Reflections without Raytracing Ever wonder how they had perfect reflections without RTX? They just built the room twice and flipped it. 🤯 CoD Ghosts: NextGen Testmap

Yes many games back then used this technique. But it has its limits to.

Ray tracing was the biggest marketing gimmick. I don't doubt it's technically superior, but look at when it first came out. People were frothing for miniscule improvements at the cost of most of their performance. What a joke.

even death stranding 2 uses this technique

Half-Life 2 famously combined this with cubic environment maps for static things like the environment. Managed to produce impressive results for only being from 2004.

classic technique, ray tracing is still objectively a "better" technique (though obviously more compute heavy and not without it's own problems) but it's amazing how far back this method goes. Even early 3D games like DN3D used this method to render mirrors

You will never not convince me ray tracing is the worst thing to happen to gaming. It's so resource heavy and almost indistinguishable to just good creative development work

Yeah, half life 2 from 2004 has a better solution and it also includes dynamics objcts

In Super Mario 64, a similar technique was used in the large mirror room; the room and Mario exist twice in this scene, so it looks as if it's mirrored. Back then, many such tricks were used to create effects that would have been impossible to render at the time.

There's also other technique called Planar reflections, which HL2 (and even GTA 5) uses for water reflections and u don't need to duplicate the building/room at all, instead it's all done by shaders.

This is computationally cheaper than ray tracing in most scenarios.

Brooooooo!

Because they had to improvise, adapt and overcome. You had to fool the machine into doing it and player into believing it. Everything had a computational cost, and resources were limited. Now they just fatten it up and pass the cost to consumers

it is worrysome that tech is still underdeveloped. they had to build it twice.

The thing I miss the most is using this technique for mirrors. Modern games often have ugly, muddy mirrors. Like the mirrors in the OG Dead Rising look fantastic, but in the newer ones they are awful

no .. it just appears like so - in reality the world is just rendered twice - exactly how mirrors worked in games. It's not fully accurate in terms of lights, but noone cares - and they dont reflect anything. raytracing: actually reflects light onto a wall etc

I have to imagine doubling the amount of everything we interact with comes with major performance drawbacks. I'm sure it works but scaling this would probably cause chaos.

We used to do this trick in Half-Life 1 ^^. Works, but all dynamic characters, explosions and whatever will not reflect ^^.

Bully from Rockstar in 2006 does the same thing, pretty cool. Portal and Portal 2 do something similar with the portal mechanic. You're not actually going through a portal you're seemlessly switching between two mirrored characters in mirrored rooms

Yeah they've been doing this since the 90s. For planer reflections it's called the duplicate room method: in older games like Super Mario 64 or Duke Nukem 3D, developers literally built a duplicate, inverted version of the room on the other side of a transparent wall. A second "mirror version" of the player character would move in tandem with the real player to complete the illusion.

Great trick for limited use cases, not scalable to larger worlds at all unfortunately. Also no dynamic reflections unless you also duplicate all the physics, particles and other actions, blowing the compute budget.

Isn't this more or just as costly as Raytracing, if it were done with new games ? just asking btw

Now you know why sometimes you'd see textures backwards on walls and such.... :P it's when they'd grab the wrong texture and use the 'reflection' one rather than the 'top-level' one :D

Old technique if I'm not mistaken. Didn't Super Mario 64 do the same thing for mirrors? Just cloned the the room and duped the player while inverting their motion?

This is a good example of why raytracing doesn’t seem as expensive as you’d think, because non raytracing tricks have to do things like this, wasting processing with an entire duplicate model

Reflections without raytracing 🤯

Build once and flip it, really.

And duke nukem 3d in 1996 did this on the fly for the mirrors:

In most 2015 and earlier rendering setups it's cheaper to have a second camera rendering a low res texture at the complementing angle of incidence to the reflecting plane. It's then layered on. Only modern pipelines would double the geometry cause of the expensive post-processing that they only want to pay for (on the GPU) once.

Literally the same technique in 1996.

Old technology as in Duke Nukem restroom

It's a good trick as long as the "reflective" surface is pretty much flat and one elevation. Otherwise, curves or steps pretty much break the illusion, and there are more limits past that. So this by no means proves raytracing is unneeded or a waste of resources.

when Battlefield stuff ? 👀

@grok what are the limits of that technique