Completing another Pulp tutorial

3/3

The last article featured my write-ups as I followed along to two of SquidGod's Playdate tutorials listed as resources on Playdate's official website.

This article is a write-up of the third tutorial, where I'll be shown how to make:

1. Directional player sprites
2. A short melee attack
3. A simple enemy pathfinding AI
4. Lock a room until all enemies are defeated

Directional player sprites

This seems simple enough!

• Create four Player tiles, one for each facing - really, it's just the eye sockets that move or disappear
• Write an on update do event listener
• Leverage the event.dx and event.dy variable members to determine which direction the player is facing
• Swap for the appropriate tile in each condition

A short melee attack

• Create four Item tiles, one for each sword facing
• Write an on confirm do event listener, which triggers when the A button is pressed
• Create two variables that store the eventual position of the sword tile
• Leverage the same dx and dy variable members to store the appropriate tile name to be used
• Swap the tile, wait a bit, then swap it back to white

Fix bug: swinging at walls

• Move the sword-swinging code into a custom function
• Store the name of the tile being swung at
• If it is white or enemy, swing the sword

Fix bug: don't move during sword swing

• Leverage ignore and listen functions to essentially disable and enable player input before and after sword swings

A simple enemy pathfinding AI

In essence:

• At a set interval...
• Determine the position of the target tile...
• Ensure it is available...
• Swap tiles only when available

It takes:

• 3 variables
• 4 conditionals
• 4 event members
• 2 tile swaps

Unexpected bug

• I made enemy a sprite, as the author did
• When playing the game, all enemies instantly moved toward the player
• I checked everything to ensure my code matched the author's
• After several minutes, I tried one last thing: change the tile type from Sprite to Item
• That worked!
• I'm not sure why Sprites and Items behave differently with respect to intervals and the game's loop event
• But now I know it's something to be mindful of

Enemy damage

• Time to duplicate a bunch of code from the previous tutorial
• It was fairly easy to toggle between games and copy code snippets
• It was wonderfully simple to export and import layer tiles
• Just a bummer that the names didn't transfer
• After play testing, my game feels nearly identical
• The only difference seems to be a delay in shake after colliding with an enemy: it happens immediately in the video, whereas in mine it seems delayed

Lock a room until all enemies are defeated

• I imported the gate sprite from the other game, placed it in the room, and added the custom event to make the gate disappear
• I added on enter do event listeners to the game and enemy scripts
• I set or updated the same variable appropriately in each function
• I updated the player script to adjust that variable and trigger the custom event on the gate when the variable is 0
• Play testing confirms everything works as expected!

Conclusion

• That was another really fun tutorial!
• When broken down, all of the code is fairly simple: checking tile type, checking positions, incrementing or decrementing values, calling functions from other functions inside conditionals
• I'm glad I took the time to re-create all the code and play test along the way

Next up - you guessed it - another tutorial!