crankani/src/bullet.lua

-- Code for bullets!
import "CoreLibs/object"
import "CoreLibs/graphics"
import "CoreLibs/sprites"

local gfx <const> = playdate.graphics
local geom <const> = playdate.geometry

class("Bullet").extends(gfx.sprite)

-- Bullet's defaults assume a (slow, weak) enemy bullet
function Bullet:init(size, damage, vector, collisionMask)
   Bullet.super.init(self)

   self.power = power
   self.damage = damage or 1
   self.vector = vector or geom.vector2D.new(-1, 0)
   local mask = collisionMask or 0x2

   local img = gfx.image.new(size, size)
   gfx.pushContext(img)
     gfx.fillCircleInRect(0, 0, size, size)
   gfx.popContext()

   self:setImage(img)
   self:setCollideRect(0, 0, self:getSize())
   self.collisionResponse = gfx.sprite.kCollisionTypeOverlap

   self:setGroupMask(0x10)
   self:setCollidesWithGroupsMask(mask)
end

function Bullet:update()
   local collisions = select(3, self:moveWithCollisions(self.x+self.vector.dx, self.y+self.vector.dy))
   for i=1, #collisions, 1 do
      -- anything the bullet can collide with should be damaged by it
      local obj = collisions[i].other
      obj:damage(self.damage)
   end

   if #collisions >= 1 or self:outOfBounds() then
      self:remove()
   end
end

function Bullet:outOfBounds()
   return self.x < 0 or self.y < 0 or self.x > 400 or self.y > 240
end