Mothback/data/scripts/entities/particle.lua

Particle = Entity:New(x,y)

 function Particle:New(x,y,particle_data)
 	local o = Entity:New(x,y)

 	o.pos = {x = x, y = y}


  o.speed = particle_data.speed or 0
  o.direction = particle_data.direction or o.direction
  o.sprite_rotation = particle_data.sprite_rotation or o.sprite_rotation
  o.sprite_offset = particle_data.sprite_offset or o.sprite_offset
  o.sprite_scale = particle_data.sprite_scale or o.sprite_scale
  o.sprite_tint = particle_data.sprite_tint or o.sprite_tint
  o.sprite_alpha = particle_data.sprite_alpha or o.sprite_alpha
  o.sprite_flip = particle_data.sprite_flip or o.sprite_flip

  o.animation_active = particle_data.animation_active or false

  o.time = 0.5
  o.timer = 0

  o.vel = {
    x = o.speed * math.cos(o.direction),
    y = o.speed * math.sin(o.direction)
  }

  -- animations
  o.body = Animation:New(particle_data.animation)
  o:centerOffset(o.body)
  if not o.animation_active then
    o.body.speed = 0
  end

  table.insert(LoadedParticles,o)
  o.id = #LoadedParticles

 	setmetatable(o, self)
 	self.__index = self
 	return o
 end

function Particle:Kill()
	if self.id ~= nil then
		for _, e in pairs(LoadedParticles) do
			if e.id > self.id then
				e.id = e.id - 1
			end
		end
		table.remove(LoadedParticles,self.id)
	end
	self = nil
end

function Particle:HandleAnimation()
  self.body:Animate()
  self.timer = self.timer + current_dt
  self.sprite_alpha = (self.time-self.timer)/self.time
  if self.sprite_alpha < 0 then self:Kill() end
  self:Draw(self.body)
end

function Particle:DoPhysics()
  if not self:isCollidingAt(self.pos.x + self.vel.x, self.pos.y, objects.collisions) then
    self.pos.x = self.pos.x + self.vel.x
  end
  if not self:isCollidingAt(self.pos.x, self.pos.y + self.vel.y, objects.collisions) then
    self.pos.y = self.pos.y + self.vel.y
  end
end