GravSim

GravSim is an extremely basic game or tech demo that simulates N-body gravitational force. It uses Ebiten, a 2D game engine for Go.

GravSim isn't a great game to play; that wasn't really my goal. It is very simplistic and boring. I only wrote it to refresh my linear algebra and graphics coding skills. The code is messy, poorly organized, and there's a lot of half implemented ideas and stubs here and there, as the goals of this project kept shifting.

But it is still a game. It has some standard game features for this sort of retro shmup:

• Toroidal play field geometry: Ship, bullets, planets, and gravity wrap around screen edges (like Asteroids)
• Player ship with 3 lives and basic controls: thrust, rotation, emergency stop, and shoot
• Shoot planets, 3 per level, to increase your score
  • Bullets are short range only
  • Only 3 bullets may in play at once
  • Earn extra lives after reaching certain score thresholds
  • Achieve the high score (max of all playthroughs since game start)
  • Once all planets are destroyed, player reaches a new level with 3 new planets
• Collision detection:
  • If the ship collides with a planet, the ship is destroyed, costing one life
    • If lives remain after ship is destroyed, ship position is reset
    • If no lives remain, game is over and everything resets except high score
  • If two planets collide, they bounce off each other (elastic collisions)
  • If a ship's bullet collides with a planet, the planet is destroyed and the player earns score.

Now that I have written this I would be much more comfortable writing a real game...