Editing ACS built-in functions

These are predefined ACS functions with no [[parameterized linedef specials|parameterized linedef special]] equivalents, accessible only through ACS scripts.

NOTE: most of these functions are meant to be compatible with those from ZDoom. For any ones not yet documented on this wiki, you can check the ZDoom wiki. A few of them may be incompletely implemented in Eternity. Don't hesitate to update the wiki in case of any mistakes. 
==Special TID info==
For functions affecting things, some TIDs (thing tags) carry special meaning. TID 0 means the activator, and TIDs -1 ... -4 mean each of the four players in the game -- this is an Eternity extension
==Data type info==
You may see specifiers such as ''void'', ''str'', ''int'' and others in ACS function signatures. They act as a guide on what kinds of values are expected, but in ACS there really are only two types: '''str''' and '''int''' (and '''str''' internally is merely a string ID number). Most importantly: 
*''void'' means that a function should be used as a procedure (command) without returning anything,
*''fixed'' means you can use the decimal point notation: 1.0 is equivalent to 65536, 1.5 to 98304 etc. In ACS, such values are still of '''int''' type, but whether you use the decimal point or not is quite relevant. A value such as 128.0 is ''not'' the same as 128: it's actually equal to 8388608 (no decimal point).
==Function list==
===Sound and music===
*[[ActivatorSound]]
*[[AmbientSound]]
*[[LocalAmbientSound]]
*[[PlayActorSound]]
*[[PlaySound]]
*[[SectorSound]]
*[[SetMusic]]
*[[LocalSetMusic]]
*[[SoundSequence]]
*[[SoundSequenceOnActor]]
*[[StopSound]]
*[[ThingSound]]

===Sectors===
*void [[ChangeCeiling]](int tag, str flatname)
:Changes the ceiling texture of tagged sectors to flatname.
*void [[ChangeFloor]](int tag, str flatname)
:Changes the floor texture of tagged sectors to flatname.
*[[GetSectorCeilingZ]]
*[[GetSectorFloorZ]]
*int [[GetSectorLightLevel]] (int tag)

===Things===
*[[CheckActorClass]]
*[[CheckActorProperty]]
*bool CheckFlag(int tid, str flag)
:Returns true if the first thing with the given tid has the given flag enabled.
*[[CheckProximity]]
*bool CheckSight(int source, int dest, int flags)
:Returns true if there's a line of sight between at least one thing tagged as source and one thing tagged as dest. Currently flags is reserved and must be 0.
*int ClassifyActor(int tid)
:Checks the kind of thing tagged tid. It returns a set of flags, possibly combined:
:*ACTOR_PLAYER (2): it's player-controlled
:*ACTOR_VOODOODOLL (8): it's a duplicate player start, not controlled by the player but still linked to it. Used in Boom maps for advanced mapping tricks
:*ACTOR_MONSTER (16): it's a monster (has COUNTKILL or KILLABLE thing type flag set)
:*ACTOR_MISSILE (128): it's a projectile in flight (has MISSILE thing type flag set)
:*ACTOR_GENERIC (256): neither a monster, nor a projectile
:*ACTOR_ALIVE (32): has positive health
:*ACTOR_DEAD (64): has health <= 0
:*ACTOR_NONE (0): no thing found with this TID
:*ACTOR_WORLD (1): TID is 0 but activator isn't a thing
*[[GetActorProperty]]
*[[GetActorVelX]]
*[[GetActorVelY]]
*[[GetActorVelZ]]
*[[IsTIDUsed]]
*void SectorDamage (int tag, int amount, str type, str protection_item, int flags)
*[[SetActivator]]
*[[SetActivatorToTarget]]
*void SetActorAngle (int tid, fixed angle)
*[[SetActorVelocity]]
*void SetActorPitch (int tid, int pitch)
*[[SetActorPosition]]
*void SetThingSpecial (int tid, int special [, int arg0 [, int arg1 [, int arg2 [, int arg3 [, int arg4]]]]])
*int SetActorState(int tid, str statename[, bool exact]);
*[[SetActorProperty]]
*int Spawn (str classname, fixed x, fixed y, fixed z [, int tid [, int angle]])
*int SpawnForced (str classname, fixed x, fixed y, fixed z [, int tid [, int angle]])
*[[SpawnProjectile]]
*[[SpawnSpot]]
*int SpawnSpotFacing (str classname, int spottid [, int tid])
*[[SpawnSpotFacingForced]]
*[[SpawnSpotForced]]
*int ThingCount (int type, int tid)
*int ThingCountName (str classname, int tid)
*int ThingCountSector (int type, int tid, int tag)
*int ThingCountNameSector (str classname, int tid, int tag)
*int Thing_Damage2 (int tid, int amount, str type);
*void Thing_Projectile2 (int tid, int type, int angle, int speed, int vspeed, int gravity, int newtid)
*int UniqueTID ([int tid[, int limit]])

===Linedefs and sidedefs===
*[[GetLineRowOffset]]
*[[GetLineX]]
*[[GetLineY]]
*[[LineSide]]
*void ReplaceTextures (str oldtexturename, str newtexturename [, int flags])
*[[SetLineSpecial]]
*void SetLineTexture(int lineid, int line_side, int sidedef_texture, str texturename);

===Sky===
*[[SetSkyScrollSpeed]]

===Scripts===
*bool ACS_NamedExecuteAlways(str script, int map, int arg1, int arg2, int arg3)
:*Executes a named script, starting a new instance if one already exists. Returns true if successfully started.
*bool ACS_NamedExecute(str script, int map, int arg1, int arg2, int arg3)
:*Executes a named script. Returns true if successfully started.
*int ACS_NamedExecuteWithResult (string script, int s_arg1, int s_arg2, int s_arg3, int s_arg4)
*bool ACS_NamedSuspend (string script, int map)
*bool ACS_NamedTerminate (string script, int map)

===Console===
*int GetCVar (str cvar)
*string GetCVarString (str cvar)
*int GetPlayerInput (int player, int input)
===Polyobjects===
*[[GetPolyobjX]]
*[[GetPolyobjY]]

===Quake===
*[[Radius_Quake2]]

===Math===
*int Random (int min, int max)
*int Sqrt (int number)
*fixed FixedSqrt (fixed number)
*[[VectorAngle]]
*int VectorLength (int x, int y)

===Strings===
*str StrLeft (str string, int length)
*str StrMid (str string, int start, int length)
*str StrRight (str string, int length)

===Level state===
*[[SetAirControl]]
*[[SetAirFriction]]

==See also==
*[[Parameterized linedef specials]]

[[Category:ACS]]
[[Category:Editing reference]]