Dart-07

Dart-07
A scrolling shooter. As the Dart-07 you fight on Emerald Islands, Outpost in Space, and in the interstellar Phoslar Mine

This is a PICO-8 game, which I made during Basic Shmup Showcase event organised by Lazy Devs Academy.

⚠️ Please be aware this game is under development. Mission 1 is complete and ready to play, but you enter missions 2 and 3 on your own risk 😄

If you want to take a look at the codebase, please visit https://github.com/beetrootpaul/dart-07 (the code inside PICO-8 carts of this game is minified, therefore not suitable for reading).

Controls

Keyboard:

• press & hold x to fire
• press c to trigger a shockwave (if available)
• press p to open the pause menu

Virtual controller (in browser, on a mobile device):

• press & hold ❎ to fire
• press 🅾️ to trigger a shockwave (if available)
• press ➖ to open the pause menu

Physical game controllers are supposed to work as well, even in a browser. Button mapping varies between models.

Gameplay

Your task is to pilot Dart-07 unit in a set of secret missions:

• first, you mess with the enemy on Emerald Islands
• then you continue to the Outpost in Space (⚠️ under development ⚠️)
• in order to reach the interstellar Phoslar Mine (⚠️ under development ⚠️) and prevent the enemy from utilizing that precious resource

Destroy enemies along the way to increase your score, grab power-ups left by them and survive a boss fight in order to complete a mission.

HUD

In your HUD you see:

• left-top: mission progression (the higher the ship's icon is placed, the close to the boss you are)
• right-top: your score, which you gain by destroying enemies and grabbing power-ups in case they cannot bring any improvement
• left-bottom: hearts left; you die when all hearts are gone
• right-bottom: shockwave charges left; you can trigger a shockwave if you have at least 1 charge left
• top-middle, during boss fight: boss' health (yes, you are supposed to bring it down to zero 😉)

Power-ups

There are 4 types of power-ups you can grab, each of them either makes your life easier or, if cannot improve further, increases your score:

•  +1 heart – you can have max 10 hearts; you lose one whenever you take damage
•  fast shoot – increases shooting speed; does not accumulate, but can be combined with the triple shoot; lost on a damage
•  triple shoot – you shoot 3 bullets instead of 1, but on a little but slower rate; does not accumulate, but can be combined with the fast shoot; lost on a damage
•  shockwave charge – allows you to trigger a destructive shockwave around you (with use of "c" / "🅾️" button); you can have max 4 shockwave charges

Credits

I implemented this game on my own, as well as drawn all sprites and composed all SFXs and music. But there are some resources I found super useful and used some of them I used in the codebase as well. With huge thanks, here are those:

• #easingcheatsheet cart by ValerADHD with copy-paste ready easing functions. See: https://www.lexaloffle.com/bbs/?tid=40577
• Circular Clipping Masks tutorial by Krystman
  
• Lua minification tool luamin by Mathias Bynens
• Pico-8 Music Tutorials by Gruber

Technical challenges

In this game I focused on learning various bits of PICO-8 API.

Some of the topics I tackled in this game are:

• multi-cart setup: this game consists of many carts – 1 main cart for the title screen etc., and 1 cart for each mission. Each mission has its own sprites and music, as well as a code responsible for available enemy types, including their attack and movement patterns. Common SFXs and sprites are copied from the main cart to missions carts with use of MEMCPY and a user data memory area (0x4300-0x55ff), preserved across loaded carts). Moreover, I implemented this in a way which allows me to use same codebase to load both locally developed carts as well as those published to Lexaloffle BBS.
• circular clipping: during shockwave a ring of inverted colors propagates from the player. To achieve that I had to learn how to implement circular clipping masks in a CPU-performant way.
• dithered fade-in/out transition: basically a set of rectangles filled with FILLP patterns, moving over screen.
• high score: usage of PICO-8's API to read and store data persisted on a host machine
• code minification: with my code style (full of spaces and long names), I found it easy to hit PICO-8's characters' count limit. Therefore I forked and modified luamin tool and incorporated it into this game's build flow, resulting with characters' count reduced by around 50%.