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LuaEvents
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List of event handlers in the Lua API
LuaFunctions
Updated Sat, 18 May 2019 16:04:32 +0100 by Wuzzy

Lua API: Event handlers

Event handlers are Lua functions that Hedgewars calls on certain events. Lua scripts are supposed to define these functions to do something. The functions are then called by Hedgewars when a certain event has occured. For an example of how this works, see LuaGuide.

This page is a list of all supported event handlers in Hedgewars.

Initialization

onGameInit()

This function is called before the game loads its resources. One can read and modify various game variables here. These variables will become globally available after onGameInit has been invoked, but changing them has only an effect in onGameInit .

Most game variables are optional, but for missions, Theme must be set by the scripter if you want to use a random map, rather than an image map. All other variables do not need to be set by the scripter and have default values. For a list of game variables that can be set here, see LuaGlobals#Game_variables.

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.

onGameStart()

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.

At this stage, the global variables LeftX , RightX , TopY , LAND_WIDTH and LAND_HEIGHT become available.

onPreviewInit()

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.

onParameters()

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.

onAmmoStoreInit()

This function is called when the game is initialized to request the available ammo and ammo probabilities. Use SetAmmo here.

onNewAmmoStore(team/clan index, hog index)

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.

Time events

onGameTick()

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 .

onGameTick20()

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.

Game events

onNewTurn()

This function calls at the start of every turn. You can set ReadyTimeLeft here to change the ready time for this turn. (See also: Ready )

onEndTurn() (0.9.24)

This function calls at the end of every turn. The end of a turn is defined as the point of time after the current hedgehog lost control and all the important gears are either gone or have settled.

CurrentHedgehog holds the gear ID of the hedgehog whose turn just ended.

This function is called at one of the earliest possible moment after the end of a turn. After this callback, Hedgewars then performs all the other stuff between turns. This includes things like: Applying poison or Sudden Death damage, calculating total hog damage, rising the water in Sudden Death, dropping a crate, checking victory, giving control to the next hog.

Because this function is called before victories are checked, this is useful to set up your victory conditions here.

onSkipTurn() (0.9.24)

This function calls when a hog skips its turn.

onCaseDrop(gear) (1.0.0)

This function calls between two turns right after the moment at which the game might drop a crate according to the game scheme settings. It does not matter if it actually wants to drop a crate.

If a crate was dropped, gear is the crate gear that was dropped, if no crate was dropped, gear is nil .

This function is useful to add custom crate drops as well.

onSuddenDeath()

This function is called on the start of Sudden Death.

onGameResult(winningClan) (0.9.25)

This function calls when the game ends with a winner or in a draw. If a clan wins, winningClan is the clan ID of the winning clan. If the game ends in a draw, winningClan is set to -1.

onAchievementsDeclaration()

This function is called after the stats for the stats screen (after the game) have been generated. You are supposed to call DeclareAchievement here.

onHogAttack(ammoType)

This function is called when a hedgehog attacks. Beginning with 0.9.21, the parameter ammoType is provided. It contains the ammo type of the weapon used for the attack.

Note: If you want to detect when a turn was skipped, use onSkipTurn() . There is no guarantee that onHogAttack(amSkip) is called in such an event.

onUsedAmmo(ammoType)

Called after a weapon has been used completely, with ammoType as the used ammo type.

For example, it is called right after a bazooka is fired, when both shots of a shotgun have been fired, when extra time is used, or when all 4 shots of a portable portal device have been fired. It is also called when using a multi-shot ammo has been aborted by changing the weapon selection mid-way, because this still uses up the ammo.

Warning: In 0.9.24 or earlier, you must not manipulate any ammo within this callback, e.g. by using AddAmmo . The ammo storage might become garbled otherwise.

Controls

onAttack()

This function is called when the current player presses the attack key.

onHJump()

This function is called when the current player presses the high jump key.

onLJump()

This function is called when the current player presses the long jump key.

onPrecise()

This function is called when the current player presses the precise key.

onLeft()

This function is called when the current player presses the left key.

onRight()

This function is called when the current player presses the right key.

onUp()

This function is called when the current player presses the up key.

onDown()

This function is called when the current player presses the down key.

onAttackUp()

This function is called when the current player releases the attack key.

onLeftUp()

This function is called when the current player releases the left key.

onRightUp()

This function is called when the current player releases the right key.

onDownUp()

This function is called when the current player releases the down key.

onUpUp()

This function is called when you release the up key.

onPreciseUp()

This function is called when the current player releases the precise key.

onSwitch()

This function is called when the current player presses the switch key.

onSetWeapon(msgParam)

It is get called when a weapon is selected or switched.

msgParam tells you which ammo type was selected.

onSlot(msgParam)

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.).

onTaunt(msgParam)

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

onTimer(msgParam)

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).

onScreenResize()

This function is called when you resize the screen. Useful place to put a redraw function for any vgtHealthTags you're using.

Gears

onGearAdd(gearUid)

This function is called when a new gear is added. Useful in combination with GetGearType(gearUid) .

onGearDelete(gearUid)

This function is called when a new gear is deleted. Useful in combination with GetGearType(gearUid) .

onVisualGearAdd(vgUid)

This function is called when a new visual gear is added. Useful in combination with GetVisualGearType(vgUid) .

onVisualGearDelete(vgUid)

This function is called when a new visual gear is deleted. Useful in combination with GetVisualGearType(vgUid) .

onGearDamage(gearUid, damage)

This function is called when a gear is damaged.

Example:

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

onGearResurrect(gearUid, spawnedVGear)

This function is called when a gear is resurrected due to the hog effect heResurrectable being set (see SetEffect ) and/or being an AI hog when the game modifier “AI Survival” ( gfAISurvival ) is active. It is not called when a hog was resurrected by the resurrector tool you can use in the game.

spawnedVGear is a visual gear handle of the “resurrection effect”. You can use this handle to modify or delete the resurrection animation.

onGearWaterSkip(gear)

This function is called when the gear gear skips over water.

onHogHide(gearUid)

This function is called when a hedgehog with the gear ID gearUid is hidden (removed from the map).

onHogRestore(gearUid)

This function is called when a hedgehog with the specified gear ID gearUid is restored (unhidden).

Map changes

onSpritePlacement(spriteId, centerX, centerY)

This function is called when a Sprite has been placed.

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

onGirderPlacement(frameIdx, centerX, centerY)

This function is called when a girder has been placed.

frameIdx is used for the length and orientation of the girder. The possible values are explained in PlaceGirder . centerX and centerY are the coordinates of the girder’s center.

onRubberPlacement(frameIdx, centerX, centerY)

This function is called when a rubber has been placed.

frameIdx is used for the rubber orientation. The possible values are explained in PlaceRubber . centerX and centerY are the coordinates of the rubber’s center.

onSpecialPoint(x, y, flags)

This is used while a special hand-drawn map is loaded. The engine is building these hand-drawn maps by reading points from the map definition. Optionally, some of these points may be “special”. These are not actually drawn on the map, but are used to store additional information for a position on the map. Special points currently need to be added manually in the map, the in-game editor is not able to add those yet. Now, when such a special point at the coordinates x and y with an assigned value of flags is added, this function is called. flags is a whole number between 0 and 255 inclusive.

This function is used in Racer and TechRacer to define waypoints.