triangle example vertex shader throws warning UnsupportedInstruction(Function, Variable)

[ncharlton02]

I was running into some warnings while trying to make some java bindings for the triangle example. I added a log callback into the C example to see if it was a problem in my code, but the same warning appeared. It appears that when wgpu_device_create_shader_module is called for the vertex shader, the following warning is logged:

WARN: Failed to parse shader SPIR-V code: UnsupportedInstruction(Function, Variable)
WARN: Shader module will not be validated

[kvark]

This is logged from naga, and it's temporary and expected at this point. There is no harm in it.
We are trying to parse the given SPIR-V into Naga's IR in order to validate the shader requirements as well as do the shader translation fully in Rust in the future.

Ideally, you'd just ignore the warnings from naga module for now, but I understand that there is no filtering ability set up in the current log callback C entry point... We could change that to pass the source module (that issues the log message) as another parameter.

[rajveermalviya]

examples were updated to use wgsl shaders a while back in #85