Godot Learning - Part 1

I’m learning how to use the Godot game engine and so I’m going to start keeping my notes on my blog so I can remember them, and hopefully gather resources that may help you.

My goal is to rebuild an ancient RPG I made called Final Existence on the Amiga in AMOS Basic, which was a YA alternate universe apocalyptic game that looked and felt a lot like Chrono Trigger. I’ve become a bigger fan of ARPGs lately, and I’ll rebuild it using that paradigm.

There are a crap ton of tutorials out there, but I’ve been having trouble gathering all the pieces I want together to build an ARPG, and there’s a lot of moving parts in Godot, so this is my attempt to wrangle all that together in one place for myself.

So, on with the notes:

What do I (think I) need next?

• TileMap/Area2D collisions for making the character walk around and get stopped by things, and know what I ran into.
• A map that’s bigger than the screen that follows the character around.

What have I found?

• Started with Your First Game to get a handle on editor in general
  • GDScript is very Python-y, which is not my strongest language, but I’m getting the hang of it
  • I wish Godot had vim keyboard shortcut support
• Learned TileMap and TileSet because I plan on using tiles to make maps
  • Still need to figure out how to get things to run into tiles
• Walked through Kinematic Character 2D
  • The official docs
  • Using KinematicBody2D on KidsCanCode
  • Still think I’m missing something with this:
    • Can’t quite get the character to walk/move as expected
    • Also this is more platformer-y than I need right now
• Watching Top-down RPG/Adventure in Godot
  • i18n in Godot
    • Looks like gettext
  • Switch scenes via “NPC” with a Screen Change custom event
    • export var to select target scene
    • export var for warp target in other scene
    • Remove old scene from DOM
      • get_tree().root.get_child()/.add_child()
      • Scene#queue_free to safely remove from memory!
    • Add new scene to DOM
    • Find player in new scene
    • Move to position of warp target
      • Put nodes into a group called “exit” to focus the search
  • Dialog box
    • Move it out of the way if the character is there
      • The scene will need a camera
      • Find the Camera2D
        • Only one camera in a scene, pick one using Camera2D#make_current()
        • Put the camera in the thing that needs to be tracked
        • Drag margins require tracked object to hit edges before moving
        • Make the camera current, or nothing will move
      • Clamp the camera scroll to the size of screen with Camera2D#limit_??
        • Grab the dimensions of something that’s as big as the scene
          • Can you get scene/child node offset size
  • Player move from scene to scene
    • Primarily to transfer player state
      • Video shows physically moving player node, since Player object contains state, but I’m thinking to have a Vuex/Redux like store external to visual scenes where such data can be stored and reconstituted
      • Moving nodes from Scene to Scene seems error-prone, more reason for external state
  • Crystal
    • Like Ruby meets C?
  • Using separate TileMaps
    • One for walkable areas, one for collisions, one for stuff outside the play area
  • Signals
    • Emit a signal on transport to recalculate camera clamping

Solution to “RPG Map with tiles and doors”

• Node2D Main scene with KinematicBody2D Player and Node2D MapContainer
  • MapContainer contains the first Map
  • Player handles own position, using move_and_collide to detect collisions, and move_and_slide to complete moves after initial collisions.
  • Player gets collision Node and determines if it is a Door
    • Door is a subclass of KinematicBody2D with the exported properties DestinationScenePath : String and ExitID : int.
    • On collision, Player emits a signal with DestinationScenePath and ExitID
  • Main listens for collision signal from Player and, once received, manually swaps out the old map in MapContainer with the loaded DestinationScenePath…
    • …then searches the new scene for nodes in the exit group and finds a node in that group with an ExitID property that matches the one received in the signal. If found, move Player to that Node2D#position.
• Map and Map2 have nodes in this order:
  • TileMap Walkable
  • Any Doors with appropriately set DestinationScenePath and ExitID
  • TileMap Walls with tiles with Collision enabled
  • ExitNodes, each in the exit group and with an ExitID that matches the Door from the other scene.