--------------------  ----------------  ----------------------  ---------------
-- yoshi's island --  -- lua script --  -- work in progress --  -- (nitsuja) --
--------------------  ----------------  ----------------------  ---------------

-- configuration
-- these describe (and determine) the basic capabilities of this script:
drawobjectnames        = true -- draws name if known, or object ID if not
drawobjecthitboxes     = false -- note: hitboxes are not 100% accurate yet
drawobjectcenterpoints = true -- draws a little dot at objects' reported centers
drawplayerhitbox       = false -- currently only correct if player is yoshi
drawsavestatehitboxes  = false -- player hitbox for other savestates (GHOST DISPLAY)
drawsavestatenumbers   = false -- draws the slot number next to them
drawplayertrail        = true -- shows 90 frames or so of speed/position info
drawsavestatetrails    = false-- show player trail for other savestates
drawspeedometer        = true -- draws xvel, yvel numbers constantly

-- if you're comparing against another movie,
-- save before the end of that movie onto this slot number
-- (you might have to rename the .luasav file to match your new movie)
specialslot = 10

-- as you get ahead in each room or level,
-- increase this by the number of frames you're ahead of the other movie
-- to resynchronize ongoing comparisons with the special slot
adjustframeaheadby = 0

-- I recommend leaving these on
smartmatchguiobjects   = true -- takes drawing time into account so GUI matches
smartmatchguicamera    = true -- takes camera update time into account for GUI
smartsyncframeupdate   = true -- sync to YI's frame counter update, things go a bit wacky otherwise (especially trails)

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------



-- TODO: save this to a file so it doesn't reset to 0 every time the script restarts
currentstatenumber = 0

emu = emu or snes9x or gens gens = emu or snes9x or gens snes9x = emu or snes9x or gens

-- prevent text from clipping off the screen edges
local oldguitext = gui.text
gui.text = function(x,y,text)
    if type(text) ~= 'string' then text = tostring(text) end
    local width = 4 * #text
    if x+width > 256 then x=256-width end
    if x < 0 then x = 0 end
    if y > 216 then y = 216 end
    if y < 0 then y = 0 end
    oldguitext(x,y,text)
end


--memory.writeword(0x70008C, memory.readword(0x70008C) + 100)

--  gui.text(30,30,memory.readword(0x7001b4)) -- standing on object flag!


-- because snes9x require numbered savestates to be 'created' to use them
local saveslot = {}
for n = 1,12 do
    saveslot[n] = savestate.create(n)
end


local copytable = function(t)
    if t == nil then return nil end
    local c = {}
    for k,v in pairs(t) do
        c[k] = v
    end
--  setmetatable(c,debug.getmetatable(t))
    return c
end

-- for copying a table in frameinforecords while discarding non-recent entries
local copytablepartial = function(t)
    if t == nil then return nil end
    local abs = math.abs
    local now = getinstantid()
    local c = {}
    for k,v in pairs(t) do
        if type(k) ~= 'number' or abs(k-now) < 3600 then
            c[k] = v
        end
    end
    return c
end






-- a record of frame information
-- looks like: {savenumber1={time1={x1,y1},time2={x2,y2},...},savenumber2=...}
frameinforecords = {} -- initially it's an empty table

-- a helper function to get the info we want to store per in-game frame
-- (for now this is only the player position)
function getperframeinfo()
    local x = memory.readword(0x70008C) + (memory.readbyte(0x70008A) / 256)
    local y = memory.readword(0x700090) + (memory.readbyte(0x70008E) / 256)
--  local y2 = memory.readword(0x700011E)
--  local yext = memory.readword(0x7000112)
    local info = {x,y}
    return info
end

-- time function, might want to use in-game time here in some games
function getinstantid()
--  return memory.readword(0x7E0030)
    return emu.framecount()
end


-- if we draw with the current camera position things will look a little off
-- when the camera is moving, so use the camera positon slightly in the past
-- (do this by keeping with a circular buffer of x and y camera positions)

xcamhist = {0,0,0,0} -- don't need so many but whatever...
ycamhist = {0,0,0,0}
local function tickcam()
    xcamhist[1 + (getinstantid() % 4)] = memory.readword(0x7E0039)
    ycamhist[1 + (getinstantid() % 4)] = memory.readword(0x7E003B)
end
local function resetcam()
    local xcam = memory.readword(0x7E0039)
    local ycam = memory.readword(0x7E003B)
    for k,v in pairs(xcamhist) do xcamhist[k] = xcam end
    for k,v in pairs(ycamhist) do ycamhist[k] = ycam end
end
resetcam()

local getxcam
local getycam

if smartmatchguicamera then

    getxcam = function()
        return xcamhist[1 + ((4-1 + getinstantid()) % 4)]
    end
    getycam = function()
        return ycamhist[1 + ((4-1 + getinstantid()) % 4)]
    end

else
    getxcam = function()
        return memory.readword(0x7E0039)
    end
    getycam = function()
        return memory.readword(0x7E003B)
    end
end









-- the game takes 2 frames to render the current game state,
-- so we have to buffer our rendering by 2 frames to make it match up.
-- it's a little more complicated than that though.
--
-- to make a long story short,
-- what you have to do is NOT call the functions like "gui.box",
-- and instead call the functions named like "drawboxinworld"
-- (using x,y coordinates in WORLD coordinates, don't subtract camera pos),
-- then also call drawdeferred at the start of each gui render.
-- that way your gui drawing should match up perfectly with the game.


local function clearoldhist(hist,now)
    for k,v in pairs(hist) do
        if k > now or k < now-4 then
            hist[k] = nil
        end
    end
end

local function gethistitem(hist,now)
    for i=-3,0 do
        local histindex = 1 + (now + i)
        items = hist[histindex]
        if items then return items end
    end
end

local boxhist = {}
local texthist = {}
local linehist = {}
local pixhist = {}

local function clearalloldhist(now)
    clearoldhist(boxhist,now)
    clearoldhist(texthist,now)
    clearoldhist(linehist,now)
    clearoldhist(pixhist,now)
end

function drawdeferred()
    local now = getinstantid()

    -- clear out old entries
    clearalloldhist(now)

    local camx = getxcam()
    local camy = getycam()

    local lineitems = gethistitem(linehist,now)
    if lineitems then
        local drawline = gui.drawline
        for i,args in ipairs(lineitems) do
            local x1,y1,x2,y2,color = unpack(args)
            drawline(x1-camx,y1-camy,x2-camx,y2-camy,color)
        end
    end

    local boxitems = gethistitem(boxhist,now)
    if boxitems then
        local drawbox = gui.drawbox
        for i,args in ipairs(boxitems) do
            local x1,y1,x2,y2,color = unpack(args)
            drawbox(x1-camx,y1-camy,x2-camx,y2-camy,color)
        end
    end

    local textitems = gethistitem(texthist,now)
    if textitems then
        local drawtext = gui.text
        for i,args in ipairs(textitems) do
            local x,y,msg = unpack(args) -- TODO: support passing through color
            drawtext(x-camx,y-camy,msg)
        end
    end

    local pixitems = gethistitem(pixhist,now)
    if pixitems then
        local drawpixel = gui.drawpixel
        for i,args in ipairs(pixitems) do
            local x,y,color = unpack(args)
            drawpixel(x-camx,y-camy,color)
        end
    end
end

local drawboxinworld
local drawtextinworld
local drawlineinworld
local drawpixelinworld

if smartmatchguiobjects then
    drawboxinworld = function (...)
        local now = getinstantid()
        local items = boxhist[now]
        if not items then items = {} boxhist[now] = items end
        items[#items+1] = {...}
    end
    drawtextinworld = function(...)
        local now = getinstantid()
        local items = texthist[now]
        if not items then items = {} texthist[now] = items end
        items[#items+1] = {...}
    end
    drawlineinworld = function(...)
        local now = getinstantid()
        local items = linehist[now]
        if not items then items = {} linehist[now] = items end
        items[#items+1] = {...}
    end
    drawpixelinworld = function(...)
        local now = getinstantid()
        local items = pixhist[now]
        if not items then items = {} pixhist[now] = items end
        items[#items+1] = {...}
    end
else
    drawlineinworld = function (x1,y1,x2,y2,color)
        local camx = getxcam()
        local camy = getycam()
        gui.drawline(x1-camx,y1-camy,x2-camx,y2-camy,color)
    end
    drawtextinworld = function (x,y,msg)
        gui.text(x-getxcam(),y-getycam(),msg) -- TODO: support passing through color
    end
    drawboxinworld = function (x1,y1,x2,y2,color)
        local camx = getxcam()
        local camy = getycam()
        gui.drawbox(x1-camx,y1-camy,x2-camx,y2-camy,color)
    end
    drawpixelinworld = function (x,y,color)
        gui.drawpixel(x-getxcam(),y-getycam(),color)
    end
end














local function renderpasttrajectory(records, id, tracknumber)

    if (tracknumber == currentstatenumber and not drawplayertrail) or (tracknumber ~= currentstatenumber and not drawsavestatetrails) then
        return
    end

    local points = {}
    local ids = {}

    local lastx
    local j = 1
    for i=id,id-90,-1 do
        local info = records[i]
        if info then
            points[j] = info
            ids[j] = i
            j = j + 1
        end
    end

    local actualcamx = getxcam()
    local actualcamy = getycam()

    local camx = 0 --getxcam()
    local camy = 0 --getycam()

    local width = 16
    local height = 32

    -- adjust the player hitbox to match up better with the world... (HACK)
    camy = camy - 3  -- y = y + 3
    height = height - 5
    camx = camx - 1  -- x = x + 1
    width = width - 2


    local outlinecolor
    if tracknumber == -1 then
        outlinecolor = 0xFFFFFFFF
    elseif tracknumber == 0 then
        outlinecolor = 0x0000FFFF
    else
        outlinecolor = 0x7F7FFFFF
    end

    local alt = math.floor(id/4)%2==0

    local skipfirst = false

    local floor = math.floor

    for i=1,j-2 do

        local a = points[i]
        local b = points[i+1]
        local ax = a[1] - camx
        local ay = a[2] - camy
        local bx = b[1] - camx
        local by = b[2] - camy

--      local transp = 255 * (j-i) / j
--      local color = OR(AND(outlinecolor, 0xFFFFFF00), transp)

        local color = '#FFFFFF'

        local dx = bx - ax
        local dy = by - ay


        if math.abs(dx) < 256 and math.abs(dy) < 208
        and math.max(ax,bx) - actualcamx < 256
        and math.min(ax,bx) - actualcamx >= 0
        and math.max(ay,by) - actualcamy < 200
        and math.min(ay,by) - actualcamy >= 0
        then

            local di = ids[i] - ids[i+1]
--      local speed = math.max(math.abs(dx),math.abs(dy)) / di
            local xspeed = math.abs(dx / di)

            local xspeeddiff = xspeed - 2.9375
            if xspeeddiff > 0 then
                local good = math.min(255,math.max(0, xspeeddiff * 255 / 2))
                local good2 = math.min(255,math.max(0, xspeeddiff * 255 / 2 - 255))
                color = string.format('#%02XFF%02X', 255-good, 255-(good-good2))
            else
                local bad = math.min(255,math.max(0, -xspeeddiff * 512))
                if tracknumber == currentstatenumber then
                    color = string.format('#FF%02X%02X', 255-bad, 255-bad)
                else
                    color = string.format('#%02X%02XFF', 255-bad, 255-bad)
                end
            end

            ax = floor(ax)
            bx = floor(bx)
            ay = floor(ay)
            by = floor(by)

            if dx < 0 or dy < 0 then
                drawlineinworld(ax,ay,bx,by, color)
            end
            if dx < 0 or dy > 0 then
                drawlineinworld(ax,ay+height,bx,by+height, color)
            end
            if dx > 0 or dy < 0 then
                drawlineinworld(ax+width,ay,bx+width,by, color)
            end
            if dx > 0 or dy > 0 then
                drawlineinworld(ax+width,ay+height,bx+width,by+height, color)
            end

            skipfirst = true
        end

    end

end


-- a helper function to draw the info of the given frame
function renderframeinfo(records, id, tracknumber)

    if records == nil then return end

    local info = records[id]
    local notcurrent = tracknumber ~= currentstatenumber

    -- don't draw anything if there's no info for this frame or it's after the last frame
    if info == nil then return end
    if notcurrent and records.endid and (id > records.endid) then return end


    renderpasttrajectory(records, id, tracknumber)


    -- draw a box where the player is
--  local camx = getxcam()
--  local camy = getycam()
    local x = math.floor(info[1]) -- - camx
    local y = math.floor(info[2]) -- - camy
    local width = 16
    local height = 32

    -- adjust the player hitbox to match up better with the world... (HACK)
    y = y + 3
    height = height - 5
    x = x + 1
    width = width - 2

    if (drawsavestatehitboxes and notcurrent) or (drawplayerhitbox and not notcurrent) then

        --local color        = notcurrent and "#7F7FFF" or "#FF7FFF"
        local outlinecolor = notcurrent and "#0000FF" or "#FF0000"

        drawboxinworld(x, y, x+width, y+height, outlinecolor)

    end

    if drawsavestatenumbers then

        -- draw the savestate number somewhere in the box
        if notcurrent then
            x = x + (tracknumber%6) * 4 - 10
            y = y + (tracknumber/6) * 6 - 15
            local message = string.format("%d", tracknumber)
            drawtextinworld(x, y, message)
        end

    end

end




local objectinfotable =
{
    -- note: default width and height is 16
    [0x061] = {name='babymario', color='#FF7F7F', width=function(i) return memory.readbyte(0x700F00+4*(i-1))==0xA and 16 or 32 end, height=function(i) return memory.readbyte(0x700F00+4*(i-1))==0x10 and 32 or 16 end, showname=false},
    [0x08C] = {name='yoshi', height=32, color='#00FF00'},
    [0x042] = {name='entrance', width=32, textyoff=8, color='#BFFF00'}, -- pipe
    [0x0D1] = {name='entrance', width=32, textyoff=8},
    [0x084] = {name='warp', width=40, height=28},
    [0x0D0] = {name='entrance', width=22, height=40},
    [0x147] = {name='entrance', width=22, height=40},
    [0x04E] = {name='door', width=11, height=32, xoff=1, yoff=8},
    [0x131] = {name='door', width=11, height=32, xoff=1, yoff=8},
    [0x093] = {name='door', width=11, height=32, xoff=1, yoff=8},
    [0x012] = {name='bossdoor', width=12, height=32, yoff=8},
    [0x001] = {name='shut', width=11, height=32, xoff=1, yoff=8},
    [0x00D] = {name='goal', height=64, yoff=-64, xoff=35, width=8},
    [0x00E] = {name='goal!', width=8, height=8},
    [0x00F] = {name='bonus', width=8, height=8},
    [0x01E] = {name='shyguy'},
    [0x0F3] = {name='jumpingshyguy'},
    [0x192] = {name='flowershyguy'},
    [0x0F2] = {name='stiltshyguy', height=48, yoff=-16},
    [0x066] = {name='pirahnaplant', width=8, height=0, guessscaling=true},
    [0x054] = {name='pirahnaplant', width=8, height=0, guessscaling=true, upsidedown=true},
    [0x09E] = {name='chomprock', width=22, height=24},
    [0x065] = {name='redcoin', color='#FF0000'},
    [0x1AF] = {name='coin', color='#FFFF00'},
    [0x115] = {name='coin'},
    [0x025] = {name='egg', color='#7FFF7F'},
    [0x024] = {name='yellowegg', color='#FFFF7F'},
    [0x023] = {name='redegg', color='#FF7F7F'},
    [0x0A0] = {name='starflower', width=32},
    [0x0AD] = {name='helpbox', scaled=true},
    [0x12C] = {name='redcoin'}, -- shyguy
    [0x08D] = {name='flyguy'}, -- stars or 1up
    [0x178] = {name='1upballoon'},
    [0x17A] = {name='yellowcoinballoon'},
    [0x1A2] = {name='star'},
    [0x100] = {name='1up'},
    [0x0BE] = {name='1up'},
    [0x0B7] = {name='1up'},
    [0x0BF] = {name='key'},
    [0x0B6] = {name='coins'},
    [0x0BC] = {name='bandit'},
    [0x0BD] = {name='coin'},
    [0x0CB] = {name='coin'},
    [0x0CC] = {name='switch'},
    [0x09D] = {name='switch', width=26, xoff=1, height=20, scaled=true, yscaled=true},
    [0x0C2] = {name='door'},
    [0x0B0] = {name='tank'},
    [0x0B1] = {name='copter'},
    [0x098] = {name='yoshiblock', width=32,height=32,yoff=-8},
    [0x06A] = {name='eggblock'}, -- yellow
    [0x06B] = {name='eggblock'}, -- green
    [0x0FA] = {name='flower', width=24, height=24},
    [0x110] = {name='flower', width=24, height=24},
    [0x064] = {name='pivot', width=8, height=8},
    [0x055] = {name='pivot', width=8, height=8},
    [0x03D] = {name='pivot', width=8, height=8},
    [0x0BA] = {name='stairs'}, -- wingedcloud
    [0x0BB] = {name='bridge'}, -- wingedcloud
    [0x0C7] = {name='beanstalk'}, -- wingedcloud
    [0x0C8] = {name='beanstalk'}, -- wingedcloud
    [0x0C0] = {name='stars'}, -- wingedcloud
    [0x0C1] = {name='stars'}, -- wingedcloud
    [0x0B7] = {name='1up'}, -- wingedcloud
    [0x0B8] = {name='flower'}, -- wingedcloud
    [0x0B5] = {name='secret'},
    [0x067] = {name='chomprocksecret', textyoff=-8},
    [0x161] = {name='bonus', width=8, height=8},
    [0x181] = {name='crazydaisy', height=24, yoff=-5},
    [0x094] = {name='growblock', width=14, height=14, scaled=true, yoff=function(i) return (memory.readword(0x701A36+4*(i-1))-256)/-32 end},
    [0x0D8] = {name='chompsign', width=24, height=24},
    [0x0A6] = {name='chomp', width=32, height=32, scaled=true},
    [0x0A9] = {name='chompshadow', width=32, height=8, scaled=true},
    [0x144] = {name='flippergate', width=16, height=64},
    [0x13C] = {name='flippergate', width=64, height=16},
    [0x04F] = {name='midring', width=16, height=44, yoff=2, xoff=function(i) return memory.readbyte(0x701400+4*(i-1)) == 2 and -14 or 16 end},
    [0x06C] = {name='bouncyarrow', width=10, xoff=1, yoff=-7, height=function(i) return 24 * 256 / memory.readword(0x701A36+4*(i-1)) end},
    [0x148] = {name='bouncyarrow', width=10, xoff=1, yoff=-7, height=function(i) return 24 * 256 / memory.readword(0x701A36+4*(i-1)) end},
    [0x06F] = {name='bouncyarrow', width=10, xoff=1, yoff=0, height=function(i) return 16 * 256 / memory.readword(0x701A36+4*(i-1)) end},
    [0x197] = {name='sign'},
    [0x198] = {name='sign'},
    [0x0EA] = {name='gusty'}, -- updown
    [0x0EB] = {name='gusty'}, -- leftright
    [0x10E] = {name='stars', width=20, height=24, scaled=true, yoff=function(i) return (memory.readword(0x701A36+4*(i-1))-256)/-6-8 end}, -- crate
    [0x17E] = {name='stars', width=20, height=20}, -- crate, balloons
    [0x177] = {name='bouncyarrow', width=20, height=20, yoff=2}, -- balloon
    [0x164] = {name='nipper'},
    [0x165] = {name='nipper'}, -- from seed
    [0x0F4] = {name='eggplant', height=24, yoff=-5, color='#7FFF7F'},
    [0x133] = {name='lanternghost'},
    [0x179] = {name='key'},
    [0x027] = {name='key'},
    [0x011] = {name='1up'},
    [0x022] = {name='egg'},
    [0x123] = {name='bucket', yoff=4},
    [0x231] = {name='babymario', width=32, height=32, color='#FF7F7F'},
    [0x230] = {name='toady', width=32, height=32},
    [0x22F] = {name='toady', width=32, height=32},
    [0x091] = {name='toadies'},
    [0x036] = {name='crusher', width=96},
    [0x051] = {name='roller', width=96, height=32, yoff=-16},
    [0x101] = {name='spikepivot'},
    [0x102] = {name='spikepivot'},
    [0x08A] = {name='platform', width=40, height=12},
    [0x089] = {name='platform', width=40, height=12},
    [0x185] = {name='platform', width=40, height=12},
    [0x186] = {name='platform', width=40, height=12},
    [0x187] = {name='platform', width=40, height=12},
    [0x188] = {name='platform', width=40, height=12},
    [0x189] = {name='platform', width=40, height=12},
    [0x18A] = {name='platform', width=40, height=12},
    [0x18B] = {name='platform', width=40, height=12},
    [0x18C] = {name='platform', width=40, height=12},
    [0x18D] = {name='platform', width=40, height=12},
    [0x18E] = {name='platform', width=40, height=12},
    [0x103] = {name='spikewidget', width=32},
    [0x0E7] = {name='burt', width=24, height=24, yoff=-4, scaled=true},
    [0x080] = {name='fireball'},
    [0x018] = {name='fire'},
    [0x194] = {name='blargg', width=32, height=32, yoff=-8},
    [0x0A5] = {name='giantblargg', width=96, height=96, yoff=-96},
    [0x076] = {name='sparky', scaled=true},
    [0x077] = {name='sparky', scaled=true},
    [0x0DA] = {name='vase', width=14, height=20, yoff=-2},
    [0x048] = {name='kamek', width=32, height=24, yoff=-4},
    [0x046] = {name='burt', width=24, height=24, xoff=-8, yoff=-18, width=128, height=function(i) return 128 - memory.readword(0x701900+4*(i-1)) end, yoff=function(i) return -72 + memory.readword(0x701900+4*(i-1))/2 end},
    [0x013] = {name='supernova', width=8, height=8},
    [0x117] = {name='donutblock'},
    [0x13D] = {name='bat'},
    [0x13E] = {name='bat'},
    [0x08B] = {name='1upbomb'},
    [0x092] = {name='rollbug'},
    [0x109] = {name='taptap'},
    [0x10A] = {name='taptap'},
    [0x10B] = {name='taptap'},
    [0x007] = {name='watermelon'},
    [0x107] = {name='seed'},
    [0x1B1] = {name='cannon', width=32, height=32, xoff=8, yoff=8},
    [0x1B2] = {name='coin'},
    [0x1B3] = {name='bandit', height=24, yoff=-6},
    [0x129] = {name='fuzzy'},
    [0x0B3] = {name='fart'},
    [0x108] = {name='milde'},
    [0x03E] = {name='weakplatform', width=64, xoff=-8},
    [0x182] = {name='dragonfly', width=8, height=8},
    [0x183] = {name='butterfly', width=8, height=8},
    [0x0F0] = {name='petal'},
    [0x0EE] = {name='petalshooter'},
    [0x143] = {name='fish', width=32},
    [0x057] = {name='platformghost', width=32},
    [0x15C] = {name='flipperswitch'},
    [0x15D] = {name='flipperswitch'},
    [0x15F] = {name='spikeplatform', width=48, height=12},
    [0x160] = {name='spikeplatform', width=48, height=12},
    [0x020] = {name='bandit', height=24, yoff=-4},
    [0x12D] = {name='yoshi', height=32, yoff=8, color='#00FF00'},
    [0x11E] = {name='spinarrow', width=28,height=28},
    [0x02D] = {name='salvo'},
    [0x02E] = {name='eyes'},
    [0x132] = {name='unshaven'},
    [0x014] = {name='bigkey', width=24, height=24},
    [0x400] = {showname=false, width=0, height=0, color='#00000000'},
    -- TODO: play through more of the game to assign the rest of these...
    -- (or discover a way to auto-calculate them)
}


local function evalnumber(x, ...)
    if type(x) == 'number' then return x
    elseif type(x) == 'function' then return x(...)
    end
end



local function drawobject(i)
    local off = 4 * (i-1)

    local status = memory.readword(0x700F00 + off)

    if status == 0 then return end -- has "doesn't exist" status flag

    local objecttype = memory.readword(0x701360 + off)
    local objectinfo = objectinfotable[objecttype] or {}

    local color = objectinfo.color or '#FFFF00'

    if status == 0x0A then --color = '#00FF00' -- has "saddled" status flag
    elseif status == 0x0E then color = '#7F7F7F' -- has "dead" status flag
    elseif status == 0x08 then color = '#007FFF' -- has "in mouth" status flag
--  else emu.message(string.format("%X %d",status,i)) color = '#000000'
    end



    local x = memory.readword(0x7010E2 + off) + (memory.readbyte(0x7010E1 + off) / 256)
    local y = memory.readword(0x701182 + off) + (memory.readbyte(0x701181 + off) / 256)

    if objectinfo.xoff then x = x + evalnumber(objectinfo.xoff, i) end
    if objectinfo.yoff then y = y + evalnumber(objectinfo.yoff, i) end

    local width = evalnumber(objectinfo.width, i) or 16
    local height = evalnumber(objectinfo.height, i) or 16

    if objectinfo.scaled then
        local scaling = memory.readwordsigned(0x701A36 + off)
        local yscaling = objectinfo.yscaled and memory.readwordsigned(0x701A38 + off) or scaling
        width = width * scaling / 256
        height = height * yscaling / 256
    end

    local origwidth = width
    local origheight = height

    local xcam = getxcam()
    local ycam = getycam()

    local y1 = y
    local y2 = memory.readword(0x701CD8 + off) -- y center

--  x = x - xcam
--  y = y - ycam

    local xcenter = memory.readword(0x701CD6 + off) -- - xcam
    local ycenter = memory.readword(0x701CD8 + off) -- - ycam

    if objectinfo.guessscaling then
        -- I don't know how to find the size of object...
        -- but this hack method gets pretty close for dynamic objects like the pirahna plants
        local xcenterguess = x+8
        local ycenterguess = y+8
        local xguessoffby = xcenterguess - xcenter
        local yguessoffby = ycenterguess - ycenter
        width = width + math.abs(xguessoffby)
        height = height + math.abs(yguessoffby)
        if xguessoffby > 0 then x = x - xguessoffby end
        if yguessoffby > 0 then y = y - yguessoffby end
    end

    -- adjust for the objectinfo width
    x = x - (origwidth - 16)/2
    y = y - (origheight - 16)/2



    if x-xcam > 256 + 32 or y-ycam > 208 + 32 or x-xcam+width < -32 or y-ycam+height < -32 then
        -- too far offscreen to draw
        return
    end





    if height < 8 then
        if not objectinfo.upsidedown then
            y = y+height-8
        end
        height = 8
    end
    if width < 8 then
        x = x+width-8
        width = 8
    end

    if height > 511 then height = 511 end
    if width > 511 then width = 511 end

    width = math.floor(width)
    height = math.floor(height)


    -- hmm, this one is in screen-space
--  local x2 = memory.readword(0x701680 + off)
--  local y2 = memory.readword(0x701682 + off)

--  local y2 = memory.readword(0x700158 + (i-1)*2)


    if drawobjectcenterpoints then
        drawboxinworld(xcenter-1,ycenter-1,xcenter+1,ycenter+1,'#000000')
        drawpixelinworld(xcenter, ycenter, color)
    end

    if drawobjecthitboxes then
        drawboxinworld(x,y,x+width-1,y+height-1,color)
    end



    -- only draw text after this point
    if objectinfo.textyoff then y = y + objectinfo.textyoff end
    if objectinfo.textxoff then x = x + objectinfo.textxoff end

    if drawobjectnames then
        if objectinfo.showname ~= false then -- here we want nil -> true
            local name = objectinfo.name
            SpriteID = off/(-4.0)+24
            if name then
                drawtextinworld(x,y-10,SpriteID)
            else
                drawtextinworld(x,y-10,SpriteID)
            end
        end
    end

--  drawtextinworld(x,y-40,'y='..string.format("%X",memory.readword(0x701182 + off)))
--  drawtextinworld(x,y-50,string.format("%08X", memory.readdword(0x701360 + 4 * (i-1))))
end






-- register a function to run when snes9x draws the screen
gui.register( function ()

    drawdeferred()

    for i = 1,24 do
        drawobject(i)
    end


    -- draw the information for this frame FOR ALL STATES
    local id = lastidvalid and lastid or getinstantid()
    for statenumber = 1,12 do
        if statenumber ~= currentstatenumber then
            local iddraw = statenumber==specialslot and id+adjustframeaheadby or id
            renderframeinfo(frameinforecords[statenumber], iddraw, statenumber)
        end
    end
    -- render the current state last so it draws on top
    renderframeinfo(frameinforecords[currentstatenumber], id, currentstatenumber)


    if drawspeedometer then

        local xvel = memory.readwordsigned(0x7000A8)
        local yvel = memory.readwordsigned(0x7000AA)
        local slope = memory.readbyte(0x7000B6) * 360 / 255
        if slope > 180 then slope = slope - 360 end
        gui.text(5,40,"xvel: "..xvel)
        gui.text(5,50,"yvel: "..yvel)
        if slope ~= 0 then
            gui.text(5,60,"angle: "..string.format("%d",math.floor(slope<0 and slope-1 or slope)))
        end

    end

end)


-- a function to run after the emulation of every frame
registeredafter = ( function ()

    local id = getinstantid()

    -- sort of a hack...
    if id == lastid then
        lastidvalid = false
    else
        lastid = id
        lastidvalid = true
    end

    -- just in case...
    if frameinforecords[currentstatenumber] == nil then frameinforecords[currentstatenumber] = {} end

    -- keep track of the last frame reached that's been saved
    frameinforecords[currentstatenumber].endid = id

    -- store the new information for this frame
    local nowinfo = getperframeinfo()
    frameinforecords[currentstatenumber][id] = nowinfo

end)


    -- run some startup code: retrieve the ghost info stored in each savestate
--  sound.clear()
    frameinforecords = {}
    for n = 1,12 do
        frameinforecords[n] = savestate.loadscriptdata(saveslot[n])
--      emu.wait()
    end


-- register a function that gets called when a numbered savestate is saved.
-- the return value(s) becomes the savestate's scriptdata saved alongside it.
savestate.registersave( function (statenumber)

    -- check for invalid save slot
    if not frameinforecords[currentstatenumber] then return end

    -- if the user switched which state they're saving to,
    -- replace that state's info table with the current one
    if statenumber ~= currentstatenumber then
        if statenumber == specialslot then
            -- F10 state is special, keep all info for it
            frameinforecords[statenumber] = copytable(frameinforecords[currentstatenumber])
        else
            -- for other states, only keep the last 1 minute of perframeinfo
            frameinforecords[statenumber] = copytablepartial(frameinforecords[currentstatenumber])
        end
        currentstatenumber = statenumber
    end

    -- save all the perframeinfo records for this state
    return frameinforecords[currentstatenumber]

end)


-- register a function that gets called when a numbered savestate is loaded.
savestate.registerload( function (statenumber)

    -- check for invalid save slot
    if not frameinforecords[currentstatenumber] then return end

    -- just switch the info record track to that state's table
    currentstatenumber = statenumber

    -- also clear rendering buffers since the time (or state) has suddenly changed
    clearalloldhist(-1)
    resetcam()
    lastidvalid = false

    -- maybe this helps
    collectgarbage()

end)

if smartsyncframeupdate then
    memory.register(0x7E0030, function()
        registeredafter()
        tickcam()
    end)
end

-- finally, the main loop
while true do
    emu.frameadvance()

    if not smartsyncframeupdate then
        registeredafter()
        tickcam()
    end
end