sprite.lua

local anim8 = require 'vendor/anim8'
local utils = require 'utils'

local Sprite = {}

Sprite.__index = Sprite

local sprite_cache = {}

local function load_sprite(name)
  if sprite_cache[name] then
    return sprite_cache[name]
  end

  local image = love.graphics.newImage(name)
  image:setFilter('nearest', 'nearest')
  sprite_cache[name] = image
  return image
end

function Sprite.new(node, collider, level)
  local sprite = {}
  local p = node.properties
  setmetatable(sprite, Sprite)

  assert(p.sheet, "'sheet' required for sprite node")

  sprite.sheet = load_sprite(p.sheet)

  sprite.animation = p.animation or false
  sprite.foreground = p.foreground == 'true'
  sprite.offsetY = p.offsetY or 0
  sprite.flip = p.flip == 'true'
  sprite.node = node

  if p.height and p.width then
    sprite.height = p.height
    sprite.width = p.width
  end

  if sprite.animation then
    sprite.random = p.random == 'true'
    sprite.speed = p.speed and tonumber(p.speed) or 0.20
    if sprite.random then
      sprite.mode = 'once'
    else
      sprite.mode = p.mode and p.mode or 'loop'
    end

    local g = anim8.newGrid(tonumber(p.width), tonumber(p.height), 
                            sprite.sheet:getWidth(), sprite.sheet:getHeight())

    sprite.animation = anim8.newAnimation( sprite.mode, g( unpack( utils.split( p.animation, '|' ) ) ), sprite.speed )

    if sprite.random then
      sprite.animation.status = 'stopped'
      --randomize the play interval
      local window = p.window and tonumber(p.window) or 5
      sprite.interval = (math.random(window * 100) / 100 ) + ( #sprite.animation.frames * sprite.speed)
    end
  end

  sprite.dt = math.random()
  sprite.x = node.x
  sprite.y = node.y

  sprite.moveable_x = p.moveable_x
  sprite.moveable_y = p.moveable_y

  if sprite.moveable_x then
    sprite.max_x = node.x + tonumber(p.max_x)
    sprite.min_x = node.x + tonumber(p.min_x)
    sprite.velocity_x = tonumber(p.velocity_x)
  end

  if sprite.moveable_y then
    sprite.max_y = node.x + tonumber(p.max_y)
    sprite.min_y = node.x + tonumber(p.min_y)
    sprite.velocity_y = tonumber(p.velocity_y)
  end

  return sprite
end

function Sprite:update(dt)
  self.dt = self.dt + dt

  if self.random and self.dt > self.interval then
    self.dt = 0
    self.animation:gotoFrame(1)
    self.animation.status = 'playing'
  end

  if self.animation then
    self.animation:update(dt)
  end

  if self.moveable_x then
    self.x = self.x - (self.velocity_x * dt)
    if self.x > self.max_x or self.x < self.min_x then
      self.velocity_x = - self.velocity_x
      self.flip = not self.flip
    end
  end

  if self.moveable_y then
    self.y = self.y - (self.velocity_y * dt)
    if self.y > self.max_y or self.y < self.min_y then
      self.velocity_y = - self.velocity_y
    end
  end  
end

function Sprite:draw()
  if self.animation then
    self.animation:draw(self.sheet, self.x, self.y + self.offsetY, 0, self.flip and -1 or 1, 1, self.flip and self.width or 0)
  else
    love.graphics.draw(self.sheet, self.x, self.y + self.offsetY, 0, self.flip and -1 or 1, 1, self.flip and self.width or 0)
  end
end

return Sprite