crankani/src/bullet.lua

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

local gfx <const> = playdate.graphics

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

local POWER_SIZE_LOOKUP <const> = {
   [1] = 2,
   [2] = 4,
   [3] = 6,
   [4] = 10,
}

local POWER_DAMAGE_LOOKUP <const> = {
   [1] = 1,
   [2] = 3,
   [3] = 5,
   [4] = 10,
}

function Bullet:init(power, friendly)
   Bullet.super.init(self)
   self.power = power
   local size = POWER_SIZE_LOOKUP[power]

   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

   local friendly = friendly or true
   if friendly then
      self:setGroupMask(0x4)
      self:setCollidesWithGroupsMask(0x8)
      self.direction = 1
   else
      self:setGroupMask(0x10)
      self:setCollidesWithGroupsMask(0x2)
      self.direction = -1
   end
end

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

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