LUA SCRIPT [All Games Shooting] ZapperFun

-- Zapper Fun
-- quick and dirty script that shows zapper position and fire button presses in FCEUX
-- Written by miau
-- http://morphcat.de/lua/

local Z_LSPAN = 20 --life span (in frames) of white box
local Z_LSPAN_CLICK = 30 --life span of red box
local Z_MAX = 60 --maximum amount of boxes on screen

local zbuf = {}
local zindex = 1
local timer = 0
local lastclick = zapper.read().fire
local lastx = zapper.read().x
local lasty = zapper.read().y

function zapper_addcoord(x,y,click)
    zbuf[zindex] = {t=timer,x=x,y=y,click=click}
    zindex = zindex + 1
    if(zindex>Z_MAX) then
        zindex = 1
    end
end

function box(x1,y1,x2,y2,color1,color2)
    if(x1>=0 and y1>=0 and x2<=255 and y2<=255) then
        gui.drawbox(x1, y1, x2, y2, color1, color2)
    end
end



 while(true) do
    local x = zapper.read().x
    local y = zapper.read().y
    local click = zapper.read().fire
    --gui.text(0, 8, string.format("x=%d",x));
    --gui.text(0, 18, string.format("y=%d",y));
    --gui.text(0, 28, string.format("click=%d",click));
    if(click==1 and click~=lastclick) then
        zapper_addcoord(x,y,1)
    elseif(x~=lastx or y~=lasty) then
        zapper_addcoord(x,y,0)
    end
    lastclick=click
    lastx=x
    lasty=y
    box(x-3, y-3, x+3, y+3, "white", 0)
   
    for i=1,Z_MAX do
        if(zbuf[i]) then
            ltime = timer-zbuf[i].t
            if(zbuf[i].click==0) then
                if(ltime<Z_LSPAN) then
                    boxsize = (zbuf[i].t-timer+Z_LSPAN) / (Z_LSPAN/3)
                    c = "white"
                    box(zbuf[i].x-boxsize, zbuf[i].y-boxsize, zbuf[i].x+boxsize, zbuf[i].y+boxsize, c, 0)
                end
            elseif(zbuf[i].click==1) then
                if(ltime<Z_LSPAN_CLICK) then
                    boxsize = (timer-zbuf[i].t) / (Z_LSPAN_CLICK/10)
                    c = "red"
                    box(zbuf[i].x-boxsize, zbuf[i].y-boxsize, zbuf[i].x+boxsize, zbuf[i].y+boxsize, c, 0)
                end
            end
        end
    end
   
     FCEU.frameadvance()
    timer = timer + 1
 end