# `spirv-std`
Core functions, traits, and more that make up a “standard library” for SPIR-V for use in [rust-gpu](https://github.com/EmbarkStudios/rust-gpu#readme).
This crate gives a `rust-gpu` shader access to the required `#![spirv(..)]` attribute, as well as povide all kinds of APIs that allows a shader to access GPU resources such as textures and buffers. Optionally, through the use of the `"glam"` feature, it includes some boilerplate trait implementations to make `glam` vector types compatible with these APIs.
## Example
Here is a small excerpt to see what a shader would look like. See [source][source] for full details of the shader that generates above image.
```rust,no_run
use spirv_std::spirv;
use glam::{Vec3, Vec4, vec2, vec3};
#[spirv(fragment)]
pub fn main(
#[spirv(frag_coord)] in_frag_coord: &Vec4,
#[spirv(push_constant)] constants: &ShaderConstants,
output: &mut Vec4,
) {
let frag_coord = vec2(in_frag_coord.x, in_frag_coord.y);
let mut uv = (frag_coord - 0.5 * vec2(constants.width as f32, constants.height as f32))
/ constants.height as f32;
uv.y = -uv.y;
let eye_pos = vec3(0.0, 0.0997, 0.2);
let sun_pos = vec3(0.0, 75.0, -1000.0);
let dir = get_ray_dir(uv, eye_pos, sun_pos);
// evaluate Preetham sky model
let color = sky(dir, sun_pos);
*output = tonemap(color).extend(1.0)
}
```
## Getting started
Check out [The `rust-gpu` Dev Guide][gpu-guide] for information on how to get started with using it in your projects.
Experiment with rust-gpu shaders in-browser at [SHADERed][shadered].
[migration]: https://github.com/EmbarkStudios/rust-gpu/blob/097ba40bedd74eeaa296e719ef7e41f2d3d76c23/docs/src/migration-to-register-tool.md
[source]: https://github.com/EmbarkStudios/rust-gpu/blob/69cb69d28f1e64420ee31ade5e7dffb7c5621e89/examples/shaders/sky-shader/src/lib.rs
[gpu-guide]: https://embarkstudios.github.io/rust-gpu/book/
[shadered]: https://shadered.org/shaders?language=rust&sort=hot