Handle invalid shaders

[fralonra]

Issues

Currently invalid shader input would panic at device.create_shader_module:

wgshadertoy/src/runtime.rs

Line 280 in 87e36ac

let fs_module = device.create_shader_module(wgpu::ShaderModuleDescriptor {

Thus makes the whole program to crash.

The approaches I've tried

• use device.on_uncaptured_error to catch it:
  

  wgshadertoy/src/context.rs

  Line 48 in 87e36ac

  // device.on_uncaptured_error(|err| {

  
  However it would continuously generate errors and block the main thread:

[wgpu_core::present] No work has been submitted for this frame
[wgshadertoy::context] Validation Err

• use naga to validate the shader beforehand:
  

  wgshadertoy/src/runtime.rs

  Line 396 in f52e882

  Ok(module) => match validator.validate(&module) {

  
  Unfortunately there are some times (vec2(0.0, 2.0, 4.0) etc.) the shader has passed the naga check, but still failed at the same check period in wgpu-core:
  https://github.com/gfx-rs/wgpu/blob/9f82504d8a3b6e234599b19cc35c299bcec8b138/wgpu-core/src/device/mod.rs#L1249

Helps needed

I'm glad to hear useful infomation about how to handle invalid shaders. Thanks a lot!

[fralonra]

Currently I skip the naga check, and use error scopes to capture validation error:
22705e4

[andrewbaxter]

I had a typo and mine output an error to the terminal and exited... I assume this is the same issue:

[2024-08-17T04:54:06Z ERROR wgshadertoy::core] Validation error: "Validation Error\n\nCaused by:\n    In Device::create_shader_module\n      note: label = `Shader`\n    \nShader 'Shader' parsing error: no definition in scope for identifier: 'cenetered_coord'\n   ┌─ wgsl:19:17\n   │\n19 │     return vec4(cenetered_coord.x / u.resolution.x, centered_coord.y / u.resolution.y, 0., 1.0);\n   │                 ^^^^^^^^^^^^^^^ unknown identifier\n\n\n    no definition in scope for identifier: 'cenetered_coord'\n"

[fralonra]

I had a typo and mine output an error to the terminal and exited... I assume this is the same issue:

[2024-08-17T04:54:06Z ERROR wgshadertoy::core] Validation error: "Validation Error\n\nCaused by:\n    In Device::create_shader_module\n      note: label = `Shader`\n    \nShader 'Shader' parsing error: no definition in scope for identifier: 'cenetered_coord'\n   ┌─ wgsl:19:17\n   │\n19 │     return vec4(cenetered_coord.x / u.resolution.x, centered_coord.y / u.resolution.y, 0., 1.0);\n   │                 ^^^^^^^^^^^^^^^ unknown identifier\n\n\n    no definition in scope for identifier: 'cenetered_coord'\n"

Looks like the shader is missing the definition for cenetered_coord

[andrewbaxter]

Ah yeah, thank you, of course, but the risk of a typo in your code shouldn't be a crash and a loss of all code. I assumed that was what this issue was about.