guidebook/docs/hacking.md

Hacking

This page discusses some advanced features of the game.

I've always loved it when developers kept debugging features in their released games, and playing around with those and figuring out what makes the game tick. I purposely left some debug features in the game that you can play around with.

Developer Console

Pressing the Enter key at any time will open the developer console at the bottom of the screen (all gameplay logic is paused while the console is open).

In the console you can type anything from simple commands, to hidden cheat codes, to JavaScript commands to operate on some of the game's internal code!

Pressing Enter again without typing a command will close the console.

Commands

At the white > prompt you can type a command. Typing help will show a listing of available commands; typing help and then a command name will show further usage of that command. For example, help echo.

The answer to your command is "flashed" in blue text at the bottom of the screen and the developer console is closed. Pressing Enter will re-open the console and show the recent history, including the answer to your last command.

>help echo
Usage: echo <message>
Flash a message back to the console

The following commands are supported:

• help, help <command>

  Shows the list of commands, or further help on a specific command.

• echo <message>

  Flashes your custom message on the bottom of the screen.

• alert <message>

  Pop up an alert box modal with a custom message.

• new

  Go to the "New Drawing" screen.

• save [filename]

  Save the current drawing. If the drawing has not been saved before, a filename is required, including the .level or .doodad suffix.

• edit <filename>

  Open a file for editing. The filename is a path on disk relative to the game's working directory.

• play <filename>

  Open a file for playing. The filename is a path on disk relative to the game's working directory. A wrong filename will play a new, blank level where Boy just falls to the bottom of the map.

• close

  Close the current level being edited and return to the title screen.

• quit, exit

  Close the developer console (an empty command would also work).

Cheat Codes

Typing these messages in the console will toggle various mundane cheat codes within the game:

• unleash the beast

  Do not cap the frames per second target of 60, allowing the game to run as fast as it's capable of. May or may not actually work.

• don't edit and drive

  While playing a level, this makes the level canvas editable and you can draw new pixels by clicking. Note that drawn pixels do not "commit" to the level until you release the cursor.

• scroll scroll scroll your boat

  While playing a level, this allows scrolling the level with arrow keys as if you're editing it. The camera still keeps the player character in view.

• import antigravity

  While playing a level, this turns off gravity for the player character. In this state the arrow keys can freely move the character in any direction. Relevant xkcd

• ghost mode

  Disable collision detection for the player character. This will also enable antigravity, otherwise you would fall to the bottom of the level.

• give all keys

  Gives all four colored keys to the player.

• drop all items

  Removes all keys and items from the player's inventory.

JavaScript Shell

The developer console also features a JavaScript shell, which exposes many of the game's internal data types and functions that can be useful when debugging the game, or just fun to see what you can break within the game!

In the developer console, the eval or $ command will run a single line of JavaScript code.

>$ 2 + 2
4
>$ d.Flash("This is %s", d.Title())
This is Project: Doodle v0.4.0-alpha

The following native objects are exposed to the JavaScript shell:

• d is the master game object.
• function RGBA(red, green, blue, alpha uint8) creates a native Color type, each value is range 0 to 255
• function Point(x, y int) creates a native Point type.
• function Rect(x, y, w, h int) creates a native Rect type.
• function Tree(ui.Widget) prints a tree of UI widgets drawn on the screen -- if you can find the widgets somewhere under d

>$ RGBA(255, 153, 0, 230).String()
Color<#ff9900+e6>
>$ Object.keys(d)
Debug,Engine,Scene,ConfirmExit,DrawCollisionBox,DrawDebugOverlay,...
>$ typeof(d.Debug)
boolean
>$ typeof(d.Flash)
function
>$ d.Flash("Flash a custom message, like the `echo` command")
undefined
>$ d.EditDrawing("filename.level")

It helps if you run Project: Doodle itself from a command line terminal, so you can see its developer console output also on your terminal window. Using Object.keys(d) will show all the exported functions and variables from the internal game state.

Understanding that my game's rendering engine and user interface toolkit are open source projects you can have fun reconfiguring widgets to change colors or whatever.