#summary List of gear-related functions in the Lua API
#labels !LuaFunctions

= Lua API: Gear functions =

This is a list of all functions in the [LuaAPI Lua API] that are related to gears and visual gears.

Gears are dynamic objects or events in the world that affect the gameplay, including hedgehogs, projectiles, weapons, land objects, active utilities and a few more esoteric things. Visual gears are decorational objects which are usually used for purely decorational graphical effects. They have no effect on gameplay. Visual gears are not the same as gears, but they share some similarities.

Refer to [LuaGuide] for a more detailed introduction into gears.

<wiki:toc max_depth="3"/>

== Creation ==

=== `AddGear(x, y, gearType, state, dx, dy, timer)` ===
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]. `timer` is the initial timer value of the gear. If a particular gear value does not matter, use `0`.

Position, velocity, state and timer can be changed afterwards with the various setter functions.

Note: If you want to create a hedgehog (`gtHedgehog`), you must call `AddHog` or `AddMissionHog` instead. If you want to spawn a crate (`gtCase`), you must call one of the several “Spawn*Crate” functions (e.g. `SpawnSupplyCrate`) below instead.

Example:

<code language="lua">    -- Spawn a target at (0,0) and place it randomly
    local gear = AddGear(0, 0, gtTarget, 0, 0, 0, 0) -- also use 0 for velocity. Also 0 for state and timer because they don't matter.
    FindPlace(gear, true, 0, LAND_WIDTH)</code>

=== `AddVisualGear(x, y, visualGearType, state, critical [, layer])` ===
This attempts to create 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 or `nil` if creation failed.  There is no guarantee that a visual gear will spawn.  *IMPORTANT: Do not rely on visual gears to spawn*. *Always* be prepared for this function to return `nil`.

Set `critical` to `true` if the visual gear is crucial to gameplay and must always be spawned when in-game.  Use `false` if it is just an effect or eye-candy, and its creation can be skipped when in fast-forward mode (such as when joining a room).

You can set an optional `layer` to specify which visual gears get drawn on top.

Most visual gears delete themselves eventually.

*NOTE:* Visual gears *must* only be used for decorational/informational/rendering purposes. *Never* use the visual gear's internal state to manipulate anything gameplay-related. Visual gears are not safe for reliable storage and using them as that would lead to strange bugs.

*NOTE:* Since 0.9.25, visual gears will never spawn when Hedgewars is run in a testing mode (i.e. not as the real game), so don't rely for visual gears to spawn even if they're critical.

Example:

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

=== `AddHog(hogname, botlevel, health, hat)` ===
Adds a new hedgehog for current team (last created one with the `AddTeam` function), with a bot level, an initial health and a 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. Note that mixing human-controlled and computer-controlled hedgehogs in the same team is not permitted, but it is permitted to use different computer difficulty levels in the same team.

Returns the gear ID.

*Warning*: This only works in singleplayer mode (e.g. missions). Also, Hedgewars only supports up to 64 hedgehogs in a game.

Example:

<code language="lua">    local player = AddHog("HH 1", 0, 100, "NoHat") -- botlevel 0 means human player
    SetGearPosition(player, 1500, 1000)
    -- hint: If you don't call `SetGearPosition`, the hog spawns randomly</code>

=== `AddMissionHog(health)` ===
Add a hedgehog for the current team, using the player-chosen team identity when playing in singleplayer missions. The “current team” is the last team that was added with `AddMissionTeam` or `AddTeam`.

The name and hat match the player's team definition. The hog is also always player-controlled.

Examples:
<code language="lua">-- Add player team with 3 hogs
AddMissionTeam(-1)
AddMissionHog(100)
AddMissionHog(100)
AddMissionHog(100)</code>

<code language="lua">-- You can also mix mission hogs with “hardcoded” hogs.
-- This adds a player team with 2 hogs taken from the player team and 1 hog with a hardcoded name, botlevel and hat.
AddMissionTeam(-2)
AddMissionHog(100)
AddMissionHog(100)
AddHog("My Hardcoded Hog", 0, 100, "NoHat")
</code>

=== `SpawnHealthCrate(x, y, [, health])` ===
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). Set `health` for the initial health contained in the health crate. If not set, the default health (`HealthCaseAmount`) is used. Do not use a negative value for `health`.

=== `SpawnSupplyCrate(x, y, ammoType [, amount])` ===
Spawns an ammo or utility crate at the specified position with the given ammo type and an optional amount (default: 1). The crate type is chosen automatically based on the ammo type.
Otherwise, this function behaves like `SpawnAmmoCrate`.

=== `SpawnAmmoCrate(x, y, ammoType [, amount])` ===
Spawns an ammo crate at the specified position with content of `ammoType` (see [AmmoTypes Ammo Types]). Any `ammoType` is permitted, an ammo crate is spawned even if the ammo is normally defined as an utility.
If `ammoType` is set to `amNothing`, a random weapon (out of the available weapons from the weapon scheme) will be selected. If `x` and `y` are set to 0, the crate will spawn on a random position (but always on land). The `amount` parameter specifies the amount of ammo contained in the crate. If `amount` is `nil` or `0`, the value set by `SetAmmo` is used, or if `SetAmmo` has not been used, it falls back to the weapon scheme's value. If `amount` is equal to or greater than `AMMO_INFINITE`, the amount is infinite.

Note that in Lua missions, the default number of ammo in crates is 0, so it has to be set to at least 1 with `SetAmmo` first, see the example:

Example:

<code language="lua">    SetAmmo(amGrenade, 0, 0, 0, 1) -- grenade ammo crates now contain 1 grenade each
    SpawnAmmoCrate(0, 0, amGrenade) -- spawn grenade ammo crate at random position</code>

=== `SpawnUtilityCrate(x, y, ammoType [, amount])` ===
Spawns an utility crate with some ammo at the specified position. The function behaves almost like `SpawnAmmoCrate`, the differences are 1) the crate looks different and 2) if `ammoType` is set to `amNothing`, a random utility out of the set of available utilities from the weapon scheme is chosen as content.

Example:

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

=== `SpawnFakeAmmoCrate(x, y [, explode [, poison]]) ` ===
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. They are optional since 1.0.0 but mandatory until 0.9.25.

If `explode` is `true`, the crate will explode when collected (default: `false`).
If `poison` is `true`, the collector will be poisoned (default: `false`).

Example:

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

=== `SpawnFakeHealthCrate(x, y [, explode [, poison]]) ` ===
Same as `SpawnFakeAmmoCrate`, except the crate will look like a health crate.

=== `SpawnFakeUtilityCrate(x, y [, explode [, poison]]) ` ===
Same as `SpawnFakeAmmoCrate`, except the crate will look like an utility crate.

== Position and velocity ==
=== `GetGearPosition(gearUid)` ===
Returns x,y coordinates for the specified gear. Not to be confused with `GetGearPos`.

=== `GetX(gearUid)` ===
Returns x coordinate of the gear.

=== `GetY(gearUid)` ===
Returns y coordinate of the gear.

=== `SetGearPosition(gearUid, x, y)` ===
Places the specified gear exactly at the position (`x`,`y`). Not to be confused with `SetGearPos`.

=== `GetGearVelocity(gearUid)` ===
Returns a tuple of dx,dy values for the specified gear.

=== `SetGearVelocity(gearUid, dx, dy)` ===
Gives the specified gear the velocity of `dx`, `dy`.

=== `CopyPV(fromGearUid, toGearUid)` ===
When given two gears as arguments, this sets the position and velocity of `toGearUid` to the position and velocity of `fromGearUid`.

=== `FindPlace(gearUid, fall, left, right[, tryHarder])` ===
Finds a place for the specified gear between x=`left` and x=`right` and places it there. `tryHarder` is optional, setting it 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>

== General gear properties ==

=== `GetGearType(gearUid)` ===
This function returns the [GearTypes gear type] for the specified gear, if it exists.  If it doesn't exist, `nil` is returned.

=== `GetVisualGearType(vgUid)` ===
This function returns the [VisualGearTypes visual gear type] for the specified visual gear, if it exists.  If it doesn't exist, `nil` is returned.

=== `GetState(gearUid)` ===
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>

=== `SetState(gearUid, state)` ===
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>


=== `GetGearMessage(gearUid)` ===
Returns the message of the gear. This is a bitmask built out of flags seen in [GearMessages].

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

=== `GetTag(gearUid)` ===
Returns the tag of the specified gear (by `gearUid`). 

The `Tag` of a gear is just another arbitrary variable to hold the gear's state. 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. See [GearTypes] for a full list. The returned value will 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].

=== `SetTag(gearUid, tag)` ===
Sets the `Tag` value of the specified gear (by `gearUid`). The `Tag` value 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. See [GearTypes] for a full list. `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].

=== `GetTimer(gearUid)` ===
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 RC plane time. See [GearTypes] for a full list.

=== `SetTimer(gearUid, timer)` ===
Sets the timer of the specified gear. Also see `GetTimer`.

=== `GetHealth(gearUid)` ===
Returns the health of the gear. Depending on the gear type, the gear's “health” can also refer to other things, see [GearTypes] for a full list.

=== `SetHealth(gearUid, health)` ===
Sets the health of the specified gear. The “health” of a gear can refer to many things, depending on the gear type.

*Hint*: If you like to increase the health of a hedgehog with nice visual effects, consider using `HealHog` instead.

Use cases:

  * Setting the health of a hedgehog (`gtHedgehog`) to 99
  * Starting the RC Plane (`gtRCPlane`) with 10 bombs
  * Starting flying saucer (`gtJetpack`) with only 50% fuel
  * Setting all the mines (`gtMine`) to duds
  * And more!

See [GearTypes] for a full description.

<code language="lua">    function onGearAdd(gear)
       if (GetGearType(gear) == gtHedgehog) then
            -- Set hedgehog health to 99
            SetHealth(gear, 99)
       end
       if (GetGearType(gear) == gtRCPlaane) then
            -- Give the plane 10 bombs
            SetHealth(gear, 10)
       end
       if (GetGearType(gear) == gtJetpack) then
            -- Set fuel to 50% only
            SetHealth(gear, 1000)
       end
       if (GetGearType(gear) == gtMine) then
            -- Turn mine into dud
            SetHealth(gear, 0)
       end
    end</code>


=== `GetGearPos(gearUid)` ===
Get the `Pos` value of the specified gear. `Pos` is just another arbitrary value to hold the state of the gear, such as `Tag` and `Health`, the meaning depends on the gear type. See [GearTypes] for the conrete meaning of a gear's `Pos` value. 

*Important*: Pos is *not* related to the gear's position, use `GetGearPosition` for that.

=== `SetGearPos(gearUid, value)` ===
Sets the `Pos` value (not the position!) of the specified gear to specified value. See `GetGearPos` for more information.

=== `GetGearCollisionMask(gearUid)` ===
Returns the current collision mask of the given gear. See `SetGearCollisionMask` for an explanation of the mask.

=== `SetGearCollisionMask(gearUid, mask)` ===
Set the collision mask of the given gear with `gearUid`.
The collision mask defines with which gears and terrain types the gear can collide.

`mask` is a number between `0x0000` and `0xFFFF` and used as a bitfield, which means you can combine these flags with `bor`. These are the available flags:

|| *Identifier* || *Collision with …* ||
|| `lfLandMask` || Terrain ||
|| `lfCurHogCrate` || Current hedgehog, and crates ||
|| `lfHHMask` || Any hedgehogs ||
|| `lfNotHHObjMask` || Objects, not hogs (e.g. mines, explosives) ||
|| `lfAllObjMask` || Hedgehogs and objects ||

Beware, the collision mask is often set by the engine as well.

Examples:
<code language="lua">SetGearCollisionMask(gear, bnot(lfCurHogCrate))
-- Ignore collision with current hedgehog</code>

<code language="lua">SetGearCollisionMask(gear, 0xFFFF)
-- Collide with everything</code>

<code language="lua">SetGearCollisionMask(gear, lfAllObjMask)
-- Collide with hedgehogs and objects</code>

<code language="lua">SetGearCollisionMask(gear, 0x0000)
-- Collide with nothing</code>

There are actual more flags availbable, but they are not as useful for use in Lua and their constants have not been exposed to Lua. You can find the full range of flags in the engine source code (in Pascal):

[https://hg.hedgewars.org/hedgewars/file/default/hedgewars/uConsts.pas#l112]

=== `GetGearRadius(gearUid)` ===
Returns the `Radius` value for the specified gear. For most [GearTypes gear types] for “projectile” gears (like `gtShell` or `gtGrenade`), the radius refers to the gear's collision radius. This is an invisible circle around the center of the gear which is used for the collision checks. For a few gear types, its radius means something different, see [GearTypes] for a full list.

To set the `Radius` value, use `SetGearValues`.

=== `GetFlightTime(gearUid)` ===
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.

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

=== `GetGearElasticity(gearUid) ` ===
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 a non-zero number.

=== `SetGearElasticity(gearUid, Elasticity) ` ===
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`.

=== `GetGearFriction(gearUid) ` ===
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.

=== `SetGearFriction(gearUid, Friction) ` ===
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.

=== `GetGearTarget(gearUid, x, y) ` ===
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. 

=== `SetGearTarget(gearUid, x, y)` ===
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.

=== `GetGearValues(gearUid)` ===
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`

That the concrete meaning of each of this variables depends on the gear type and can vary wildly. For most gear types, many of these variables are unused and have no effect.

Here's an overview of the purpose of these variables:

 * `Angle`: Angle the gear was launched in (usually)
 * `Power`: Power the gear was launched in (usually)
 * `WDTimer`: An alternative timer variable, used by some more complex gears like air mines
 * `Radius`: Effect or collision radius, most of the time
 * `Density`: A high density makes the gear less prone to being pushed by forces, like explosions, wind and stuff. Gears with a higher density also make a larger splash
 * `Karma`: Used to track karma damage for hedgehogs in the Karma game modifier, but abused for different purposes for other gears, too
 * `DirAngle`: ???
 * `AdvBounce`: ???
 * `ImpactSound`: Sound it makes on a collision (see [Sounds])
 * `nImpactSounds`: Must be used together with `ImpactSound`. Number of different impact sounds to use. `0`: Disable impact sound. `1`: Use sound selected in `ImpactSound`. `2` or higher: Uses a random impact sound each impact. The first possible sound is `ImpactSound`, the second possible sound is `ImpactSound+1`, and so on. The order of sounds is specified at [https://hg.hedgewars.org/hedgewars/file/default/hedgewars/uTypes.pas#l120]. For example, if `ImpactSound` is `sndHellishImpact1` and `nImpactSounds` equals 4, the impact sounds will be `sndHellishImpact1` to `sndHellishImpact4`
 * `Tint`: Colorization of gear. The color is in RGBA format. Not supported by all gears.
 * `Damage`: Amount of damage taken by gear. Only used by a few gears.
 * `Boom`: Used by most gears to determine the potential damage / explosion size

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

=== `SetGearValues(gearUid, Angle, Power, WDTimer, Radius, Density, Karma, DirAngle, AdvBounce, ImpactSound, ImpactSounds, Tint, Damage, Boom)` ===
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. If `gearUid` is invalid or the gear does not exist, nothing happens.

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>

=== `GetVisualGearValues(vgUid)` ===
This returns the typically set visual gear values for the specified visual gear `vgUid`, useful if manipulating things like smoke, bubbles or circles. On success, it returns the following values:

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

The meaning of these values is the same as in `SetVisualGearValues`.

If the visual gear does not exist, `nil` is returned. Always check the result for `nil` before you plug in the values anywhere.

Most visual gears require little to no modification of parameters.

Example:

<code language="lua">-- Return visual gear values
local X, Y, dX, dY, Angle, Frame, FrameTicks, State, Timer, Tint, Scale = GetVisualGearValues(vgUid)
</code>

=== `SetVisualGearValues(vgUid, X, Y, dX, dY, Angle, Frame, FrameTicks, State, Timer, Tint, Scale)` ===
This allows manipulation of the internal state of the visual gear `vgUid`. If `vgUid` is invalid or the `vgUid` does not refer to an existing visual gear, the function does nothing. Thus, you can safely call this function even if you are not sure if the visual gear actually exists.

All visual gear values are numbers. Each visual gear may be using these parameters differently, but the *usual* meaning of these is the following:

 * `X`, `Y`: Position
 * `dX`, `dY`: Speed along the X and Y axis
 * `Angle`: Current rotation
 * `Frame`: Image frame, if using a sprite sheet
 * `FrameTicks` is usually an animation counter
 * `State`: Helper value to save some internal state
 * `Timer`: Time in milliseconds until it expires
 * `Tint`: RGBA color
 * `Scale` is a scale factor (not used by all visual gears)

Some visual gears interpret these values differently, just like normal gears. See [VisualGearTypes] for details.  Also, most visual gears are not using all possible values, while some values are just ignored.

Note that most visual gears require little to no modification of their values.

*NOTE*: *Never* use the visual gear's internal state to manipulate/store anything gameplay-related.  Visual gears are not safe for reliable storage and using them as that would lead to strange bugs.

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>

Only the first argument is required. Everything else is optional. Any such argument which is declared as `nil` will not overwrite the corresponding value of the visual gear.

Example 2:

<code language="lua">  -- set a visual gear to position 1000,1000
    SetVisualGearValues(circleUid, 1000, 1000)</code>
<code language="lua">  -- set the tint of a visual gear to bright red.
    SetVisualGearValues(circleUid, nil, nil, nil, nil, nil, nil, nil, nil, nil, 0xff0000ff)</code>
    
=== `SetGearAIHints(gearUid, aiHint)` ===
Set some behaviour hints for computer-controlled hedgehogs for any given gear with `gearUid`.

Set `aiHint` to either of:

 * `aihUsualProcessing`: AI hogs treat this gear the usual way. This is the default.
 * `aihDoesntMatter`: AI hogs don't bother attacking this gear intentionally, or don't bother collecting it if it's a crate
<wiki:comment>aihAmmosChanged is intentionally not included. This AI hint is for internal use only.</wiki:comment>

Example:

<code language="lua">
SetGearAIHints(uselessHog, aihDoesntMatter)
-- This makes AI hogs stop caring about attacking uselessHog</code>

== Hedgehog-specific gear properties ==
=== `IsHogAlive(gearUid)` ===
Returns `true` if specified gear is a hedgehog, alive, not about to die and not hidden. Returns `false` otherwise.

=== `GetHogName(gearUid)` ===
Returns the name of the specified hedgehog gear.

=== `SetHogName(gearUid, name)` ===
Sets the name of the specified hedgehog gear.

=== `GetHogTeamName(gearUid)` ===
Returns the name of the specified gear’s team. `gearUid` can be a hedgehog or a grave.

=== `SetHogTeamName(gearUid, name)` ===
Sets the team name of the specified gear. The gear can be a hedgehog or grave.

=== `GetHogClan(gearUid)` ===
Returns the clan ID of the specified hedgehog gear.

=== `GetHogLevel(gearUid)` ===
Returns the bot level ranging from `0` to `5`. `1` is the strongest bot level and `5` is the weakest one (this is the reverse of what players see). `0` is for human player.

=== `SetHogLevel(gearUid, level)` ===
Sets the bot level from 0 to 5. `1` is the strongest bot level and `5` is the weakest one (this is the reverse of what players see). `0` means human player.

=== `GetEffect(gearUid, effect)` ===
Returns the state of given effect for the given hedgehog gear.

See `SetEffect` for further details.

=== `SetEffect(gearUid, effect, effectState)` ===
Sets the state for one of the effects `heInvulnerable, heResurrectable, hePoisoned, heResurrected, heFrozen` 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 safe location on death. Resurrection may fail and the hedgehog can still die when there is no or very, very little land left. `0` disables this. ||
|| `heResurrected` || Whether the hedgehog has been resurrected by the Resurrector utility (resurrection by `heResurrectable` does not count). This is only a subtle graphical effect. || With a non-zero value, the hedgehog was resurrected, `0` otherwise. ||
|| `heFrozen` || Freeze level. Frozen hedgehogs skip turn, are heavy and take half damage || The hog is considered frozen if the value is `256` or higher, otherwise not. A number of `256` or higher 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`. The values `0` to `255` are used for the freeze/melt animations. ||
|| `heArtillery` || If enabled, the hedgehog can't walk. || `0` = disabled. `1` = permanently enabled. `2` = temporarily enabled (used by sniper rifle between shots) ||

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>

=== `GetHogHat(gearUid)` ===
Returns the hat of the specified hedgehog gear.

=== `SetHogHat(gearUid, hat)` ===
Sets the hat of the specified hedgehog gear. `hat` is the hat name, which equals the file name (case-sensitively) without the file name suffix. If the hat file can not be found on the local computer, the hog will wear no hat.

=== `GetHogFlag(gearUid)` ===
Returns the name of the flag of the team of the specified hedgehog gear.

=== `GetHogFort(gearUid)` ===
Returns the name of the fort of the team of the specified hedgehog gear.

=== `GetHogGrave(gearUid)` ===
Returns the name of the grave of the team of the specified hedgehog gear.

=== `GetHogVoicepack(gearUid)` ===
Returns the name of the voicepack of the team of the specified hedgehog gear.

=== `GetAmmoCount(gearUid, ammoType)` ===
Returns the ammo count of the specified ammo type for the specified hedgehog gear. If infinite, returns `AMMO_INFINITE`.

=== `GetAmmoTimer(gearUid, ammoType)` ===
Returns the currently configured ammo timer (in milliseconds) for the given hedgehog gear and specified ammo type. This is the timer which is set by the player by using the timer keys (1-5). For ammo types for which the timer cannot be changed, `nil` is returned.

Example:
<code lang="lua">GetAmmoTimer(CurrentHedgehog, amGrenade)
-- May return 1000, 2000, 3000, 4000 or 5000</code>

=== `HealHog(gearUid, healthBoost[, showMessage[, tint]])` ===
Convenience function to increase the health of a hedgehog with default visual effects.

Specifically, this increases the health of the hedgehog gear with the given ID `gearUid` by `healthBoost`, displays some healing particles at the hedgehog and shows the health increae as a message. This is similar to the behavour after taking a health crate, or getting a health boost from vampirism.

If `showMessage` is false, no message is shown. With `tint` you can set the RGBA color of the particles (default: `0x00FF00FF`).

This function does not affect the poison state, however (see `SetEffect`).

=== `HogTurnLeft(gearUid, boolean)` ===
Faces the specified hog left or right.

Example:

<code language="lua">    HogTurnLeft(CurrentHedgehog, true) -- turns CurrentHedgehog left 
    HogTurnLeft(CurrentHedgehog, false) -- turns CurrentHedgehog right</code>

=== `IsHogHidden(gearUid)` ===
Returns true if hedgehog gear is hidden (e.g. via `HideHog` or the !TimeBox), false if it isn't, nil if that hedgehog never existed.

=== `HideHog(gearUid)` ===
Removes a hedgehog from the map. The hidden hedgehog can be restored with `RestoreHog(gearUid)`. Returns `true` on success and `false` on failure (if gear does not exist / hog is already hidden). You must not hide all hogs at once.

Example: 

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

=== `RestoreHog(gearUid)` ===
Restores a previously hidden hedgehog.  Nothing happens if the hedgehog does not exist or is not hidden.

Example: 

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

=== `IsHogLocal(gearUid)` ===
Returns `true` if the specified hedgehog gear is controlled by a human player on the computer on which Hedgewars runs on (i.e. not over a computer over the network). Also returns `true` if the hog is a member of any of the local clans. Returns `false` otherwise.

If the game has a mission team (see `AddMissionTeam`), this function behaves a little different: It only may return `true` for hogs in the same clan as the mission team and always returns `false` for hogs from other clans.

Returns `nil` if `gearUid` is invalid.

This is perfect to hide certain captions like weapon messages from enemy eyes.

== Special gear actions ==
=== `GetFollowGear()` ===
Returns the uid of the gear that is currently being followed.

=== `FollowGear(gearUid)` ===
Makes the game client follow the specifiec gear (if it exists). Does not work for visual gears.

=== `HogSay(gearUid, text, manner [,vgState])` ===
Makes the specified gear say, think, or shout some text in a comic-style speech or thought bubble. `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) ||

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>

== Deletion ==
=== `DeleteGear(gearUid)` ===
Deletes a gear.  If the specified gear did not exist, nothing happens.

Example:

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

=== `DeleteVisualGear(vgUid)` ===
Deletes a visual gear.  If it does not exist, nothing happens. 

Note, most visual gears delete themselves after a while.



Example:

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