4 ms·

I know some people coded up raytracers with glsl texture shaders, but rayracers are massive parrallel with no shared state needed algorithms (the entire scene i

I know some people coded up raytracers with glsl texture shaders, but rayracers are massive parrallel with no shared state needed algorithms (the entire scene is tiny in those examples). Would this new API enable shared state (to some extent)? For example, someone may want to solve numerically the diff equation of the liquid flow. This usually involves dealing with big lattices where parts of the lattices can be updated in parallel, but on the edges, there need to be some data sharing involved. Same question, but for multiplying big matrices, as many of those numerical methods allow to reduce the task to multiplying huge matrices.

lachlan-sneff 6y ago
Yes, compute shaders will enable slightly more ability to do computations that are less parallel than just fragment shaders can handle.
kvark 6y ago
We are exposing writable storage buffers and textures in all shader stages (there is a caveat discussion [1] on the topic though), which means you can write data out directly. Sharing data between shader threads can be efficiently in the compute shaders (via the shared group memory), which are included in the core of WebGPU. P.S. vange-rs [2] is written on wgpu-rs and uses ray-tracing in fragment shaders for the terrain. I hope to run it in the browser one day! [1] https://github.com/gpuweb/gpuweb/issues/639 [2] https://github.com/kvark/vange-rs
- gpugpugpugpu 6y ago
  > writable storage buffers and and textures in all shader stages Beware the behaviour of writes will not be consistent between vendors or shader stages, and may be surprising.
  - kvark 6y ago
    Yes, we are fully aware of that. There must be a line drawn somewhere between work that we can make portable, and the work that is platform-dependent. Enforcing any ordering on storage writes is completely unfeasible.
sidewaysgc 6y ago
Shameless plug of my own WebGL based ray/path tracer: https://github.com/apbodnar/FSPT https://github.com/apbodnar/FSPT Compute shaders will allow for some performance wins over my current fragment shader version by being able to do a ray binning/sorting pass to shoot rays coherently allowing for better cache behavior and shared shader state.
- dchyrdvh 6y ago
  Are those pics in the readme the actual output? If so, this is freaking astonishing cinematic-level quality.

lachlan-sneff 6y ago

Yes, compute shaders will enable slightly more ability to do computations that are less parallel than just fragment shaders can handle.

kvark 6y ago

We are exposing writable storage buffers and textures in all shader stages (there is a caveat discussion [1] on the topic though), which means you can write data out directly. Sharing data between shader threads can be efficiently in the compute shaders (via the shared group memory), which are included in the core of WebGPU. P.S. vange-rs [2] is written on wgpu-rs and uses ray-tracing in fragment shaders for the terrain. I hope to run it in the browser one day! [1] https://github.com/gpuweb/gpuweb/issues/639 [2] https://github.com/kvark/vange-rs

gpugpugpugpu 6y ago
> writable storage buffers and and textures in all shader stages Beware the behaviour of writes will not be consistent between vendors or shader stages, and may be surprising.
- kvark 6y ago
  Yes, we are fully aware of that. There must be a line drawn somewhere between work that we can make portable, and the work that is platform-dependent. Enforcing any ordering on storage writes is completely unfeasible.

sidewaysgc 6y ago

Shameless plug of my own WebGL based ray/path tracer: https://github.com/apbodnar/FSPT https://github.com/apbodnar/FSPT Compute shaders will allow for some performance wins over my current fragment shader version by being able to do a ray binning/sorting pass to shoot rays coherently allowing for better cache behavior and shared shader state.

dchyrdvh 6y ago
Are those pics in the readme the actual output? If so, this is freaking astonishing cinematic-level quality.