copy the atomic like all my coworkers keep having to write and potentially introduce errors in
* filesystem API, very excited for that but sort of worried it will not work on every platform and especially that it'll work terrible on windows. I have to write Windows/Linux/iOS/Android C++ so a bunch of my gripes are "the standard is inconsistently supported" and I supposed that's not the job of the standards committee to enforce... but maybe they could stop inventing new stuff for Microsoft to screw up...
* few other misc things. The fact X const& and const X& are both valid leads to every project having its own "standard" of const placement and it's not great to read, etc. not major stuff. But things that are of concerns to working programmers.
I'm not really complaining, I love C++ and being a C++ programmer and you couldn't pay me enough to go integrate idiosyncratic web frameworks. However I think you must admit that the C++ community, beyond the language itself, is a little exclusive and not super friendly to people who are not as knowledgeable as others. I have a little time to learn some of this stuff, and I would be happy to, but I will never be an expert like most of the standard committee is. Based on your message I think that makes me and my opinion not welcome? If so that's OK, but, um, there's a lot more of me than there are of them in this industry.
(edited for formatting)
It's a fairly involved process to get a new library standardized. Functionality that's not included in the standard library may be missing because it's hard to get agreement on what is required, because there isn't anyone sufficiently motivated to drive it through standardization or because the committee just hasn't got round to it yet.
I don't consider this particularly problematic in many cases. Some functionality probably shouldn't be part of the standard IMO. For example, there's been some effort to standardize a 2D graphics library and I'm of the opinion that should not be part of the C++ standard. I'm inclined to think the same thing for geometric primitives, for similar reasons. Certain types of library are better left to competing open source libraries for now I believe.
Implementations are not the domain of the standards committee. It's rather inconsistent to demand relatively niche new library functionality for geometric primitives at the same time as wanting the committee to stop adding things to the standard faster than Microsoft can keep up however.
Concurrency is complicated and there are a lot of pitfalls which the standard library has gone to great lengths to avoid. It sounds like you're misunderstanding the best way to use atomics but without knowing more about your use case I'm not clear exactly how.
Coding standards are not really the domain of the standard and some things that have multiple possible ways to write them have to be maintained for backwards compatibility. If you want to standardize things like const placement however, tools for automatic formatting and transformation of C++ are getting better all the time thanks to clang/llvm.
C++ occupies a niche which necessitates it being a bit less beginner friendly than some languages and a bit more demanding on users putting in the effort to learn the language. That's what makes it fairly uniquely suited to certain use cases. I don't see that as a bad thing. I don't really know what you're asking for to be honest. My advice to anybody who uses C++ as a major part of their career to invest a decent amount of time into learning it better though, just as I'd advise them to spend time learning more in any domain that is a big part of their professional life.
Again, I think concurrency is one of the parts the standard library does best. (And I think part of the specifics of this is it has primitives like async and future that are higher level and are much easier to explain. I happen to write lock free data structures often enough that finding blog posts at a good level to explain the API for atomic to my code reviewers is a need/bother for me, but there are also plenty of concurrency use cases where I don't need atomics, and I also read that there was a plan to allow parallel execution for most of the algorithms in the standard lib, I don't know if that's in MSVC yet but that's an example of things I like).
I don't blame the standards committee for implementors. In general, it must be terribly difficult to be on the standards committee, and have to deal with stuff implementors have already done, stuff they won't do, and stuff they are telling you they are doing but will not do right in the end. OTOH, as a end user, you have to understand that I have to deal with implementors, and they affect how I think of a given C++ feature, some of which look awesome in the text but are impractical because of implementor differences. I'm not alone: every C++ dev I know has a subset of C++ features they have deemed "practical", based on things like implementation performance, compiler error messages, how many characters the function names have, etc., and part of the problem is it's not the same subset for all C++ devs. Sometimes I wonder if there shouldn't be a subset of the standard (and I don't mean the C subset!) that's earmarked as beginner-safe and compilers could enforce the, well, beginner-safeness of code that is meant to be foolproof... but I suppose your angle is code meant to be foolproof should either never allow a beginner within 50 feet of it or be written in Java (or Rust?). Which, I get.
I would like to clear up a misunderstanding that I think you had: I do not spend zero time learning about C++. I'm not super confident and I think by HN standards I am not very experienced in C++ (or anything else), I'm definitely not at the level where people at CppCon would want me in the room, but people at my workplace do come to me for help with that stuff a bunch of the time. I tend to volunteer to explain newer or more complicated parts, etc. I'm a mid-level dev generally and C++ is my main language, and I'm not significantly more ignorant than my coworkers about it. If that is below the threshold at which you will consider someone worthy of talking about C++ on the Internet, maybe that's why C++ doesn't have that many beginner-friendly communities around.
There's never been a better time to learn C++ - there's a wealth of free resources online from conference videos to blogs to podcasts like CppCast. C++ standardization is more active than ever and the language is getting better with each update to the standard and there is a real effort to also make it simpler which I believe is mostly succeeding. Implementations have also improved a lot in recent years. It's just the pace of change is such that there is work to do to effectively communicate that fact to people who don't pay much attention to the development of the language.
I think if you want a long term career in this industry you need to dedicate at least ~5 hours / week of your own time to professional development on an ongoing basis. If you work with C++ on a daily basis then spending some of that time working through CppCon videos (I like to watch at 1.25x speed) and other free online resources is a good idea IMO. I'd also advocate writing a bunch of small programs from scratch to explore unfamiliar features or libraries. Working through programming interview type problems can be good practice, or just try things out to satisfy your own curiosity. I'd say getting in the habit of writing a small program to experiment with something new was the biggest factor in increasing my comfort level and understanding of the language.
Then I know what I'm doing tonight. I like the computational geometry aspect much better than the programming language part. The thing with C++ is very often the stuff you don't know sneaks up on you at the worst time when starting on a new library, or trying to reuse code more complex than you're used to. It's strange to think of it as something to study, but 5h/week is something I could do instead of more overtime.
>What I don't particularly like is people complaining about things they don't seem to have made much effort to understand.
The main thing I was complaining about was C++ takes (relatively to e.g. Python) a ton of work to understand accurately, but also to explain properly to other people. You must know that from answering on StackOverflow too. (There are features of C++ I don't use because I/my coworkers don't yet know them, and studying will help me with that, but I can't complain about them yet!) StackOverflow is actually great for C++ though, so thank you for answering on it. Usually there's always an answer with a detailed explanation even for strange code samples. Often it's through reading the other people's questions that I can understand how a construct can be useful in practice.
One of the nice features about C++ IMO is that there is very little "magic" in the standard library. Unlike some languages, all the features of the standard library can be implemented with standard language facilities that are available to you for use in your own code. Some of the more complex areas of the language however are there primarily to support library authors writing very general code and you don't need to fully grok them to be an effective user of the language. Learning about some of them over time however will likely pay dividends for your own code even if you are not writing widely used libraries.
Is there a way I can "get involved" and does my voice have any value?
That said, you (and several of the other posters) are being awfully dismissive of the notion that there are people who work in your language but don't feel confident with it. I may have major imposter syndrome or something but I've (before this weekend) thought if I didn't get a talk at first it meant I was too stupid for all talks. I don't have mentors at my company because most senior developers have other subjects of expertise than C++, which is just a tool to us. My city has several Javascript meetups but nothing on C++. And I think the way I've been treated when saying, essentially, relative to the C++ community, "I use C++ every single day but I don't think I'm one of them", which is being told, "you're not good enough/disciplined enough/confident enough to be one of us", shows that.
Most of programming is slowly waking up to the idea that being exclusive and giving people tough love instead of guidance is starving companies out of potentially good developers. I know my coworkers and most of them would give up on a learning resource that they felt was too advanced and would be turned off from any effort if all everyone was telling then was "try harder". (Even though in this case trying harder is 100% the solution.)
In most other fields, including medicine, there are high-EQ people hired to fix exactly that, by bridging the gap between where the practitioners currently are, and where the industry wants them to be, usually in a way that's either very high touch or very structured. And in those other fields, if most practitioners aren't reached by the information, or are consistently misapplying it, the industry guilds put the blame on the way their information is being transmitted, not on the practitioners.
The truth is that C++ standardization is not full of "academics", and people involved voice these same concerns.
One of my fellow committee members, Guy Davidson, is in the games industry, and the subject of the 2D graphics proposal has been a regular topic at our meetings.
* http://cppcast.com/2018/07/guy-davidson/
Anyway, originally in my OP, I read the blog post and at the end, he was saying to people that have any industry-specific concern with the way they use C++, and the way C++ is changing, to get involved. I was just saying, as a C++ end-user, even one who cares enough to write this, there is no readily accessible way to do that, because I don't work with anyone who's already on the committee nor at Microsoft. So it feels a bit like an empty rebuttal on his side. Writing this here, it's basically the longest discussion I've ever had my whole career with people who really know deep things about C++ and the process it's made by. I'm glad for it but I'm clearly not the demographic the original blogger was addressing! Even though I definitely feel those same issues he outlines.
https://groups.google.com/a/isocpp.org/forum/#!forum/std-pro... https://groups.google.com/a/isocpp.org/forum/#!forum/sg14
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/ All the papers here provide the email address of the author, so you can contact them if you have concerns.
Most often I learn code by reading code. OpenSceneGraph is an example of an open source project that has modern ish C++ but no deliberately abstract misdirection. Open source usually does not have super clean code but it's a good way to sample the variety of structures you can find in a project. Of course the classics (sqlite and the Linux kernel) are much too C-like for where I'm getting at but they are still full of lessons for how to organize modules and APIs, how many arguments to pass and where, where to park I/O code, that sort of thing.
I posted it here for the benefit of HN readers who may have the same question but I'll write you an email too so you can share what you want to improve and such. There aren't many C++ programmers left in the HN-reading, not just punching a clock demographic, and I kind of miss talking to people who get that. Like the prototypical game dev in the article I go to one conference a year, and it's not about C++.
[1]: https://yosefk.com/blog/ [2]: https://blogs.msdn.microsoft.com/oldnewthing/
> I find reading C++ "standards" papers onerous and feel like they're written in a way that's deliberately inaccessible.
Sadly, it's somehow true; standard wordings are typically not readable for laypeople because its primary purpose is unambiguous specification but not education. Generally, I find that it's a good idea to avoid "wording for ~~" proposals if I haven't followed that specific line of proposals from its beginning.
But many proposals are still fairly readable technical papers; for instance, Herb Sutter's proposals are generally easy to follow. (ex. https://wg21.link/P0709)
> I feel like I'd be marginalized for not using template metaprogramming, not knowing the new hotness by heart, and generally being a proponent of C-with-classes.
https://www.youtube.com/watch?v=rX0ItVEVjHc
Don't worry. Mike Acton is not known to be a strong proponent of "Modern C++", but his session[1] is one of the most popular CppCon video on Youtube. Even if you don't like templates, people will generally respect you.
> I just feel like so much of the C++ "standards" work feels like it's led by academics who think the concerns of working programmers like me are beneath them.
http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/n479...
You can find the list of the participants for the last meeting. Most of them are just engineers and even Bjarne is now working for Morgan Stanley (I think most of "designed by Ivory Tower" concerns can be generally credited to Bjarne being a professor before) They're just writing C++ code as their daily job like you (and very likely suffering from C++ as well). That's why they're writing proposals to improve the language.
Some tangential story: except for few exceptions, PL academics are generally not working on languages like C++ because it typically doesn't align well with their interests. Usually they tend to use more elegant, academic friendly languages like Haskell or ML. Or even fancier languages like Coq, Adga, Idris, depending on topics. Or design their own languages. For formal verification researches, maybe C or Java. But C++ is typically considered as a complex, inelegant beast for researches.
But his argument fits well with C++'s history of finding exceedingly complex solutions for simple problems. Want to have efficient matrix calculation? Well, who needs native support for matrices when you can do the same with expression templates and static polymorphism/CRTP (see: Eigen library).
The last section of the article says you either do nothing or you get involved. I'm afraid it is missing the obvious third option: switch to another language which actually supports your use case.
I have to defend C++ here - "native matrices" is under-specified. In practice, "Matrix" is one of the leakiest abstractions in programming and you have to care about representation and choice of algorithm pretty much from the get-go, and IMO C++ is actually the best available option for managing that complexity, especially when you're solving large systems in parallel (and it's worth pointing out that one of the front-running open-source libs in this space is written in C++[1]).
I would expand more on the first bullet point of why game devs don't test. Tests are anti-agile and game development is extremely agile. Usually you don't know what kind of game you're making until you're done.
Not when you're constantly prototyping, which is what game dev essentially is for the most part of the process...
Except that it isn't. You don't maintain the equal velocity of changes throughout the process, even for indie games. And there are always portions of the game amenable to tests.
Not so much actual gameplay though. That does constantly get tweaked.
First they had made it so if someone was playing the game and saw a bug they could press the "file a bug" key, type in a description and the game would save out enough info to bring someone back to that point in the game, same camera, and possibly other state. From the bug database they could click a link that would launch the game back into that state, let someone verify the fix and mark it as fixes.
The also had a waypoint system for bots to play through the puzzles (this was the Talos Principle they were talking about). If the bots ever got stuck, as in didn't make to the next waypoint within some time limit they bots would file a bug using the system above.
https://www.gdcvault.com/play/1022784/Fast-Iteration-Tools-i...
As another interesting idea apparently the creator of Thumber built a URL system so people press a button which would generate a URL into the clipboard, they could then paste that URL into Slack (or email/chat/etc) that would launch the game in a particular state to pass that other users on the team.
Testing, in general, is pretty essential to writing code that does what you want. Test code is just automating what you'd be doing manually and it's a lot faster to have the code do it than for me to do it 10 times. Even if that's printing out a value or showing it in a debugger. Testing frameworks or libraries to fuzz out problems and harden code are quite common. Game dev often has a lot of manual play testers. Most engines and dev consoles have a lot of tools to either just record the screen or save state when problems are seen.
Heck, most "cheat codes" were added to jump around the came to test for bugs. That's technically "test code."
Shipped 17 games, several AAA games with no automated testing. Not saying that was good only that it happened and so is at least some evidence that automated testing is not essential.
The problem with automated testing in games is most of it will be content specific and the content changes multiple times a day. A product like say GTA5 has 20-30 programmers and 300 artists and game designers. Those 300 artists and game designers are adding new content and or changing old constantly. Often they also use a scripting language or a blueprint like visual language to setup in-game logic like "open blue door if player has blue key". There's just too much to test. Every day 1000s of tests would have to be re-written because some boxes, doors, etc were moved .5 units to the left.
There isn't zero value in automated testing (see above) but my experience with testing on a large project, Chrome, was that it really slowed down my velocity. Easily by much more than 50%. Of course Chrome is a platform and absolutely needs the tests IMO. I think a game engine would benefit from lots of automated tests. The game itself though it gets harder to figure out where the balance is between automated testing and manual testing.
As others pointed out as well big teams, like an OS team or a browser team often have dedicated staff to setup and maintain a testing infrastructure. Game teams rarely have this. Maybe they should but few games are given the budget.
Tests are NOT anti-agile, that is just dumb. I feel like a bunch of hacker news hipsters read an article about TDD 3 years ago and then said "Yep that's my opinion! Tests are bad." Despite every major software company requiring unit tests for their production code-bases. ( Hint: It's because they did the research and found tests beneficial. ) Tests enable agility.
Let's just get this out of the way now: Tests are not about catching bugs. Tests are about allowing your to safely refactor your code without breaking previously declared behavior.
Testing enables you to iterate and refactor code without constantly releasing new regressions. Testing IS code quality. If you lack tests you lack a core piece of code quality.
From the playing experience: yes, there are way more games with internal manual and external community testing.
Game project managers are infamous for not being great planners, so it wouldn't surprise me that they dismissed automated tests as "a waste of time" or "something that we can't do now because we don't have time now" (so we end up wasting more time in the end, having to do death marches, etc)
* None of the problems that have been commented on are unique to the games industry at all. Slow debug builds suck for all C++ developers and weird template meta-programming is confusing for practically everyone.
* He makes these broad hand-wavey statements like "individuals don't feel pain from slow compile times", or "big companies can just can throw processor power at it" to which I would say, BS. Fast iteration in C++ is really hard because of the delay and it's a big problem for everyone.
* "Participate more" -- isn't that exactly what people are doing on twitter? Not everyone can go to CppCon.
This problem was worst in my experience in the Xbox 360 / PS3 generation because the in order processors handled debug builds very poorly and were different enough from a PC that it was common to have to debug on target rather than on a PC build on a much more powerful development machine. It's less of an issue with current generation consoles that are basically PCs as they don't suffer as badly with debug performance and many issues can be debugged on a PC build on a more powerful system. It may be more of an issue for mobile still.
Fortunately many of the newer features of C++ 17 and 20 help both with improving debug performance and with simplifying / reducing the need for "weird template meta-programming". Several also help with compile times and modules in particular are quite focused on tackling the biggest root cause of slow compiles in C++.
Rarely do I see workstation-grade hardware in the wild, and when I have, they're build slaves that are incredibly anti-agile.
Part of this is just people complaining on a platform that over values short pithy complaints.
"Before about the early 90s, we didn’t trust C compilers, so we wrote in assembly."
There a lot of games released during the 80's, were they really all written in assembly ?
https://www.myabandonware.com/browse/year/
I don't have experience in the game industry at all, I must add.
Some things like texture mapping you could only write in assembler, because you'd need to use x86 lower/higher half of word (like AL and AH registers) due to register pressure. Spilling to stack could have caused 50%+ slowdown.
486 era you needed assembler to work around quirks like AGI stalls.
On Pentium the reason for assembler was to use FPU efficiently in parallel with normal code (FPU per pixel divide for perspective correction). Of course you also needed to carefully hand optimize for Pentium U and V pipes. If you did it correctly, you could execute up to 2 instructions per clock. If not, you lose up to half of the performance (or even more if you messed up register dependency chains, which were a bit weird sometimes).
One also needs to remember compilers in the nineties were not very amazing at optimization. You could run circles around them by using assembler.
Mind you, I still need to write some things in assembler even on modern x86. But it's pretty little nowadays. SIMD stuff (SSE/AVX) you can mostly do in "almost assembler" with instruction intrinsics, but without needing to worry about instruction scheduling and so on.
Plus, nobody had a 486 in the 80s (it was released in 1989). People would be lucky to have a 286, but usually just some home computer (Apple II, Spectrum, Commodore 64, Atari ST, Amiga 500, Amstrad CPC, etc).
Yeah, back then assembler was even more pervasive. It was the only way to write something publishable on 8-bit systems. Well, there were some action games (like C64 Beach Head), trivia and adventure games written in BASIC.
You spent a lot of time on 8-bitters getting code and asset size down, so that it'd even fit on the machine in the first place. Forget about luxuries like division and multiply, most advanced math those things could do was little more than adding (add, sub, and, or, xor) two 8 bit numbers together. Even shifts and rotates could only handle 1 bit left or right.
CPU clocks were measured in low single digit MHz. On top of that, 8 bitters were very inefficient — each instruction would take 2-8 clock cycles (6510) or 4-23 cycles (Z80).
On PAL C64 you have 19656 clock cycles per 50Hz screen frame minus 25 bad lines. So you could realistically expect to execute only 5-8k instructions. If you used all the frame time for just copying memory, you'd be able to transfer just about 2 kB. Just scrolling character RAM (ignoring color RAM) took half of the available raster time (yes, I know about VSP tricks, but it wasn't known in the eighties).
16-bit systems allowed some C, but most Amiga and Atari ST games were written in assembler. I'd guess same is true for 286 era, but not sure.
What I mean is: we perceived it as being slow because of the rumours. Just typical nerd attitude that we still see now.
Some games were prototyped in C and optimized afterwards.
For example Amiga Turrican 2 required 33 MHz 68030 CPU during the development phase. Of course the final version ran fine on 7 MHz 68000 Amiga.
I tried the same algorithm in godbolt with some clang versions and it was slightly better, using two or three registers, but not by much. So I had to break it into inline assembly.
I wonder if GCC has improved since then.
Yeah, that's a common problem and leads to nasty dependency stalls. MSVC is horrible in the same way, at least 2015. Haven't tried newer versions yet. Intel's ICC seems to generate good code most of the time.
Yes, it has. I've written a lot of SIMD code and spent a good amount of time reading the compiler assembly output and there has been huge improvement over the last decade.
GCC register allocation wasn't great, then it got better with x86 SSE but still sucked at ARM NEON, and now it seems to be decent with both.
Clang was better at SIMD code before GCC was. It was equally good with SSE and NEON.
In my experience, compilers are much better than humans at instruction scheduling. Especially when using portable vector extensions, you don't have to write the same code twice and then tweak the scheduling for every architecture separately.
It'd be more accurate to say they're much better than humans when the heuristics or whatever they use works. Sometimes the compiler messes up badly.
The workflow is often to compile and then examine disassembly to see whether the compiler managed to generate something sensible or not.
Other issue is that compiler pattern matching is sometimes not working and generating correct SIMD instruction. Even when data is SIMD width aligned. For example, recently I saw ICC not generating a horizontal add in the most basic scenario imaginable. * shrug *.
The minimalist in me wonders if maybe just using some kind of macro system on top of assembler plus a bytecode VM with the ability to drop to native instructions wouldn't ultimately be better.
Debugging predictable single thread single core system was also child's play compared to distributed networked beasts each running on lots of cores and thousands of threads.
Nineties problems were contained in a small box. Oh, and no internet like today, so needed to order books and magazines. And to use BBS and usenet. Even then, a lot of it was reinventing the wheel again and again.
Modern problems are sometimes nearly uncontained (think software like web browsers, etc.).
In the 90's the code I wrote was more difficult. Today coding is much easier (better languages, tooling, etc..). However the systems I build are many times more complex.
In the 90's we hired the best programmers, today we hire the people who are best at managing ambiguity and complexity.
All of this is very hand-wavy as there are certainly still disciplines where pure programming skill is most important, but those seem to be fewer and fewer every day.
Back than you felt pretty skilled I am sure, now I feel anybody could do my job, often. Unless you are working for the big 4 or similar, many jobs don't give you that excitement.
He gets a simple graphical effect going on the Amiga in only a few lines of assembly. Doing the same thing using DirectX in c++ would take you all day!
This is an interesting line of argument - in what way, and what could be done to improve the ergonomics?
> He gets a simple graphical effect going on the Amiga in only a few lines of assembly. Doing the same thing using DirectX in c++ would take you all day!
This is absolutely true, but in something like ShaderToy you can go back to producing complex pixel-bashing effects with a huge amount of processing power.
It's just the external Tower of Babel from boot to usability has got a lot larger.
In 68k you had 8 32-bit data registers, (d0-d7) and 8 address registers (a0-a7)
If you wanted to access bytes or 16 or 32 bits you could do so like this:
move.w #123,d0 ; move 16bit number into d0
move.b #123,d1 ; move byte into d1
move.l #SOME_ADDRESS,a0; set address reg a0 to point to a memory location.
move.b d1,(a0) ; move contents of d1 to memory location a0 is pointing to.
On x86, thanks to its long and convoluted history you have all kinds of doubled up registers which you have to refer to by different names depending on what you are doing, and tons of historical cruft.
On top of the CPU, the old home computers had no historical cruft and it was very easy to talk to the hardware or system firmware; usually you'd just be getting and setting data at fixed memory locations. I can read an Amiga mouse click in one line of 68k. I've no idea how you'd do it on a modern PC or even Java! Modern systems just aren't as integrated, for better and worse.
Assembly language was also part of mainstream programming back then. You'd learn Basic then go straight to assembly if you wanted to do anything serious. So there were computer magazine articles on assembly, childrens books[1]. My first assembler, Devpac, came from a magazine coverdisk with a tutorial from Bullfrog, Peter Molyneaux's old game company[2].
So there were a whole range of cultural and technical reasons for assembly language being much more of a human-useable technology back in the day.
>It's just the external Tower of Babel from boot to usability has got a lot larger.
Yes I agree, I kinda miss being able to see the ground, which is probably why I find retro programming so appealing.
[1]https://archive.org/details/machine-code-for-beginners [2]https://archive.org/details/amigaformat39/page/n61
Due to the enormous complexity of modern CPUs I'm not sure there's anything that could be done. With the 486 and contemporary (and earlier) uarches you could largely expect the CPU to execute exactly what you wrote so understanding the performance impact of any given bit of assembly was pretty straightforward. Then CPUs started adding features like superscalar, speculative, and out-of-order execution, branch prediction, deep pipelines, register renaming, and multi-level caching that massively complicate modeling the performance of any given code.
For example you may need to explicitly clear an architectural register before reusing it for a new calculation to avoid creating a false dependency in the uarch which would prevent the CPU from executing the calculations in parallel. Knowing when this is necessary can be hard and the rules are usually different between different uarches, even within the same uarch family.
Good assembly programmers who are aware of all this complexity can still beat compilers but they certainly can't do that for the scale of code that compilers routinely generate. Thankfully compilers are generally "good enough" these days and assembly only needs to be hand-written for very hot inner loops for performance-critical code or for cryptographic code where the exact performance characteristics of the code could potentially leak information if they're not handled correctly.
In a way that's true. I also enjoyed writing assembler back then, especially on 68k.
However, to really extract the last cycle you often ended up generating a block of code at runtime (kind of very basic JIT).
Sometimes self-modifying code provided the final oomph to get something running fast enough. The reasons varied: sometimes it was because of running out of registers, sometimes dynamically changing the performed operation without branch.
Too bad for the later CPUs with instruction prefetching and caching...
No need to go full shit ape and creation of 3D images in bmp is excellent exercise you should try.
> you can't use OpenGL without it.
Yes you can. You can't even pretend that coding once against SDL will absolve you of having to deal with platform issues, it just helps a lot.
> and creation of 3D images in bmp is excellent exercise you should try.
I'm a hobbiest game dev who almost exclusively uses software rendering (albeit to a framebuffer that gets pasted onto the screen with OpenGL as the path of least resistance). I've also written image libraries. None of this has anything to do with the parent comment.
This only changed slowly with 16-bit machines like the Amiga or Atari ST, they had more memory, the Motorola 68000 instruction set was more suited for compiled languages, and the custom chips (like copper and blitter) freed the CPU from many graphics tasks. Yet even on those machines the critical parts were usually written in assembly.
Most of them, yes. Here's a well known game:
Slower-moving adventure and RPG games might be in a higher-level language. (IIRC the original Wizardry was written in a VM-based Pascal for Apple II?)
Companies that specialized in adventure games would have their own interpreter and VM — Infocom's ZIL, Sierra's AGI, Lucasfilm's SCUMM. Game developers would write code in a scripting language against that company-standard VM.
Amateur games might be written in BASIC because every computer under the sun shipped with a BASIC interpreter back then.
C wasn't a practical option because decent compilers didn't exist for most non-Unix systems until the end of the 1980s — or if they did, they'd cost an arm and a leg. (I think the retail price for Microsoft's C compiler for DOS was several thousand dollars.)
Also, Microsoft Visual C became good, but it was not before version 4. I remember watching a team at Activision literally take more than an hour to compile their game. Perhaps they were doing something wrong, but similar teams had much less of a problem when 4.0 came out. You cannot imagine what a drag that is to a team's productivity and creativity.
EDIT: Found it. Of course Fabien wrote about it: http://fabiensanglard.net/prince_of_persia/
Every time I use it I get really frustrated by the difficulty of entering complex instructions. The GUI is more discoverable but I find myself missing gdb ‘s functions and parser.
However, one thing in gdb that’s become steadily worse is the ability to evaluate STL’s operator[] and the like in optimized code, with the debugger frequently whining about inlining. It’s pretty horrible having to decipher the _m_data or whatever of various implementations.
I’m actually not sure if gcc is not compiling the inlines into the object code (I thought it was required by the standard) or if gdb just can’t find them.
I'm also of the opinion that GDB is getting worse in terms of what it shows (or more often won't) these days, especially with regards to >= C++11 - maybe it's just out-of-date python pretty-printers, but on multiple recent linux distro machines, it won't even show the contents of std::string these days without diving inside the structure or using expressions.
Like in the article he mentions not being able to see custom data types, but my .gdbinit has a few pretty printers in it for exactly that purpose.
And when you do get something customized in MSVC like a specific PGO build or something, it tends to be tightly coupled to that project. It’s less easy to cut and paste into another project since the primary interface is really a dozen little text fields modifying XML somewhere.
Regarding gdb, during the mid-90's I got by calling it from XEmacs, until I discovered DDD.
I got spoiled with Borland debuggers, typing n, s, l, p all the time and drawing structures on paper gets tiring after a while.
Basically it was such a pain to debug on the actual game console platform that we made a PC build of the game just so that we could have the pleasure of debugging in Visual Studio and avoid having to debug on the console, even though we were not planning to ship on PC. Maintaining a separate PC rendering engine and other platform specific libraries at a fair expense, but it was always worth it in terms of being able to solve problems faster. We had other motivations as well, on some game platforms the tools for linking and building an executable "ROM" could be quite slow, so having a PC build would save quite a bit of turnaround time.
I have always had a very high opinion of Visual Studio's debugger because it has a few features that are invaluable that other debuggers lack:
- "Immediate Mode", a.k.a., the ability to run C++ functions while stopped at a breakpoint. We use this a lot for writing functions which log out a bunch of useful information which would otherwise be tricky or time consuming to find via the debugger's usual interface (watch window, or whatever). In particular, we encode all our strings in the game as 32-byte hashes but in debug modes we keep a u32-->string lookup table around, and calling functions in the immediate window is invaluable for getting identifying information from out of those string-hashes.
- Data Breakpoints, i.e. stop when a particular memory address is written to. Critical for debugging "memory stomp" bugs such as array-overflow issues or writes to dangling pointers.
- Custom "visualization". Visual Studio's debugger has an XML language called .natvis which allows you to define a custom way to pretty-print specific types. Basically the equivalent of defining a custom "ToString" in a language like C#. The .natvis language is kind of annoying to use, but without it certain data types would be a real pain to look at in the debugger. (e.g. rather than using pointers everywhere, we have a safer Handle type which is essentially a lookup into a table that has a pointer. These indirections would be a pain to follow manually in the debugger, but .natvis allows us to present the target object in the debugger automatically, so that it is as easy as following a normal pointer)
- Automation. There's a fairly rich automation API ("ENVDTE") which allows you to drive the debugger from outside tools. I'm currently using this with Python to provide a convenient way for non-technical people (e.g. QA testers) to bundle up and send all of the relevant details from a crash to other members of the team. (e.g. callstack with all the locals, and contents of log)
> 1. Do nothing (...) You can deal with that by imposing rules on what is and isn’t allowed in your codebase, (...)
This is what everybody is already doing in gamedev
> 2. Get involved (...) C++ committee participation is open to everyone. (...)
Most game dev studios are Small or Mediums sized companies, and don't really have the time to waste in Committee meatings...
Irrelevant. What counts is where the C++ game devs are, and it's in the big companies. And participating in the design of a language is not a waste of time...
If you are under pressure to ship something now/soon, and may not exist as a company in the next standards cycle, then it is probably a waste of time for that company.
In fact the most popular CppCon video in Youtube is from Mike Acton: “Data Oriented Design and C++”
But I'm curious if there are any console development companies that are successfully using Rust or other languages which perhaps can link with C++ libraries?
We use C# in our studio for tools, and are able to link it with our game C++ so that we can run some of the game's subsystems within the tools (e.g. animation engine) but shipping the game with C# code is not an option for several reasons, performance being the most important, but also we need to build our game for the console using CLang/LLVM, and I suspect it's not possible to write C# which interfaces with C++ using LLVM, only with Microsoft's compiler.
There are other game companies doing stuff, but we have less details including platform: EA’s SEED division, Ready At Dawn, and Embark (some ex-SEED devs making a new studio where Rust is the primary language.)
It's now dominated by C++ for a good reason, since it requires tight performance control. So Rust is a valid candidate for fixing C++ issues. C# - not really.
Rust? I don't see it either.
If you are allocating memory in your renderloop, your likely doing it wrong. Allocation outside of this critical path, well, chose your poison.
GC will consume more memory, but likely to be faster when it comes to allocating and deallocating large amount of small blocks.
Reference counting, if you do it properly (to avoid thread starvation), is costly. Cheap atomic reference counting, involves a calculated risk that you may have threads hanging.
Manual memory management, well, we all know the cost of that :)
That being said, many many games are today developed with Unit which uses C# as its primary programming language.
[1] http://www.3rdeyestudios.fi/downward-spiral-horus-station/
CPU performance is barely going anywhere. Developers should instead try to figure out how to do more with less growth.
GPUs are also overpriced, and playing older games and comparing them to new ones doesn't show great payoff. As far as I'm concerned, we've plateaued. Maybe going from a GTX 760 to a 1060 would give me a few more frames, but frankly, more often than not, the games are programmed like utter shit.