# luminance-front
[luminance], but with a backend type picked at compile-time.
This crate re-exports _aliases_ to all [luminance] types, methods, and any kind of symbols
requiring a backend type variable (typically written `B`) by selecting the proper type based on
the platform you target and/or feature flags. Selection is done mainly automatically in the
`Cargo.toml` file, and can customize on a per-target basis which backend you want to select.
> Important note: the existence of this crate was made a need so that people who don’t care
> about genericity can start using [luminance] without having to worry about backend
> implementations. It’s the case for people writing small binaries, “final” graphics libraries
> and/or 2D/3D/animation engines, etc. If you are writing a [luminance] middleware, please
> stick to the [luminance] crate and its polymorphic types.
Some symbols are re-exported even though they are not polymorphic in a backend type variable in
[luminance]. That is only for convenience purposes.
# Documentation
Because this crate re-exports the content of [luminance], you are strongly advised to go read
the documentation on [luminance]. Documentation will not be duplicated here.
# How to setup
For a starter experience, you have nothing specific to do: simply add `luminance-front` as a
direct dependency and you should be good to go:
```ignore
[dependencies]
luminance-front = "…"
```
This will select a _default_ backend implementation for the target you currently compile for.
See the list of features below for further information.
To switch target to use, you are advised to either put a `.cargo/config` file in a directory
inside your project, or compile with the `--target` option.
The default setup will provide a default implementation that should work great on as
many machines as possible for all supported targets. If for some reason you want to pick another
implementation (for instance an older version of WebGL, OpenGL or an experimental, more modern
implementation), you will have to use specific platform features, such as `"gl33"`.
```ignore
[dependencies]
luminance-front = { version = "…", no-default-features = true, features = ["gl33", "webgl2"] }
```
As you can see, you can specify features for different targets at the same time. Target
features are checked in the `lib.rs`, so it’s possible to define both OpenGL and WebGL
features at the same time. The current target will narrow down which one to use.
## List of features
- _Default_: `["gl33", "webgl2"]`.
- **OpenGL**:
- `"gl33"`: OpenGL 3.3 implementation.
- **WebGL 2**:
- `"webgl2"`: WebGL 2 implementation.
[luminance]: https://crates.io/crates/luminance