Make Ebi move, refactor bullet code to make more logic per-entity type.

src/bullet.lua

@@ -7,25 +7,14 @@ 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,
-}
 
 -- Bullet's defaults assume a friendly bullet
-function Bullet:init(power, vector, collisionMask)
+function Bullet:init(size, damage, vector, collisionMask)
    Bullet.super.init(self)
+
    self.power = power
-   local size = POWER_SIZE_LOOKUP[power]
+   self.damage = damage or 1
+   self.vector = vector or {x=5, y=0}
    local mask = collisionMask or 0x4
 
    local img = gfx.image.new(size, size)
@@ -39,8 +28,6 @@ function Bullet:init(power, vector, collisionMask)
 
    self:setGroupMask(0x10)
    self:setCollidesWithGroupsMask(mask)
-
-   self.vector = vector or {x=3, y=0}
 end
 
 function Bullet:update()
@@ -48,7 +35,7 @@ function Bullet:update()
    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])
+      obj:damage(self.damage)
    end
 
    if #collisions >= 1 then

src/enemy/ebi.lua

@@ -13,4 +13,18 @@ function Ebi:init()
    Ebi.super.init(self, img, 5)
 
    self:setCollidesWithGroupsMask(0x3)
+   local dir = 1
+   if math.random(2) == 1 then
+      dir = -1
+   end
+   self.vector = {x=0, y=dir}
+end
+
+function Ebi:update()
+   local collisions = Ebi.super.update(self)
+   for i=1, #collisions, 1 do
+      if collisions[i].other:getGroupMask() == 0x1 then
+         self.vector.y *= -1
+      end
+   end
 end

src/entity.lua

@@ -12,6 +12,10 @@ function Entity:init(img, health, armor)
    self.health = health or 10
    self.armor = armor or 0
 
+   -- movement direction, every update() the entity will move along this vector and return
+   -- collision data to the subclass
+   self.vector = {x=0,y=0}
+
    self:setCollideRect(0, 0, self:getSize())
 
    -- most entities will be enemies, so we configure this mask by default
@@ -29,3 +33,8 @@ function Entity:damage(amount)
       self:remove()
    end
 end
+
+function Entity:update()
+   local collisions = select(3, self:moveWithCollisions(self.x + self.vector.x, self.y + self.vector.y))
+   return collisions
+end

src/kani.lua

@@ -20,13 +20,28 @@ local WEAPON_CHARGE_LOOKUP <const> = {
    [3]=50
 }
 
+-- size of bullet at each power level
+local POWER_SIZE_LOOKUP <const> = {
+   [1] = 2,
+   [2] = 4,
+   [3] = 6,
+   [4] = 10,
+}
+
+-- damage of bullet at each power level
+local POWER_DAMAGE_LOOKUP <const> = {
+   [1] = 1,
+   [2] = 3,
+   [3] = 5,
+   [4] = 10,
+}
+
 class("Kani").extends(Entity)
 
 function Kani:init(ui)
    local img = gfx.image.new("images/kani.png")
    Kani.super.init(self, img, 100)
 
-   self.vector = {x=0,y=0} -- movement direction
    self:setGroupMask(0x2)
    self:setCollidesWithGroupsMask(0xd)
 
@@ -96,7 +111,7 @@ function Kani:fire()
       return
    end
 
-   local bullet = Bullet(self.weaponPower)
+   local bullet = Bullet(POWER_SIZE_LOOKUP[self.weaponPower], POWER_DAMAGE_LOOKUP[self.weaponPower])
    bullet:moveTo(self.x+16, self.y)
    bullet:add()
    self.weaponPower = 0
@@ -122,7 +137,7 @@ end
 
 -- move that crab!
 function Kani:update()
-   local collisions = select(3, self:moveWithCollisions(self.x + self.vector.x, self.y + self.vector.y))
+   local collisions = Kani.super.update(self)
    for i=0, #collisions, 1 do
       -- handle player-triggered collisions
    end