LaserMod = lasers + geometric optics

lasermod.lua

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--LUA Lag Compensation version 1.0.1 + LaserMod by FlooD--------
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--thx to Jermuk for his custom server, which first encouraged---
--    me to make lag compensation.------------------------------
--thx to lasthope and def3ct for initial testing.---------------
--thx to 3rr0r for ideas and suggestions for refining the code.-
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--visit cs2d.nl/index.php?mod=board&action=thread&where=120 for-
--    the lastest version and information-----------------------
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--[[initialization, arrays, reseting]]--------------------------
math.randomseed(os.time())
math.randomseed(os.time() * math.sin(os.time() * math.random()))

images = 0
max_images = 12 --lower to decrease lag
IOR = {1, 1.5, 0} --index of refraction of ground, obstacle, wall. < 1 means mirror.
power_threshold = 0.01 --raise to decrease lag
gamma = 1 / 2.2 --how bright faint lines are
fade_time = 1000 --how long lines last

ping = {} --array of filtered pings of living players
mode = {{}, {}, {}} --glock burst, famas burst, zoom
buffer = {{}, {}} --buffer of current and past positions in x and y coordinates
enable = {} --whether lag comp is enabled for one player
disabled = {} --weapons whose bullets are not compensated
for i, v in ipairs({0, 47, 51, 72, 73, 75, 76, 77, 86, 87, 253, 254, 255}) do
	disabled[v] = true
end

armor = {} --special armor protection values
for i, v in ipairs({25, 50, 75, 50, 95}) do
	armor[200 + i] = 1 - (v / 100)
end

function reset(id)
	mode[1][id] = 0
	mode[2][id] = 0
	mode[3][id] = 0
	buffer[1][id] = {}
	buffer[2][id] = {}
	ping[id] = nil
end

function clear(id)
	reset(id)
	enable[id] = 1
end

for i = 1, 32 do --initial
	clear(i)
end
addhook("leave", "clear")
addhook("die", "reset")

function updateping(id)
	local actualping = player(id, "ping")
	local lastping = ping[id]
	if not lastping then lastping = 0 end
	if actualping then
		if actualping - lastping <= 30 or lastping == 0 then --regular
			ping[id] = actualping
		else --spike is "damped"
			ping[id] = 0.7 * lastping + 0.3 * actualping
		end
	end
end
addhook("spawn", "updateping")
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--[[periodic functions]]----------------------------------------
frame = 1
BUFFER_SIZE = 25
function updatebuffer()
	frame = frame + 1
	for i in pairs(ping) do
		buffer[1][i][frame], buffer[2][i][frame] = player(i, "x"), player(i, "y")
		buffer[1][i][frame - BUFFER_SIZE], buffer[2][i][frame - BUFFER_SIZE] = nil, nil
	end
	images = 0
end
addhook("always", "updatebuffer")

function onsecond()
	for i in pairs(ping) do
		updateping(i)
	end
end
addhook("second", "onsecond")
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--[[new hit system]]--------------------------------------------
addhook("hit", "onhit")
function onhit(v, id, wpn)
	if disabled[wpn] or id == 0 or enable[id] ~= 1 then --preserve cs2d's internal hit system in these cases
		return 0
	end
	return 1
end

addhook("attack", "onattack")
function onattack(id)
	local wpn = player(id, "weapon")
	
	if disabled[wpn] or enable[id] ~= 1 then --preserve cs2d's internal hit system in these cases
		return
	end

	local dmg = itemtype(wpn, "dmg") * game("mp_damagefactor")

	if (wpn == 2 and mode[1][id] == 1) or (wpn == 39 and mode[2][id] == 1) then --burst weapons
		dmg = math.floor(dmg * 0.64 + 0.5)
		local rot1 = player(id, "rot") - 6 + 12 * math.random()
		local rot2 = player(id, "rot") + 6 + 8 * math.random()
		local rot3 = player(id, "rot") - 6 - 8 * math.random()
		simulate_attack(id, wpn, dmg, rot1)
		simulate_attack(id, wpn, dmg, rot2)
		simulate_attack(id, wpn, dmg, rot3)
		return
	elseif wpn == 10 or wpn == 11 then
		for i=1,5 do
			simulate_attack(id, wpn, dmg, player(id, "rot") - 20 + 40 * math.random(), 180)
		end
		return
	end
	
	if mode[3][id] == 1 then --scoped weapons
		dmg = itemtype(wpn, "dmg_z1") * game("mp_damagefactor")
	elseif mode[3][id] == 2 then
		dmg = itemtype(wpn, "dmg_z2") * game("mp_damagefactor")
	end

	local rot = player(id, "rot") + itemtype(wpn, "dispersion") * (2 * math.random() - 1)
	simulate_attack(id, wpn, dmg, rot)
end

addhook("attack2", "onattack2")
function onattack2(id, m)
	local wpn = player(id, "weapon")
	if wpn == 50 or wpn == 69 then
		if enable[id] == 1 then
			simulate_attack(id, wpn, itemtype(wpn, "dmg_z1") * game("mp_damagefactor"))
		end
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--[[syncs burst/zoom for each player to actual cs2d burst/zoom]]
	elseif wpn == 2 then
		mode[1][id] = m
	elseif wpn == 39 then
		mode[2][id] = m
	elseif wpn ~= 32 and wpn >= 31 and wpn <= 37 then
		mode[3][id] = m
	end	
end

addhook("reload", "unzoom")
addhook("select", "unzoom")
function unzoom(id)
	mode[3][id] = 0
end

addhook("drop", "ondrop")
function ondrop(id,iid,wpn,ain,a,m)
	mode[3][id] = 0
	if wpn == 2 then
		mode[1][id] = 0
	elseif wpn == 39 then
		mode[2][id] = 0
	end
end

addhook("collect", "oncollect")
function oncollect(id,iid,wpn,ain,a,m)
	if wpn == 2 then
		mode[1][id] = m
	elseif wpn == 39 then
		mode[2][id] = m
	end
end
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--[[bullet simulation]]-----------------------------------------

--[[simulates the shooting of a bullet of damage (dmg) from
(wpn) by (id) with angle (rot) and range (range). it has two
parts. part 1 finds bullet's path before hitting a wall; part 2
calculates hits on other players (with lag compensation).]]
function simulate_attack(id, wpn, dmg, rot, range)
	if not wpn then wpn = player(id, "weapon") end
	if not dmg then dmg = itemtype(wpn, "dmg") * game("mp_damagefactor") end
	if not rot then rot = player(id, "rot") end
	if not range then range = itemtype(wpn, "range") end

	local start_x = player(id, "x")
	local start_y = player(id, "y")

	--part 1 - split up beams
	local beams = flattenbeam(get_rays(start_x, start_y, rot, 3 * range, 1))

	--part 2 - detect hits
	local frames = math.floor(ping[id] / 20)
	if frames > (BUFFER_SIZE - 1) then
		frames = (BUFFER_SIZE - 1)
	end

	local victims = {}
	if game("sv_friendlyfire") == "0" and game("sv_gamemode") ~= "1" then
		for i in pairs(ping) do
			if player(i, "team") ~= player(id, "team") then
				victims[i] = true
			end
		end
	else
		for i in pairs(ping) do
			victims[i] = true
		end
		victims[id] = nil
	end
	local olddmg = dmg
	for _, beam in ipairs(beams) do
		dmg = olddmg * (beam[5] or 1)
		for i in pairs(victims) do
			if intersect(beam[1], beam[2], beam[3], beam[4], buffer[1][i][frame - frames], buffer[2][i][frame - frames], 12) then
				parse("sv_sound2 "..id.." player/hit"..math.ceil(3 * math.random())..".wav")
				parse("sv_sound2 "..i.." player/hit"..math.ceil(3 * math.random())..".wav")
				local newhealth
				local newarmor = player(i, "armor")

				if newarmor <= 200 then
					newarmor = newarmor - dmg
					if newarmor < 0 then
						newarmor = 0
					end
					newhealth = player(i, "health") - (dmg - math.floor(game("mp_kevlar") * (player(i, "armor") - newarmor)))
					parse("setarmor "..i.." "..newarmor)
				else --special armor values
					newhealth = player(i, "health") - math.floor((dmg * (armor[newarmor] or 1)))
				end

				if newhealth > 0 then
					parse("sethealth "..i.." "..newhealth)
				else
					parse("customkill "..id.." "..itemtype(wpn, "name").." "..i)
				end
			end
		end
	end
end

--the following functions are used in simulate_attack.
function get_rays(start_x, start_y, rot, range, power)
	if range <= 0 then return end
	if power <= power_threshold then return end
	if not rot then return end
	local end_x = start_x + (range) * math.sin(math.rad(rot))
	local end_y = start_y - (range) * math.cos(math.rad(rot))

	local inc_x, inc_y
	if rot < 0 then
		inc_x = -1
	elseif rot > 0 and rot ~= 180 then
		inc_x = 1
	end
	if math.abs(rot) > 90 then
		inc_y = 1
	elseif math.abs(rot) < 90 then
		inc_y = -1
	end

	local tile_x = math.floor(start_x / 32)
	local tile_y = math.floor(start_y / 32)
	if (inc_x or 0) == -1 and start_x % 32 == 0 then tile_x = tile_x - 1 end
	if (inc_y or 0) == -1 and start_y % 32 == 0 then tile_y = tile_y - 1 end

	local beams = {}
	local n2 = tile_IOR(tile_x, tile_y)
	while true do
		n1 = n2
		n2 = tile_IOR(tile_x, tile_y)
		if n2 < 1 then --mirror, 100% reflection.
			local i
			end_x, end_y, i = intersect(start_x, start_y, end_x, end_y, topixel(tile_x), topixel(tile_y), 16)
			if i == 1 then --vertical reflection
				rot = -rot
			elseif i == 0 then --horizontal reflection
				rot = ((1 + (inc_x or 1)) * 180 - rot) % 360 - 180
			else
				--msg("wtf")
				break
			end
			range = range - math.sqrt((end_x - start_x) ^ 2 + (end_y - start_y) ^ 2)
			beams[#beams + 1] = {start_x, start_y, end_x, end_y, power} --incident
			beams[#beams + 1] = get_rays(end_x, end_y, rot, range, power) --reflected
			break
		elseif n1 ~= n2 then --interface. fresnel + snell.
			local i
			end_x, end_y, i = intersect(start_x, start_y, end_x, end_y, topixel(tile_x), topixel(tile_y), 16)
			
			local rot_r, rot_t --reflection and transmission angles
			local R --fraction of power reflected. T = 1 - R by conservation of energy.
			local a, b --helpers
			if i == 1 then
				rot_r = -rot
				local something = n1 / n2 * math.sin(math.rad(rot - (inc_x or 1) * 90))
				if math.abs(something) <=1 then
					rot_t = (inc_x or 1) * 90 + math.deg(math.asin(something)) --snell's law
				end
				a = rot_t and n1 * math.cos(math.rad(rot - (inc_x or 1) * 90)) or 1
				b = rot_t and n2 * math.cos(math.rad(rot_t - (inc_x or 1) * 90)) or 0
			elseif i == 0 then
				rot_r = (inc_x or 1) * 180 - rot
				local something = n1 / n2 * math.sin(math.rad(90 * (1 + (inc_y or 1)) - rot))
				if math.abs(something) <= 1 then
					rot_t = (90 * (3 + (inc_y or 1)) - math.deg(math.asin(something))) % 360 - 180
				end
				a = rot_t and n1 * math.cos(math.rad(90 * (1 + (inc_y or 1)) - rot)) or 1
				b = rot_t and n2 * math.cos(math.rad(90 * (1 + (inc_y or 1)) - rot_t)) or 0
			else
				--msg("debug: wtf")
				break
			end
			R = ((a - b) / (a + b)) ^ 2 -- fresnel's equation
			range = range - math.sqrt((end_x - start_x) ^ 2 + (end_y - start_y) ^ 2)
			beams[#beams + 1] = {start_x, start_y, end_x, end_y, power} --incident
			if R < 0.5 then --this makes sure beam is sorted by power
				rot_r, rot_t = rot_t, rot_r
				R = 1 - R
			end
			beams[#beams + 1] = get_rays(end_x, end_y, rot_r, range, power * R)
			beams[#beams + 1] = get_rays(end_x, end_y, rot_t, range, power * (1 - R))
			break
		end
		local temp_x, temp_y = tile_x, tile_y
		if inc_x and intersect(start_x, start_y, end_x, end_y, topixel(temp_x + inc_x), topixel(temp_y), 16) then
			tile_x = temp_x + inc_x
		end
		if inc_y and intersect(start_x, start_y, end_x, end_y, topixel(temp_x), topixel(temp_y + inc_y), 16) then
			tile_y = temp_y + inc_y
		end
		if tile_x == temp_x and tile_y == temp_y then
			--msg("range")
			beams[#beams + 1] = {start_x, start_y, end_x, end_y, power}
			break
		end
	end
	return beams
end

function tile_IOR(tile_x, tile_y)
	if tile(tile_x, tile_y, "wall") then
		return IOR[3]
	elseif tile(tile_x, tile_y, "obstacle") then
		return IOR[2]
	else
		return IOR[1]
	end
end

function isbeam(tab)
	if type(tab) ~= "table" or #tab ~= 5 then return false end
	for i, v in ipairs(tab) do
		if type(v) == "table" then return false end
	end
	return true
end

function flattenbeam(tab) --also draws them :D
	local flat = {}
	for i, v in ipairs(tab) do
		if isbeam(v) then
			drawbeam(v)
			flat[#flat + 1] = {}
			for a, b in ipairs(v) do
				flat[#flat][a] = b
			end
		else
			for c, d in ipairs(flattenbeam(v)) do
				flat[#flat + 1] = {}
				for e, f in ipairs(d) do
					flat[#flat][e] = f
				end
			end
		end
	end
	return flat
end

function drawbeam(beam)
	if images <= max_images then
		images = images + 1
		local x, y = (beam[1] + beam[3]) / 2, (beam[2] + beam[4]) / 2
		local id = image("gfx/sprites/laserbeam1.bmp", x, y, 1)
		imagealpha(id, beam[5] ^ gamma) --crude srgb gamma correction
		imagecolor(id, 0, 255, 0)
		imagescale(id, 0.25, math.sqrt((beam[4] - beam[2]) ^ 2 + (beam[3] - beam[1]) ^ 2) / 32)
		imagepos(id, x, y, 90 + math.deg(math.atan2((beam[4] - beam[2]) , (beam[3] - beam[1]))))
		tween_alpha(id, fade_time, 0)
		timer(fade_time, "freeimage", id)
	end
end

--converts a tile number to the tile's center pixel.
function topixel(tile)
	return (tile * 32) + 16
end

--quick test to see if i is in between s and e. used in intersect().
function isinorder(s, i, e)
	return (e >= i and i >= s) or (e <= i and i <= s)
end

--[[returns the first point of intersection between a box centered at (bx, by) with
half side length (bl) and a line segment starting from (sx, sy) and ending at (ex, ey).
if the line segment is enclosed by the box, (ex, ey) is returned.]]
function intersect(sx, sy, ex, ey, bx, by, bl)
	if not (bx and by) then return end --fixes rare lua error

	if math.abs(sx - bx) <= bl and math.abs(sy - by) <= bl then
		if math.abs(ex - bx) <= bl and math.abs(ey - by) <= bl then
			if math.abs(ey - by) == bl then
				return ex, ey, 0
			end
			return ex, ey, 1
		else
			sx, sy, ex, ey = ex, ey, sx, sy
		end
	end

	local i_x, i_y

	if ey > sy then
		i_y = by - bl
	elseif ey < sy then
		i_y = by + bl
	end
	if i_y and isinorder(sy, i_y, ey) then
		i_x = ((ex - sx) * i_y + (sx * ey - sy * ex)) / (ey - sy)
		if math.abs(i_x - bx) <= bl and isinorder(sx, i_x, ex) then
			return i_x, i_y, 0 -- collision with horizontal edge
		end
	end

	if ex > sx then
		i_x = bx - bl
	elseif ex < sx then
		i_x = bx + bl
	end
	if i_x and isinorder(sx, i_x, ex) then
		i_y = ((ey - sy) * i_x + (sy * ex - sx * ey)) / (ex - sx)
		if math.abs(i_y - by) <= bl and isinorder(sy, i_y, ey) then
			return i_x, i_y, 1 -- collision with vertical edge
		end
	end
end
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--[[debug stuff]]-----------------------------------------------
addhook("serveraction","onserveraction")
function onserveraction(id, action)
	if action == 1 then
		msg2(id, "This server is running LaserMod by FlooD. your current ping: "..(ping[id] or (player(id, "ping").." (dead)")))
	end
end
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