Macro pixels::include_spv

macro_rules! include_spv {
    ($path:expr) => { ... };
}

Provides a macro and type for including SPIR-V shaders in const data.

In an ideal world, a shader will be compiled at build-time directly into the executable. This is opposed to the typical method of including a shader, which reads a GLSL source code file from the file system at start, compiles it, and sends it to the GPU. That process adds a non-trivial amount of time to startup, and additional error handling code at runtime.

This macro moves all of that complexity to build-time. At least for the SPIR-V part of the shader pipeline. (gfx-hal backends have their own SPIR-V-to-native compilers at runtime.)