particle.lua

local G = love.graphics


Particle = BatchDrawer(300, {
	color = { 1, 1, 1 },
	alive = true,
	frame_length = 3,
	layer = "front",
})
function Particle:init(x, y)
	table.insert(self.list, self)
	self.x = x
	self.y = y
	self.tick = 0
end
function Particle:draw()
	if self.tick < 0 then return end
	local f = math.floor(self.tick / self.frame_length) + 1
	if self.quads[f] then
		self.quads.batch:setColor(unpack(self.color))
		self.quads.batch:add(self.quads[f], self.x, self.y, 0, 4, 4, self.size / 2, self.size / 2)
	else
		self.alive = false
	end
end
function Particle:update()
	self.y = self.y + game.walls.speed
	self.tick = self.tick + 1
	if not self.alive then return "kill" end
end



SparkParticle = Particle:New {
	friction = 1
}
SparkParticle:InitQuads("media/spark.png")
function SparkParticle:init(x, y)
	table.insert(self.list, self)
	self.x = x
	self.y = y
	local ang = math.random() * 2 * math.pi
	local s = math.random() * 2 + 2
	self.vx = math.sin(ang) * s
	self.vy = math.cos(ang) * s
	self.ttl = math.random(3, 7)
end
function SparkParticle:update()
	self.x = self.x + self.vx
	self.y = self.y + self.vy + game.walls.speed
	self.vx = self.vx * self.friction
	self.vy = self.vy * self.friction
	self.ttl = self.ttl - 1
	if self.ttl <= 0 then return "kill" end
end
function SparkParticle:draw()
	self.quads.batch:setColor(unpack(self.color))
	self.quads.batch:add(self.quads[1], self.x, self.y, 0, 4, 4, 1.5, 1.5)
end


LaserParticle = SparkParticle:New {
	color = {0, 0.61, 0.61},
	friction = 0.7,
}



ExplosionSparkParticle = SparkParticle:New {
	friction = 0.95,
}
function ExplosionSparkParticle:init(x, y)
	table.insert(self.list, self)
	self.x = x
	self.y = y
	local ang = math.random() * 2 * math.pi
	local s = math.random() * 2 + 2
	self.vx = math.sin(ang) * s
	self.vy = math.cos(ang) * s
	self.ttl = math.random(10, 15)
	self.color = {1, math.random(), 0}
end
function ExplosionSparkParticle:draw()
	local c = self.color
	self.quads.batch:setColor(c[1], c[2], 0, math.min(1, self.ttl * 0.2))
	self.quads.batch:add(self.quads[1], self.x, self.y, 0, 4, 4, 1.5, 1.5)
end




SmokeParticle = Particle:New {
	size = 8,
	friction = 0.8,
	layer = "back"
}
SmokeParticle:InitQuads("media/smoke.png")
function SmokeParticle:init(x, y)
	table.insert(self.list, self)
	self.x = x
	self.y = y
	local ang = math.random() * 2 * math.pi
	local s = math.random() * 2 + 3
	self.vx = math.sin(ang) * s
	self.vy = math.cos(ang) * s
	self.ttl = math.random(20, 25)
end
SmokeParticle.update = SparkParticle.update
function SmokeParticle:draw()
	local f = math.max(1, #self.quads - math.floor(self.ttl / 3))
	self.quads.batch:setColor(0.12, 0.12, 0.12, 0.59)
	self.quads.batch:add(self.quads[f], self.x, self.y, 0, 4, 4, self.size / 2, self.size / 2)
end



ExplosionParticle = Particle:New { size = 16 }
ExplosionParticle:InitQuads("media/explosion.png")

function makeExplosion(x, y)
	sound.play("explosion", x, y)
	-- heat wave
	Boom(x, y)

	for i = 1, 10 do
		SmokeParticle(x, y)
	end
	for i = 1, 20 do
		ExplosionSparkParticle(
			x + math.random(-10, 10),
			y + math.random(-10, 10))
	end
	ExplosionParticle(x, y)
end


SparkleParticle = Particle:New { size = 8 }
SparkleParticle:InitQuads("media/sparkle.png")
function SparkleParticle:update()
	self.tick = self.tick + 1
	if not self.alive then return "kill" end
end

FastSparkleParticle = Particle:New {
	size = 8,
	quads = SparkleParticle.quads,
}
function makeFastSparkleParticle(x, y)
	local r = math.random() * 10
	for i = 0, 2 do
		local f = FastSparkleParticle(
			x + math.sin(r) * 12,
			y + math.cos(r) * 12)
			r = r + 2/3 * math.pi
		f.tick = i * -5
	end
end