Meeting 2020-11-12

[repi]

Previous meeting: #213

Time: 17:00 CET
Where: #rust-gpu voice channel on Ark Discord.

Agenda (please add)

• @khyperia project update
• Triage: PR Add step, step_select, mix to spirv_std::MathExt #223 - discuss approaches for math extensions for f32 and vector types
• pub use glam;? overrides in workspace or package? Add trunc and fract to MathExt #222
• @Jake-Shadle moving out spirv-tools tomorrow

[repi]

Meeting notes

Participants

• @repi - Embark
• @khyperia - Embark
• @VZout - Embark
• @Jake-Shadle - Embark
• @arirawr - Embark
• @XAMPPRocky - Embark
• @termhn - Embark
• @davidpdrsn - Embark
• @vojd - Embark
• @eddyb
• @Tobski - AMD
• @msiglreith
• @DJMcNab

Minutes

What are we working on

@termhn - converting Ark shaders from GLSL to Rust #36

• Porting over utility functions and getting situated properly
• could put in Embark's macaw layer above glam, seems to be working out pretty well
• Adding some low-level stuff, step/mix/fract. stuff you expect to have in a shader language
  • f32::step maybe be in spirv-std, maybe
• Added issues for compiler backend implementations that are needed: Ark shader blockers #233

@khyperia

• loooked into structurization with new ideas with @VZout
• looking into asm! macro support Support asm! #230
  • allows us to implement in user mode, faster than doing compiler changes!
  • barrier proposals requires OpMem barrier with specific flag, so could expose that with just asm instruction
  • texture intrusctions also and things like ddx/ddy

@XAMPPRocky - build system work #239

• had working yesterday so you have have spriv-builder so it works in any program
• you just say the path to a shader crate and where to output stuff (such as outdir)
• downloads Rust GPU from git as a bootstrap, but want to change to specify a system default where you are expected to have installed it in the system before
• Have to build something like cargo xtask

@VZout - structured control flow #97

• fixing issue for when having 2 breaks and a destructor
• can reuse this for multiple level breaks
• have not gotten example shader in yet

@repi - created draft PR for hot-reloading of shaders in example #231

• Requires additional fix up and spirv-builder causes slow iteration times by somehow rebuilding core all the time
• @XAMPPRocky will take over and continue the PR

@Jake-Shadle - moving spirv-tools to a separate repo #237

• Now published and open! https://github.com/embarkStudios/spirv-tools-rs

Glam discussion

• Should spriv-std re-export glam? Follow up from Add trunc and fract to MathExt #222

• A bunch of discussion but overall conclusion was: likely not. Let's in our shaders for now use the Embark (unpublished) high-level layer on top of glam: macaw.

• Need to rebase our glam SPIRV fork (Initial SPIRV no_std implementation bitshifter/glam-rs#85) to latest no_std version of Glam and latest fixes.

• @khyperia will take over the PR from @repi and drive it.

• @bitshifter did fantastic named field access in glam now with some good implementation suggestions from @termhn! bitshifter/glam-rs@44d3208. This will make it a lot more ergonomic to write shaders and code in general with glam! 🎉

Render graph discussion #21

• @vojd: Has anyone started? What could it be? Curious and interested!

  • No not yet, it is more of a longer term goal and connection for the project.
  • @repi: First focus is Ergonomic Rust CPU to Rust GPU / SPIRV bindings #10 and ergonomic bindings between CPU & GPU, that could help us build something quite unique

• Multiple at Embark has experience from Frostbite and the one of the first and very extensive render graph implementations

• Can use issue Render graph design #21 to start discussing and gathering information and examples. But likely no work for on it for the next few months

• List example documentation and other render graph examples: Frostbite, Unreal, Rendy, Bevy