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Bit idea : The Witcher 3 written in assembly with 40 billion lines of code so you can run it on an old windows 98 desktop
(hexbear.net)
I don’t wanna any nerds in here explaining why this is impossible I choose to believe it could be done in theory
As a nerd, I gotta say, this is almost definitely possible. Modern games are so incredibly inefficient in ways beyond our understanding, that if you stripped it down to custom assembly brass tacks, I really don't doubt you could run Witcher 3 on Windows 98 (albeit in a lower resolution).
I'm reminded of this guy who coded Minecraft in Unity, but by focusing on optimisations, made it at least 1000x faster at most benchmarks.
I'd say two things:
Modern compilers are way better at generating code than they were in the 90s so hand-rolled assembly is not that useful anymore
Vast majority of frame time in a game like Witcher 3 comes from rendering, not gameplay code and you can't really write rendering code in asm since GPU vendors don't allow you to program their hardware directly. Also running it on a 25 year old GPU would require way more compromises than just lower resolution because 98 era GPUs don't even have basic things like vertex buffers or programmable shaders
I think you could make Witcher 3 run on a computer from 2008 if you optimize it properly but that's about it
Modern compilers are very good, but I'd argue you're overestimating the gains. Unless you're using some very strict typing and compiling options, you're still missing out on enormous efficiency even from the most modern compilers, like orders of magnitude in some case. Stuff that with proper coding you'd have in assembly. And in '98, you absolutely could program GPU hardware directly in assembly.
I'm not saying it'd be anywhere near easy, but I absolutely contend it'd be possible.
In my experience writing straightforward C code is gonna give you basically the same thing as well-written asm would. I'm not saying modern compilers are perfect but they generally do the right thing (or it's very easy to coax then into doing the right thing). They usually vectorize properly, they know how to avoid obvious pipeline stalls etc. These days order of magnitude performance improvements generally don't come from hand-written assembly but from using better algorithms and data structures
Also you could look at what games of that era actually looked like. Something like Quake 2 already pushed contemporary hardware to it's limits and I wouldn't argue it's a poorly optimized game
I was alive and played games during that era, so I am aware! I'm very personally aware how much work we crammed from a tiny slow processor and a few kb.
And though we probably wouldn't describe those games as 'poorly optimised', there's still absolutely huge room for optimisations. As you say, compilers have gotten a lot better, and we have better algorithms and data structures. In Quake especially, they basically did have order-of-magnitude gains by writing some parts in assembly. And they'll have undoubtedly have written most of those parts very imperfectly.
I may be skirting the bounds of reality more than you, by talking about what's 'theoretically possible' compared to what's possible by today's knowledge and human practices. We agree there'd be some graphical compromise, maybe we're just disagreeing over details of the scale of that compromise and the hardware that would be 'permittable' by this scenario.
I was imagining something that looks and plays almost exactly like Witcher 3 except at lower resolution, which doesn't seem possible to me. I'd say if you simplify the graphics (replace dynamic lighting with pre-baked lightmaps, do gouraud shading instead of PBR, remove most post-processing effects etc etc) and make all models look like half-life assets, you could definitely render something at an acceptable frame rate. However asset streaming would still be a huge issue for a large and detailed open world like Witcher 3, considering memory limits and slow disk reads