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The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

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Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#81

Post by applfanboysbgon »

ryandrake wrote: post #40
timschmidt wrote: post #11

Earlier quoted context omitted.

Absolutely. I have written a small but growing CAD kernel which is seeing use in some games and realtime visualization tools ( https://github.com/timschmidt/csgrs ) and can say that computing with numbers isn't really even a solved problem yet. All possible numerical representations come with inherent trade-offs around speed, accuracy, storage size, complexity, and even the kinds of questions one can ask (it's often…

Back in the early, early days, the game designer was the graphic designer, who also was the programmer. So, naturally, the game's rules and logic aligned closely with the processor's native types, memory layout, addressing, arithmetic capabilities, even cache size. Now we have different people doing different roles, and only one of them (the programmer) might have an appreciation for the computer's limits and happy-p…

Not all, or even most, games are made by billion dollar studios. Overlapping roles are still the norm in small studios. And even those that do have bespoke designer roles would likely benefit from telling them that computers have certain limitations where trade-offs in game design need to be selected for, because many AAA games run like shit. Many times for reasons other than the game design, sure, but also sometimes because of ways that could be worked around more easily if the game design were accomodating the tradeoffs.

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#82

Post by applfanboysbgon »

lifis wrote: post #48
applfanboysbgon wrote: post #7

> Imagine a programmer asking a game designer if they could change their formula to use an 8 instead of a 9.5 because it is a number that the CPU prefers to calculate with. There is a very good argument to be made that a game designer should never have to worry about the runtime performance characteristics of binary arithmetic in their life, that’s a fate reserved for programmers Numeric characteristics are absolutel…

That makes no sense since multiplication has been fast for the last 30 years (since PS1) and floating point for the last 25 years (since PS2) and anyway numbers relevant for game design are usually used just a few times per frame so only program size matters, which has not been significantly constrained for the last 40 years (since NES)

I wasn't talking about the specific example in the article. There are many, many other ways in which numeric characteristics can constrain game design, particularly if your game has any kind of scale to it (say, simulations with tons of moving parts or many NPCs, like RCT, or large open worlds like Minecraft, or large multiplayer games like WoW, as examples all mentioned in the thread).

If your game is small-scale, something like Super Mario Bros., you should be able to get away with not thinking about it in theory. But even then people manage to write simple games with bloated loading times and stuttery performance, so never underestimate the impressive ability of people who are operating solely at the highest level of abstraction to make computers cry.

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#83

Post by egypturnash »

I have to wonder how much of the original assembly source looked a lot more succinct than whatever's in OpenRCT due to the use of macros. Looking up his gameography on Mobygames, Chris had been writing stuff since 1984 when RCT came out in 1999, it's hard to imagine he was still writing every single opcode out by hand given that I had some macros in the assembler I was fooling around with on my c64 back in the eighties.

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#84

Post by moregrist »

cogman10 wrote: post #49
applfanboysbgon wrote: post #7

> Imagine a programmer asking a game designer if they could change their formula to use an 8 instead of a 9.5 because it is a number that the CPU prefers to calculate with. There is a very good argument to be made that a game designer should never have to worry about the runtime performance characteristics of binary arithmetic in their life, that’s a fate reserved for programmers Numeric characteristics are absolutel…

> Numeric characteristics are absolutely still a consideration for game designers even in 2026, one that influences what numbers they use in their game designs. The good ones, anyways. I used to think like this, not anymore. What convinced me that these sort of micro-optimizations just don't matter is reading up on the cycle count of modern processors. One a Zen 5, Integer addition is a single cycle, multiplication 3…

> Integer tricks and optimizations are pointless.

They’re not pointless; they’re just not the first thing to optimize.

It’s like worrying about cache locality when you have an inherently O(n^2) algorithm and could have a O(n log n) or O(n) one. Fix the biggest problem first.

Once your data layout is good and your cpu isn’t taking a 200 cycle lunch break to chase pointers, then you worry about cycle count and keeping the execution units fed.

That’s when integer tricks can matter. Depending on the micro arch, you may have twice as many execution units that can take integer instructions. And those instructions (outside of division) tend to have lower latency and higher throughput.

And if you’re doing SIMD, your integer SIMD instructions can be 2 or 4x higher throughput than float32 if you can use int16 / int8 data.

So it can very much matter. It’s just usually not the lowest hanging fruit.

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#85

Post by ukuina »

calvinmorrison wrote: post #68
scns wrote: post #21

Earlier quoted context omitted.

> it is mainly a question if the game is fun to play. 10000x this. Miyamoto starts with a rudimentary prototype and asks himself this. Sadly it seems for many fun is an afterthought they try to patch in somehow.

When Halo 2 (anniversary edition? ) was released there was also a video on in the game about the development. The point that always stuck with me was "you must nail that 2 seconds that will keep people playing forever". The core mechanic of that game is just excellent.

"30 seconds of fun"

https://youtu.be/0q69Msy8ttM?t=287

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#86

Post by danbolt »

applfanboysbgon wrote: post #7

> Imagine a programmer asking a game designer if they could change their formula to use an 8 instead of a 9.5 because it is a number that the CPU prefers to calculate with. There is a very good argument to be made that a game designer should never have to worry about the runtime performance characteristics of binary arithmetic in their life, that’s a fate reserved for programmers Numeric characteristics are absolutel…

Yeah, I’m quite surprised at this comment. Commercial video games are mass-produced products, and as much as I dislike designers being bogged down in technical minutiae, having a sense of industrial design for the thing you’re making is an incredible boon.

Fumito Ueda was notably quite concerned with the technical/production feasibility of his designs for Shadow of the Colossus. [1] Doom was an exercise in both creativity and expertise.

[1] https://www.designroom.site/shadow-of-the-colossus-oral-hist...

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#87

Post by biglost »

WalterBright wrote: post #64
ryandrake wrote: post #40

Earlier quoted context omitted.

Back in the early, early days, the game designer was the graphic designer, who also was the programmer. So, naturally, the game's rules and logic aligned closely with the processor's native types, memory layout, addressing, arithmetic capabilities, even cache size. Now we have different people doing different roles, and only one of them (the programmer) might have an appreciation for the computer's limits and happy-p…

I wrote the Intellivision Mattel Roulette cartridge game back in the 1970s. It was all in assembler on a 10 bit (!) CPU. In order to get the game to fit in the ROM, you had to do every feelthy dirty trick imaginable.

Please, write a comment, pastebin, gist or whatever, I would love to read it, that are stories in computer science i enjoy the most

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#88

Post by Cold_Miserable »

shaggie76 wrote: post #35
shakow wrote: post #15

Earlier quoted context omitted.

That's what I would have thought as well, but looks like that on x86, both clang and gcc use variations of LEA. But if they're doing it this way, I'm pretty sure it must be faster, because even if you change the ×4 for a https://godbolt.org/z/EKj58dx9T

Not only is LEA more flexible I believe it's preferred to SHL even for simple operations because it doesn't modify the flags register which can make it easier to schedule.

shlx doesn't alter the flag register.

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#89

Post by crq-yml »

lukan wrote: post #19
applfanboysbgon wrote: post #7

> Imagine a programmer asking a game designer if they could change their formula to use an 8 instead of a 9.5 because it is a number that the CPU prefers to calculate with. There is a very good argument to be made that a game designer should never have to worry about the runtime performance characteristics of binary arithmetic in their life, that’s a fate reserved for programmers Numeric characteristics are absolutel…

"and in many cases it is one of many silent contributing factors to a noticeable decrease in the quality of their game" Game designers are not so constrained anymore by the limits of the hardware, unless they want to push boundaries. Quality of a game is not just the most efficient runtime performance - it is mainly a question if the game is fun to play. Do the mechanics work. Are there severe bugs. Is the story cons…

There's an artistic thread in game coding - one that isn't the norm, but which I think RCT is exemplary of - that holds that mechanical sympathy is important to the game design process. A limit set around NPOT maximums and divisions and lengths of pathfinding is allowing the machine to opine, "you will actually do less work if you set the boundary here". Setting those limits tends to inform the shape of resulting assets as something tiny and easy to hardcode.

The thing that changed during the 90's is that mechanical sympathy became optional to achieving a large production. The data input defining the game world was decoupled into assets authored in disconnected ways and "crunched down" to optimized forms - scans, video, digital painting, 3D models. RCT exhibits some of this, too, in that it's using PCM audio samples and prerendered sprites. If the game weren't also a massive agent simulator it would be unremarkable in its era. But even at this time more complex scripting and treating gameplay code as another form of asset was becoming normalized in more genres.

From the POV of getting a desired effect and shipping product, it's irrelevant to engage with mechanical sympathy, but it turns out that it's a thing that players gradually unravel, appreciate and optimize their own play towards if they stick with it and play to competitive extremes, speedrun, mod, etc.

The 64kb FPS QUOD released earlier this year is a good example of what can happen by staying committed to this philosophy even today: the result isn't particularly ambitious as a game design, but it isn't purely a tech demo, nor does it feel entirely arbitrary, nor did it take an outrageous amount of time to make(about one year, according to the dev).

Re: The gold standard of optimization: A look under the hood of RollerCoaster Tycoon

#90

Post by CursedSilicon »

netcoyote wrote: post #73

Warcraft 1 (1994), Warcraft 2 (1995), and StarCraft (1998) all use power-of-2 aligned map sizes (64 blocks, 128 blocks, and 256 blocks) so the shift-factor could be pre-computed to avoid division/multiplication, which was dang slow on those old 386/486 computers. Each map block was 2x2 cells, and each cell, 8x8 pixels. Made rendering background cells and fog-of-war overlays very straightforward assembly language. All…

It's a shame that when a Redditor discovered the source code for the original StarCraft "gold master" on a CD, they sent it back to Blizzard in exchange for some fucking blizzard merch [1]

EA a while back released the source code to (most) of the old Command & Conquer games [2] though interestingly left out Tiberian Sun and Red Alert 2, StarCraft's closest competitors at the time.

Would've been nice for historical preservation to be able to peek behind the curtain and see StarCraft's code in a similar fashion

[1] https://old.reddit.com/r/gamecollecting/comments/68xzxt/star...

[2] https://github.com/electronicarts

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