# Part 0 - Setting Up

## Prior Knowledge
This tutorial will attempt to be beginner friendly, but some experience with programming will help.  For the sake of simplicity, I will be using DragonRuby on Windows 10, but DragonRuby Game Toolkit is highly portable and the same instructions should run on multiple operating systems.

## Getting Help
Throughout this guide we will frequently reference The Dragon Ruby Docs [http://docs.dragonruby.org/](http://docs.dragonruby.org/) as well as various other Ruby documentation sites.  We will make an effort to provide links to the various references we use. 
Additonally, the Dragon Ruby Discord, an extremely helpful community, can be found at [http://discord.dragonruby.org](http://discord.dragonruby.org)

## Project Setup
### Download DragonRuby
You will need a copy of DragonRuby Game Toolkit for th is tutorial.
You can acquire it from either of these sites.  You may even already own a copy if you back lots of bundles on Itch.io. 

* http://dragonruby.org/toolkit/game
* https://dragonruby.itch.io/

### Creating the game
Unzip your new copy of DragonRuby, and name the folder something like `DR_Snake_Tutorial`

### Using DragonRuby Game Toolkit
Open your game folder, and double-click on `dragonruby.exe` to run the game engine.

You will probably receive a Windows Protection popup like this one:
![Windows Protection Dialog](../tutorial/Windows_Protect_1.png?raw=true "Windows Protection Dialog")

Click on the `More Info` link to expand to the following
![Windows Protection More Info](../tutorial/Windows_Protect_2.png?raw=true "Windows Protection More Info")

Verify the app is "dragonruby.exe" and click `Run Anyway` to actually run DR.

You should now have the DragonRuby Hello World Application on your screen
![Dragon Ruby Hello World](../tutorial/DRGTK_Default.png?raw=true "Hello World from DragonRuby Game Toolkit")

Open `DR_Snake_Tutorial/mygame/app/main.rb` in your favorite editor (VSCode, Atom, RubyMine, Notepad), and you will be met with:
```ruby
def tick args
  args.outputs.labels  << [640, 500, 'Hello World!', 5, 1]
  args.outputs.labels  << [640, 460, 'Go to docs/docs.html and read it!', 5, 1]
  args.outputs.labels  << [640, 420, 'Join the Discord! http://discord.dragonruby.org', 5, 1]
  args.outputs.sprites << [576, 280, 128, 101, 'dragonruby.png']
end
```

A quick breakdown:
* `def tick args`  -  Create a function named `tick` that accepts a parameter named `args`
  * `tick` is a special function.  DragonRuby will call it 60 times per second, and expects it to perform any needed calculations and draw the screen.
  * `args` is DragonRuby's special power, it holds information about inputs, and is where you set up your actual screen draws
* `args.outputs.labels  << [640, 500, 'Hello World!', 5, 1]`
  * The `args` variable has an `outputs` collection which accepts a number of different types of thing to draw.
  * In this case we're drawing a `label`, which we can create with an array
    * Label array definition `[ X, Y, Text, Size, Alignment ]`
      * `X`  X position of the bottom-left corner of the label
      * `Y`  Y position of the bottom-left corner of the label
      * `Text` The text to display
      * `Size` The size of the text.  A 0 represents the "default size".  Negative values lead to smaller text, while positive values lead to larger text
      * `Alignment`  0: Left, 1: Center, 2: Right
* `args.outputs.labels  << [640, 460, 'Go to docs/docs.html and read it!', 5, 1]`
* `args.outputs.labels  << [640, 420, 'Join the Discord! http://discord.dragonruby.org', 5, 1]`
* `args.outputs.sprites << [576, 280, 128, 101, 'dragonruby.png']`
  * This example shows a `sprite` output.   Sprites are powerful and let you place images anywhere in your window that you like.
    * A minimal Sprite array defition: `[ X, Y, W, H, Path ]`
      * `X`  X position of the bottom-left corner of the sprite
      * `Y`  Y position of the bottom-left corner of the sprite
      * `W`  The sprite's width
      * `H`  The desired height for the sprite
      * `Path`  The path to the image to display on the sprite.
* `end` - end the function block.
  * If you're used to other languages, you may be looking for a `return`.  In Ruby, a function returns the result of the last statement in the function.

A note on position in DragonRuby.  Unlike some other engines, DragonRuby coordinates start at the bottom left of the screen and proceed to 1280 pixels wide and 720 pixels tall.

References:
* [DragonRuby Docs: How to Render a Label](http://docs.dragonruby.org/#---how-to-render-a-label)
* [DragonRuby Docs: How to Render a Sprite Using an Array](http://docs.dragonruby.org/#---how-to-render-a-sprite-using-an-array)
* [DragonRuby Docs: Coordinate System and Virtual Canvas](http://docs.dragonruby.org/#---coordinate-system-and-virtual-canvas)

### Edit-Test-Loop
Development in DR is easy:  Make an edit, save it, and watch your project reload with your change in place.

Let's make a change and see it in action.
* Locate the line `args.outputs.labels  << [640, 500, 'Hello World!', 5, 1]`
* Change `'Hello World!'` to `'Hello DragonRuby!'`
* Save your file.
* Your running project will reload and you'll see your changed greeting:
  ![Dragon Ruby Hello](../tutorial/DRGTK_HelloDR.png?raw=true "Hello DragonRuby")

If you've reached this point with me, then celebrate your success!  Next up we'll start making a game using DragonRuby.

# Next
![Part 1 - Drawing The Background](./tutorial/part-1.md)