#summary API for writing Lua scripts in Hedgewars.
#labels Featured

= Core Lua API documentation =

== Introduction ==

Version 0.9.13 of Hedgewars introduced the ability to use Lua scripts to modify Hedgewars behaviour for different maps without having to recompile the whole game. The till then used triggers (only appeared in training maps) were removed.

Lua is an easy to learn scripting language that’s implemented using open source libraries. If you’d like to learn more about Lua, have a look at [http://www.lua.org Lua's official homepage]. Even though its easy to learn syntax this wiki page won't explain all basics of using Lua, e.g. declaring variables or using control structures. There are tons of step-by-step tutorials and documentation available on the internet. Just throw “Lua” into your favourite search engine and give it a try.

=== About this wiki page ===
This page tends to become outdated. For a list of undocumented functions, see [http://hw.ercatec.net/docs/lua_wiki_check.php].

<wiki:toc max_depth="4" />

== Overview ==f
=== How Hedgewars handles Lua scripts ===
As of Version 0.9.20, Hedgewars supports Lua scripts for two similar tasks: Define tutorial missions, campaign missions or provide special map behaviour for precreated maps. It is also used for multiplayer scripts to create new game styles.

=== Tutorial missions ===
Tutorial missions are located within text files inside `share/hedgewars/Data/Missions/Training`. The game will list all files with the lua extension inside this directory in the Training selection screen. You’ll find some premade example scripts within this directory that contain several comments on the script lines and what they do.

See [Missions] for details.

=== Special maps ===
In addition to tutorial missions predrawn maps (maps not created using the random map creator) may contain a single lua script file named `map.lua`. If it’s there, it will be used once the map is played. This way it’s possible to play maps alone or over the internet using custom goals. Mission maps can be found in singleplayer mode under the “training” button and in multiplayer mode, it is selectable as a map type.

See also [PresetMaps] for more information about such maps.

=== How Lua scripts are used ===
Several parts of script files are executed multiple times. In general, the whole script file is read while loading the map. Declarations as well as function calls outside functions are executed at once. Later on the game will call special predefined function names at special occassions such as the creation of new game objects (called “gears”).


=== Important things to know ===
It is possible to play missions in multiplayer. However this requires all participating players to have the exact same version of the map files, including the `map.lua` script file. If this isn’t the case the game will probably desync and “kick” at least the one player using a different version of the map files. To avoid problems when running prepackaged maps, you should never modify any maps provided with the Hedgewars default package. Instead, create a copy of the existing map and modify this one. Feel free to share your work on the forums.

Another thing to note is the current status of our scripting implementation. Similar to the whole game, this is still work in progress and we can’t guarantee that scripts working in this version will run in future revisions of the game as we might extend, change or rename parts of the scripting engine.

=== Global variables/constants ===
Global variables are used by the game to interact with the scripts by passing and retrieving their values. While some of the variables are never read by the engine some allow you to modify the engine’s behaviour, e.g. the theme to be used for the current map.

  	  	 
=== Functions called by the game: Event handlers ===
After successfully loading the Lua script the game will call the following functions on different occasions. To be used, they have to use the exact same name as defined below.

== Data types ==
This section defines some commonly used non-primitive parameter types which are used in multiple functions. This section is a bit incomplete at the moment.

=== Color ===
Some functions take a `color` parameter.

Colors are stored in RGB or RGBA format and are specified as a three- or four-byte number, respecively.
In 3-byte (RGB) colors, each byte represents a color component. The value 0 means no intensity and 255 is largest intensity of the component.
The first byte is for the red component, the second byte for the green component and the third byte for the blue component.
Four-byte (RGBA) colors use the first 3 bytes for the color components (like for the 3-byte colors) and the fourth byte is used for opacity, where 255 means maximum opacity and 0 means fully transparent (also called the “alpha channel”).

Specifying the color number becomes much easier if you write it in hexadecimal notation.

Examples for RGB (3-byte) colors:
<code language="lua">
c = 0x000000 -- black (R, G, B are all 0)
c = 0xFF0000 -- red
c = 0x00FF00 -- green
c = 0x0000FF -- blue
c = 0xFFFFFF -- white
c = 0x808080 -- gray (50%)</code>


== Globally available variables and constants ==
The following variables are made available by Hedgewars in Lua and can be used to quickly query a value. Lua scripts schould normally *not* write to these variables, only read from them.

=== General variables and constants ===
Here are some unsorted variables or constants which are available in Lua. You shouldn’t write to most of them.

|| *Identifier* || *Description* ||
|| `LAND_WIDTH` || The width of the landscape in pixels ||
|| `LAND_HEIGHT` || The height of the landscape in pixels ||
|| `LeftX` || X coordinate of the leftmost point of the landsacpe ||
|| `RightX` || X coordinate of the rightmost point of the landsacpe ||
|| `TopY` || Y coordinate of the topmost point of the landsacpe ||
|| `CursorX` || The X position of the cursor if the player is choosing a target. Otherwise, this is `-2147483648` ||
|| `CursorY` || The Y position of the cursor if the player is choosing a target. Otherwise, this is `-2147483648` ||
|| `WaterLine` || The y position of the water, used to determine at which position stuff drowns. Use `SetWaterLine` to change. ||
|| `ClansCount` || Number of clans in the game (teams with the same color belong to one clan) ||
|| `TeamsCount` || Number of teams in the game ||
|| `TurnTimeLeft` || Number of game ticks (milliseconds) left until the current turn ends. You can change this variable directly. ||
|| `GameTime` || Number of total game ticks ||
|| `TotalRounds` || Number of rounds that have passed ||
|| `CurrentHedgehog` || The hedgehog gear that is currently in play ||

=== !GameFlags ===
The !GameFlags are used to store simple boolean settings of the game.
You can read/modify them using the [LuaAPI#GameFlags_functions GameFlags-Functions].

|| *Identifier* || *Description (active state)* ||
|| `gfOneClanMode` || Used when only one clan is in the game. This game flag is primarily used for training missions. ||
|| `gfMultiWeapon` || TODO (Used in training missions.) ||
|| `gfForts` || Fort Mode ||
|| `gfDivideTeams` || The teams will start at opposite sites of the terrain. Two clans maximum. ||
|| `gfBorder` || An indestructible border is active around the map. ||
|| `gfBottomBorder` || There is an indestructable border at the bottom of the map. ||
|| `gfShoppaBorder` || The terrain edge will be replaced by a decorative black/yellow “danger stripe”. This has no gameplay effect. ||
|| `gfSolidLand` || The terrain is indestructible. ||
|| `gfLowGravity` || The gravity is low. ||
|| `gfLaserSight` || A laser sight is almost always active. ||
|| `gfInvulnerable` || All hedgehogs are invulnerable. ||
|| `gfVampiric` || All hedgehogs become vampires and get 80% of the damage they deal as health. ||
|| `gfKarma` || Attackers share the damage they deal to enemies. ||
|| `gfArtillery` || Hedgehogs can’t walk. ||
|| `gfRandomOrder` || The game is played in random order. ||
|| `gfPlaceHog` || Placement mode: At the beginning of the round, all hedgehogs are placed manually first. ||
|| `gfKing` || King Mode: One hedgehog per team becomes their king, if the king dies, the team loses. ||
|| `gfSharedAmmo` || Teams in the same clan share their ammo. ||
|| `gfDisableGirders` || No girders will be created in random maps ||
|| `gfDisableLandObjects` || No land objects will be created in random maps ||
|| `gfAISurvival` || Computer-controlled hedgehogs will be revived after they die. ||
|| `gfInfAttack` || Attacks don’t end the turn. ||
|| `gfResetWeps` || The weapons will be reset to the initial state each turn. ||
|| `gfPerHogAmmo` || Each hedgehog has its own weapon stash. ||
|| `gfDisableWind` || There is no wind. ||
|| `gfMoreWind` || There is always strong wind. ||
|| `gfTagTeam` || Tag Team: Teams in the same clan share their turn time. ||
|| `gfResetHealth` || The health of all living hedgehogs is reset at the end of each turn. ||

=== Land flags ===
The land flags denote several types of terrain. Like all flags, they can be combined at will.

|| *Identifier* || *Meaning* ||
|| `lfIce` || Slippery terrain, hogs will slide on it. ||
|| `lfBouncy` || Bouncy terrain, hogs and some other gears will bounce off when they collide with it. ||
|| `lfIndestructible` || Almost indestructible terrain, most weapons will not destroy it. ||
|| `lfNormal` || Normal destroyable terrain. Note that this is only actually the case when no other land flag is set. ||

=== More constants ===
More constants are at at [GearTypes Gear Types] , [AmmoTypes Ammo Types], [Sounds], [States], [Sprites], [VisualGearTypes Visual Gear Types].

== Event handlers ==
Lua scripts are supposed to _define_ these functions to do something. The functions are then _called_ by Hedgewars when a certain even has occoured.

=== <tt>onGameInit()</tt> ===
This function is called before the game loads its resources. One can modify various game variables here:
 * <tt>Seed = 0</tt> - seed of the random number generator
 * <tt>!GameFlags</tt> - all !GameFlags combined as a bitmask. See [LuaAPI#GameFlags_functions] for easier manipulation of !GameFlags
 * <tt>Ready = 5000</tt> - the ready timer at the start of the round (in milliseconds)
 * <tt>Delay = 0</tt> - delay between each round in ms
 * <tt>!GetAwayTime = 100</tt> set the retreat time in percent
 * <tt>!TurnTime = 60000</tt> - set the turn time in ms
 * <tt>!CaseFreq = 0</tt> - frequency of crate drops
 * <tt>!HealthCaseProb = 35</tt> - chance of receiving a health crate
 * <tt>!HealthCaseAmount = 25</tt> - amount of health in a health crate
 * <tt>!DamagePercent = 100</tt> - percent of damage to inforce
 * <tt>!RopePercent = 100</tt> - rope length in percent
 * <tt>!MinesNum = 0</tt> - number of mines being placed (before 0.9.14 !LandAdds)
 * <tt>!MinesTime = 3000</tt> - time for a mine to explode from activated (in milliseconds), -1000 for random
 * <tt>!MineDudPercent = 0</tt> - chance of mine being a dud
 * <tt>Explosives = 0</tt> - number of explosives being placed
 * <tt>!SuddenDeathTurns = 30</tt> - turns until sudden death begins
 * <tt>!WaterRise = 47</tt> - height of water rise at sudden death in pixels
 * <tt>!HealthDecrease = 5</tt> - amount of health decreased on sudden death
 * <tt>Map = "Bamboo"</tt> - the map being played
 * <tt>Theme = "Bamboo"</tt> - the theme to be used
 * <tt>!MapGen</tt> - type of map generator. One of `mgRandom`, `mgMaze`, `mgPerlin`, `mgDrawn`.
 * <tt>Goals = "Jumping is disabled"</tt> - Use this to add additional text to the goal text popup shown at the beginning and when using the quit or pause keys. The text is added to the default text which usually explains the game modifiers and does not replace it. Use `|` for line breaks. Also, all text before and including a `:` in a line will be highlighted. See also !ShowMission.
 * <tt>!TemplateFilter</tt> - _unknown meaning_
 * <tt>!TemplateNumber</tt> - _unknown meaning_
 * <tt>!MapFeatureSize</tt> - Used by random maps to determine its “curvyness” or complexity. This value can be set by the user with the slider under the random map preview in the game setup screen. The user-set value ranges from 1 (leftmost position) to 25 (rightmost position).
 * <tt>!ScreenWidth</tt> - width of the Hedgewars window
 * <tt>!ScreenHeight</tt> - heigtht of the Hedgewars window

If you want to add teams or hogs manually you have to do it here. If you want to draw your own map using `AddPoint` and `FlushPoints`, you have to do this within this function as well.

=== <tt>onGameStart()</tt> ===
This function is called when the first round starts.

Can be used to show the mission and for more setup, for example initial target spawning.

=== <tt>onPreviewInit()</tt> (0.9.21) ===
This function is called when the map preview in the frontend is initialized. This happens when the script is selected or you change a map generator parameter.

It is useful for scripts which create their own maps (see `AddPoint` and `FlushPoints`). If you create a map in this function, a preview will be generated from this map and is exposed to the frontend.

=== <tt>onParameters()</tt> (0.9.21) ===
This function is called when the script parameters (as specified in the game scheme) become available. The script parameter string is stored in the global variable `ScriptParam`.

Please note that it is normally not safe to call many of the other functions inside this function, this function is called very early in the game, only use this to initialize variables and other internal stuff like that.

*Tip*: If you use the Params library  (`/Scripts/Params.lua`), you can make the task of dissecting the string into useful values a bit easier, but it’s not required. (The Params library is not documented yet, however).

*Tip*: If you use this callback, make sure to document the interpretation of the parameters so others know how to set the parameters properly.

=== <tt>onGameTick()</tt> ===
This function is called on every game tick, i.e. 1000 times a second. If you just need to check on something periodically, consider `onGameTick20`.

=== <tt>onGameTick20()</tt> ===
This function is called every 20 game ticks, which equals 50 times a second. It reduces Lua overhead for simple monitoring that doesn’t need to happen every single tick.

=== <tt>onNewTurn()</tt> ===
This function calls at the start of every turn.

=== <tt>onSuddenDeath()</tt> (0.9.22) ===
This function is called on the start of Sudden Death.

=== <tt>onGearAdd(gearUid)</tt> ===
This function is called when a new gear is added. Useful in combination with `GetGearType(gearUid)`.

=== <tt>onGearDelete(gearUid)</tt> ===
This function is called when a new gear is deleted. Useful in combination with `GetGearType(gearUid)`.

=== <tt>onGearDamage(gearUid, damage)</tt> ===
This function is called when a gear is damaged.

Example:

<code language="lua">    function onGearDamage(gear, damage)
        if (GetGearType(gear) == gtHedgehog) then
            -- adds a message saying, e.g. "Hoggy H took 25 points of damage"
            AddCaption(GetHogName(gear) .. ' took ' .. damage .. ' points of damage')
        end
    end</code>
=== <tt>onGearResurrect(gearUid) </tt> ===
This function is called when a gear is resurrected. CPU Hogs will resurrect if the !GameFlag `gfAISurvival` is enabled. Alternatively, specific gears can have `heResurrectable` set to true via `SetEffect`.

=== <tt>onAmmoStoreInit()</tt> ===
This function is called when the game is initialized to request the available ammo and ammo probabilities. Use `SetAmmo` here.

=== <tt>onNewAmmoStore(team/clan index, hog index)</tt> ===
This function is identical to `onAmmoStoreInit` in function, but is called once per ammo store.  This allows different ammo sets for each clan, team or hedgehog depending on the mode.
If `gfSharedAmmo` is set, the parameters passed are the clan index, and `-1`, and the function will be called once for each clan.
If `gfPerHogAmmo` is set, the parameters passed are the team index and the hog index in that team, and the function will be called once for each hedgehog.
If neither is set, the parameters passed are the team index and `-1`, and the function will be called once for each team.

These indexes can be used to look up details of the clan/team/hedgehog prior to gear creation. Routines to do these lookups will be created as needed.
If you add this hook, the expectation is that you will call SetAmmo appropriately. Any values from `onAmmoStoreInit` are ignored.

=== <tt>onGearWaterSkip(gear)</tt> (0.9.21) ===
This function is called when the gear `gear` skips over water.

=== <tt>onScreenResize()</tt> (0.9.16) ===
This function is called when you resize the screen. Useful place to put a redraw function for any `vgtHealthTags` you're using.

=== <tt>onAttack()</tt> ===
This function is called when your Hedgehog attacks.

=== <tt>onHJump()</tt> ===
This function is called when you press the high jump key.

=== <tt>onLJump()</tt> ===
This function is called when you press the long jump key.

=== <tt>onPrecise()</tt> ===
This function is called when you press the precise key.

=== <tt>onLeft()</tt> ===
This function is called when you press the left key.

=== <tt>onRight()</tt> ===
This function is called when you press the right key.

=== <tt>onUp()</tt> ===
This function is called when you press the up key.

=== <tt>onDown()</tt> ===
This function is called when you press the down key.

=== <tt>onAttackUp()</tt> ===
This function is called when you release the attack key.

=== <tt>onDownUp()</tt> ===
This function is called when you release the down key.
 
=== <tt>onHogAttack(ammoType)</tt> ===
This function is called when you press the attack key. Beginning with 0.9.21, the parameter `ammoType` is provided. It contains the ammo type of the weapon used for the attack.

=== <tt>onLeftUp()</tt> ===
This function is called when you release the left key.

=== <tt>onPreciseUp()</tt> ===
This function is called when you release the precise key.

=== <tt>onRightUp()</tt> ===
This function is called when you release the right key.

=== <tt>onSetWeapon(msgParam)</tt> ===
It is get called when a weapon is selected or switched.

`msgParam` tells you which ammo type was selected.

=== <tt>onSlot(msgParam)</tt> ===
This function is called when one of the weapon slot keys has been pressed.

`msgParam` tells the slot number minus 1 (i.e. `0` is for slot number 1, `1` is for slot number 2, etc.).

=== <tt>onSwitch()</tt> ===
This function is called when a hog is switched to another.

=== <tt>onTaunt(msgParam)</tt> ===
This function is called when the player uses an animated emote for example by using the chat commands `/wave`, `/juggle`, etc.

`msgParam` tells you which animation was played:

|| *`msgParam`* || *Animation* || *Associated chat command* ||
|| 0 || Rolling up || `/rollup` ||
|| 1 || Sad face || `/sad` ||
|| 2 || Waving hand || `/wave` ||
|| 3 || Stupid winner's grin / “Awesome” face || `/hurrah` ||
|| 4 || Peeing || `/ilovelotsoflemonade` ||
|| 5 || Shrug || `/shrug` ||
|| 6 || Juggling || `/juggle` ||

=== <tt>onTimer(msgParam)</tt> ===
This function is called when one of the timer keys is pressed.

`msgParams` tells the set timer in seconds (i.e. `3` for the 3 seconds timer key).

=== <tt>onUpUp()</tt> ===
This function is called when you release the up key.

=== <tt>onHogHide(gearUid)</tt> (0.9.16) ===
This function is called when a hedgehog with the gear ID `gearUid` is hidden (removed from the map).

=== <tt>onHogRestore(gearUid)</tt> (0.9.16) ===
This function is called when a hedgehog with the specified gear ID `gearUid` is restored (unhidden).

=== <tt>onSpritePlacement(spriteId, centerX, centerY)</tt> (0.9.21) ===
This function is called when a [Sprites Sprite] has been placed.

`spriteID` is the type of the sprite, you find a list at [Sprites Sprites]. `centerX` and `centerY` are the coordinates of the center of the sprite.

=== <tt>onGirderPlacement(frameIdx, centerX, centerY)</tt> (0.9.21) ===
This function is called when a girder has been placed.

`frameIdx` is an integer and declares the length and orientation of the girder:
|| *`frameIdx`* || *Length* || *Orientation* ||
|| 0 || short || horizontal ||
|| 1 || short || decreasing right ||
|| 2 || short || vertical ||
|| 3 || short || increasing right ||
|| 4 || long || horizontal ||
|| 5 || long || decreasing right ||
|| 6 || long || vertical ||
|| 7 || long || increasing right ||

`centerX` and `centerY` are the coordinates of the girder’s center.

=== <tt>onRubberPlacement(frameIdx, centerX, centerY)</tt> (0.9.21) ===
This function is called when a rubber has been placed.

`frameIdx` is an integer which stands for the orientation of the rubber.

|| *`frameIdx`* || *Orientation* ||
|| 0 || horizontal ||
|| 1 || decreasing right ||
|| 2 || vertical ||
|| 3 || increasing right ||

`centerX` and `centerY` are the coordinates of the rubber’s center.

== Functions for creating gears ==

=== <tt>!AddGear(x, y, gearType, state, dx, dy, timer)</tt> ===
This creates a new gear at position x,y (measured from top left) of kind `gearType` (see [GearTypes Gear Types]). The initial velocities are `dx` and `dy`. All arguments are numbers. The function returns the `uid` of the gear created. Gears can have multple states at once: `state` is a bitmask, the flag variables can be found in [States].

Example:

<code language="lua">    local gear = AddGear(0, 0, gtTarget, 0, 0, 0, 0)
    FindPlace(gear, true, 0, LAND_WIDTH)</code>

=== <tt>!AddVisualGear(x, y, visualGearType, state, critical)</tt> ===
This creates a new visual gear at position x,y (measured from top left) of kind `visualGearType` (see [VisualGearTypes Visual Gear Types]). The function returns the `uid` of the visual gear created.  Set `critical` to `true` if the visual gear is crucial to game play. Use `false` if it is just an effect, and can be skipped when in fast-forward mode (such as when joining a room). A critical visual gear will always be created, a non-critical one may fail. Most visual gears delete themselves. 

Example:

<code language="lua">  -- adds an non-critical explosion at position 1000,1000. Returns 0 if it was not created.
    vgear = AddVisualGear(1000, 1000, vgtExplosion, 0, false) 
</code>

=== <tt>!SpawnHealthCrate(x, y)</tt> ===
Spawns a health crate at the specified position. If `x` and `y` are set to 0, the crate will spawn on a random position (but always on land).

=== <tt>!SpawnAmmoCrate(x, y, ammoType)</tt> ===
Spawns an ammo crate at the specified position with content of ammoType (see [AmmoTypes Ammo Types]). If `x` and `y` are set to 0, the crate will spawn on a random position (but always on land).
Because by default settings the number of ammo in crates is zero it has to be increased to at least one with `SetAmmo` first, see the example:

Example:

<code language="lua">    SetAmmo(amGrenade, 0, 0, 0, 1) -- see below
    SpawnAmmoCrate(0, 0, amGrenade) -- x=y=0 means random position on map</code>

=== <tt>!SpawnUtilityCrate(x, y, ammoType)</tt> ===
Spawns an utility crate at specified position with content of ammoType. If `x` and `y` are set to 0, the crate will spawn on a random position (but always on land).

Example:

<code language="lua">    SetAmmo(amLaserSight, 0, 0, 0, 1)
    SpawnUtilityCrate(0, 0, amLaserSight)</code>

=== <tt>!SpawnFakeAmmoCrate(x, y, explode, poison) </tt> ===
Spawns a crate at the specified coordinates which looks exactly like a real ammo crate but contains not any ammo. It can be use useful for scripted events or to create a trap. If `x` and `y` are set to 0, the crate will spawn on a random position (but always on land).
`explode` and `poison` are booleans.
If `explode` is `true`, the crate will explode when collected.
If `poison` is `true`, the collector will be poisoned.

Example:

<code language="lua">SpawnFakeAmmoCrate(500, 432, false, false) -- Spawns a fake ammo crate at the coordinates (500, 434) without explosion and poison.
</code>

=== <tt>!SpawnFakeHealthCrate(x, y, explode, poison) </tt> ===
Spawns a crate at the specified coordinates which looks exactly like a real health crate but it will not heal the player. It can be use useful for scripted events or to create a trap. If `x` and `y` are set to 0, the crate will spawn on a random position (but always on land).
`explode` and `poison` are booleans.
If `explode` is `true`, the crate will explode when collected.
If `poison` is `true`, the collector will be poisoned.

=== <tt>!SpawnFakeUtilityCrate(x, y, explode, poison) </tt> ===
Spawns a crate at the specified coordinates which looks exactly like a real utility crate but contains not any ammo. It can be use useful for scripted events or to create a trap. If `x` and `y` are set to 0, the crate will spawn on a random position (but always on land).
`explode` and `poison` are booleans.
If `explode` is `true`, the crate will explode when collected.
If `poison` is `true`, the collector will be poisoned.

=== <tt>!AddHog(hogname, botlevel, health, hat)</tt> ===
Adds a new hedgehog for current team (last created one with the `AddTeam` function), with bot level and specified health, also hat.
`botlevel` ranges from `0` to `5`, where `0` denotes a human player and `1` to `5` denote the skill level of a bot, where `1` is strongest and `5` is the weakest. Note that this is the reverse order of how the bot level is displayed in the game.

*Warning*: This works only for singleplayers training missions for now and will desync multiplayer games.

Example:

<code language="lua">    local player = AddHog("HH 1", 0, 100, "NoHat") -- botlevel 0 means human player
    SetGearPosition(player, 1500, 1000)</code>
== Functions to get gear properties ==

=== <tt>!GetGearType(gearUid)</tt> ===
This function returns one of [GearTypes Gear Types] for the specified gear.

=== <tt>!GetGearPosition(gearUid)</tt> ===
Returns x,y coordinates for the specified gear.

=== <tt>!GetGearRadius(gearUid)</tt> ===
Returns radius for the specified gear.

=== <tt>!GetGearVelocity(gearUid)</tt> ===
Returns a tuple of dx,dy values for the specified gear.

=== <tt>!GetFlightTime(gearUid)</tt> ===
Returns the `FlightTime` of the specified gear. The `FlightTime` is a gear varialbe used to store a general time interval. The precise meaning of the `FlightTime` depends on the gear type.

For example: The `FlightTime` of a hedgehog (`gtHedgehog`) is the time since they last have stood on solid ground. For most projectile gear types (i.e. `gtShell`), it stores the time after it has been launched.

=== <tt>!GetGearElasticity(gearUid) </tt> ===
Returns the elasticity of the specified gear. The elasticity normally determines how strong the gear will bounce after collisions, where higher elasticity is for stronger bounces.

This is also useful for determining if a hog is on a rope or not. If a hog is attached to a rope, or is busy firing one, the elasticity of the rope will be non-zero.

=== <tt>!GetGearFriction(gearUid) </tt> ===
Returns the friction of the specified gear. The friction normally determines how well the gear will slide on terrain. Higher values are for increased sliding properties.

=== <tt>!GetHogClan(gearUid)</tt> ===
Returns the clan ID of the specified hedgehog gear.

=== <tt>!GetHogTeamName(gearUid)</tt> ===
Returns the name of the specified hedgehog gear’s team.

=== <tt>!GetHogName(gearUid)</tt> ===
Returns the name of the specified hedgehog gear.

=== <tt>!GetEffect(gearUid, effect)</tt> ===
Returns the state of given effect for the given hedgehog gear.

See `SetEffect` for further details.

=== <tt>!GetHogHat(gearUid)</tt> ===
Returns the hat of the specified hedgehog gear.

=== <tt>!GetHogFlag(gearUid)</tt> (0.9.22) ===
Returns the name of the flag of the team of the specified hedgehog gear.

=== <tt>!GetHogGrave(gearUid)</tt> (0.9.22) ===
Returns the name of the grave of the team of the specified hedgehog gear.

=== <tt>!GetHogVoicepack(gearUid)</tt> (0.9.22) ===
Returns the name of the voicepack of the team of the specified hedgehog gear.

=== <tt>!GetAmmoCount(gearUid, ammoType) (0.9.16)</tt> ===
Returns the ammo count of the specified ammo type for the specified hedgehog gear.

=== <tt>!GetGearTarget(gearUid, x, y)  (0.9.16)</tt> ===
Returns the x and y coordinate of target-based weapons/utilities. 
<b>Note:</b>: This can’t be used in `onGearAdd()` but must be called after gear creation. 

=== <tt>GetX(gearUid)</tt> ===
Returns x coordinate of the gear.

=== <tt>GetY(gearUid)</tt> ===
Returns y coordinate of the gear.

=== <tt>!GetState(gearUid)</tt> ===
Returns the state of the gear. The gear state is a bitmask which is built out of the variables as shown in [States].

This function is usually used in combination with `band` to extract the truth value of a single flag. It is also used together with `SetState` and `bor` in order to activate a single flag.

Examples:
<code language="lua">
local state = GetState(gear)
--[[ Stores the full raw bitmask of gear in state. Usually
useless on its own. ]]
</code>

<code language="lua">
isDrowning = band(GetState(CurrentHedgehog),gstDrowning) ~= 0
--[[ GetState(CurrentHedgehog) returns the state bitmask of
CurrentHedgehog, gstDrowning is a bitmask where only the
“drowning” bit is set. band does a bitwise AND on both, if
it returns a non-zero value, the hedgehog is drowning.]]
</code>

<code language="lua">
SetState(CurrentHedgehog, bor(GetState(CurrentHedgehog), gstInvisible))
--[[ first the state bitmask of CurrentHedgehog is bitwise ORed with
the gstInvisible flag, thus making the bit responsible for
invisiblity to become 1. Then the new bitmask is applied to
CurrentHedgehog, thus making it invisible.]]
</code>


=== <tt>!GetGearMessage(gearUid)</tt> ===
Returns the message of the gear. This is a bitmask built out of flags seen in [GearMessages].

=== <tt>!GetTag(gearUid)</tt> ===
Returns the tag of the specified gear (by `gearUid`). 

A “tag” of a gear is simply an extra variable to modify misc. things. The meaning of a tag depends on the gear type. For example, for gtBall gears, it specifies the ball color, for gtAirAttack gears (airplane) it specifies the direction of the plane, etc. `tag` has to be an integer.

Note that the word “tag” here does _not_ refer to the name and health tags you see above hedgehogs, this is something different. 

<code language="lua">
-- This adds a ball (the one from the ballgun) at (123, 456):
ball = AddGear(123, 456, gtBall, 0, 0, 0, 0)
-- The tag of a ball defines its color. It will automatically chosen at random when created.
colorTag = GetTag(ball)
-- Now colorTag stores the tag of ball (in this case a number denoting its color)
</code>

The meaning of tags are described in [GearTypes].

=== <tt>!GetFollowGear()</tt> ===
Returns the uid of the gear that is currently being followed.

=== <tt>!GetTimer(gearUid)</tt> ===
Returns the timer of the gear. This is for example the time it takes for watermelon, mine, etc. to explode. This is also the time used to specify the blowtorch or rcplane time.

=== <tt>!GetHealth(gearUid)</tt> ===
Returns the health of the gear.

=== <tt>!GetHogLevel(gearUid)</tt> ===
Returns the bot level ranging from `0` to `5`. `1` is the strongest bot level and `5` is the weakest one. `0` is for human player.

=== <tt>!GetGearPos(gearUid)</tt> ===
Get pos of specified gear.

=== <tt>!GetGearValues(gearUid)</tt> (0.9.22) ===
This returns a bunch of values associated with the gear, their meaning is often depending on the gear type and many values might be unused for certain gear types.

This is returned (all variables are integers):

`Angle, Power, WDTimer, Radius, Density, Karma, DirAngle, AdvBounce, ImpactSound, nImpactSounds, Tint, Damage, Boom`

Boom is 0.9.23+

A rough description of some of the parameters:

 * `Radius`: Effect or collision radius, most of the time
 * `ImpactSound`: Sound it makes on a collision (see [Sounds])
 * `Tint`: Used by some gear types to determine its colorization. The color is in RGBA format.
 * `Boom`: Used by most gears to determine the damage dealt. (0.9.23+)

Example:
<code language="lua">
-- Get all values in a single line of code (omit Boom in 0.9.22) :
local Angle, Power, WDTimer, Radius, Density, Karma, DirAngle, AdvBounce, ImpactSound, nImpactSounds, Tint, Damage, Boom = GetGearValues(myGear)
</code>

=== <tt>!GetVisualGearValues(vgUid)</tt> ===
This returns the typically set visual gear values, useful if manipulating things like smoke or bubbles or circles. It returns the following values:

`X, Y, dX, dY, Angle, Frame, FrameTicks, State, Timer, Tint`

 * `X`, `Y`: typically position
 * `dX`, `dY`: typically speed
 * `Angle` is usually the rotation angle
 * `Frame` is typically the animation frame
 * `FrameTicks` is usually an animation counter
 * `State` can have a variety of values, but is typically bit packed
 * `Timer` is usually the gear lifetime
 * `Tint` is the RGBA color

Most visual gears require little to no modification of parameters.

Example:

<code language="lua">    GetVisualGearValues(vgUid) -- return visual gear values
</code>

== Functions to modify gears ==

=== <tt>!HideHog(gearUid)</tt> ===
Removes a hedgehog from the map. The hidden hedgehog can be restored with `RestoreHog(gearUid)`. The current hedgehog cannot be hidden!

Example: 

<code language="lua">    gear = AddGear(...)
     HideHog(gear) -- Hide the newly created gear.</code>

=== <tt>!RestoreHog(gearUid)</tt> ===
Restores a previously hidden hedgehog.

Example: 

<code language="lua">    gear = AddGear(...)
     HideHog(gear) -- Hide the newly created gear.
     RestoreHog(gear) -- Restore the newly hidden gear.</code>

=== <tt>!DeleteGear(gearUid)</tt> ===
Deletes a gear.

Example:

<code language="lua">    gear = AddGear(...)
    DeleteGear(gear) -- Delete the newly created gear.</code>

=== <tt>!DeleteVisualGear(vgUid)</tt> ===
Deletes a visual gear. Note, most visual gears delete themselves.

Example:

<code language="lua">    vgear = AddVisualGear(...)
    DeleteVisualGear(vgear) -- Delete the newly created visual gear.</code>

=== <tt>!SetGearValues(gearUid, Angle, Power, WDTimer, Radius, Density, Karma, DirAngle, AdvBounce, ImpactSound, ImpactSounds, Tint, Damage, Boom)</tt> (0.9.22) ===
Sets various gear value for the specified gear (`gearUid`). The meaining of each value often depends on the gear type. See the documentation on !GetGearValues for a brief description of the gear values.  Boom is 0.9.23+.

Set `nil` for each value you do not want to change.

Example:
<code language="lua">
-- Paints all RC planes into a white color
function onGearAdd(gear)
    if GetGearType(gear) == gtRCPlane then
         SetGearValues(gear, nil, nil, nil, nil, nil, nil, nil, nil, nil, nil, 0xFFFFFFFF)
    end
end
</code>

=== <tt>!SetVisualGearValues(vgUid, X, Y, dX, dY, Angle, Frame, !FrameTicks, State, Timer, Tint)</tt> ===
This allows manipulation of many of the visual gear values. In the case of `vgtCircle`, the visual gear values are mapped as follows:

 * `X`, `Y`: Position
 * `State`: Radius.
 * `Timer`: Thickness
 * `FrameTicks`: Pulsation speed (`0` to disable)
 * `dX`, `dY`: min/max pulsation opacity (`0`-`255`)
 * `Tint`: RGBA color

Most visual gears require little to no modification of parameters.

Example 1:

<code language="lua">  -- set a circle to position 1000,1000 pulsing from opacity 20 to 200 (8%-78%), radius of 50, 3px thickness, bright red.
    SetVisualGearValues(circleUid, 1000,1000, 20, 200, 0, 0, 100, 50, 3, 0xff0000ff)</code>

Beginning from 0.9.21-dev, the 2nd to 11th arguments are optional. Any such argument which is declared as `nil` will not overwrite the corresponding value of the visual gear. With this change, it is not required anymore to call `GetVisualGearValues` beforehand.

Example 2:

<code language="lua">  -- set a circle to position 1000,1000
    SetVisualGearValues(circleUid, 1000, 1000)</code>
<code language="lua">  -- set the color of a circle to bright red.
    SetVisualGearValues(circleUid, nil, nil, nil, nil, nil, nil, nil, nil, nil, 0xff0000ff)</code>


=== <tt>!FindPlace(gearUid, fall, left, right, tryHarder) (0.9.16)</tt> ===
Finds a place for the specified gear between x=`left` and x=`right` and places it there. 0.9.16 adds an optional fifth parameter, `tryHarder`. Setting to `true`/`false` will determine whether the engine attempts to make additional passes, even attempting to place gears on top of each other.

Example:

<code language="lua">    gear = AddGear(...)
    FindPlace(gear, true, 0, LAND_WIDTH) -- places the gear randomly between 0 and LAND_WIDTH</code>
=== <tt>!HogSay(gearUid, text, manner [,vgState])</tt> ===
Makes the specified gear say, think, or shout some text in a comic-style speech or thought bubble. In 0.9.21 `gearUid` is _not_ limited to hedgehogs, altough the function name suggests otherwise.

The `manner` parameter specifies the type of the bubble and can have one of these values:

|| *Value of `manner`* || *Looks* ||
|| `SAY_THINK` || Thought bubble ||
|| `SAY_SAY` || Speech bubble ||
|| `SAY_SHOUT` || Exclamatory bubble (denotes shouting) ||

As of 0.9.21, there is a optional 4th parameter `vgState`, it defines wheather the speechbubble is drawn fully opaque or semi-transparent. The value `0` is the default value.

|| *Value of `vgState`* || *Effect* ||
|| `0` || If the specified gear is a hedgehog, and it’s the turn of the hedgehog’s team, the bubble is drawn fully opaque.<br>If the gear is a hedgehog, and it’s another team’s turn, the bubble is drawn translucent.<br>If the gear is not a hedgehog, the bubble is drawn fully opaque. ||
|| `1` || The bubble is drawn translucent. ||
|| `2` || The bubble is drawn fully opaque. ||

Examples:

<code language="lua">HogSay(CurrentHedgehog, "I wonder what to do …", SAY_THINK) -- thought bubble with text “I wonder what to do …”</code>
<code language="lua">HogSay(CurrentHedgehog, "I'm hungry.", SAY_SAY) -- speech bubble with text “I’m hungry.”</code>
<code language="lua">HogSay(CurrentHedgehog, "I smell CAKE!", SAY_SHOUT) -- exclamatory bubble with text “I smell CAKE!”</code>
=== <tt>!HogTurnLeft(gearUid, boolean)</tt> ===
Faces the specified hog left or right.

Example:

<code language="lua">    HogTurnLeft(CurrentHedgehog, true) -- turns CurrentHedgehog left 
    HogTurnLeft(CurrentHedgehog, false) -- turns CurrentHedgehog right</code>
=== <tt>!SetGearPosition(gearUid, x, y)</tt> ===
Places the specified gear exactly at the position (`x`,`y`).

=== <tt>!SetGearVelocity(gearUid, dx, dy)</tt> ===
Gives the specified gear the velocity of `dx`, `dy`.

=== <tt>!SetFlightTime(gearUid, flighttime)</tt> ===
Sets the `FlightTime` of the given gear to `flighttime`. The meaning of `FlightTime` is explained in the section `GetFlightTime`.

=== <tt>!SetGearElasticity(gearUid, Elasticity) </tt> ===
Sets the elasticity of the specified gear. For most gears, the elasticity determines how strong the gear will bounce after collisions, where higher elasticity is for stronger bounces. Recommended are values between `0` and `9999`.

=== <tt>!SetGearFriction(gearUid, Friction) </tt> ===
Sets the friction of the specified gear. The friction normally determines how well the gear will slide on terrain. Higher values are for increased sliding properties. `0` is for no sliding whatsoever, where `9999` is for very long slides, greater values are not recommended.

=== <tt>!SetAmmo(ammoType, count, probability, delay, numberInCrate)</tt> ===
This updates the settings for a specified [AmmoTypes Ammo Type] as of count available for players, spawn probability, availability delay in turns, and the number available in crates. This is supposed to be used in the `onAmmoStoreInit()` event handler.

Example:

<code language="lua">    SetAmmo(amShotgun, 9, 0, 0, 0) -- unlimited amount of shotgun ammo for players
    SetAmmo(amGrenade, 0, 0, 0, 3) -- crates should contain always three grenade</code>

=== <tt>!SetAmmoDelay(ammoType, delay)</tt> ===
Changes the delay of a specified [AmmoTypes Ammo Type].

=== <tt>!AddAmmo(gearUid, ammoType, ammoCount) (0.9.16) </tt> ===
Adds `ammoType` to the specified gear. The amount added is determined by the arguments passed via `SetAmmo()` in the `onAmmoStoreInit()` event handler. In 0.9.16 ammo can be set directly via the optional third parameter, `ammoCount`. A value of 0 will remove the weapon, a value of 100 will give infinite ammo.

*Note:* The effectiveness of this function may be limited due to problems with `gfPerHogAmmo` in Lua scripting.


=== <tt>!SetHealth(gearUid, health)</tt> ===
Sets the health of the specified gear.
This can be used for purposes other than killing hedgehogs.

For example:

  * Starting the RC Plane 10 shots
  * Starting Flying Saucer (`gtJetpack`) with only 50% fuel.
  * Setting all the mines to duds.
  * (And more!)

<code language="lua">    function onGearAdd(gear)
       if (GetGearType(gear) == gtRCPlaane) then
            SetHealth(gear, 10)
       end
       if (GetGearType(gear) == gtJetpack) then
            SetHealth(gear, 1000)
       end
       if (GetGearType(gear) == gtMine) then
            SetHealth(gear, 0)
       end
    end</code>



=== <tt>!SetEffect(gearUid, effect, effectState)</tt> ===
Sets the state for one of the effects <tt>heInvulnerable, heResurrectable, hePoisoned, heResurrected, heFrozen</tt> for the specified hedgehog gear.
A value of 0 usually means the effect is disabled, values other than that indicate that it is enabled and in some cases specify e.g. the remaining time of that effect.

|| *`effect`* || *Description* || *`effectState`* ||
|| `heInvulnerable` || Wether hog is invulnerable || Any non-zero value turns on invulnerability. `0` turns it off. ||
|| `hePoisoned` || Poison damage, damages hog each turn. || Amount of damage per turn. Use `0` to disable poisoning. ||
|| `heResurrectable` || Whether to resurrect the hog on death || With a non-zero value, the hedgehog will be resurrected and teleported to a random location on death. `0` disables this. ||
|| `heResurrected` || Whether the hedgehog has been resurrected once. This is only a subtle graphical effect. || With a non-zero value, the hedgehog was resurrected, `0` otherwise. ||
|| `heFroze` || Freeze level. Frozen hedgehogs skip turn, are heavy and take half damage || The number denotes “how frozen” the hedgehog is, i.e. how long it takes to melt. The freezer sets this to `199999` initially. The value will be reduced by `50000` each round. Being hit by a flame reduces this number by `1000`. If `0`, the hedgehog is not frozen. The value will also be used for some other things by the engine, like animation, etc. ||

Example (sets all bots poisoned with poison damage of 1):

<code language="lua">    function onGearAdd(gear)
        if (GetGearType(gear) == gtHedgehog) and (GetHogLevel(gear) > 0) then
            SetEffect(gear, hePoisoned, 1)
        end
    end</code>

*Historic note*: prior to the ice-gun release, 0.9.19 (commit r10a0a31804f3) `effectState` was of boolean type (`true` = effect enabled, `false` = effect disabled)

=== <tt>CopyPV(gearUid, gearUid)</tt> ===
This sets the position and velocity of the second gear to the first one.

=== <tt>!FollowGear(gearUid)</tt> ===
Makes the game client follow the specifiec gear.

=== <tt>!SetHogName(gearUid, name)</tt> ===
Sets the name of the specified hedgehog gear.

=== <tt>!SetHogTeamName(gearUid, name)</tt> ===
Sets the team name of the specified hedgehog gear.

=== <tt>!SetWeapon(ammoType)</tt> ===
Sets the selected weapon of `CurrentHedgehog` to one of the [AmmoTypes Ammo Type].

Example:

<code language="lua">
  AddAmmo(CurrentHedgehog, amBazooka, 1) -- give the CurrentHedgehog a bazooka
  SetWeapon(amBazooka) -- select the Bazooka.</code>


=== <tt>!SetNextWeapon()</tt> (0.9.21) ===
This function makes the current hedgehog switch to the next weapon in list of available weapons. It can be used for example in trainings to pre-select a weapon.


=== <tt>!SetHogHat(gearUid, hat)</tt> ===
Sets the hat of the specified hedgehog gear.

=== <tt>!SetGearTarget(gearUid, x, y) (0.9.16)</tt> ===
Sets the x and y coordinate of target-based weapons/utilities.
*Note*: This can’t be used in onGearAdd() but must be called after gear creation.

=== <tt>!SetState(gearUid, state)</tt> ===
Sets the state of the specified gear to the specified `state`. This is a bitmask made out of the variables as seen in [States].

This function is often used together with `GetState` and the bitmask utility functions `band` and `bnot` in order to manipulate a single flag.

Examples:
<code language="lua">
SetState(CurrentHedgehog, bor(GetState(CurrentHedgehog), gstInvisible))
--[[ first the state bitmask of CurrentHedgehog is bitwise ORed with
the gstInvisible flag, thus making the bit responsible for
invisiblity to become 1. Then the new bitmask is applied to
CurrentHedgehog, thus making it invisible. ]]
</code>

<code language="lua">
SetState(CurrentHedgehog, band(GetState(CurrentHedgehog), bnot(gstInvisible)))
--[[ The reverse of the above: This function toggles CurrentHedgehog’s
gstInvisible flag off, thus making it visible again. ]]
</code>

=== <tt>!SetGearMessage(gearUid, message)</tt> ===
Sets the gear messages of the specified gear. `message` is a bitmask built out of flags seen in [GearMessages].

=== <tt>!SetTag(gearUid, tag)</tt> ===
Sets the tag of the specified gear (by `gearUid`). A “tag” of a gear is simply an extra variable to modify misc. things. The meaning of a tag depends on the gear type. For example, for gtBall gears, it specifies the ball color, for gtAirAttack gears (airplane) it specifies the direction of the plane, etc. `tag` has to be an integer.

Note that the word “tag” here does _not_ refer to the name and health tags you see above hedgehogs, this is something different. 

<code language="lua">
-- This adds a ball (the one from the ballgun) at (123, 456):
ball = AddGear(123, 456, gtBall, 0, 0, 0, 0)
-- This sets the tag of the gear. For gtBall, the tag specified the color. “8” is the color white.
SetTag(ball, 8) -- 
</code>

The meaning of tags are described in [GearTypes].

=== <tt>!SetTimer(gearUid, timer)</tt> ===
Sets the timer of the specified gear. Also see `GetTimer`

=== <tt>!SetHogLevel(gearUid, level)</tt> ===
Sets the bot level from 0 to 5. `0` means human player.

=== <tt>!SetGearPos(gearUid, value) (0.9.18-dev)</tt> ===
Set pos of specified gear to specified value.


== Gameplay functions ==

=== `GameFlags` functions ===

==== <tt>!ClearGameFlags()</tt> ====
Disables *all* !GameFlags.

==== <tt>!DisableGameFlags(gameflag, ...)</tt> ====
Disables the listed !GameFlags, without changing the status of other !GameFlags.

==== <tt>!EnableGameFlags(gameflag, ...)</tt> ====
Enables the listed !GameFlags, without changing the status of other !GameFlags.

==== <tt>!GetGameFlag(gameflag)</tt> ====
Returns `true` if the specified gameflag is enabled, otherwise `false`.

=== Environment ===

==== <tt>!SetGravity(percent)</tt> ====
Changes the current gravity of the game in percent (relative to default, integer value).
Setting it to 100 will set gravity to default gravity of hedgewars, 200 will double it, etc.

==== <tt>!GetGravity()</tt> ====
Returns the current gravity in percent.

==== <tt>!SetWaterLine(waterline)</tt> ====
Sets the water level (`WaterLine`) to the specified y-coordinate.

==== <tt>!SetWind(windSpeed)</tt> ====
Sets the current wind in the range of -100 to 100. Use together with `gfDisableWind` for full control.

==== <tt>!SetMaxBuildDistance(distInPx)</tt> (0.9.22) ====
Sets the maximum building distance for of girders and rubber bands in pixels to `distInPx`. If `distInPx` is `0`, the limit is disabled. If called without arguments, the distance will be reset to the default value.

==== <tt>!EndGame()</tt> ====
Makes the game end.

=== Map ===
==== <tt>!MapHasBorder()</tt> ====
Returns `true`/`false` if the map has a border or not.

==== <tt>!TestRectForObstacle(x1, y1, x2, y2, landOnly) (0.9.16) </tt> ====
Checks the rectangle between the given coordinates for possible collisions. Set `landOnly` to `true` if you don’t want to check for collisions with gears (hedgehogs, etc.).

==== <tt>!PlaceGirder(x, y, state)</tt> (0.9.16) ====
Places a girder with centre points `x`, `y` and a certain length and orientation, specified by `state`.

These are the accepted states:

|| *`state`* || *Length* || *Orientation* ||
|| 0 || short || horizontal ||
|| 1 || short || decreasing right ||
|| 2 || short || vertical ||
|| 3 || short || increasing right ||
|| 4 || long || horizontal ||
|| 5 || long || decreasing right ||
|| 6 || long || vertical ||
|| 7 || long || increasing right ||

==== <tt>!PlaceSprite(x, y, sprite, frameIdx, tint, behind, flipHoriz, flipVert, [, landFlag, ...])</tt> ====
Places a [Sprites sprite] at the specified position (`x`, `y`) on the map, it behaves like terrain then. `frameIdx` is the frame index starting by 0. This is used if the sprite consists of several sub-images. Only a subset of the sprites is currently supported by this function:

 * `sprAmGirder`
 * `sprAmRubber`
 * `sprAMSlot`
 * `sprAMAmmos`
 * `sprAMAmmosBW`
 * `sprAMCorners`
 * `sprHHTelepMask`
 * `sprTurnsLeft`
 * `sprSpeechCorner`
 * `sprSpeechEdge`
 * `sprSpeechTail`
 * `sprTargetBee` (since 0.9.23)
 * `sprThoughtCorner`
 * `sprThoughtEdge`
 * `sprThoughtTail`
 * `sprShoutCorner`
 * `sprShoutEdge`
 * `sprShoutTail`
 * `sprSnow`
 * `sprBotlevels`
 * `sprIceTexture`
 * `sprCustom1`
 * `sprCustom2`

`tint` is for an RGBA colouring to apply, this works about the same as `Tint` in gears. `behind` indicates the sprite should not replace existing land. `flipHoriz` and `flipVert` are for mirroring the sprite vertically and horizontally before placing, respectively.
The 9th and later arguments specify land flags (see the constants section) to be used for the newly created terrain. If omited, `lfNormal` is assumed.

Example:

<code language="lua">PlaceSprite(2836, 634, sprAmGirder, 5)
-- Places the girder sprite as normal terrain at (2836, 634). The `frameIdx` 5 is for the long decreasing right girder.</code>
<code language="lua">PlaceSprite(1411, 625, sprAmRubber, 1, nil, nil, nil, nil, lfBouncy)
-- Places the rubber band sprite as bouncy terrain at (2836, 634). The `frameIdx` 1 is for the decreasing right rubber band.</code>

==== <tt>!EraseSprite(x, y, sprite, frameIdx, eraseOnLFMatch, onlyEraseLF, flipHoriz, flipVert, [, landFlag, ...])</tt> ====
Erases a [Sprites sprite] at the specified position (`x`, `y`) on the map. `frameIdx` is the frame index starting by 0. `sprite`, `frameIdx`, `flipHoriz` and `flipVert` behave the same as in `PlaceSprite`. For `sprite`, the same subset of sprites is permitted.

Set `eraseOnLFMatch` to `true` to erase all land for a pixel that matches any of the passed in land flags.  This is useful if, for example, an `lfBouncy` sprite was placed “behind” land using `PlaceSprite` and you want to remove it without destroying the non-bouncy terrain.

Set `onlyEraseLF` to `true` to only remove specific land flags. If for example a sprite consists of `lfIndestructible` and `lfBouncy`, and you call `EraseSprite` with `onlyEraseLF` and `lfIndestructible` set, the sprite will remain bouncy but can be destroyed.  You can use this to entirely remove all land flags from a sprite—at this point the sprite will be visual only, painted on the map but with no collision.

Examples:

<code language="lua">EraseSprite(2836, 634, sprAmGirder, 5)
-- Removes the girder sprite at (2836, 634). The frameIdx 5 is for the long decreasing right girder.</code>
<code language="lua">EraseSprite(1411, 625, sprAmRubber, 1, true, true, nil, nil, lfIndestructible)
-- Removes indestructibility from a rubber band sprite at (2836, 634). The frameIdx 1 is for the decreasing right rubber band.</code>

==== <tt>!AddPoint(x, y [, width [, erase] ])</tt> (0.9.21) ====
This function is used to draw your own maps using Lua. The maps drawn with this are of type “hand-drawn”.

The function takes a `x`,`y` location, a `width` (means start of a new line) and `erase` (if `false`, this function will draw normally, if `true`, this function will erase drawn stuff).

This function must be called within `onGameInit`, where `MapGen` has been set to `mgDrawn`. You also should call `FlushPoints` when you are finished with drawing.

==== <tt>!FlushPoints()</tt> (0.9.21) ====
Makes sure that all the points/lines specified using `AddPoint` are actually applied to the map. This function must be called within `onGameInit`.

=== Current hedgehog ===

==== <tt>!GetCurAmmoType()</tt> (0.9.16) ====
Returns the currently selected [AmmoTypes Ammo Type].

==== <tt>!SwitchHog(gearUid)</tt> (0.9.16) ====
This function will switch to the hedgehog with the specifiedd `gearUid`.

==== <tt>!SetInputMask(mask)</tt> ====
Masks specified player input. This means that Hedgewars ignores certain player inputs, such as walking or jumping.

Example: 
<code language="lua">    -- masks the long and high jump commands
SetInputMask(band(0xFFFFFFFF, bnot(gmLJump + gmHJump))) 
    -- clears input mask, allowing player to take actions
    SetInputMask(0xFFFFFFFF) 
		</code>
*Note*: Using the input mask is an effective way to script uninterrupted cinematics, or create modes such as No Jumping.

See also [GearMessages].

==== <tt>!GetInputMask()</tt> ====
Returns the current input mask of the player.

=== Randomness ===
==== <tt>!GetRandom(number)</tt> ====
Returns a randomly generated number in the range of 0 to number - 1. This random number uses the game seed, so is synchronised, and thus safe for multiplayer and saved games. Use `GetRandom` for anything that could impact the engine state. For example, a visual gear could simply use Lua’s `math.random`, but adding a regular gear should use `GetRandom`.

=== Clans and teams ===
==== <tt>!AddTeam(teamname, color, grave, fort, voicepack, flag)</tt> ====

Adds a new team. Note that this can only be done in `onGameInit`, not at a later time.
You *must* add at least one hedgehog with `AddHog` after calling this. The engine does not support empty teams.

Arguments:

 * `teamname`: The name of the team.
 * `color`: The RGB color of the team as defined in [LuaAPI#Color]
 * `grave`: The name of the team’s grave (equals file name without the suffix)
 * `fort`: The name of the team’s fort (equals file name without the suffix and without the letter “L” or “R” before that suffix)
 * `voicepack`: The name of the team’s voice pack (equals the directory name)
 * `flag`: Optional argument for the name of the team’s flag (equals file name without the suffix). If set to `nil`, the flag “hedgewars” is used.

*Note*: This works only for singleplayer training missions for now and will desync multiplayer games.

Example:

<code language="lua">AddTeam("team 1", 0xDD0000, "Simple", "Tank", "Default", "hedgewars")
--[[ Adds a new team with name “team 1”, red color (hexadecimal notation), the grave “Simple”,
the fort “Tank” the voicepack “Default” and the flag “hedgewars”. ]]</code>

==== <tt>!DismissTeam(teamname)</tt> ====
Removes the team with the given team name from the game.

==== <tt>!GetClanColor(clan)</tt> ====
Returns the RGB color of the chosen clan by its number. The color data type is described in [LuaAPI#Color].

==== <tt>!SetClanColor(clan, color)</tt> ====
Sets the RGB color of the chosen clan by its number. The color data type is described in [LuaAPI#Color].

=== Campaign management ===
==== <tt>!SaveCampaignVar(varname, value)</tt> ====
Stores the value `value` (a string) into the campaign variable `varname` (also a string). Campaign variables allow you to save progress of a team in a certain campaign. Campaign variables are saved on a per-team per-campaign basis. They are written into the team file (see [ConfigurationFiles#TeamName.hwt]).

There are some special campaign variables which are used by Hedgewars to determine which missions to display in the campaign menu. This is described [ConfigurationFiles#%5BCampaign%20%3CCAMPAIGN_NAME%3E%5D here].

==== <tt>!GetCampaignVar(varname)</tt> ====
Returns the value of the campaign variable `varname` as a string. See also `SaveCampaignVar`.

== Functions affecting the GUI ==

=== <tt>!AddCaption(text)</tt> ===
Display an event text in the upper part of the screen. The text will be white and the caption group will be `capgrpMessage`.

Example:
<code language="lua">
AddCaption("Hello, world!")
</code>

=== <tt>!AddCaption(text, color, captiongroup)</tt> ===
Display an event text in the upper part of the screen with the specified RGBA [LuaAPI#Color color] and caption group. Although an RBGA color is used, Hedgewars does not actually support transparent or semi-transparent captions, so the fourth byte is ignored. We recommend you to always specify a full opacity (`FF` in hexadecimal) for the caption.

|| *`captiongroup`* || *Meaning* ||
|| `capgrpGameState` || Used for important global game events, like Sudden Death ||
|| `capgrpAmmoinfo` || Used for new weapon crates and some other events ||
|| `capgrpVolume` || Used when adjusting volume ||
|| `capgrpMessage` || Generic message ||
|| `capgrpMessage2` || Generic message ||
|| `capgrpAmmostate` || Used to show information about weapon state, i.e. bounce level, timer, remaining shots, etc. ||

Example:
<code language="lua">
AddCaption("Melon bomb rain in 2 rounds!", 0xFF0000FF, capgrpGameState)
-- Green example message.
</code>

=== <tt>!ShowMission(caption, subcaption, text, icon, time)</tt> ===
Use to tell the player what he is supposed to do. If you use this function, a mission pop-up is shown for the amount of time specified in `time` (in milliseconds). If `time` is set to 0, it will be displayed for a default amount of time.
This function replaces the *entire* text of the pop-up. Compare this to the global `Goals` variable, which *adds* to the default text without replacing it.

`caption` is the text displayed in the first line, `subcaption` is displayed in the second line and `text` is the text displayed in the third and following lines.

`text` uses some special characters for formatting: `|` is used for a line break, and everything written before and including a `:` in a line is written in a lighter color.

As of version 0.9.22, `icon` accepts the following values:

|| *`icon`* || *What is shown* ||
|| _negative number_ || Icon of an ammo type. It is specified as the negative of an ammo type constant (see [AmmoTypes]), i.e. `-amBazooka` for the bazooka icon. ||
|| `0` || Golden crown ||
|| `1` || Target ||
|| `2` || Exclamation mark ||
|| `3` || Question mark ||
|| `4` || Golden star ||
|| `5` || Utility crate ||
|| `6` || Health crate ||
|| `7` || Ammo crate ||
|| `8` || Barrel ||

Example:
<code language="lua">
ShowMission(loc("Nobody Laugh"), loc("User Challenge"), loc("Eliminate the enemy before the time runs out"), 0, 0)
</code>

=== <tt>!HideMission()</tt> ===
Hides the mission. This function is currently bugged somehow and will completely ruin your life, and your script should you happen to use it.

=== <tt>!SetZoom(zoomLevel)</tt> ===
Sets the zoom level. The value for maximum zoom is currently 1.0 and for minimum 3.0 The default zoom level is 2.0

=== <tt>!GetZoom()</tt> ===
Returns the current zoom level.

=== `SetCinematicMode(enable)` (0.9.23) ===
Turns on or off cinematic mode. Cinematic mode can be used for cutscenes etc.
If `enable` is set to `true`, cinematic mode is enabled,
if it is `false`, cinematic mode is disabled.

== Sound functions ==
=== <tt>!PlaySound(soundId)</tt> ===
Plays the specified sound. Possible values for `soundId` are listed on the [Sounds] page.

=== <tt>!PlaySound(soundId, gearUid)</tt> ===
Plays the specified sound for the chosen hedgehog gear. This can be used to play a taunt with the voicepack of the hedgehog’s team.

Possible values for `soundId` are listed on the [Sounds] page. See also [Taunts].

== File system functions ==
=== <tt>!HedgewarsScriptLoad(scriptPath)</tt> ===
Loads a script (i.e. a [LuaLibraries library]) from the specified `scriptPath`. The root directory is here Hedgewars’ data directory.

Example:
<code language="lua">
HedgewarsScriptLoad("/Scripts/Locale.lua")  -- loads locale library
</code>

=== <tt>!GetDataPath()</tt> ===
Returns the path to the data directory, used when adding libraries.

=== <tt>!GetUserDataPath()</tt> ===
Returns the path to the user data directory, used when adding libraries.





== Stats functions ==
=== <tt>!SendStat(TStatInfoType, statMessage[, teamName])</tt> (0.9.20) ===

This function exposes the uIO SendStat to the Lua scripts. Use it to produce custom stat pages.

`TStatInfoType` is the piece of information you want to manipulate. The result of this functions varies greatly for different `TStatInfoType`s. The parameter `statMessage` is mandatory and is a string used for the statistics, its meaning depends on the `TStatInfoType`. The parameter `teamName` contains the name of a team which is relevant to the chosen stat. This parameter is not always required, this also depends on `TStatInfoType`.

This tables explains the different behaviours of this function for different values of `TStatInfoType`:

|| *`TStatInfoType`* || *Meaning of `statMessage`* || *Team parameter used?* ||
|| `siGraphTitle` || Title of the graph. If you use this, the health icon changes into a star. || No ||
|| `siGameResult` || Title of the stats screen, used to show the result of the game, i.e. who won the game || No ||
|| `siCustomAchievement` || A freeform text for a single “bullet point” in the “bullet point” list in the details section. For each time you call `SendStat` with this `TStatInfoType`, a new “bullet point” gets added to the list. || No ||
|| `siPointType` || Replaces the word “kills” in the ranking list. You have to call this each time before you report the score or kills of a team with `siPlayerKills`. Sadly, grammatical number is currently not respected at all here. || No ||
|| `siPlayerKills` || The number of kills for the specified team (converted to a string), as shown in the ranking list. Unless the word “kills” has been replaced by `siPointType`, then that word is used instead. Only integers (converted to string) are possible. || Yes ||
|| `siClanHealth` || Value of a data point (converted to a string). This sets a single data point on the graph for the specified team. Subsequent calls will draw the next point along the horizontal axis; the frontend will then simply connect the dots in the final graph. The graphs are treated independently for each other. Currently the graph only can display positive values. You also should have called `SendHealthStatsOff` if you use this to prevent the default health graphs to be drawn. || Yes ||
|| `siMaxStepKills` || Most hedgehogs killed in a round. `statText` must be in format “`<kills> <name of killer hedgehog> (<team name of killer>)`”. || No ||
|| `siMaxTeamDamage` || Hedgehog with most damage inflicted to his own team. `statText` must be in the format “`<damage> <hedgehog name>`”. || No ||
|| `siKilledHHs` || Total number of killed hedgehogs (converted to string). || No ||
|| `siTeamStats` || Increases the wins of local teams in case the given number is greater than 0. || No ||
|| `siMaxStepDamage` || Best shot award (most damage in one turn). `statText` must be in format “`<damage> <hedgehog name> (<team name>)`”. || No ||
|| `siMaxTurnSkips` || Team with most skips. `statText` must be of format “`<number> <teamName>`”. || No ||


<b>Examples:</b>

<code language="lua">
-- will automatically change the health icon to a star
SendStat(siGraphTitle,'Custom Graph Title')
SendStat(siGameResult,'Winner is Team A!')
SendStat(siCustomAchievement,'This is a custom message posted in the Details section!')
-- Changes the word kill to Point, call it just before sending kills/score for each hog
-- in case you want to change the word i.e. print Point or Points
SendStat(siPointType,'Point')
-- if above function call was not used it will print 3 kills for teamName in Ranking section.
-- if it was used it will print 3 Point for teamName in Ranking section.
SendStat(siPlayerKills,'3',teamName)
-- call siClanHealth to send the "value" of a clan that will be used for the graph creation
-- a good idea is to call it always for every hog by using the runOnGears(function)
-- in normal mode "value" represents clan health
SendStat(siClanHealth, "100",teamName)
-- most hedgehogs killed in a round (hedgeHogName is who killed them)
SendStat(siMaxStepKills, "1 hedgeHogName (teamName)")
-- hog with most damage inflicted to his own team
SendStat(siMaxTeamDamage, "100 hedgeHogName")
-- total number of killed hedgehogs
SendStat(siKilledHHs, "1")
-- increases the wins of local teams in case the given number is greater than 0
SendStat(siTeamStats, "teamName:0:")
-- best shot award
SendStat(siMaxStepDamage, "30 hedgeHogName (teamName)")
-- team with most kills of own hedgehogs
SendStat(siMaxStepDamage, "2 teamName")
-- team with most skips
SendStat(siMaxTurnSkips, "3 teamName")
</code>

<b>Important:</b>

  * As the game engine send stats to the frontend at the end of the game one should send her stats when the game is going to finish and right before the call of `EndGame()`. (Note: Stats are sent from the engine in `CheckForWin`. If conditions are met (win or draw) then `SendStats(uStats)` is called.)
  * Calling just `EndGame()` won’t produce any stats.
  * If one would like to produce a custom graph see also `SendHealthStatsOff()`.

=== <tt>!SendHealthStatsOff()</tt> (0.9.20) ===
Prevents the engine of sending health stats to the frontend. 

If any health stats haven’t been sent before this will cause the health graph to the stats page to be hidden. Use this function in the Lua scripts to produce custom graphs by calling it inside `onGameStart()` and using the `SendStat()`.

== Math Functions ==

=== <tt>div(dividend, divisor)</tt> ===
Performs an integer division and returns the result.
The result is an integer and has the value of the first parameter (an integer) divided by the second parameter (another integer), rounded towards zero.

=== <tt>band(value1, value2)</tt> ===
Returns the bitwise logical AND of `value1` and `value2`.

=== <tt>bor(value1, value2)</tt> ===
Returns the bitwise logical OR of `value1` and `value2`.

=== <tt>bnot(value)</tt> ===
Returns the bitwise logical NOT of `value`.


== Debugging Functions ==
=== `WriteLnToConsole(string)` ===
Writes `string` to `Logs/game0.log`, found in the user data directory.

=== `DumpPoint(x, y)` (0.9.23) ===
Converts the whole numbers `x` and `y` to strings and writes them to `Logs/game0.log`, one line each.

=== <tt>!ParseCommand(string)</tt> ===
Makes the game client parse the specified custom command.

*Note*: Please be aware that the *engine protocol can (and will) change* between releases.

If you use `ParseCommand` to overcome a shortcoming in our Lua API (e.g. a missing function), please make sure to [https://code.google.com/p/hedgewars/issues/entry report the issue].

With your report we can fix the shortcoming in future releases.
This will allow scripts to use the previously missing feature in a way that won’t break!