One thing that can be done is playing around with the numbers / uniforms in the fragment shader to change the look. For many use cases you can get pretty far with that without actually changing the implementation in this demo.
If a more physically based level of realism is needed (like the water ripples on click in the demo that you linked) you can use techniques like height simulation based on a wave equation [1].
You'll of course need to balance realism with realtime feasibility - but often times getting a much better look comes down to tweaking some numbers until things look good!
[1] - https://developer.nvidia.com/gpugems/GPUGems/gpugems_ch01.ht...
> The way that the water appear to move comes from slightly altering the point on the refraction and reflection textures that we sample from every frame. > > These slight offsets comes from sampling a du/dv map, which is just a texture that encodes different x and y offsets.
The app in the link you posted does indeed look like it's solving at least a shallow water system of equations, and looks very excited to me as a wave physicist.
https://www.figma.com/blog/building-a-professional-design-to...
- I see that I poorly communicated this in the title, but I was actually shooting less for "Rust/WASM makes this better!!" and more for "Hey, this is possible with pretty much just Rust/WASM!" I ended up hand writing about 10 lines of JS [1] in total
- More minor point - WebGL commands don't need to be called via JS [2] after anyref and host bindings land, and I think that it's important for people to know that it's possible to do things on the web without JS (whether that's a good idea is very situational)!
So yeah apologies if the title could be a bit better - but the main goal was to share with others that it's possible to build 3d experiences on the web with Rust today!
And - just to not come off wrong here - I'm not saying whether this is right or wrong and when to go this route. I am just interested in demonstrating how to do it :)
But all in all you're right - all of this same experience could totally be built with only JS if someone so desired!
[1] - https://github.com/chinedufn/webgl-water-tutorial/blob/maste...
[2] - https://github.com/WebAssembly/reference-types/blob/master/p...
That said, it's unnecessarily dismissive. It's still a cool project! And a useful resource for anyone who does need to use Rust with WebGL for whatever reason.
fn render_reflection_fbo(
&mut self,
gl: &WebGlRenderingContext,
state: &State,
assets: &Assets,
) {
gl.bind_framebuffer(...);
gl.viewport(...);
gl.clear_color(...);
gl.clear(...);
Why is it designed this way? Is this design considered sound, or is it a hack?
There's a recent issue [1] in the wasm-bindgen repo that explains this, but essentially:
- In this demo the WebGLRenderingContext was created on the Rust side (technically by calling a light JS shim), but it could've just as well have been passed in from JS.
- This means that JS could very easily have had access to the WebGLRenderingContext.
- This means that we cannot guarantee that it is immutable. Who is to say that there isn't a line of JS `gl.mutated! = true;` that we don't know about? We have no guarantees that whoever instantiated this WebAssembly module isn't doing something funky.
- So we treat most DOM / JS APIs as if they have interior mutability, so more or less you can think of them as `RefCell`'s [2]
---
As an aside. When you work with WebGL you're just making calls to the GPU and your state on the GPU gets mutated. The object just controls state (WebGlRenderingContext) does not get mutated (aside from maybe a couple things that I'm forgetting..?).
As in.. `gl.viewport` doesn't actually mutate `gl`. But again.. just a small aside!
In general the idea here is that we can't guarantee that there is only one mutable reference so there is no point in calling these things `&mut`, even for things that really do mutate.
---
So yup! Interior mutability without runtime checks for many of the APIs is "the right way" in today's idiomatic Rust + WASM + DOM access since you can't guarantee that there isn't foul play going on from whoever instantiated the module.
---
Does this cause issues? It hasn't (noticeably) for me yet but I'm only a couple months into using `web_sys` so I haven't worked with every single DOM API.. so grain of salt!
[1] - https://github.com/rustwasm/wasm-bindgen/issues/1061
[2] - https://doc.rust-lang.org/std/cell/struct.RefCell.html
- https://www.youtube.com/watch?v=M6RLvGqQU10&list=PLgC1L0fKd7...