# ScenicNew

The `scenic.new` mix task, which generates out a starter application for you.
This is the easiest way to set up a new Scenic project.

## Erlang/Elixir versions

Please note, it currently needs OTP 21 and Elixir 1.7. If you have trouble
compiling, please check that you are running those versions first.

## Install Prerequisites

The design of Scenic goes to great lengths to minimize its dependencies to just
the minimum. Namely, it needs Erlang/Elixir and OpenGL.

Rendering your application into a window on your local computer (MacOS, Ubuntu
and others) is done by the `scenic_driver_glfw` driver. It uses the GLFW and
GLEW libraries to connect to OpenGL.

The instructions below assume you have already installed Elixir/Erlang. If you
need to install Elixir/Erlang there are instructions on the [elixir-lang
website](https://elixir-lang.org/install.html).

### Installing on MacOS

The easiest way to install on MacOS is to use Homebrew. Just run the following
in a terminal:

```bash
brew update
brew install glfw3 glew pkg-config
```

Once these components have been installed, you should be able to build the
`scenic_driver_glfw` driver.

### Installing on Ubuntu 16

The easiest way to install on Ubuntu is to use apt-get. Just run the following:

```bash
sudo apt-get update
sudo apt-get install pkgconf libglfw3 libglfw3-dev libglew1.13 libglew-dev
```

Once these components have been installed, you should be able to build the
`scenic_driver_glfw` driver.

### Installing on Ubuntu 18

The easiest way to install on Ubuntu is to use apt-get. Just run the following:

```bash
sudo apt-get update
sudo apt-get install pkgconf libglfw3 libglfw3-dev libglew2.0 libglew-dev
```

Once these components have been installed, you should be able to build the
`scenic_driver_glfw` driver.

### Installing on Arch Linux

`glew` and `glfw-x11` are available in [Extra](https://www.archlinux.org/packages/extra/x86_64/glew/) and [Community](https://www.archlinux.org/packages/community/x86_64/glfw/), respectively. Ensure that these are enabled in your `pacman.conf`, then run:

```bash
sudo pacman -S pkgconf glew glfw-x11
```

Once these components have been installed, you should be able to build the
`scenic_driver_glfw` driver.

### Installing on FreeBSD

The easiest way to install on FreeBSD is to use `pkg`. Just run the following,
to install development toolchain, and build/runtime graphics libraries:

```bash
sudo pkg install devel/gmake devel/pkgconf devel/elixir-hex devel/rebar3 \
  graphics/glew graphics/glfw
```

Once these components have been installed, you should be able to build the
`scenic_driver_glfw` driver.

### Installing on NixOS 18.09

The easiest way to install on NixOS is with a custom shell. Create a file titled `shell.nix` that includes the following: 

```nix
{ pkgs ? import <nixpkgs> {} }:

with pkgs;

let
  inherit (lib) optional optionals;
  elixir = beam.packages.erlangR21.elixir_1_7;
in

mkShell {
  buildInputs = [
    elixir
    glew glfw
    git
    pkgconfig
    x11
    xorg.libpthreadstubs
    xorg.libXcursor
    xorg.libXdmcp
    xorg.libXfixes
    xorg.libXinerama
    xorg.libXrandr
    xorg.xrandr
  ];
}
```

Then use `nix-shell` to build and run the shell as your development environment:

```bash
nix-shell shell.nix
```

## Install `scenic.new`

```bash
mix archive.install hex scenic_new
```

To build and run scenic applications, you will also need to install a few
dependencies. See the [Getting
started](https://hexdocs.pm/scenic/getting_started.html#install-dependencies)
for more information.

### Build and install locally

To build and install this archive locally ensure any previous archive versions
are removed:

```bash
mix archive.uninstall scenic_new
```

Then run:

```bash
cd scenic_new
MIX_ENV=prod mix do archive.build, archive.install
```

## Build the Basic Application

First, navigate the command-line to the directory where you want to create your
new Scenic application. Then run the following commands: (change `my_app` to
the name of your application)

```bash
mix scenic.new my_app
cd my_app
mix do deps.get, scenic.run
```

This will create a bare-bones application


## Build the Example Application

First, navigate the command-line to the directory where you want to create your
new Scenic application. Then run the following commands: (change `my_app` to
the name of your application)

```bash
mix scenic.new.example my_app
cd my_app
mix do deps.get, scenic.run
```

## Build the Basic [Nerves](https://nerves-project.org/) Application

This assumes you are already familiar with the basics of [Nerves](https://nerves-project.org/) applications.

Note: You will first need to install the standard Nerves build tools for this to work. You can [find instructions here](https://hexdocs.pm/nerves/getting-started.html).

Navigate the command-line to the directory where you want to create your
new Scenic application. Then run the following commands: (change `my_app` to
the name of your application)

```bash
mix scenic.new.nerves my_app
cd my_app
mix do deps.get, scenic.run
```

Then navigate into the new app directory. Once there you can build the app.

To buid run on the "host", which is your dev machine do this:

```bash
export MIX_TARGET=host
mix deps.get
mix scenic.run
```

To buid run on a Raspberry Pi 3 computer, do this:

```bash
export MIX_TARGET=rpi3
mix deps.get
mix nerves.release.init
mix firmware.burn
```

## Running and Debugging on Your Dev Machine

Once the application and its dependencies are set up, there are two main ways
to run it.

If you want to run your application under `IEx` so that you can debug it,
simply run

```bash
iex -S mix
```

This works just like any other Elixir application.

If you want to run your application outside of `IEx`, you should start it like
this:

```bash
mix scenic.run
```

## The Example Application

The starter application created by the generator above shows the basics of
building a Scenic application. It has four scenes, two components, and a
simulated sensor.

Scene | Description
--- | ---
Splash | The Splash scene is configured to run when the application is started in the `config/config.exs` file. It runs a simple animation, then transitions to the Sensor scene. It also shows how intercept basic user input to exit the scene early.
Sensor | The Sensor scene depicts a simulated temperature sensor. The sensor is always running and updates it's data through the `Scenic.SensorPubSub` server.
Primitives | The Primitives scenes displays an overview of the basic primitive types and some of the styles that can be applied to them.
Components | The Components scene shows the basic components that come with Scenic. The crash button will cause a match error that will crash the scene, showing how the supervision tree restarts the scene. It also shows how to receive events from components.

Component | Description
--- | ---
Nav | The navigation bar at the top of the main scenes shows how to navigate between scenes and how to construct a simple component and pass a parameter to it. Note that it references a clock, creating a nested component. The clock is positioned by dynamically querying the width of the ViewPort
Notes | The notes section at the bottom of each scene is very simple and also shows passing in custom data from the parent.

The simulated temperature sensor doesn't collect any actual data, but does show
how you would set up a real sensor and publish data from it into the
`Scenic.SensorPubSub` service.

## What to read next

Next, you should read guides describing the overall Scenic structure. This is
in the documentation for Scenic itself