rombyte = memory.readbyte(0x00013F)
if rombyte == 0x47 then -- Sonic 1
	print("Detected Sonic 1")

	addr_xcamera = 0xFFF700
	addr_ycamera = 0xFFF616
	addr_startedflag = 0xFFFE02
	addr_ost = 0xFFD000
	addr_ostend = 0xFFEFFF
	ost_length = 0x40
elseif rombyte == 0x32 then -- Sonic 2
	print("Detected Sonic 2")

	addr_xcamera = 0xFFEE00
	addr_ycamera = 0xFFEE04
	addr_startedflag = 0xFFF711
	addr_ost = 0xFFB000
	addr_ostend = 0xFFD5FF
	ost_length = 0x40
elseif rombyte == 0x33 then -- Sonic 3

elseif rombyte == 0x20 then -- SK/S3K

end

xmouse = 0
ymouse = 0
xmousedelta = 0
ymousedelta = 0

pinned = {}
rightclickdown = false

memory.register(addr_startedflag, function()
	if memory.readbyte(addr_startedflag) == 0 then
		pinned = {}
	end
end)

gens.registerbefore( function()
	local xcamera = memory.readword(addr_xcamera)
	local ycamera = memory.readword(addr_ycamera)
	local input_state = input.get()
	
	xmousedelta = input_state.xmouse - xmouse
	ymousedelta = input_state.ymouse - ymouse
	xmouse = input_state.xmouse
	ymouse = input_state.ymouse
	
	local i, entry, x1, y1, x2, y2, outline_color
	for i=addr_ost,addr_ostend,ost_length do
		entry = ostentry(i)
		if entry then
			local width, height
			
			if entry.widthhalf == 0 then
				width = entry.width
			else
				width = entry.widthhalf
			end
			
			if entry.heighthalf == 0 then
				height = 8
			else
				height = entry.heighthalf
			end
			
			if pinned[tostring(entry.baseaddr)] == nil then
				x1 = (entry.x - width) - xcamera
				y1 = (entry.y - height) - ycamera
				x2 = (entry.x + width) - xcamera
				y2 = (entry.y + height) - ycamera
			else
				local x = pinned[tostring(entry.baseaddr)][1]
				local y = pinned[tostring(entry.baseaddr)][2]
			
				x1 = x - width
				y1 = y - height
				x2 = x + width
				y2 = y + height
				
				memory.writeword(i + 0x08, xcamera + x) -- x
				memory.writeword(i + 0x0C, ycamera + y) -- y
				memory.writeword(i + 0x10, 0) -- xspeed
				memory.writeword(i + 0x12, 0) -- yspeed
			end
			    
			if (xmouse >= x1 and ymouse >= y1) and
				(xmouse <= x2 and ymouse <= y2) then
				outline_color = {255, 0, 0, 255}
				
				if input_state.leftclick then
					if pinned[tostring(entry.baseaddr)] ~= nil then
						pinned[tostring(entry.baseaddr)][1] = xmouse
						pinned[tostring(entry.baseaddr)][2] = ymouse
					end
					
					memory.writeword(i + 0x08, xcamera + xmouse) -- x
					memory.writeword(i + 0x0C, ycamera + ymouse) -- y
					memory.writeword(i + 0x10, xmousedelta * 100) -- xspeed
					memory.writeword(i + 0x12, ymousedelta * 100) -- yspeed
				end
				
				if input_state.rightclick then
					if not rightclickdown then
						if pinned[tostring(entry.baseaddr)] == nil then
							pinned[tostring(entry.baseaddr)] = {xmouse, ymouse}
						else
							pinned[tostring(entry.baseaddr)] = nil
						end
						
						rightclickdown = true
					end
				else
					rightclickdown = false
				end
			else
				if pinned[tostring(entry.baseaddr)] ~= nil then
					outline_color = {0, 255, 0, 255}
				else
					outline_color = {255, 255, 255, 255}
				end
			end
			
			gui.box(x1, y1, x2, y2, {0, 0, 0, 0}, outline_color)
		end
	end
end)

function ostentry(address)
	local entry = {}
	
	entry.baseaddr = address
	
	entry.id          = memory.readbyte(address)
	if entry.id == 0 or entry.id == nil then return nil end
	
	entry.renderflags = memory.readbyte(address + 0x01)
	entry.artindex    = memory.readword(address + 0x02)
	entry.mappings    = memory.readdword(address + 0x04)
	entry.x           = memory.readword(address + 0x08)
	entry.xsub        = memory.readword(address + 0x0A)
	entry.y           = memory.readword(address + 0x0C)
	entry.ysub        = memory.readword(address + 0x0E)
	entry.xspeed      = memory.readword(address + 0x10)
	entry.yspeed      = memory.readword(address + 0x12)
	entry.inertia     = memory.readword(address + 0x14)
	entry.heighthalf  = memory.readbyte(address + 0x16)
	entry.widthhalf   = memory.readbyte(address + 0x17)
	entry.priority    = memory.readbyte(address + 0x18)
	entry.width       = memory.readbyte(address + 0x19)
	entry.dispframe   = memory.readbyte(address + 0x1A)
	entry.animframe   = memory.readbyte(address + 0x1B)
	entry.animnum     = memory.readbyte(address + 0x1C)
	entry.animrestart = memory.readbyte(address + 0x1D)
	entry.animtime    = memory.readbyte(address + 0x1E)
	entry.collision   = memory.readbyte(address + 0x20)
	entry.colcustom   = memory.readbyte(address + 0x21)
	entry.status      = memory.readbyte(address + 0x22)
	entry.respawn     = memory.readbyte(address + 0x23)
	entry.counter     = memory.readbyte(address + 0x24)
	entry.counter2    = memory.readbyte(address + 0x25)
	entry.angle       = memory.readbyte(address + 0x26)
	entry.angle2      = memory.readbyte(address + 0x27)
	entry.subtype     = memory.readbyte(address + 0x28)
	entry.parent      = memory.readword(address + 0x3E)
	
	return entry
end