local dirPX = 0
local dirNX = 1
local dirPY = 2
local dirNY = 3
local dirPZ = 4
local dirNZ = 5
local sizex = const.SlabSizeX
local sizey = const.SlabSizeY
local sizez = const.SlabSizeZ

MapVar("MapIncendiaryGrenadeZones", {})
MapVar("MapSmokeZones", {})
MapVar("MapFlareOnGround", {})

DefineClass.Grenade = {
	__parents = { "QuickSlotItem", "GrenadeProperties", "InventoryStack", "BaseWeapon", "BobbyRayShopOtherProperties" },
	RolloverClassTemplate = "Throwables",
	base_skill = "Dexterity",
}

function Grenade:GetRolloverType()
	return self.ItemType or "Throwables"
end

function Grenade:GetAccuracy(dist)
	return 100
end

function Grenade:GetMaxAimRange(unit)
	local str = IsKindOf(unit, "Unit") and unit.Strength or 100
	local range = MulDivRound(self.BaseRange, Max(0, 100 - str), 100) + MulDivRound(self.ThrowMaxRange, Min(100, str), 100)
	return Max(1, range)
end

function Grenade:GetMaxRange()
	return self.AreaOfEffect * const.SlabSizeX * 3 / 2
end

function Grenade:IsGasGrenade(aoeType)
	aoeType = aoeType or self.aoeType
	return aoeType == "smoke" or aoeType == "teargas" or aoeType == "toxicgas"
end

function Grenade:IsFireGrenade(aoeType)
	return (aoeType or self.aoeType) == "fire"
end

function Grenade:OnPrepareThrow(thrower, visual)
	if InventoryItemDefs[self.class] and InventoryItemDefs[self.class].group == "Grenade - Explosive" then
		ShowThrowingTutorial()
	end
end

function Grenade:OnFinishThrow(thrower)
	if GetCurrentOpenedTutorialId() == "Throwing" then
		TutorialHintsState.Throwing = true
	end
end

function Grenade:OnThrow(thrower, visual_objs)	
	for _, obj in ipairs(visual_objs) do
		if obj:HasAnim("fly") then
			obj:SetAnim(1, "fly")
		end
	end
	
	if GetCurrentOpenedTutorialId() == "Throwing" then
		TutorialHintsState.Throwing = true
	end
end

function Grenade:OnLand(thrower, attackResults, visual_obj)
	if not CurrentThread() then
		CreateGameTimeThread(Grenade.OnLand, self, thrower, attackResults, visual_obj)
		return
	end
	Sleep(160)
	if self.ThrowNoise > 0 then
		-- <Unit> Heard a thud
		PushUnitAlert("noise", visual_obj, self.ThrowNoise, Presets.NoiseTypes.Default.ThrowableLandmine.display_name)
	end
	if self.Noise > 0 then
		PushUnitAlert("noise", visual_obj, self.Noise, Presets.NoiseTypes.Default.Grenade.display_name)
	end
	attackResults.aoe_type = self.aoeType
	attackResults.burn_ground = self.BurnGround
	ApplyExplosionDamage(thrower, visual_obj, attackResults)
	if IsValid(visual_obj) and not IsKindOf(visual_obj, "GridMarker") then
		DoneObject(visual_obj)
	end
end

Grenade.PrecalcDamageAndStatusEffects = ExplosionPrecalcDamageAndStatusEffects

function GetGrenadeDamageBonus(unit)
	return MulDivRound(const.Combat.GrenadeStatBonus, unit.Explosives, 100)
end

function Grenade:GetAreaAttackParams(action_id, attacker, target_pos, step_pos)
	target_pos = target_pos or self:GetPos()
	local aoeType = self.aoeType
	local max_range = self.AreaOfEffect
	if aoeType == "fire" then
		max_range = 2
	end
	local params = {
		attacker = false,
		weapon = self,
		target_pos = target_pos,
		step_pos = target_pos,
		stance = "Prone",
		min_range = self.AreaOfEffect,
		max_range = max_range,
		center_range = self.CenterAreaOfEffect,
		damage_mod = 100,
		attribute_bonus = 0,
		can_be_damaged_by_attack = true,
		aoe_type = aoeType,
		explosion = true, -- damage dealt depends on target stance
		explosion_fly = self.DeathType == "BlowUp",
	}
	if self.coneShaped then
		params.cone_length = self.AreaOfEffect * const.SlabSizeX
		params.cone_angle = self.coneAngle * 60
		params.target_pos = RotateRadius(params.cone_length, CalcOrientation(step_pos or attacker, target_pos), target_pos)
		if not params.target_pos:IsValidZ() or params.target_pos:z() - terrain.GetHeight(params.target_pos) <= 10*guic then
			params.target_pos = params.target_pos:SetTerrainZ(10*guic)
		end
	end
	if IsKindOf(attacker, "Unit") then
		params.attacker = attacker
		--params.attribute_bonus = GetGrenadeDamageBonus(attacker) -- already applied in GetBaseDamage
	end
	return params
end

local GrenadeCustomDescriptions = {
	["fire"] = T(933586341461, "Sets an area on fire and inflicts <em>Burning</em>."),
	["smoke"] = T(487595290755, "Ranged attacks passing through gas become <em>grazing</em> hits."),
	["teargas"] = T(411101296173, "Inflicts <em>Blinded</em>, making affected characters less accurate. Ranged attacks passing through gas become <em>grazing</em> hits."),
	["toxicgas"] = T(298305721189, "Inflicts <em>Choking</em>, forcing affected characters to take damage and lose energy, eventually fall <em>unconscious</em>. Ranged attacks passing through gas become <em>grazing</em> hits."),
}

function Grenade:GetCustomActionDescription(units)
	return GrenadeCustomDescriptions[self.aoeType] -- if the table value is nil the default action description will be used
end

function ExplosionDamage(attacker, weapon, pos, fx_actor, force_flyoff, disableBurnFx, ignore_targets)
	local aoe_params = weapon:GetAreaAttackParams(nil, attacker, pos)
	local effects = {}
	if not aoe_params.aoe_type or aoe_params.aoe_type == "none" then
		effects[1] = "CancelShot"
	end
	if (weapon.AppliedEffect or "") ~= "" then
		effects[#effects + 1] = weapon.AppliedEffect
	end
	aoe_params.prediction = false
	local original_mask
	if attacker and attacker.spawned_by_explosive_object then
		original_mask = collision.GetAllowedMask(attacker.spawned_by_explosive_object)
		local ignore_self = 0
		collision.SetAllowedMask(attacker.spawned_by_explosive_object, ignore_self)
	end
	
	local results = GetAreaAttackResults(aoe_params, 0, effects)
	CompileKilledUnits(results)
	
	if original_mask then
		collision.SetAllowedMask(attacker.spawned_by_explosive_object, original_mask)
	end
	
	if force_flyoff then
		for i, h in ipairs(results) do
			h.explosion_fly = true
		end
	end
	if IsKindOf(weapon, "ExplosiveProperties") then
		results.burn_ground = weapon.BurnGround
	end
	results.weapon = weapon
	ApplyExplosionDamage(attacker, fx_actor, results, weapon.Noise, disableBurnFx, ignore_targets)
end

function GetExplosionDecalPos(pos)
	local offset = guim
	local lowest_z = pos:z()
	for dx = -offset, offset, offset do
		for dy = -offset, offset, offset do
			local z = terrain.GetHeight(pos + point(dx, dy, 0))
			lowest_z = (z < lowest_z) and z or lowest_z
		end
	end
	lowest_z = Max(lowest_z, pos:z() - guim)
	return pos:SetZ(lowest_z - 25 * guic)
end

MapVar("g_LastExplosionTime", false)

local function igMolotovDestroyOrBurn(obj, dist2)
	if dist2 < sizex*sizex then
		return "destroy"
	end
	if dist2 > 2*sizex*sizex then
		return "impact"
	end
	return InteractionRand(100, "Explosion") < 50 and "destroy" or "burn"
end

local function igExplosionDestroyOrBurn(obj, dist2, range)
	if dist2 > range*range then
		return "impact"
	end
	return "destroy"
end

local function GetExplosionFXPos(visual_obj_or_pos)
	local pos = IsPoint(visual_obj_or_pos) and visual_obj_or_pos or visual_obj_or_pos:GetPos() --light fx use this pos, alternatively we could make them not affect stealth
	if not pos:IsValidZ() then
		pos = pos:SetTerrainZ() -- only when pos is on invalidz so we can still get walkable slabs that are over the terrain if the position is right
	end
	local slab, slab_z = WalkableSlabByPoint(pos)
	local z = pos:z()
	
	if slab_z then
		if slab_z <= z and slab_z >= z - guim then
			pos = pos:SetZ(slab_z)
		end
	else
		pos = GetExplosionDecalPos(pos)
	end
	
	return pos
end

function ApplyExplosionDamage(attacker, fx_actor, results, noise, disableBurnFx, ignore_targets)
	if not CurrentThread() then
		CreateGameTimeThread(ApplyExplosionDamage, attacker, fx_actor, results, noise, disableBurnFx)
		return
	end

	local gas = results.aoe_type == "smoke" or results.aoe_type == "teargas" or results.aoe_type == "toxicgas"
	local fire = results.aoe_type == "fire"
	
	local pos
	local surf_fx_type
	local fx_action
	if fx_actor then
		pos = GetExplosionFXPos(fx_actor)
		surf_fx_type = GetObjMaterial(pos)
		if fire then
			fx_action = "ExplosionFire"
		elseif gas then
			fx_action = "ExplosionGas"
		else
			fx_action = "Explosion"
		end
		PlayFX(fx_action, "start", fx_actor, surf_fx_type, pos)
	end
	Sleep(100)
	if fx_actor and not disableBurnFx then
		PlayFX(fx_action, "end", fx_actor, surf_fx_type, pos)
	end
	local burn_ground = true
	if results.burn_ground ~= nil then
		burn_ground = results.burn_ground
	end
	if not fire and not gas and burn_ground and results.target_pos then
		--PlaceWindModifierExplosion(results.target_pos, results.range)
		if not disableBurnFx then
			local fDestroyOrBurn = (results.aoe_type == "fire") and igMolotovDestroyOrBurn or igExplosionDestroyOrBurn
			Explosion_ProcessGrassAndShrubberies(results.target_pos, results.range/2, fDestroyOrBurn)
		end
	end

	local attack_reaction, weapon
	if IsKindOf(attacker, "DynamicSpawnLandmine") and IsKindOf(attacker.attacker, "Unit") then
		attack_reaction = true
		weapon = attacker
		attacker = attacker.attacker
	elseif IsKindOf(attacker, "Unit") then
		attack_reaction = true
		weapon = results.weapon
	end
	
	local hit_units = {}
	ignore_targets = ignore_targets or empty_table
	for _, hit in ipairs(results) do
		local obj = hit.obj
		hit.explosion = true
		if IsValid(obj) then --after fx sleep this obj can no longer be valid
			if not ignore_targets[obj] then
				if IsKindOf(obj, "Unit") then
					if not hit_units[obj] then
						hit_units[obj] = hit
					else
						hit_units[obj].damage = hit_units[obj].damage + hit.damage
					end
				elseif IsKindOf(obj, "CombatObject") then
					obj:TakeDamage(hit.damage, attacker, hit)
				elseif IsKindOf(obj, "Destroyable") and hit.damage > 0 then
					obj:Destroy()
				end
			end
		end
	end
	--pp units so they know wheather they would need to fall down before dying
	for u, hit in sorted_handled_obj_key_pairs(hit_units or empty_table) do
		if not ignore_targets or not ignore_targets[u] then
			u:ApplyDamageAndEffects(attacker, hit.damage, hit, hit.armor_decay)
		end
	end
	
	if fx_actor and attacker and not attacker.spawned_by_explosive_object then
		PushUnitAlert("thrown", fx_actor, attacker)
	end
	if fx_actor and noise then
		PushUnitAlert("noise", fx_actor, noise, Presets.NoiseTypes.Default.Explosion.display_name)
	end
	
	if fire then
		ExplosionCreateFireAOE(attacker, results, fx_actor)
	elseif gas then
		ExplosionCreateSmokeAOE(attacker, results, fx_actor)
	end

	if attack_reaction then
		AttackReaction("ThrowGrenadeA", {obj = attacker, weapon = weapon}, results)
	end
	NetUpdateHash("g_LastExplosionTime_set")
	g_LastExplosionTime = GameTime()
end

function GrenadesComboItems(items)
	items = items or {}
	ForEachPresetInGroup("InventoryItemCompositeDef", "Grenade", function(o) items[#items+1] = o.id end)
	return items
end

function Grenade:CalcTrajectory(attack_args, target_pos, angle, max_bounces)
	local attacker = attack_args.obj
	local anim_phase = attacker:GetAnimMoment(attack_args.anim, "hit") or 0
	local attack_offset = attacker:GetRelativeAttachSpotLoc(attack_args.anim, anim_phase, attacker, attacker:GetSpotBeginIndex("Weaponr"))
	local step_pos = attack_args.step_pos
	if not step_pos:IsValidZ() then
		step_pos = step_pos:SetTerrainZ()
	end
	local pos0 = step_pos:SetZ(step_pos:z() + attack_offset:z())
	if not angle then
		if target_pos:z() - pos0:z() > const.SlabSizeZ / 2 then
			angle = const.Combat.GrenadeLaunchAngle_Incline
		else
			angle = const.Combat.GrenadeLaunchAngle
		end
	end
	local sina, cosa = sincos(angle)
	local aim_pos = pos0 + Rotate(point(cosa, 0, sina), CalcOrientation(pos0, target_pos))
	local grenade_pos = GetAttackPos(attack_args.obj, step_pos, axis_z, attack_args.angle, aim_pos, attack_args.anim, anim_phase, attack_args.weapon_visual)
	if grenade_pos:Equal2D(target_pos) then
		return empty_table
	end

	local dir = target_pos - grenade_pos
	local bounce_diminish = 40
	local vec
	local can_bounce = self.CanBounce
	if attack_args.can_bounce ~= nil then
		can_bounce = attack_args.can_bounce
	end
	max_bounces = can_bounce and max_bounces or 0
	if can_bounce then
		max_bounces = 1
	end
	if max_bounces > 0 then
		local coeff = 1000
		local d = 10 * bounce_diminish
		for i = 1, max_bounces do
			coeff = coeff + d
			d = MulDivRound(d, bounce_diminish, 100)
		end
		local bounce_target_pos = grenade_pos + MulDivRound(dir, 1000, coeff)
		vec = CalcLaunchVector(grenade_pos, bounce_target_pos, angle, const.Combat.Gravity)
	else
		vec = CalcLaunchVector(grenade_pos, target_pos, angle, const.Combat.Gravity)
	end
	local time = MulDivRound(grenade_pos:Dist2D(target_pos), 1000, Max(vec:Len2D(), 1))
	if time == 0 then
		return empty_table
	end
	local trajectory = CalcBounceParabolaTrajectory(grenade_pos, vec, const.Combat.Gravity, time, 20, max_bounces, bounce_diminish)
	return trajectory
end

function Grenade:ValidatePos(explosion_pos)
	return explosion_pos
end

function Grenade:GetTrajectory(attack_args, attack_pos, target_pos, mishap)
	if not attack_pos and attack_args.lof then
		local lof_idx = table.find(attack_args.lof, "target_spot_group", attack_args.target_spot_group)
		local lof_data = attack_args.lof[lof_idx or 1]
		attack_pos = lof_data.attack_pos
	end

	if not attack_pos then 
		return {}
	end
	
	-- sanity-check the target pos
	local pass = SnapToPassSlab(target_pos)
	local valid_target = true
	if pass then
		pass = pass:IsValidZ() and pass or pass:SetTerrainZ()
		if abs(pass:z() - target_pos:z()) >= 2*const.SlabSizeZ then
			valid_target = false
		end
	else 
		valid_target = false
	end
		
	-- try the different trajectories to pick a suitable one
	local angles = {}
		
	if valid_target or mishap then 
		if target_pos:z() - attack_pos:z() >= 2*const.SlabSizeZ then
			angles[1] = const.Combat.GrenadeLaunchAngle_Incline
			angles[2] = const.Combat.GrenadeLaunchAngle
		else
			-- throwing down/level, prefer low arc
			if target_pos:z() - attack_pos:z() <= const.SlabSizeZ / 2 then
				angles[1] = const.Combat.GrenadeLaunchAngle_Low
			end
			angles[#angles+1] = const.Combat.GrenadeLaunchAngle
			if not GameState.Underground then
				angles[#angles+1] = const.Combat.GrenadeLaunchAngle_Incline
			end
		end
	end
	
	local attacker = attack_args.obj

	local best_dist, best_trajectory = attacker:GetDist(target_pos), {}
	for _, angle in ipairs(angles) do		
		local trajectory = self:CalcTrajectory(attack_args, target_pos, angle, (angle == const.Combat.GrenadeLaunchAngle_Low) and 1 or 0)		
		local hit_pos = (#trajectory > 0) and trajectory[#trajectory].pos
		if hit_pos and (hit_pos:Dist(trajectory[1].pos) > 0) then 
			if IsCloser(hit_pos, target_pos, const.SlabSizeX) then
				return trajectory
			end
			local dist = hit_pos:Dist(target_pos)
			if dist < best_dist then
				best_dist, best_trajectory = dist, trajectory
			end
		end
	end
	return best_trajectory
end

function Grenade:GetAttackResults(action, attack_args)
	local attacker = attack_args.obj
	local explosion_pos = attack_args.explosion_pos
	local trajectory = {}
	local mishap
	if not explosion_pos and attack_args.lof then
		local lof_idx = table.find(attack_args.lof, "target_spot_group", attack_args.target_spot_group)
		local lof_data = attack_args.lof[lof_idx or 1]
		local attack_pos = lof_data.attack_pos
		local target_pos = lof_data.target_pos

		-- mishap & stealth kill checks
		if not attack_args.prediction and IsKindOf(self, "MishapProperties") then
			local chance = self:GetMishapChance(attacker, target_pos)
			if CheatEnabled("AlwaysMiss") or attacker:Random(100) < chance then
				mishap = true

				-- Try a couple of times to get a valid deviated position
				local validPositionTries = 0
				local maxPositionTries = 5
				while validPositionTries < maxPositionTries do
					local dv = self:GetMishapDeviationVector(attacker, target_pos)
					local deviatePosition = target_pos + dv
					local trajectory = self:GetTrajectory(attack_args, attack_pos, deviatePosition, "mishap")
					local finalPos = #trajectory > 0 and trajectory[#trajectory].pos
					if finalPos and self:ValidatePos(finalPos, attack_args) then
						target_pos = deviatePosition
						break
					end
					validPositionTries = validPositionTries + 1
				end
				attacker:ShowMishapNotification(action)
			end
		end

		trajectory = self:GetTrajectory(attack_args, attack_pos, target_pos, mishap)
		if #trajectory > 0 then
			explosion_pos = trajectory[#trajectory].pos
		end
		explosion_pos = self:ValidatePos(explosion_pos, attack_args)
	end
	
	local results
	if explosion_pos then
		local aoe_params = self:GetAreaAttackParams(action.id, attacker, explosion_pos, attack_args.step_pos)
		if attack_args.stealth_attack then
			aoe_params.stealth_attack_roll = not attack_args.prediction and attacker:Random(100) or 100
		end
		aoe_params.prediction = attack_args.prediction
		if aoe_params.aoe_type ~= "none" or IsKindOf(self, "Flare") then
			aoe_params.damage_mod = "no damage"
		end
		results = GetAreaAttackResults(aoe_params)
		CompileKilledUnits(results)

		local radius = aoe_params.max_range * const.SlabSizeX
		local explosion_voxel_pos = SnapToVoxel(explosion_pos) + point(0, 0, const.SlabSizeZ / 2)
		local impact_force = self:GetImpactForce()
		local unit_damage = {}
		for _, hit in ipairs(results) do
			local obj = hit.obj
			if not obj or hit.damage == 0 then goto continue end
			
			local dist = hit.obj:GetDist(explosion_voxel_pos)
			if IsKindOf(obj, "Unit") then
				if not obj:IsDead() then
					unit_damage[obj] = (unit_damage[obj] or 0) + hit.damage
					if unit_damage[obj] >= obj:GetTotalHitPoints() then
						results.killed_units = results.killed_units or {}
						table.insert_unique(results.killed_units, obj)
					end
				end
			end
			hit.impact_force = impact_force + self:GetDistanceImpactForce(dist)
			hit.explosion = true
			::continue::
		end
	else
		results = {}
	end
	results.trajectory = trajectory
	results.explosion_pos = explosion_pos
	results.weapon = self
	results.mishap = mishap
	results.no_damage = IsKindOf(self, "Flare")
	
	return results
end

function Grenade:CreateVisualObj(owner)
	local grenade = owner:AttachGrenade(self)
	return grenade
end

function Grenade:GetVisualObj(attacker, force)
	local grenade = attacker:GetAttach("GrenadeVisual")
	if not grenade or force then
		-- AI has skipped the UI part
		grenade = attacker:AttachGrenade(self)
	end
	return grenade
end

---[[
function DbgAddVoxel(pt, color)
	pt = SnapToVoxel(pt)
	local x, y, z = pt:xyz()
	local bx = box(x - const.SlabSizeX/2, y - const.SlabSizeY/2, z, x + const.SlabSizeX/2, y + const.SlabSizeY/2, z + const.SlabSizeZ)
	DbgAddBox(bx, color)
end

function CalcLaunchVector(start_pt, end_pt, angle, gravity)
	if not start_pt or not end_pt then
		return
	end
	assert(start_pt:IsValidZ() and end_pt:IsValidZ())

	angle = angle or const.Combat.GrenadeLaunchAngle

	local dist = start_pt:Dist2D(end_pt)
	local dir = SetLen((end_pt - start_pt):SetZ(0), guim)

	local y0 = start_pt:z()
	local yt = end_pt:z()

	local sina, cosa = sin(angle), cos(angle)

	local t1 = MulDivRound(gravity or const.Combat.Gravity, dist*dist, guim) -- scale guim^2
	local t2 = 2*cosa*cosa -- scale 4k^2
	local t3 = (yt - y0) * guim -- scale guim^2
	local t4 = MulDivRound(dist, sina * guim, cosa) -- scale guim^2

	local v0 = MulDivRound(sqrt(t1), guim, Max(1, MulDivRound(sqrt(t2), sqrt(Max(0, -t3+t4)), 4096)))
	local v0x = MulDivRound(v0, cosa, 4096)
	local v0y = MulDivRound(v0, sina, 4096)

	return SetLen(dir, v0x) + point(0, 0, v0y)
end

function IsBreakableWindow(obj)
	return IsKindOf(obj, "SlabWallWindow") and obj:IsWindow() and obj:IsBreakable() and not obj:IsBroken()
end

--[[
function CalcBounceParabolaTrajectory(start_pt, launch_speed, gravity, time, tStep, max_bounces, diminish, no_collision)
	local t = 0	
	local pos = start_pt
	local v = launch_speed
	local vg = point(0, 0, -(gravity or const.Combat.Gravity))
	local trajectory = {}
	local bounce_flags = const.efVisible + const.efCollision

	if not v:IsValidZ() then
		v = v:SetZ(0)
	end

	while terrain.IsPointInBounds(pos) and pos:z() >= terrain.GetHeight(pos) do
		table.insert(trajectory, { pos = pos, t = t })

		t = t + tStep
		local vnext = v + MulDivRound(vg, tStep, 1000)
		local posnext = pos + MulDivRound(vnext, tStep, 1000)
		local hit_water

		local function bounce(pt, normal, obj)
			if hit_water then 
				return 
			end
			
			if normal == point30 then
				normal = axis_z
			end
			local len = Dot(normal, v) / normal:Len()
			-- reflect the velocity vector
			local proj = SetLen(normal, len)
			local velocity = vnext:Len()
			vnext = SetLen(vnext - (2 * proj), velocity)
			if diminish then
				vnext = MulDivRound(vnext, diminish, 100)
			end

			-- correct the position
			local move_dist = posnext:Dist(pos)
			local hit_dist = pos:Dist(pt)
			local refl_dist = move_dist - hit_dist
			if refl_dist > 0 and vnext ~= point30 then
				table.insert(trajectory, {pos = pt, t = t - tStep + MulDivRound(tStep, hit_dist, move_dist), obj = obj, bounce = true})
				pos = pt
				posnext = pt + SetLen(vnext, refl_dist)
			end
			max_bounces = max_bounces - 1
		end

		-- window detection
		local ipt = terrain.IntersectSegment(pos, posnext)
		if not no_collision then
			local obj, pt, normal = GetClosestRayObj(pos, ipt or posnext, bounce_flags, 0, function(obj, x, y, z)
				local window = IsBreakableWindow(obj) or nil
				local water = IsKindOf(obj, "WaterPlane") or nil
				if window or water then
					local pt = point(x, y, z)
					local move_dist = posnext:Dist(pos)
					local hit_dist = pos:Dist(pt)
					if hit_dist > 0 and move_dist > 0 and vnext ~= point30 then
						local time = t - tStep + MulDivRound(tStep, hit_dist, move_dist)
						local step = { pos = pt, t = time, obj = obj }
						if window then
							step.window = true
						end
						if water then
							hit_water = #trajectory
							step.water = true
						end
						table.insert(trajectory, step)
						pos = pt
						posnext = pt + SetLen(vnext, hit_dist)
						t = time + tStep
					end
					return false
				end
				return true
			end, 0, const.cmDefaultObject)
			if obj and (not obj:IsKindOf("SlabWallDoor") or obj:IsDead() or obj.pass_through_state ~= "open") then				
				bounce(pt, normal, obj)
				if t >= time or max_bounces < 0 then
					-- end before collision pos to avoid detonating inside collision geometry
					local dist = pos:Dist(pt)
					local adj_dist = dist - 10*guic
					if adj_dist <= 0 then
						break
					end
					local end_pt = pos + SetLen(pt - pos, adj_dist)
					local time = t - tStep + MulDivRound(tStep, adj_dist, dist)
					table.insert(trajectory, { pos = end_pt, obj = obj, t = time })
					break
				end
			end
		end

		if ipt then
			bounce(ipt, terrain.GetTerrainNormal(ipt), "terrain")
			if max_bounces < 0 or t >= time then
				break
			end
		end

		pos, v = posnext, vnext
	end

	-- before returning make sure the trajectory stays above ground & has contents
	if #trajectory == 0 then
		table.insert(trajectory, { pos = start_pt, t = 0 })
	end
	if #trajectory == 1 then
		table.insert(trajectory, { pos = start_pt + SetLen(launch_speed, 10*guic), t = 1 })
	end
	
	for _, step in ipairs(trajectory) do
		if step.pos:z() < terrain.GetHeight(step.pos) then
			step.pos = step.pos:SetTerrainZ()
		end
	end
	
	return trajectory
end
--]]

function AnimateThrowTrajectory(visual_obj, trajectory, rotation_axis, rpm, surf_fx, explosion_fx)
	local time = trajectory[#trajectory].t
	local angle = MulDivTrunc(rpm * 360, time, 1000)
	local hit_water

	if rpm ~= 0 then
		visual_obj:SetAxis(rotation_axis)
	end

	local t = 0
	local pos, dir
	
	for i, step in ipairs(trajectory) do
		local step_time = step.t - t
		local dist = pos and step.pos:Dist(pos) or 0
		if dist > 0 then
			dir = step.pos - pos
			--[[if i == 1 and step_time == 0 then
				local idx = i
				local dt, d = 0, 0
				while dt <= 0 or d <= 0 do
					idx = idx + 1
					d = trajectory[idx].pos:Dist(trajectory[i].pos)
					dt = trajectory[idx].t - trajectory[i].t
				end
				step_time = MulDivRound(dt, dist, d)
			end--]]
		end

		step_time = Max(0, step_time)
		pos = step.pos
		visual_obj:SetPos(pos, step_time)
		local st = 0
		while st < step_time do
			local dt = Min(20, step_time - st)
			if rpm ~= 0 then
				visual_obj:SetAngle(visual_obj:GetAngle() + MulDivTrunc(angle, dt, time), dt)
			end
			st = st + dt
			Sleep(dt)
		end
		t = step.t
		local obj = IsValid(step.obj) and step.obj or nil
		if IsBreakableWindow(obj) then
			obj:SetWindowState("broken")
			obj = nil
		end
		if surf_fx and not hit_water and (obj or i == #trajectory or step.bounce) then
			local surf_fx_type = GetObjMaterial(pos, obj)
			local fx_target = surf_fx_type or obj
			PlayFX(surf_fx, "start", visual_obj, fx_target, pos)
		end
		if step.water then
			hit_water = true
		end
	end

	visual_obj:SetAxis(axis_z)
	visual_obj:SetAngle(dir and dir:Len2D() > 0 and CalcOrientation(dir) or 0)

	if explosion_fx then
		local pos = GetExplosionFXPos(visual_obj)
		local surf_fx_type = GetObjMaterial(pos)
		dir = dir and dir:SetZ(0)
		if dir and dir:Len() > 0 then
			dir = SetLen(dir, 4096)
		else
			dir = axis_z
		end
		PlayFX(explosion_fx, "start", visual_obj, surf_fx_type, pos, dir)
	end
	Msg("GrenadeDoneThrow")
end

function ResolveGrenadeTargetPos(target, startPos, grenade)
	target = IsValid(target) and target:GetPos() or target
	if not IsPoint(target) then return false end
	
	-- Move target pos a bit behind cursor for cone shaped explosions
	if grenade and grenade.coneShaped and startPos:Dist(target) > 0 then
		local z = target:z()
		target = target + SetLen(startPos - target, const.SlabSizeX/2)
		if z and target:z() ~= z then
			target = target:SetZ(z)
		end
	end
	
	if target:IsValidZ() then
		target = target:SetZ(target:z() + const.SlabSizeZ / 2)
	else
		target = target:SetTerrainZ(const.SlabSizeZ / 2)
	end
	return target
end

DefineClass.FXGrenade = {
	__parents = { "SpawnFXObject", "ComponentCustomData" },
	flags = { efCollision = false, efApplyToGrids = false, gofRealTimeAnim = false }
}

DefineClass.GrenadeVisual = {
	__parents = { "FXGrenade" },
	custom_equip = false,
	equip_index = 0,
}

MapGameTimeRepeat("ExplosionFiresUpdate", 500, function()
	if g_Combat or g_StartingCombat then return end -- handled on NewCombatTurn msg

	local change
	for _, fire in ipairs(MapIncendiaryGrenadeZones) do
		if fire:UpdateRemainingTime(500) then
			change = true
		end
	end
	if change then
		UpdateMapBurningState(GameState.FireStorm)
	end
	for _, zone in ipairs(MapSmokeZones) do
		zone:UpdateRemainingTime(500)
	end
	for _, flare in ipairs(MapFlareOnGround) do
		flare:UpdateRemainingTime(500)
	end
end)

local function EnvEffectReaction(zone_type, attacker, target, damage)
	if not attacker then return end

	local attack_args = {obj = attacker, target = target}
	local results = {}
	results.area_hits = { {obj = target, aoe = true, damage = damage} }
	results.hit_objs = { target }
	results.hit_objs[target] = true
	results.killed_units = {}
	results.env_effect = true
	if target:IsDead() then
		table.insert(results.killed_units, target)
		if target:IsCivilian() and target.Affiliation == "Civilian" and attacker then
			CivilianDeathPenalty()
		end		
	end
	AttackReaction(zone_type, attack_args, results)
end

function EnvEffectBurningTick(unit, voxels, combat_moment)
	local inside
	if next(g_DistToFire) ~= nil then
		if not voxels then
			voxels = unit:GetVisualVoxels()
		end
		local fire, dist = AreVoxelsInFireRange(voxels)
		inside = fire and dist < const.SlabSizeX
	end
	local effect = unit:GetStatusEffect("Burning")
	if effect then
		if not inside then
			local x, y, z = unit:GetVisualPosXYZ()
			if terrain.IsWater(x, y, z) then
				local water_z = terrain.GetWaterHeight(x, y)
				local dz = (z or terrain.GetHeight(x, y)) - water_z
				if dz >= const.FXWaterMinOffsetZ and dz <= const.FXWaterMaxOffsetZ then
					unit:RemoveStatusEffect("Burning")
					return
				end
			end
		end
		local start_time
		if combat_moment ~= "end turn" then
			if g_Combat or g_StartingCombat then
				return
			end
			start_time = effect:ResolveValue("burning_start_time")
			if GameTime() - start_time < 5000 then
				return
			end
		end
		local damage = Burning:ResolveValue("damage")
		unit:TakeDirectDamage(damage, T{529212078060, "<damage> (Burning)", damage = damage})
		if inside then
			if g_Combat or g_StartingCombat then
				start_time = GameTime()
			else
				start_time = (start_time or effect:GetParameter("burning_start_time")) + 5000
			end
			effect:SetParameter("burning_start_time", start_time)
		else
			unit:RemoveStatusEffect("Burning")
		end
	elseif inside then
		unit:AddStatusEffect("Burning")
	end
end

function EnvEffectToxicGasTick(unit, voxels, combat_moment)
	local inside, protected, attacker
	if next(g_SmokeObjs) ~= nil then
		if not voxels then
			voxels = unit:GetVisualVoxels()
		end
		local smoke
		for _, voxel in ipairs(voxels) do
			local smoke_obj = g_SmokeObjs[voxel]
			if smoke_obj and smoke_obj:GetGasType() == "toxicgas" then
				smoke = smoke_obj
				inside = true
				break
			end
		end
		if inside then
			local mask = unit:GetItemInSlot("Head", "GasMaskBase")
			protected = mask and mask.Condition > 0
			for _, zone in ipairs(smoke.zones) do
				if zone.owner then
					attacker = zone.owner
					break
				end
			end
		end
	end
	
	if inside and protected and attacker then
		-- awareness reactions (there will be no damage/negative effects)
		PushUnitAlert("attack", attacker, unit)
	end
	
	inside = inside and not protected
	
	local effect = unit:GetStatusEffect("Choking")
	if effect then
		local start_time = effect:ResolveValue("choking_start_time")
		if (combat_moment == "end turn") or (not g_Combat and not g_StartingCombat and GameTime() >= start_time + 5000) then			
			local damage = Choking:ResolveValue("damage")
			unit:TakeDirectDamage(damage, T{698692719911, "<damage> (Choking)", damage = damage})
			EnvEffectReaction("toxicgas", attacker, unit, damage)
			if g_Combat or g_StartingCombat then
				start_time = GameTime()
			else
				start_time = start_time + 5000
			end
			if inside then
				effect:SetParameter("choking_start_time", start_time)
			else
				unit:RemoveStatusEffect("Choking")
			end
			local tiredness = RollSkillCheck(unit, "Health") and 1 or 2
			unit:ChangeTired(tiredness)
		end
	elseif inside then
		unit:AddStatusEffect("Choking")
		EnvEffectReaction("toxicgas", attacker, unit, 0)
	end	
end

function EnvEffectTearGasTick(unit, voxels, combat_moment)
	local inside, protected, attacker
	if next(g_SmokeObjs) ~= nil then
		if not voxels then
			voxels = unit:GetVisualVoxels()
		end
		local smoke
		for _, voxel in ipairs(voxels) do
			local smoke_obj = g_SmokeObjs[voxel]
			if smoke_obj and smoke_obj:GetGasType() == "teargas" then
				smoke = smoke_obj
				inside = true
				break
			end
		end
		if inside then
			local mask = unit:GetItemInSlot("Head", "GasMaskBase")
			protected = mask and mask.Condition > 0
			for _, zone in ipairs(smoke.zones) do
				if zone.owner then
					attacker = zone.owner
					break
				end
			end
		end
	end
	
	if inside and protected and attacker then
		-- awareness reactions (there will be no damage/negative effects)
		PushUnitAlert("attack", attacker, unit)
	end
	inside = inside and not protected
	
	local effect = unit:GetStatusEffect("Blinded")
	if effect then
		local start_time = effect:ResolveValue("blinded_start_time")
		if (combat_moment == "end turn") or (not g_Combat and not g_StartingCombat and GameTime() >= start_time + 5000) then
			-- choking damage/end will happen on end turn in combat		
			if g_Combat or g_StartingCombat then
				start_time = GameTime()
			else
				start_time = start_time + 5000
			end
			if inside then
				effect:SetParameter("blinded_start_time", start_time)
			else
				unit:RemoveStatusEffect("Blinded")
			end
		elseif combat_moment == "start turn" and inside then
			if not RollSkillCheck(unit, "Health") then
				unit:AddStatusEffect("Panicked")
			end
		end
	elseif inside then
		unit:AddStatusEffect("Blinded")
		EnvEffectReaction("teargas", attacker, unit, 0)
	end	
end

function EnvEffectSmokeTick(unit, voxels, combat_moment)
	local inside
	if next(g_SmokeObjs) ~= nil then
		if not voxels then
			voxels = unit:GetVisualVoxels()
		end
		for _, voxel in ipairs(voxels) do
			local smoke = g_SmokeObjs[voxel]
			if smoke and (smoke:GetGasType() == "smoke") then
				inside = true
				break
			end
		end
	end
	
	local effect = unit:GetStatusEffect("Smoked")
	if effect then
		local start_time = effect:ResolveValue("smoked_start_time")
		if (combat_moment == "end turn") or (not g_Combat and not g_StartingCombat and GameTime() >= start_time + 5000) then
			if g_Combat or g_StartingCombat then
				start_time = GameTime()
			else
				start_time = start_time + 5000
			end
			if inside then
				effect:SetParameter("smoked_start_time", start_time)
			else
				unit:RemoveStatusEffect("Smoked")
			end
		end
	elseif inside then
		unit:AddStatusEffect("Smoked")
	end	
end

function EnvEffectDarknessTick(unit, voxels)
	if IsIlluminated(unit, voxels, "sync") then
		if unit:HasStatusEffect("Darkness") then
			unit:RemoveStatusEffect("Darkness")
		end
	else
		if not unit:HasStatusEffect("Darkness") then
			unit:AddStatusEffect("Darkness")
		end
	end
end

function EnvEffectsUpdate(side_type, time)
	if IsSetpiecePlaying() then
		Sleep(time)
		return
	end
	local units = {}
	for _, team in ipairs(g_Teams) do
		if side_type == "player" then
			if team.player_team then
				table.iappend(units, team.units)
			end
		else
			local team_side = team.side
			if team_side == "enemyNeutral" then
				team_side = GameState.Conflict and "enemy1" or "neutral"
			end
			if side_type == "neutral" then
				if team_side == "neutral" then
					table.iappend(units, team.units)
				end
			else
				if team_side ~= "neutral" then
					table.iappend(units, team.units)
				end
			end
		end
	end
	local count = #units
	if count == 0 then
		Sleep(time)
		return
	end
	local iclear = table.iclear
	local voxels = {}
	for i = 1, count do
		Sleep(i * time / count - (i - 1) * time / count)
		local unit = units[i]
		if IsValid(unit) and not unit:IsDead() then
			iclear(voxels)
			unit:GetVisualVoxels(nil, nil, voxels)
			EnvEffectBurningTick(unit, voxels)
			EnvEffectToxicGasTick(unit, voxels)
			EnvEffectTearGasTick(unit, voxels)
			EnvEffectSmokeTick(unit, voxels)
			EnvEffectDarknessTick(unit, voxels)
		end
	end
end

MapGameTimeRepeat("EnvEffectsPlayer", 0, function() return EnvEffectsUpdate("player", 100) end)
MapGameTimeRepeat("EnvEffectsNeutral", 0, function() return EnvEffectsUpdate("neutral", 500) end)
MapGameTimeRepeat("EnvEffectsOther", 0, function() return EnvEffectsUpdate("other", 300) end)

function OnMsg.NewCombatTurn()
	local change
	for _, fire in ipairs(MapIncendiaryGrenadeZones) do
		if fire:UpdateRemainingTime(5000) then
			change = true
		end
	end
	if change then
		UpdateMapBurningState(GameState.FireStorm)
	end
	for _, zone in ipairs(MapSmokeZones) do
		zone:UpdateRemainingTime(5000)
	end
	for _, flare in ipairs(MapFlareOnGround) do
		flare:UpdateRemainingTime(5000)
	end
end

MapVar("g_FireAreas", {})

function OnMsg.DoneMap()
	for _, fire in ipairs(g_FireAreas) do
		DoneObject(fire)
	end
end

DefineClass.MolotovFireObj = {
	__parents = { "SpawnFXObject" },
}

DefineClass.IncendiaryGrenadeZone = {
	__parents = { "GameDynamicSpawnObject", "SpawnFXObject" },
	
	remaining_time = false,
	fire_positions = false,
	campaign_time = false,
	owner = false,
	
	visuals = false,
}

function IncendiaryGrenadeZone:GameInit()
	table.insert(MapIncendiaryGrenadeZones, self)
	self.campaign_time = self.campaign_time or Game.CampaignTime
	PlayFX("FireZone", "start", self)
end

function IncendiaryGrenadeZone:UpdateRemainingTime(delta)
	local remaining = self.remaining_time - delta
	
	if remaining <= 0 or self.campaign_time < Game.CampaignTime then
		DoneObject(self)
		return true
	elseif self.remaining_time > 5000 and remaining <= 5000 then
		-- update particles
		PlayFX("FireZone", "subside", self)
		for i, obj in ipairs(self.visuals) do
			if IsKindOf(obj, "MolotovFireObj") then
				PlayFX("MolotovFire", "subside", obj)
			end
		end
	end
	self.remaining_time = remaining
end

function IncendiaryGrenadeZone:Init()
	table.insert_unique(g_FireAreas, self)
end

function IncendiaryGrenadeZone:Done()
	table.remove_value(MapIncendiaryGrenadeZones, self)
	for _, obj in ipairs(self.visuals) do
		DoneObject(obj)
	end
	self.visuals = nil
	table.remove_value(g_FireAreas, self)
	PlayFX("FireZone", "end", self)
end

function IncendiaryGrenadeZone:GetDynamicData(data)
	data.remaining_time = self.remaining_time or nil
	data.fire_positions = self.fire_positions and table.copy(self.fire_positions) or nil
	data.campaign_time = self.campaign_time or nil
	data.owner = IsValid(self.owner) and self.owner:GetHandle() or nil
end

function IncendiaryGrenadeZone:SetDynamicData(data)
	self.remaining_time = data.remaining_time
	self.campaign_time = data.campaign_time or Game.CampaignTime
	self.owner = HandleToObject[data.owner or false]
	if self.campaign_time < Game.CampaignTime then
		return
	end
	if data.fire_positions then
		self.fire_positions = table.copy(data.fire_positions)
		self:CreateVisuals("instant")
	end
	CreateGameTimeThread(function()
		Sleep(1) -- delay until loading is done and game has started for real, otherwise PlaySound can fail due to actor being too far
		PlayFX("FireZone", "start", self)
	end)
end

function IncendiaryGrenadeZone:CreateVisuals(instant)
	for _, obj in ipairs(self.visuals) do
		DoneObject(obj)		
	end
	self.visuals = {}
	
	local pos = GetExplosionFXPos(self)
	PlayFX("MolotovExplosion", "start", self, false, pos)
	
	if not instant then
		Sleep(150)
	end
		
	for i, pos in ipairs(self.fire_positions) do
		local fire = PlaceObject("MolotovFireObj")
		fire:SetPos(pos)
		PlayFX("MolotovFire", "start", fire)
		table.insert(self.visuals, fire)
		
		if not instant then
			for _, unit in ipairs(g_Units) do
				if not unit:IsDead() and unit:GetDist(pos) < const.SlabSizeX / 2 and not unit:HasStatusEffect("Burning") then
					unit:AddStatusEffect("Burning")
				end
			end
			Sleep(100)
		end
	end
end

function ExplosionCreateFireAOE(attacker, attackResults, fx_actor)
	local trajectory = attackResults.trajectory	or empty_table
	local pos = #trajectory > 0 and trajectory[#trajectory].pos or attackResults.target_pos
	if not pos then return end
	
	local water = terrain.IsWater(pos) and terrain.GetWaterHeight(pos)
	if water and (not pos:IsValidZ() or water >= pos:z()) then
		pos = pos:IsValidZ() and pos or pos:SetTerrainZ()
		PlayFX("GrenadeSplash", "start", fx_actor, false, pos)
		CreateFloatingText(pos:SetZ(water), T(760226092433, "Sunk"))
		return
	end
	local radius = const.SlabSizeX + const.SlabSizeX / 2
	
	local x, y, z = VoxelToWorld(WorldToVoxel(pos))
	pos = GetExplosionFXPos(point(x, y, z))

	-- possible locations are terrain + floor slabs in range
	local zoffs = point(0, 0, const.SlabSizeZ / 2)

	local target_locs = MapGet(pos, radius + const.SlabSizeX, "FloorSlab") or {}
	table.imap_inplace(target_locs, function(slab) return slab:GetPos() end)
	target_locs = table.ifilter(target_locs, function(idx, loc, pos)
		return pos:Dist2D(loc) / const.SlabSizeX <= 1
	end, pos)

	local limit = DivCeil(radius, const.SlabSizeX) * const.SlabSizeX
	for dx = -limit, limit, const.SlabSizeX do
		for dy = -limit, limit, const.SlabSizeY do
			local epos = GetExplosionFXPos(point(x+dx, y+dy, z))
			if epos and epos:Dist2D(pos) / const.SlabSizeX <= 1 then
				target_locs[#target_locs + 1] = epos
			end
		end
	end
	
	target_locs = table.ifilter(target_locs, function(idx, loc)
		return not terrain.IsWater(loc) or terrain.GetWaterHeight(loc) < loc:z()
	end)
	table.sort(target_locs, function(a, b) return a:Dist(pos) < b:Dist(pos) end)
	
	local los_targets = table.map(target_locs, function(loc)
		if loc:IsValidZ() then
			return loc + zoffs
		end
		return loc:SetTerrainZ(const.SlabSizeZ / 2)
	end)
		
	local los_any, los_to_targets = CheckLOS(los_targets, pos)
	if not los_any then
		return
	end
	
	local fire_locs = {}
	
	local explosion_pos, min_dist
	for i, loc in ipairs(los_targets) do
		if los_to_targets[i] then
			fire_locs[#fire_locs + 1] = target_locs[i]
			local dist = target_locs[i]:Dist(pos)
			if not explosion_pos or dist < min_dist then
				explosion_pos, min_dist = target_locs[i], dist
			end			
		end
	end
			
	if #fire_locs > 0 then
		local num_turns = 4	
		local step_pos = SnapToPassSlab(explosion_pos) or point(VoxelToWorld(WorldToVoxel(explosion_pos)))
		local volume = EnumVolumes(step_pos, "smallest")
		if not volume then	
			if GameState.RainHeavy or GameState.DustStorm then
				num_turns = 2
			elseif GameState.FireStorm then
				num_turns = 6
			end
		end
		local fire = IncendiaryGrenadeZone:new{
			fire_positions = fire_locs,
			remaining_time = num_turns * 5000,
		}
		if IsKindOf(attacker, "Unit") then
			fire.owner = attacker
		end
		fire:SetPos(explosion_pos)
		CreateGameTimeThread(IncendiaryGrenadeZone.CreateVisuals, fire)
		UpdateMapBurningState(GameState.FireStorm)		
	end
end

local function IsOutsideSmokeArea(x, y, z)
	if x < -2 or x > 3 or y < -2 or y > 3 then
		return true
	end
	if (x == -2 or x == 3) and (y == -2 or y == 3) then
		return true
	end
	if x > -1 and x < 2 and y > -1 and y < 2 then
		return abs(z) >= 3
	elseif x > -2 and x < 3 and y > -2 and y < 3 then
		return abs(z) >= 2
	end
	return z ~= 0
end

function calc_voxelblocking(iter)
	iter = iter or 1
	ic("start")
	local slabs = MapGet("map", "Slab")
	ic("map enum done")

	local block_slabs = {}
	local function set_block_slab(gx, gy, gz, dir)
		local key = bor(band(gx, 0xffff), shift(band(gy, 0xffff), 16), shift(band(gz, 0xffff), 32), shift(dir, 48))
		block_slabs[key] = true
	end
	
	local tStart = GetPreciseTicks()
	local g0x, g0y, g0z = 0, 0, 0
	for i = 1, iter do
		block_slabs = {}
		for _, slab in ipairs(slabs) do
			local gx, gy, gz, side = slab:GetGridCoords()
			if IsKindOf(slab, "FloorSlab") then
				set_block_slab(gx-g0x, gy-g0y, gz-g0z, dirNZ)
				set_block_slab(gx-g0x, gy-g0y, gz-1-g0z, dirPZ)
			elseif IsKindOf(slab, "CeilingSlab") then
				set_block_slab(gx-g0x, gy-g0y, gz-g0z, dirPZ)
				set_block_slab(gx-g0x, gy-g0y, gz+1-g0z, dirNZ)
			elseif IsKindOf(slab, "WallSlab") then
				local blocked = slab.isVisible
				local height = 1
				if not blocked and slab.wall_obj then
					height = slab.wall_obj.height
					if IsKindOf(slab.wall_obj, "SlabWallDoor") then
						blocked = not slab.wall_obj:IsDead() and slab.wall_obj.pass_through_state == "closed"
					elseif IsKindOf(slab.wall_obj, "SlabWallWindow") then
						blocked = slab.wall_obj.pass_through_state == "intact"
					end
				end
				if blocked then
					local dir = Rotate(point(1, 0, 0), slab:GetAngle())
					local x, y = dir:xy()
					local neg
					if x > 0 then
						dir = dirPX
						neg = dirNX
					elseif x < 0 then
						dir = dirNX
						neg = dirPX
					elseif y > 0 then
						dir = dirPY
						neg = dirNY
					else -- y < 0
						dir = dirNY
						neg = dirPY
					end
					for i = 1, height do
						set_block_slab(gx-g0x, gy+i-1-g0y, gz-g0z, dir)
						set_block_slab(gx+x-g0x, gy+y+i-1-g0y, gz-g0z, neg)
					end
				end
			end
		end
	end
	local time = GetPreciseTicks() - tStart
	printf("%d recalcs on %d slabs done in %d ms, %d ms/recalc", iter, #slabs, time, time/iter)
	
	return block_slabs
end

MapVar("g_VoxelBlock", false)
function IsVoxelBlocked(gx, gy, gz, dir)
	local key = bor(band(gx, 0xffff), shift(band(gy, 0xffff), 16), shift(band(gz, 0xffff), 32), shift(dir, 48))
	return g_VoxelBlock[key]
end

function VoxelCanReach(x1, y1, z1, x2, y2, z2)
	if x1 == x2 and y1 == y2 and z1 == z2 then
		return true, false
	end
	local reached, blocked = false, false
	if x2 > x1 then
		if IsVoxelBlocked(x1, y1, z1, dirPX) then
			blocked = true
		else
			local r, b = VoxelCanReach(x1+1, y1, z1, x2, y2, z2)
			reached = reached or r
			blocked = blocked or b
		end
	end
	if x2 < x1 then
		if IsVoxelBlocked(x1, y1, z1, dirNX) then
			blocked = true
		else
			local r, b = VoxelCanReach(x1-1, y1, z1, x2, y2, z2)
			reached = reached or r
			blocked = blocked or b
		end
	end
	if y2 > y1 then
		if IsVoxelBlocked(x1, y1, z1, dirPY) then
			blocked = true
		else
			local r, b = VoxelCanReach(x1, y1+1, z1, x2, y2, z2)
			reached = reached or r
			blocked = blocked or b
		end
	end
	if y2 < y1 then
		if IsVoxelBlocked(x1, y1, z1, dirNY) then
			blocked = true
		else
			local r, b = VoxelCanReach(x1, y1-1, z1, x2, y2, z2)
			reached = reached or r
			blocked = blocked or b
		end
	end
	if z2 > z1 then
		if IsVoxelBlocked(x1, y1, z1, dirPZ) then
			blocked = true
		else
			local r, b = VoxelCanReach(x1, y1, z1+1, x2, y2, z2)
			reached = reached or r
			blocked = blocked or b
		end
	end
	if z2 < z1 then
		if IsVoxelBlocked(x1, y1, z1, dirNZ) then
			blocked = true
		else
			local r, b = VoxelCanReach(x1, y1, z1-1, x2, y2, z2)
			reached = reached or r
			blocked = blocked or b
		end
	end
	return reached, blocked
--[[	
	if x1 == x2 and y1 == y2 and z1 == z2 then
		return true
	end
	if x2 < x1 and not IsVoxelBlocked(x1, y1, z1, dirPX) and VoxelCanReach(x1+1, y1, z1, x2, y2, z2) then
		return true
	end
	if x2 < x1 and not IsVoxelBlocked(x1, y1, z1, dirNX) and VoxelCanReach(x1-1, y1, z1, x2, y2, z2) then
		return true
	end
	if y2 > y1 and not IsVoxelBlocked(x1, y1, z1, dirPY) and VoxelCanReach(x1, y1+1, z1, x2, y2, z2) then
		return true
	end
	if y2 < y1 and not IsVoxelBlocked(x1, y1, z1, dirNY) and VoxelCanReach(x1, y1-1, z1, x2, y2, z2) then
		return true
	end
	if z2 > z1 and not IsVoxelBlocked(x1, y1, z1, dirPZ) and VoxelCanReach(x1, y1, z1+1, x2, y2, z2) then
		return true
	end
	if z2 < z1 and not IsVoxelBlocked(x1, y1, z1, dirNZ) and VoxelCanReach(x1, y1, z1+1, x2, y2, z2) then
		return true
	end
	return false--]]
end

function VoxelLOS(unit1, unit2)
	local head1 = select(2, unit1:GetVisualVoxels())
	local head2 = select(2, unit2:GetVisualVoxels())
	
	if not g_VoxelBlock then
		g_VoxelBlock = calc_voxelblocking()
	end
	
	local voxel_box = box(point(-const.SlabSizeX/2, -const.SlabSizeY/2, 0), point(const.SlabSizeX/2, const.SlabSizeY/2, const.SlabSizeZ))

	--clear_smoke_dbg_visuals()
	
	local gx1, gy1, gz1 = point_unpack(head1)
	local gx2, gy2, gz2 = point_unpack(head2)
	
	--local mesh = PlaceBox(voxel_box + point(VoxelToWorld(gx1, gy1, gz1)), const.clrGreen, nil, false)
	--table.insert(g_dbgSmokeVisuals, mesh)	
	--mesh = PlaceBox(voxel_box + point(VoxelToWorld(gx2, gy2, gz2)), const.clrBlue, nil, false)
	--table.insert(g_dbgSmokeVisuals, mesh)
	
	local dx, dy, dz = abs(gx2-gx1), abs(gy2-gy1), abs(gz2-gz1)
	local sx = (gx2 > gx1) and 1 or -1
	local sy = (gy2 > gy1) and 1 or -1
	local sz = (gz2 > gz1) and 1 or -1
	local p1, p2
	local x, y, z = gx1, gy1, gz1
	local voxels = {}
	if dx > dy and dx > dz then
		p1 = 2*dy-dx
		p2 = 2*dz-dx
		while x ~= gx2 do
			x = x + sx
			if p1 >= 0 then
				y = y + sy
				p1 = p1 - 2*dx
			end
			if p2 >= 0 then
				z = z + sz
				p2 = p2 - 2*dx
			end
			p1 = p1 + 2*dy
			p2 = p2 + 2*dz
			table.insert(voxels, point_pack(x, y, z))
		end
	elseif dy > dz then
		p1 = 2*dx-dy
		p2 = 2*dz-dy
		while y ~= gy2 do
			y = y + sy
			if p1 >= 0 then
				x = x + sx
				p1 = p1 - 2*dy
			end
			if p2 >= 0 then
				z = z + sz
				p2 = p2 - 2*dy
			end
			p1 = p1 + 2*dx
			p2 = p2 + 2*dz
			table.insert(voxels, point_pack(x, y, z))
		end
	else
		p1 = 2*dx-dz
		p2 = 2*dy-dz
		while z ~= gz2 do
			z = z + sz
			if p1 >= 0 then
				x = x + sx
				p1 = p1 - 2*dz
			end
			if p2 >= 0 then
				y = y + sy
				p2 = p2 - 2*dz
			end
			p1 = p1 + 2*dx
			p2 = p2 + 2*dy
			table.insert(voxels, point_pack(x, y, z))
		end
	end
	x, y, z = gx1, gy1, gz1	
	local los_reached, los_blocked
	for _, pt in ipairs(voxels) do
		local nx, ny, nz = point_unpack(pt)
		local reached, blocked = VoxelCanReach(x, y, z, nx, ny, nz)
		los_reached = los_reached or reached
		los_blocked = los_blocked or blocked
		if los_reached and los_blocked then
			break
		end
		--[[local color
		if reached and not blocked then
			color = const.clrWhite
		elseif reached then
			color = const.clrYellow
		else
			color = const.clrRed
		end
		mesh = PlaceBox(voxel_box + point(VoxelToWorld(nx, ny, nz)), color, nil, false)
		table.insert(g_dbgSmokeVisuals, mesh)--]]
		x, y, z = nx, ny, nz
	end
	if los_reached and los_blocked then
		return "partial"
	elseif los_reached then
		return "clear"
	end
	return "blocked"
end

function test_voxel_los()
	g_VoxelBlock = calc_voxelblocking()
	
	local t = GetPreciseTicks()
	local num = 10
	local total = 0
	local stats = {}
	for i = 1, num do
		for _, unit in ipairs(g_Units) do
			if not IsValid(unit) or unit:IsDead() then 
				goto continue 
			end
			for _, other in ipairs(g_Units) do
				if IsValid(other) and not other:IsDead() then
					local result = VoxelLOS(unit, other)
					stats[result] = (stats[result] or 0) + 1
					total = total + 1
				end
			end
			::continue::
		end	
	end
	local time = GetPreciseTicks() - t
	printf("%d recalcs done in %d ms, %d ms/cycle", num, time, time / num)
	printf("results received: %d", total)
	if total > 0 then
		for k, n in sorted_pairs(stats) do
			printf("  %s: %d (%d%%)", k, n, MulDivRound(n, 100, total))
		end
	end
end

function PropagateSmokeInGrid(g0x, g0y, g0z, gdx, gdy)
	local smoke = {}
	local queue = { point_pack(0, 0, 0) }
	local blocked = {}
	local block_slabs = {}
	
	local function set_block_slab(gx, gy, gz, dir)
		local key = bor(band(gx, 0xffff), shift(band(gy, 0xffff), 16), shift(band(gz, 0xffff), 32), shift(dir, 48))
		block_slabs[key] = true
	end
	local function is_blocked(gx, gy, gz, dir)
		local key = bor(band(gx, 0xffff), shift(band(gy, 0xffff), 16), shift(band(gz, 0xffff), 32), shift(dir, 48))
		return block_slabs[key]
	end

	local wpt = point(VoxelToWorld(g0x, g0y, g0z))
	local slabs = MapGet(wpt, 5*const.SlabSizeX, "Slab")
	for _, slab in ipairs(slabs) do
		local gx, gy, gz, side = slab:GetGridCoords()
		if IsKindOf(slab, "FloorSlab") then
			set_block_slab(gx-g0x, gy-g0y, gz-g0z, dirNZ)
			set_block_slab(gx-g0x, gy-g0y, gz-1-g0z, dirPZ)
		elseif IsKindOfClasses(slab, "CeilingSlab", "RoofSlab") then
			set_block_slab(gx-g0x, gy-g0y, gz-g0z, dirPZ)
			set_block_slab(gx-g0x, gy-g0y, gz+1-g0z, dirNZ)
		elseif IsKindOf(slab, "WallSlab") then
			local blocked = slab.isVisible
			local height = 1
			if not blocked and slab.wall_obj then
				height = slab.wall_obj.height
				if IsKindOf(slab.wall_obj, "SlabWallDoor") then
					blocked = not slab.wall_obj:IsDead() and slab.wall_obj.pass_through_state == "closed"
				elseif IsKindOf(slab.wall_obj, "SlabWallWindow") then
					blocked = slab.wall_obj.pass_through_state == "intact"
				end
			end
			if blocked then
				local dir = Rotate(point(1, 0, 0), slab:GetAngle())
				local x, y = dir:xy()
				local neg
				if x > 0 then
					dir = dirPX
					neg = dirNX
				elseif x < 0 then
					dir = dirNX
					neg = dirPX
				elseif y > 0 then
					dir = dirPY
					neg = dirNY
				else -- y < 0
					dir = dirNY
					neg = dirPY
				end
				for i = 1, height do
					set_block_slab(gx-g0x, gy+i-1-g0y, gz-g0z, dir)
					set_block_slab(gx+x-g0x, gy+y+i-1-g0y, gz-g0z, neg)
				end
			end
		end
	end

	local function try_spill(px, py, pz, dx, dy, dz)
		local vx, vy, vz = px + dx, py + dy, pz + dz
		local prevpack = point_pack(px, py, pz)
		local packed = point_pack(vx, vy, vz)
		if IsOutsideSmokeArea(vx*gdx, vy*gdy, vz) then
			local dir
			if dx > 0 then 
				dir = dirPX 
			elseif dx < 0 then
				dir = dirNX
			elseif dy > 0 then
				dir = dirPY
			elseif dy < 0 then
				dir = dirNY
			elseif dz > 0 then
				dir = dirPZ
			else
				dir = dirNZ
			end
			blocked[prevpack] = bor(blocked[prevpack] or 0, shift(1, dir))
			return
		end
		
		local pt = point(VoxelToWorld(g0x, g0y, g0z))
		local wpt = pt + point(vx * const.SlabSizeX, vy * const.SlabSizeY, vz * const.SlabSizeZ)
		smoke[point_pack(0, 0, 0)] = wpt
		-- check terrain
		if dz < 0 and terrain.GetHeight(wpt) > wpt:z() + sizez/2 then
			--DbgAddVector(pt + point(px * sizex, py * sizey, pz * sizez + sizez/4), point(0, 0, -sizez/2), const.clrRed)
			blocked[prevpack] = bor(blocked[prevpack] or 0, shift(1, dirNZ))
			return
		end
		if dz > 0 then
			-- check the floor of the new tile
			if is_blocked(px, py, pz, dirPZ) then
				--DbgAddVector(pt + point(px * sizex, py * sizey, vz * sizez - sizez/4), point(0, 0, sizez/2), const.clrRed)
				blocked[prevpack] = bor(blocked[prevpack] or 0, shift(1, dirPZ))
				return
			end
		elseif dz < 0 then
			-- check the floor of the previous tile
			if is_blocked(px, py, pz, dirNZ) then
				--DbgAddVector(pt + point(px * sizex, py * sizey, pz * sizez + sizez/4), point(0, 0, -sizez/2), const.clrRed)
				blocked[prevpack] = bor(blocked[prevpack] or 0, shift(1, dirNZ))
				return
			end
		else
			-- check for wall slabs (at the respective edge)
			local side
			local dirShift
			if dx > 0 then
				side = "E" -- 0
				dirShift = dirPX
			elseif dx < 0 then
				side = "W" -- 180
				dirShift = dirNX
			elseif dy > 0 then
				side = "S" -- 90
				dirShift = dirPY
			else -- dy < 0
				side = "N" -- 270
				dirShift = dirNY
			end
			if is_blocked(px, py, pz, dirShift) then
				--DbgAddVector(pt + point(px*sizex + dx*sizex/4, py*sizey + dy*sizey/4, pz*sizez + sizez/2), point(dx*sizex/2, dy*sizey/2, 0), const.clrRed)
				blocked[prevpack] = bor(blocked[prevpack] or 0, shift(1, dirShift))
				return
			end
		end
		if smoke[packed] then return end -- needs to be after the blocked checks to make sure we're not missing information about blocked voxel to voxel transition
				
		smoke[packed] = wpt
		queue[#queue + 1] = packed
	end
	
	local idx = 1
	while idx <= #queue do
		local x, y, z = point_unpack(queue[idx])
		idx = idx + 1
		
		try_spill(x, y, z,  1, 0, 0)
		try_spill(x, y, z, -1, 0, 0)
		try_spill(x, y, z, 0,  1, 0)
		try_spill(x, y, z, 0, -1, 0)
		try_spill(x, y, z, 0, 0,  1)
		try_spill(x, y, z, 0, 0, -1)
	end
	
	return smoke, blocked
end

local function FindSmokeObjPos(smoke, blocked)
	-- find a place for the smoke grenade obj: nearest voxel to original target (0, 0, 0)
	local smoke_obj_ppos, min_dist2
	local mask = bor(shift(1, dirPX), shift(1, dirPY), shift(1, dirNX), shift(1, dirNY))
	for packed, _ in pairs(smoke) do
		-- only consider voxels that are blocked downwards and do not have blocked x/y sides
		local value = blocked[packed] or 0
		if band(value, shift(1, dirNZ)) ~= 0 and band(value, mask) == 0 then 
			local x, y, z = point_unpack(packed)
			local dist2 = (x*x*guim*guim) + (y*y*guim*guim) + (z*z*guim*guim)
			if not smoke_obj_ppos or min_dist2 > dist2 then
				smoke_obj_ppos, min_dist2 = packed, dist2
			end
		end
	end
	return smoke_obj_ppos
end

MapVar("g_dbgSmokeVisuals", {})

function clear_smoke_dbg_visuals()
	DbgClearVectors()
	DbgClearTexts()
	for _, obj in ipairs(g_dbgSmokeVisuals) do
		DoneObject(obj)
	end
end

function test_smoke(target)
	if not CurrentThread() then
		CreateRealTimeThread(test_smoke, target)
		return
	end
	local target = target or GetTerrainCursor()
	local pt = SnapToPassSlab(target) or target
	local voxel_box = box(point(-const.SlabSizeX/2, -const.SlabSizeY/2, 0), point(const.SlabSizeX/2, const.SlabSizeY/2, const.SlabSizeZ))

	local g0x, g0y, g0z = WorldToVoxel(pt)

	target = target:SetTerrainZ()
	if not pt:IsValidZ() then
		pt = pt:SetTerrainZ()
	end
	
	clear_smoke_dbg_visuals()
	DbgAddVector(target, point(0, 0, 2*guim), const.clrGreen)
	
	local smoke_box, mesh
	smoke_box = voxel_box + pt	
	mesh = PlaceBox(smoke_box, const.clrGreen, nil, false)
	table.insert(g_dbgSmokeVisuals, mesh)
	
	local cx, cy = pt:xy()
	local tx, ty = target:xy()
	local ax, ay 
	if SelectedObj then
		ax, ay = SelectedObj:GetPosXYZ()
	end
	
	-- pick directions to form the 2x2 block
	local gdx = tx - cx
	if gdx == 0 and ax then gdx = tx - ax end
	gdx = (gdx ~= 0) and (gdx / abs(gdx)) or 1
	
	local gdy = ty - cy
	if gdy == 0 and ay then gdy = ty - ay end
	gdy = (gdy ~= 0) and (gdy / abs(gdy)) or 1

	-- check for walls in the direction of the spill
	local sizex = const.SlabSizeX
	local sizey = const.SlabSizeY
	local sizez = const.SlabSizeZ

	local midpt = pt + point(gdx*sizex/2, gdy*sizey/2, 0) 

	DbgAddVector(midpt, point(0, 0, 5*guim), const.clrMagenta)

	DbgAddVector(pt + point(gdx * sizex / 4, 0, sizez / 2), point(gdx*2*guim, 0, 0), const.clrGreen)
	DbgAddVector(pt + point(0, gdy * sizey / 4, sizez / 2), point(0, gdy*2*guim, 0), const.clrGreen)
			
	local smoke, blocked = PropagateSmokeInGrid(g0x, g0y, g0z, gdx, gdy)
	local voffset = {
		point(sizex/4, 0, sizez/2), point(-sizex/4, 0, sizez/2),
		point(0, sizey/4, sizez/2), point(0, -sizey/4, sizez/2),
		point(0, 0, 3*sizez/4), point(0, 0, sizez/4),
	}
	local vbody = {
		point(sizex/2, 0, 0), point(-sizex/2, 0, 0),
		point(0, sizey/2, 0), point(0, -sizey/2, 0),
		point(0, 0, sizez/2), point(0, 0, -sizez/2),
	}
	for packed, wpt in pairs(smoke) do
		local smoke_box = voxel_box + wpt
		assert(IsPoint(wpt))
		local mesh = PlaceBox(smoke_box, const.clrGray, nil, false)
		table.insert(g_dbgSmokeVisuals, mesh)
		
		local block_mask = blocked[packed]
		
		for i = dirPX, dirNZ do
			local color = band(block_mask, shift(1, i)) == 0 and const.clrGreen or const.clrRed
			DbgAddVector(wpt + voffset[i+1], vbody[i+1], color)
		end
	end
	
	local smoke_obj_ppos = FindSmokeObjPos(smoke, blocked)
	
	if smoke_obj_ppos then
		local x, y, z = point_unpack(smoke_obj_ppos)
		local pos = pt + point(x*sizex, y*sizex, z*sizez)
		local obj = PlaceObject("GrenadeVisual", {fx_actor_class = "SmokeGrenadeSpinner"} )
		obj:SetPos(pos)
		table.insert(g_dbgSmokeVisuals, obj)
	end
end

function ExplosionCreateSmokeAOE(attacker, results, fx_actor)
	local trajectory = results.trajectory	or empty_table
	local pos = #trajectory > 0 and trajectory[#trajectory].pos or results.target_pos
	if not pos then return end
	
	local water = terrain.IsWater(pos) and terrain.GetWaterHeight(pos)
	if water and (not pos:IsValidZ() or water >= pos:z()) then
		pos = pos:IsValidZ() and pos or pos:SetTerrainZ()
		PlayFX("GrenadeSplash", "start", fx_actor, false, pos)	
		CreateFloatingText(pos:SetZ(water), T(760226092433, "Sunk"))
		return
	end
	pos = SnapToPassSlab(pos) or pos
	
	local dx, dy = 1, 1
	for i = #trajectory - 1, 1, -1 do
		local step = trajectory[i]
		if step.pos:Dist2D(pos) > 0 then
			local px, py = step.pos:xy()
			local x, y = pos:xy()
			dx = (px == x) and 1 or ((x - px) / abs(x - px))
			dy = (py == y) and 1 or ((y - py) / abs(y - py))
			break
		end
	end
	
	local turns = 4
	local step_pos = SnapToPassSlab(pos) or point(VoxelToWorld(WorldToVoxel(pos)))
	local volume = EnumVolumes(step_pos, "smallest")
	if not volume then	
		if GameState.RainHeavy or GameState.DustStorm then
			turns = 2
		else
			turns = 3
		end
	end
		
	local zone = SmokeZone:new{smoke_dx = dx, smoke_dy = dy, remaining_time = turns * 5000, gas_type = results.aoe_type}
	if IsKindOf(attacker, "Unit") then
		zone.owner = attacker
	end
	zone:SetPos(pos)
	zone:PropagateSmoke()
end

MapVar("g_SmokeObjs", {}) -- ppos -> smoke obj

DefineClass.SmokeObj = {
	__parents = { "SpawnFXObject" },
	flags = { efVisible = false, efApplyToGrids = false, cfSmokeObj = true },
	
	entity = "SolidVoxel",	
	zones = false, -- zone refs
}

function SmokeObj:GetGasType()
	return self.zones and self.zones[1] and self.zones[1].gas_type
end

function SmokeObj:Init()
	self.zones = {}
	InvalidateVisibility()
end

function SmokeObj:Done()
	InvalidateVisibility()
end

DefineClass.SmokeZone = {
	__parents = { "GameDynamicSpawnObject", "SpawnFXObject" },
	
	remaining_time = false,
	gas_type = false,
	smoke_positions = false,
	owner = false,
	smoke_dx = 1,
	smoke_dy = 1,
	
	spinner = false,
	campaign_time = false,
}

function SmokeZone:GameInit()
	table.insert(MapSmokeZones, self)
	self.campaign_time = self.campaign_time or Game.CampaignTime
	PlayFX("SmokeZone", "start", self, self.gas_type)
end

function SmokeZone:Done()
	table.remove_value(MapSmokeZones, self)
	for _, wpt in pairs(self.smoke_positions) do
		self:RemoveSmokeFromPos(point_pack(WorldToVoxel(wpt)))
	end
	if IsValid(self.spinner) then
		DoneObject(self.spinner)
	end
	self.spinner = nil
	PlayFX("SmokeZone", "end", self, self.gas_type)
end

function SmokeZone:RemoveSmokeFromPos(ppos)
	local obj = g_SmokeObjs[ppos]
	if not IsValid(obj) then return end
	table.remove_value(obj.zones, self)
	PlayFX("VoxelGas", "end", obj, self.gas_type)
	if #obj.zones == 0 then
		DoneObject(obj)
		g_SmokeObjs[ppos] = nil
	else
		PlayFX("VoxelGas", "start", obj, obj:GetGasType())
	end
end

function SmokeZone:PropagateSmoke()
	local gx, gy, gz = WorldToVoxel(self)
	local smoke, blocked = PropagateSmokeInGrid(gx, gy, gz, self.smoke_dx, self.smoke_dy)
	
	-- remove existing smoke if it no longer propagates there (e.g. a fire started there, door closed, etc)
	for ppos, wpt in pairs(self.smoke_positions) do
		local gppos = point_pack(WorldToVoxel(wpt))
		if not smoke[ppos] then
			self:RemoveSmokeFromPos(gppos)
		end
	end
	
	-- update self.smoke_positions from smoke & create smoke objs if necessary
	for _, wpt in pairs(smoke) do
		local ppos = point_pack(WorldToVoxel(wpt))
		local obj = g_SmokeObjs[ppos]
		local gas_type = obj and obj:GetGasType()
		if not obj then
			obj = PlaceObject("SmokeObj")
			obj:SetPos(wpt)
			g_SmokeObjs[ppos] = obj
		end
		table.insert_unique(obj.zones, self)
		if not gas_type then
			PlayFX("VoxelGas", "start", obj, self.gas_type)
		end
	end
	self.smoke_positions = smoke
	
	if not self.spinner then
		local ppos = FindSmokeObjPos(smoke, blocked)
		if ppos then
			local x, y, z = point_unpack(ppos)
			local pos = self:GetPos() + point(x*sizex, y*sizex, z*sizez)
			local fx_class = "SmokeGrenadeSpinner"
			if self.gas_type == "teargas" then
				fx_class = "TearGasGrenadeSpinner"
			elseif self.gas_type == "toxicgas" then
				fx_class = "ToxicGasGrenadeSpinner"
			end
			local obj = PlaceObject("GrenadeVisual", {fx_actor_class = fx_class} )
			obj:SetPos(pos)
			obj:SetAnim(1, "rotating")
			PlayFX("SmokeGrenadeSpin", "start", obj)
			self.spinner = obj
		else
			self.spinner = "none" -- non-false/nil value to indicate we couldn't find a place for the object
		end
	end
end

function SmokeZone:UpdateRemainingTime(delta)
	local remaining = self.remaining_time - delta
	
	if remaining <= 0 or self.campaign_time < Game.CampaignTime then
		DoneObject(self)
		return true
	end
	self.remaining_time = remaining
	
	self:PropagateSmoke()
end

function SmokeZone:GetDynamicData(data)
	data.remaining_time = self.remaining_time or nil
	data.gas_type = self.gas_type or nil
	data.campaign_time = self.campaign_time or nil
	data.owner = self.owner and self.owner:GetHandle() or nil
	data.smoke_positions = self.smoke_positions and table.copy(self.smoke_positions) or nil
	if self.spinner and not IsValid(self.spinner) then
		data.spinner = self.spinner
	end
end

function SmokeZone:SetDynamicData(data)
	self.remaining_time = data.remaining_time
	self.gas_type = data.gas_type
	self.spinner = data.spinner
	self.owner = HandleToObject[data.owner or false]
	self.campaign_time = data.campaign_time or Game.CampaignTime
	if self.campaign_time < Game.CampaignTime then
		return
	end
	if data.smoke_positions then
		self.smoke_positions = table.copy(data.smoke_positions)
		self:PropagateSmoke()
	end
	CreateGameTimeThread(function() 
		Sleep(1) -- delay until loading is done and game has started for real, otherwise PlaySound can fail due to actor being too far
		PlayFX("SmokeZone", "start", self)
	end)
end

function ToggleGasDebug()
	if g_dbgSmokeVisuals then
		for _, obj in ipairs(g_dbgSmokeVisuals) do
			DoneObject(obj)
		end
		g_dbgSmokeVisuals = false
		return
	end
	
	g_dbgSmokeVisuals = {}
	local voxel_box = box(point(-const.SlabSizeX/2, -const.SlabSizeY/2, 0), point(const.SlabSizeX/2, const.SlabSizeY/2, const.SlabSizeZ))
	for ppos, obj in pairs(g_SmokeObjs) do
		local pt = point(VoxelToWorld(point_unpack(ppos)))		
		if not pt:IsValidZ() then
			pt = pt:SetTerrainZ()
		end
		
		local gas_box = voxel_box + pt
		local color = const.clrGray
		local gas = obj:GetGasType()
		if gas == "teargas" then
			color = const.clrYellow
		elseif gas == "toxicgas" then
			color = const.clrGreen
		end
		local mesh = PlaceBox(gas_box, color, nil, false)
		table.insert(g_dbgSmokeVisuals, mesh)
	end
	
	for _, unit in ipairs(g_Units) do
		local voxels, head = unit:GetVisualVoxels()		
		for _, voxel in ipairs(voxels) do
			local pt = point(VoxelToWorld(point_unpack(voxel)))
			local unit_box = MulDivRound(voxel_box, 9, 10) + pt
			local color = const.clrWhite
			if voxel == head then
				if g_SmokeObjs[head] then
					color = const.clrRed
				else
					color = const.clrBlue
				end
			end
			local mesh = PlaceBox(unit_box, color, nil, false)
			table.insert(g_dbgSmokeVisuals, mesh)
		end
	end
end

DefineClass.Flare = {
	__parents = { "Grenade" },
	properties = {
		{ category = "Combat", id = "Expires", editor = "bool", default = true, template = true, },
		{ category = "Combat", id = "ExpirationTurns", editor = "number", min = 1, default = 4, template = true, },
		{ category = "Combat", id = "Despawn", editor = "bool", default = false, template = true },
	},
}

function Flare:OnPrepareThrow(thrower, visual)
	--this happens on one client only
	PlayFX("Flare", "start", visual)
	ResetVoxelStealthParamsCache()
end

function Flare:OnFinishThrow(thrower)
	ResetVoxelStealthParamsCache()
end

function Flare:OnLand(thrower, attackResults, visual_obj)
	local pos = attackResults.explosion_pos
	local snapped = false
	local sync = false
	if pos then
		snapped = SnapToPassSlab(pos:xyz()) or pos
		if snapped then
			sync = true
		end
	end
	if not snapped then
		snapped = IsValid(visual_obj) and visual_obj:GetPos()
	end
	if not snapped then
		return
	end
	pos = pos or snapped
	if snapped:IsValidZ() then
		pos = pos:SetZ(snapped:z())
	else
		pos = pos:SetInvalidZ()
	end
	local flare = PlaceObject("FlareOnGround")
	flare:SetPos(pos)
	flare.item_class = self.class
	flare.campaign_time = Game.CampaignTime
	flare.Despawn = self.Despawn
	if self.Expires then
		flare.remaining_time = self.ExpirationTurns * 5000
	end
	flare:UpdateVisualObj()
	PushUnitAlert("thrown", flare, thrower)
	
	if self.ThrowNoise > 0 then
		-- <Unit> Heard a thud
		PushUnitAlert("noise", visual_obj, self.ThrowNoise, Presets.NoiseTypes.Default.ThrowableLandmine.display_name)
	end
	if IsValid(visual_obj) then
		DoneObject(visual_obj)
	end
end

DefineClass.FlareOnGround = {
	__parents = { "GameDynamicSpawnObject" },
	item_class = "FlareStick",
	visual_obj = false,
	remaining_time = -1,
	campaign_time = false,
	Despawn = true,
}

function FlareOnGround:GameInit()
	table.insert(MapFlareOnGround, self)
end

function FlareOnGround:Done()
	table.remove_value(MapFlareOnGround, self)
end

function FlareOnGround:UpdateVisualObj(start_fx)
	if not IsValid(self.visual_obj) then
		self.visual_obj = PlaceObject("GrenadeVisual", {fx_actor_class = self.item_class .. "_OnGround"})
	end
	self:Attach(self.visual_obj)
	if start_fx then
		PlayFX("Flare", "start", self.visual_obj)
	end
	ResetVoxelStealthParamsCache()
end

function FlareOnGround:UpdateRemainingTime(delta)
	if Game.CampaignTime ~= self.campaign_time then
		DoneObject(self)
		return
	end
	if self.remaining_time < 0 then return end
	
	self.remaining_time = Max(0, self.remaining_time - delta)
	if self.remaining_time == 0 then
		PlayFX("Flare", "end", self.visual_obj)
		local attaches = self.visual_obj:GetAttaches("Weapon_FlareStick_OnGround")
		for _, obj in ipairs(attaches) do
			PlayFX("Flare", "end", obj)
		end
		if self.Despawn then
			DoneObject(self)
		else
			self.remaining_time = -1
		end
		ResetVoxelStealthParamsCache()
	end
end

function TestKillFlares()
	for _, f in ipairs(MapFlareOnGround) do
		f:UpdateRemainingTime(99999999)
	end
end

function FlareOnGround:GetDynamicData(data)
	data.item_class = self.item_class
	data.remaining_time = self.remaining_time
	data.campaign_time = self.campaign_time
end

function FlareOnGround:SetDynamicData(data)
	self.item_class = data.item_class
	self.remaining_time = data.remaining_time
	self.campaign_time = data.campaign_time
	self:UpdateVisualObj(self.remaining_time ~= 0)
end

DefineClass.Weapon_SmokeGrenade = { __parents = {"Weapon_SmokeGrenade_Base"}, entity = "Weapon_SmokeGrenade", }
DefineClass.Weapon_SmokeGrenade_Spinning = { __parents = {"Weapon_SmokeGrenade_Base"}, entity = "Weapon_SmokeGrenade", }
DefineClass.Weapon_TearGasGrenade = { __parents = {"Weapon_SmokeGrenade_Base"}, entity = "Weapon_SmokeGrenade", }
DefineClass.Weapon_TearGasGrenade_Spinning = { __parents = {"Weapon_SmokeGrenade_Base"}, entity = "Weapon_SmokeGrenade", }
DefineClass.Weapon_ToxicGasGrenade = { __parents = {"Weapon_SmokeGrenade_Base"}, entity = "Weapon_SmokeGrenade", }
DefineClass.Weapon_ToxicGasGrenade_Spinning = { __parents = {"Weapon_SmokeGrenade_Base"}, entity = "Weapon_SmokeGrenade", }

DefineClass.Weapon_PipeBomb = { __parents = {"GrenadeVisual"}, entity = "Weapon_PipeBomb", }
DefineClass.Weapon_PipeBomb_OnGround = { __parents = {"GrenadeVisual"}, entity = "Weapon_PipeBomb", }

DefineClass.Weapon_FlareStick = { __parents = {"GrenadeVisual"}, entity = "World_Flarestick_01", }
DefineClass.Weapon_FlareStick_OnGround = { __parents = {"GrenadeVisual"}, entity = "World_Flarestick_01", }
DefineClass.Weapon_GlowStick = { __parents = {"GrenadeVisual"}, entity = "Weapon_GlowStick", }
DefineClass.Weapon_GlowStick_OnGround = { __parents = {"GrenadeVisual"}, entity = "Weapon_GlowStick", }

DefineClass.Weapon_ProximityTNT = { __parents = {"GrenadeVisual"}, entity = "Explosive_TNT", }
DefineClass.Weapon_ProximityTNT_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_TNT", }
DefineClass.Weapon_RemoteTNT = { __parents = {"GrenadeVisual"}, entity = "Explosive_TNT", }
DefineClass.Weapon_RemoteTNT_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_TNT", }
DefineClass.Weapon_TimedTNT = { __parents = {"GrenadeVisual"}, entity = "Explosive_TNT", }
DefineClass.Weapon_TimedTNT_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_TNT", }

DefineClass.Weapon_ProximityC4 = { __parents = {"GrenadeVisual"}, entity = "Explosive_C4", }
DefineClass.Weapon_ProximityC4_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_C4", }
DefineClass.Weapon_RemoteC4 = { __parents = {"GrenadeVisual"}, entity = "Explosive_C4", }
DefineClass.Weapon_RemoteC4_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_C4", }
DefineClass.Weapon_TimedC4 = { __parents = {"GrenadeVisual"}, entity = "Explosive_C4", }
DefineClass.Weapon_TimedC4_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_C4", }

DefineClass.Weapon_ProximityPETN = { __parents = {"GrenadeVisual"}, entity = "Explosive_PETN", }
DefineClass.Weapon_ProximityPETN_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_PETN", }
DefineClass.Weapon_RemotePETN = { __parents = {"GrenadeVisual"}, entity = "Explosive_PETN", }
DefineClass.Weapon_RemotePETN_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_PETN", }
DefineClass.Weapon_TimedPETN = { __parents = {"GrenadeVisual"}, entity = "Explosive_PETN", }
DefineClass.Weapon_TimedPETN_OnGround = { __parents = {"GrenadeVisual"}, entity = "Explosive_PETN", }