Time_Tripper Particle Test , with some optimizations

Ptest.lua

-- title:  Particle test 2
-- author: Time_Tripper
-- desc:   Particle test 2
-- script: lua
-- input:  mouse
-- Optimization from MonstersGoBoom 
-- create a single table for everything , reducing lookups
local particle = {}
function particle:new (o,x,y,vx,vy,c,l)
	o = o or {}   -- create object if user does not provide one
	o.x = x or 0 
	o.y = y or 0 
	o.vx = vx or 0 
	o.vy = vy or 0 
	o.c = c or 15
	o.l = l or 10
	setmetatable(o, self)
	self.__index = self
	return o
end
--	a list of them 
particles = {}
bmx=0
bmy=0
scr={}
ti=0
-- note // is Integer division, so //1 is faster yet similar enough to floor to work for this
local random=math.random	--	this is faster than math.random
function pallet()
	i=0x3FC0
	cr=random(256)-1
	cg=random(256)-1
	cb=random(256)-1
	cr2=random(256)-1
	cg2=random(256)-1
	cb2=random(256)-1
	for k=8,1,-1 do
		poke(i  ,(cr-(cr/8)*k)//1)
		poke(i+1,(cg-(cg/8)*k)//1)
		poke(i+2,(cb-(cb/8)*k)//1)
		i=i+3
	end
	for k=1,8 do
		poke(i  ,(cr+((cr2-cr)/8)*k)//1)
		poke(i+1,(cg+((cg2-cg)/8)*k)//1)
		poke(i+2,(cb+((cb2-cb)/8)*k)//1)
		i=i+3
	end
	poke(0x3FC0,0)
	poke(0x3FC1,0)
	poke(0x3FC2,0)
end
-- movement
function move()
	for i=#particles,1,-1 do
		local p = particles[i]
		p.x = p.x + p.vx
		p.y = p.y + p.vy
		if p.x>1 and p.x<238 and p.y>1 and p.y<135 then
			if random(2)==1 then
				scr[(p.x//1)+(p.y//1)*240]=p.c
			end
			p.vx=p.vx*0.98+(random(3)-2)*0.1
			p.vy=p.vy*0.98+(random(3)-2)*0.1
			p.l=p.l-1
		else
			p.l=0
		end
		if p.l<1 then
			table.remove(particles,i)
		end
	end
end	
-- rendering 
function draw()
	for y=1,134 do
		local y240 = y*240
		local scr_addr=0x0000*2 + (y240)	--	address of the screen for each line
		for x=1,239 do
			local i=x+y240
			local scri = scr[i]							--	we use this twice so reduce lookup 
			poke4(scr_addr+x,scri//1)				--	poke is faster than pix
			scr[i]=(scri+scr[i-1]+scr[i+1]+scr[i-240]+scr[i+240])/5.05
		end
	end	
end
--
function reset()
	for i=1,32640 do
		scr[i]=0
	end
end
--
function init()
	cls()
	pallet()
	reset()
end
--------------------
	init()
--------------------
function TIC()
	mx,my,md=mouse()
	if md then
		for i=1,5 do
		p = particle:new(	nil,
											mx+(random(20)-10),
											my+(random(20)-10),
											(mx-bmx)*0.5,
											(my-bmy)*0.5,
											15,
											random(150)+150)
		table.insert(particles,p)
		end
		bmx=mx
		bmy=my
	end
	if random(1)==1 then
		p = particle:new(nil,	(random(230)+5),
													(random(130)+5),
													0,0,15,random(150)+150)
		table.insert(particles,p)
	end
	if ti%200==0 then pallet() end
	move()
	draw()
	ti=ti+1
end