That looks neat but why would you need a react-style reconciler to render a webgl scene? It's immediate mode...every frame is rendered according to the latest state available. What is even being reconciled?
> That looks neat but why would you need a react-style reconciler to render a webgl scene? It's immediate mode...every frame is rendered according to the latest state available. What is even being reconciled?
You don't, it might be a case of VRML cargo-culting or something.
While the DOM has some issues which makes React handy, Three.js and its "display list" have none of these problems, but I guess shoving React somewhere will translate in a better conversion for the authors of that article...
Describing WebGL as immediate mode is a little misleading. The rendering is immediate but the API is definitively not. There is a ton of state that needs to be allocated up front, mutated rather than re-created, and eventually torn down. Buffers, textures, shaders, and uniforms are all retained state. There's also the whole OpenGL state machine.
OpenGL used to have a true immediate mode where you called a function for each triangle vertex, and you didn't need shaders or buffers. That mode is not present in WebGL.
Three.js has an imperative/stateful API for constructing and updating objects, not dissimilar to the DOM. So if your state lives in a separate place, then just like the DOM, you'd have to imperatively patch the view state to keep it in sync. Adding a layer that does this syncing automatically makes a lot of sense to me.
Doing it through React seems a little bit odd... but I haven't looked closely enough to understand why/whether this coupling is actually necessary
That makes sense, but it seems like a case of building an abstraction to solve a problem caused by another abstraction. If a scene graph creates a new chore for me that necessitates yet another dependency, i think it'd be simpler to not fuss with these layers at all. That's a choice i don't have with the DOM.
> i think it'd be simpler to not fuss with these layers at all
You should check out some example code for react-three-fiber (e.g. https://codesandbox.io/embed/r3f-bones-3i7iu). If you have any experience with writing raw webgl, it will become abundantly clear that something is gained by going through three.js before returning to React's more declarative style.
Most of the savings in the example are coming from three.js itself (not r3f), which is maybe the key point: three.js offers much more than a scenegraph, which is why it's worthwhile (check out the official examples to get an idea: https://threejs.org/examples/). Webgl as an API doesn't even really talk about 3d objects for the most part; the language it provides is primarily about moving data around in buffers. The difference in possible time savings in three.js vs webgl is on the level of writing in C vs an assembly language.
And once you're building an application with a non-trivial amount of state mutation (on which the view depends)—you're faced with the same dilemma as traditional web dev and the DOM, hence the desirability of react-three-fiber.
That said, I think it would be super interesting to see a three.js alternative that was 'natively' reactive/declarative, because I'll readily admit the tower of abstractions involved in writing a react-three-fiber app has its downsides. (Then again, I consider three.js to be a rare gem, know of nothing comparable in terms of simplicity/quality for building 3d apps, and would be [pleasantly] surprised to see anything like the above anywhere in the near future.)
You don't really have the choice with graphics either. The GPU keeps mesh and texture data in memory between frames, and I would imagine something similar happens for lighting, etc at some layer in the pipeline. Reconstructing the entire scene every time would not be feasible.
You can still hold on to references to textures and meshes you uploaded to the GPU without using a full-blown scene graph. Some state is necessary no doubt, but this seems more like unnecessary state that could be replaced by something more direct. But i don't know, i'm not familiar with three.js; the click handlers seem useful.
Regardless: the reason for having a base API be imperative is usually because it's maximally flexible and performant. By your own admission, any reactive API for 3D rendering will at least have to hold on to references to GPU objects in-between iterations, which means it could never be a truly stateless API; it would always be an abstraction over something stateful.
So given that constraint, I think it's better for the base API not to hide that statefulness behind an abstraction, and to leave the abstracting to a higher-level API
I believe React developers think in terms of Components now as we used to think of Object/modules in the past. I personally find it easier to encapsulate logic into a Component because it seems more tangible than a plain JS file/module. You can also nest React components to compose logic, for example: composing multiple shaders.
Agreed. Haven't checked out the code but it might because of the text labels in the first example?
Last time I checked rendering text into a webgl context was basically reinventing harfbuzz or using a proper game engine like unity.
Edit: So a reactive way to lay over HTML which properly hooks into the 3d context doesn't sound beyond crazy, at least for web tech standards.
Yup thanks, typo.
Yes, but they are using Three.js, which provides a scene graph structure, basically wrapping WebGL in a retained mode.
react-three-fiber is a really nice library to make web 3D things with. Three.js is brilliant, but there's a metric ton of boilerplate to get complicated things up and running. react-three-fiber just shuffles that away so you can concentrate on building a graph out of components. I've been getting up to speed with it for a little while and I've been chucking things I've learned in to a Github Pages site - https://onion2k.github.io/r3f-by-example/ Each example can be spun up on Codesandbox with the click of a link eg https://onion2k.github.io/r3f-by-example/examples/geometry/i... (Click the "Fork on Codesandbox" link)
There are tons of good examples of how to use react-three-fiber on Codesandbox - https://codesandbox.io/search?query=react-three-fiber&page=1
When I went to your site, the “screenshot coming soon” for each of them caught all of my attention so I didn’t notice the fork on codesandbox link.
But why not just have the live WebGL thing on each page itself?
I'm writing something to generate screenshots at the moment. They'll be there fairly soon.
I could embed the live WebGL, or a codesandbox embed. I might do that eventually.
Thanks for the helpful repo and linking to it! Been looking fwd to playing w react-three-fiber...
Nice writeup, I always like it when the shaders are highlighted like this. I got started in a similar way 7 years ago and have been making 3D terrains with THREE.js & WebGL since.
The real fun begins when you need to implement some sort of Level-of-Detail system and streaming in data to give the illusion of high detail everywhere without sacrificing performance.
Last year I released an open-source framework (https://github.com/felixpalmer/procedural-gl-js) for creating 3D terrains for web applications, you can see Uluru here: https://www.procedural.eu/map/?longitude=131.036&latitude=-2... (unfortunately the aerial imagery from our default provider isn't as high resolution as other places in Europe)
If you like this type of stuff, Paul Henschel shares similar content on Twitter  and it's absolutely amazing. For example, incredible stuff like this .
Maybe someday we can have geometry shaders in WebGL 3, so we can make nice adaptive LOD.
It's confirmed that I'm an idiot who happens to just be into WebGl and threejs these last few months. But I must ask about the choice to use React. Is there an actual benefit to using React or is it popular enough to justify its use?
I think React's main role here is just to provide structure to the code base: React component as the basic unit of logic encapsulation and then composing logic by combining React components.
Excellent write up. I've been using elevation models for the past few months to create real time shadows overlaid on slippy maps using WebGL. 
One thing I learned is that if you really want to recreate "real-world" terrain you have to account for the curvature of the earth. Uluru is over 3km wide and I estimate your image is around 5km. Across this distance the earth will curve 2 meters so you could modify the elevation model to drop off a meter gradually from the center to the edges.
That's ace when it loads, but modifying the time on the bar at the bottom of the screen makes the shadow disappear. I get a NaN in the URL which is presumably related (eg https://shademap.app/#47.62769,24.44286,4z,NaNt). Chrome 88.0.4324.182, OSX, no plugins to speak of. There's a bunch of 404s from Mapbox (eg https://api.mapbox.com/v4/mapbox.terrain-rgb/3/3/6.pngraw?ac...) but no other console errors.
The 404s from Mapbox are for elevation map tiles over the ocean where elevation is assumed to be 0.
As you pan, zoom and change the time, the url updates so you can share a permalink with others and they see exactly what you do. It looks like somehow you got an invalid timestamp (NaNt should be a timestamp: 1614115393106t). Will dig more into this. Thanks.
Very cool demo! And also nice to know my laptop fans still work. (2019 MBP 16", Chrome v84)
Looks very cool and there's a ton of good info here. But the final product is unusably laggy on my Dell XPS 13 i7 - not something I'd be happy to put into production.
Edit - thank you for all the replies, we have now established that different hardware renders at different speeds, quite the discovery.
It probably lacks a discrete graphics card. Not much to be done about that for a fundamentally graphics-concerned project; the only thing I can think of for production would be to disable the 3D content when the client lacks discrete graphics (which, I'm not actually sure whether that can be detected)
Edit: Here's something. You could probably hack something up that would check if the vendor name includes AMD or NVIDIA, or something. Might be fragile though https://developer.mozilla.org/en-US/docs/Web/API/WebGLRender...
The demo in the article would still run full speed on several year old integrated graphics. Probably chrome blacklisted his gpu driver and it's doing pure cpu rendering (or else his driver itself is bugged in a way that is killing the performance).
Ah, yeah, it's running smooth on my MBP without switching to discrete
FWIW it’s zippy as hell on my iPhone 11 Pro.
The iPhone/iPad GPU's are actually faster than the Intel MacBooks in my experience. I haven't tried an M1 yet, but hopefully it eliminates this performance gap.
Ran perfectly fine on my Dell Precision with an i7-9850H.
Same here. Probably the turbo encabulator on that XPS.
Yes I understand that different hardware renders things at different speeds, thanks for your input? I'm saying that if something runs like shit on my $3,000 laptop I wouldn't be comfortable putting it into production for a user base that likely has, on average, far less.
Runs silky smooth on my 2015 MBP - it’s possibly a system specific issue
A guide to rendering photo-real terrain with React + Three.js
At first the thought of combining React with Three.js left me scratching my head - but upon closer inspection the added abstraction actually makes sense and it's quite elegant. Thanks for sharing.
Also I had no idea what "frijoles" was, but I now have recipes bookmarked.