Lua Reference

_PlayerShowScoreboard(playerid) - Shows the scoreboard on the specified players screen.
_PlayerSetSprint(playerid, bool) - Enable/Disable sprint for player.
_PlayerFreeze(playerid, bool) - Freeze the specified player.
_PlayerGetShootPos(playerid) - Returns the vector of the player's shoot position.
_PlayerGetShootAng(playerid) - Returns the forward vector of the player's shoot angle.
_PlayerGetActiveWeapon(playerid) - Returns the player's active weapon id.
_PlayerKill(playerid) - Kill the specified player.
_PlayerGiveAmmo(playerid, amount, ammotype, playsounds) - Give specified player ammo. playsounds is bool.
_PlayerRespawn(playerid) - Force player to respawn.
_PlayerSetDrawTeamCircle(playerid, bool) - Sets whether to draw the team circle or not.
_PlayerInfo(playerid, request) - Returns info about a specific layer. Check _PlayerInfo page for usage.
_PlayerChangeTeam(playerid, teamid) - Changes a player's team.
_PlayerSetModel(playerid, model) - Changes a player's model.
_PlayerGetRandomAllowedModel() - Returns a random allowed player model. _PlayerSetHealth(playerid, health) - Changes a player's health.
_PlayerSetArmor(playerid, armor) - Changes a player's armor.
_PlayerSetMaxSpeed(playerid, speed) - Changes a player's maximum speed.
_PlayerAddScore(playerid, score) - Add to players score (can be minus).
_PlayerSetScore(playerid, score) - Sets to players score.
_PlayerAddDeath(playerid, score) - Add to players deaths score (can be minus).
_PlayerGiveItem(playerid, item) - Give player named item.
_PlayerGiveSWEP(playerid, script) - Give player scripted weapon.
_PlayerRemoveAllWeapons(playerid) - Strip all o a player's weapons.
_PlayerRemoveWeapon(playerid, item) - Strip a specific weapon.
_PlayerAllowDecalPaint(playerid) - Allow the player to spraypaint now rather than waiting the 30 or so seconds.
_PlayerSetDrawViewModel(playerid, bool) - Sets whether to draw the player's view model.
_PlayerSelectWeapon(playerid, item) - Select weapon.
_PlayerSetDrawWorldModel(playerid, bool) - Sets whether to draw the player's world model.
_PlayerOption(playerid, callback, timeout) - Player has an option to select.
_PlayerSetVecView(playerid, vector) - Sets the position of the view vector (0, 0, 64) default.
_PlayerIsKeyDown(playerid, key) - Check whether specified key is pressed.
_PlayerSpectatorStart(playerid, mode) - Start spectating.
_PlayerSpectatorTarget(playerid, target) - Set spectator target for player.
_PlayerSpectatorEnd(playerid) - Stop spectating mode.
_PlayerSetVecDuck(playerid, vector) - Sets the position of the duck view vector (0, 0, 24) default.
_ScreenText(playerid, message, x, y, r, g, b, a, fadeid, fadeout, holdtime, effect, channel) - Advanced function to print text to the screen. effect can be set to 0-2 and channel 0-5.
_PrintMessage(playerid, type, message) - Print a message to a specific player.
_PrintMessageAll() - Is like _PrintMessage() but for everyone on the server.
_PlayerPreferredModel(playerid) - Returns the player's preferred model. Returns a blank if the model isn't valid.
_PlayerSilentKill(playerid, respawn_time, dissolve) - Silently kill a player.
_PlayerDetonateTripmines(playerid)
_PlayerHolsterWeapon(playerid)
_PlayerSetFOV(playerid, fov, time)
_PlayerSetFlashlight(playerid, state)
_PlayerStopZooming(playerid)
_PlayerSetChaseCamDistance(playerid, distance)
_PlayerLockInPlace(playerid, bool)
_PlayerRemoveAllAmmo(playerid)
_PlayerDisableAttack(playerid, bool)
_PlayerShowCrosshair(playerid, bool)
_PlayerEnableSprint(playerid, bool)
_PlayerViewModelSequence(playerid, sequence) - If successful returns the length of the sequence in seconds.
_PlayerGetLimit(playerid, limit)
_PlayerSetAnimation(playerid, sequence) - Sets a player's animation.
_PlayerSetWeaponSequence(player, sequence) - Sets a players weapon activity.
_PlayerIsCrouching(playerid) - Returns true if a player is crouching.
_PlayerUseVehicle(playerid, vehicle) - Make a player attempt to enter a vehicle.
_PlayerGod(playerid, bool) - Give a player God Mode.
_PlayerHasWeapon(playerid, item) - Returns true if the player has this weapon.
_PlayerWeaponTranslateSequence(player, sequence) - Let the player's weapon decide how we should act out specific sequence.
_player.ShowPanel - Show/Hide a panel by name.
_player.SetContextMenu(playerid, name) - Set the player's context menu.
_player.GetFlashlight(player) - returns true if flashlight is on.
_player.SetFlashlight(player, on) - Set player FL on/off.
_player.LastHitGroup(player) - Get the las place the player was hit.
_player.ShouldDropWeapon(player, bool) - Should player drop weapon on death?

_EntSetMaterial(entid, material_filename) - Set the material of specified entity.
_EntSetGravity(entid, gravity) - Set the gravity for specified entity.
_EntGetType(entid) - Returns a entity type name.
_EntGetByName(name) - Returns an entity by target name (0 if not found).
_EntGetPos(entid) - Returns a vector representing the position of the entity.
_EntEmitSound(entid, filename) - Make entity emit sound.
_EntEmitSoundEx(entid, filename, volume_multiplier, pitch_multiplier) - Make entity emit sound.
_EntSetPos(entid, vector3 pos) - Sets the position of the entity.
_EntGetVelocity(entid) - Gets the entity velocity. Returned as a vector3.
_EntSetVelocity(entid, vector3_velocity) - Sets the velocity of the entity.
_EntGetForwardVector(entid) - Returns the forward vector.
_EntGetRightVector(entid) - Returns the right vector.
_EntGetUpVector(entid) - Returns the up vector.
_EntFire(entid, action, value, delay) - ent_fire an entity.
_EntCreate(entname) - Creates but doesn't spawn specified entity.
_EntSpawn(entindex) - Spawns specified entity.
_EntActivate(entindex) - Activate an entity.
_EntSetKeyValue(entindex, string_keyname, string_keyvalue) - Sets an entity keyvalue (Must be done before spawning!).
_EntSetModel(ent, model_name) - Sets the model of an entity. PRE-CACHE THE MODEL FIRST.
_EntSetOwner(ent, ownerid) - Sets the owner.
_EntGetOwner(ent) - Gets the entity's owner.
_EntRemove(entindex) - Removes entity..
_EntExists(entindex) - Check if entity exists.
_EntPrecacheModel(model_name) - Pre-caches a model.
_EntSetAng(entid, vector3_ang) - Sets the angle of the entity (using a forward vector).
_EntSetAngAngle(entid, vector3_angle) - Sets the ANGLE of the entity.
_EntGetAng(entid) - Returns the angle as a normalized 'forward' vector.
_EntGetAngAngle(entid) - Returns the angle as a vector3.
_EntGetModel(entid) - Returns the entity's model name.
_EntitiesFindByClass(classname) - Returns a table of entities (or nil if none).
_EntitiesFindInSphere(vector_position, radius) - Returns a table of entities contained in the sphere.
_EntitiesFindByName(targetname) - Returns a table of entities (or nil if none).
_EntityGetPhysicsAttacker(entity) - Returns the last physics attacker.
_EntitySetPhyscsAttacker(entity, attacker) - Sets the physics attacker on a specified object.
_EntSetGroundEntity(entity, groundentity) - Pass entity as -1 to clear the ground entity.
_EntGetGroundEntity(entity, groundentity) - Pass entity as -1 to clear the ground entity.
_EntSetMoveType(entity, type) - Sets the movetype.
_EntGetMoveType(entity) - Gets the movetype.
_EntSetMoveCollide(entity, type) - Sets the movecollide.
_EntGetMoveCollide(entity) - Gets the movecollide.
_EntSetSolid(entity, type) - Sets the solid type.
_EntGetSolid(entity) - Gets the solid type.
_EntSetCollisionGroup(entity, group) - Sets the collision group.
_EntGetCollisionGroup(entity) - Gets the collision group.
_EntGetWaterLevel(entity) - Returns a number representing how under water an entity is. 0 means not underwater. 3 is totally underwater.
_EntSetActivity(entid, int_sequence) - Sets anactivity for an ent. Works for NPC's only.
_EntGetDisposition(npc, entity) - Gets an enemy disposition.
_EntSetParent(entid, parent, attachment) - Sets an entities parent.
_EntGetParent(entid) - Gets an entities parent.
_EntGetName(entid) - Gets an entities name.
_EntSetName(entid, name) - Sets an entities name.
_EntSetMaxHealth(entid, health) - Gets entity max health.
_EntGetMaxHealth(entid) - Sets entity max health.

_EffectInit() - Resets the effect data
_EffectSetOrigin(vector)
_EffectSetAngles(vector)
_EffectSetNormal(vector)
_EffectSetStart(vector)
_EffectSetEnt(entid)
_EffectSetFlags(int)
_EffectSetScale(float)
_EffectSetMagnitude(float)
_EffectSetRadius(float)
_EffectSetAttachIndex(int)
_EffectDispatch(name)

File manipulation

_file.Exists(filename) - Returns true if file exists.
_file.Read(filename) - Reads a file into a string.
_file.Write(filename, string) - Writes a string to a file.
_file.CreateDir(folder) - Creates Dir Hierarchy.
_file.IsDir(folder) - Returns true if is Dir.
_file.Find(wildcard) - Finds files, returns table, parameter should be like "maps/-.bsp".
_file.Delete(wildcard) - Deletes specified file.
_file.Rename(before, after) - Renames specified file.
_ForceFileConsistency(filename) - Force the file to be the same on client and server. Should be called after pre-caching the file.

_StartNextLevel(map_name) - Starts the next level.
_GetNextMap() - Returns next map name.
_GetCurrentMap() - Returns current map name.
_GetRule(rule_string) - Gets a rule.
_ServerCommand(command) - Runs a console command. Don't forget to put \n in the end.
_GameSetTargetIDRules(int_rule) - Sets targetID rules.
_PluginMsg(playerid, title, message, time, r, g, b, a, level) - Sends a plugin message.
_PluginText(playerid, title, message, time, r, g, b, a, level) - Sends plug in text.
_GetConVar_Float(name) - Get a server convar float.
_GetConVar_String(name) - Get a server convar string.
_GetConVar_Bool(name) - Get a server convar bool.
_GetClientConVar_String(playerid, name) - Get a client convar string.
_CurTime() - Returns the current time in seconds.
_MaxPlayers() - Returns the max players in the server.
_RunString(command) - Runs a command in the main gameplay script.
_GetModPath() - Gets the path to the gmod folder (on the server). No trailing slash.
_IsDedicatedServer() - Returns whether dedicated server or not.
_Msg(message) - Outputs message to console.
_OpenScript(filename) - Opens a script.
_ALERT(message) - Internal Lua usage. Outputs error message.

Trace

_TraceAttack(victim, inflictor, attacker, amount) - Attack using the last trace.
_TraceSetCollisionGroup(group) - Sets the collision group for the next trace to use. _TraceSetMask(group) - Sets the MASK_ to use for the next trace.
_TraceLine(vector_start, vector_direction, length, ignore) - Traces a line. ignore is optional.
_TraceEndPos() - Return the end pos from the last trace.
_TraceFraction() - Return the fraction of trace completed.
_TraceHitWorld() - Return the true if the last trace hit the world.
_TraceHitNonWorld() - Return the true if the last trace hit non world.
_TraceHit() - Return the true if the last trace hit something.
_TraceGetEnt() - Return the entity that the last trace hit.
_TraceGetSurfaceNormal - Return the normal of the surface that the trace hit.
_TraceDidHitSky() - Returns true if last hit was the sky.
_TraceDidHitHitbox() - Returns true if last hit was some kind of hitbox.
_TraceGetTexture() - Returns the name of the texture that we hit.
_TraceDidHitWater() - Returns true if we hit water.
_MakeDecal(decal) - Makes a decal using the last trace.
PlayerLookTrace(playerid, length) - Traces a line where player's looking

Sounds

_PlaySound(sound_name) - Play a sound.
_PlaySoundPlayer(playerid, sound_name) - Play a sound to a specific player.

GModText

_GModText_Start(font_name) - Initialize the text.
_GModText_SetPos(x, y) - Set Position.
_GModText_AllowOffscreen(bool) - Allow the text to go offscreen.
_GModText_SetEntity(entindex) - Set entity to hover over.
_GModText_SetColor(r, g, b, a) - Set Colour.
_GModText_SetTime(duration, fadein, fadeout) - Set Times.
_GModText_SetDelay(delay) - Set delay time.
_GModText_SetText(text) - Set Times.
_GModText_SetAdditive(bool) - Set Additive mode.
_GModText_SetEntityOffset(vector) - Set entity offset to draw the text at.
_GModText_Send(playerid, index) - If player is 0 it is sent to everyone. Index says which slot this text should fill.
_GModText_Hide(playerid, index, fade_time, delay) - Hides specified text.
_GModText_HideAll(playerid) - Hides All texts.
_GModText_SendAnimate(playerid, index, length, ease) - The same as normal send but will animate from Send to the new values.

GModRect

_GModRect_Start(material) - Initialize the rect.
_GModRect_SetPos(x, y, width, height) - Set Position.
_GModRect_SetEntity(entindex) - Set entity to hover over.
_GModRect_SetColor(r, g, b, a) - Set Colour.
_GModRect_SetTime(duration, fadein, fadeout)- Set Times.
_GModRect_SetDelay(delay) - Set delay time.
_GModRect_SetAdditive(bool) - Set Additive mode.
_GModRect_SetEntityOffset(vector) - Set entity offset to draw the text at.
_GModRect_Send(playerid, index) - If player is 0 it is sent to everyone. Index says which slot this text should fill.
_GModRect_SendAnimate(playerid, index, length, ease) - If player is 0 it is sent to everyone. Index says which slot this text should fill.
_GModRect_Hide(playerid, index, fade_time, delay) - Hides specified rect.
_GModRect_HideAll(playerid) - Hides All rects.

GModQuad

_GModQuad_Hide(playerid, index, fade_time, delay) - Hides specified world quads.
_GModQuad_HideAll(playerid) - Hides All world quads.
_GModQuad_Start(material) - Initialize the quad.
_GModQuad_SetVector(corner, vector) - Set a vector of one of the quad's corners. Acceptable corner values: 0-3.
_GModQuad_SetTimings(delay, fadein, life, fadeout) - Set Timings.
_GModQuad_SetEntity(entityid) - SetEntity to follow.
_GModQuad_Send(playerid, index) - Send a quad to player. All players if player is 0.
_GModQuad_SenAnimate(playerid, index, length, ease) - Send a quad to player. All players if player is 0.

Game Events

_gameevent.Start(name) - Starts a (fake) gameevent.
_gameevent.SetString(name, value) - Set Variable.
_gameevent.SetInt(name, value) - Set Variable.
_gameevent.Fire() - Fire event.

Spawnmenu

_spawnmenu.AddItem(playerid, category, name, modelent)
_spawnmenu.RemoveCategory(playerid, category)
_spawnmenu.RemoveAll(playerid)
_spawnmenu.SetCategory(playerid, category)

_SetDefaultRelationship(class, class, disposition) - Sets the default relationship between two life types.
_npc.ExitScriptedSequence(ent)
_npc.SetSchedule(end, sched)
_npc.SetLastPosition(ent, vector)
_npc.AddRelationship(ent, ent, disposition, priority) - priority is int

_phys.EnableMotion(entid, boo) - Enable/Disable motion.
_phys.EnableDrag(entid, bool) - Enable/Disable drag.
_phys.EnableGravity(entid, bool) - Enable/Disable gravity.
_phys.EnableCollisions(entid, bool) - Enable/Disable Collisions.
_phys.GetMass(entid) - Gets mass.
_phys.SetMass(entid, mass) - Sets mass.
_phys.Sleep(entid) - Make object sleep.
_phys.Wake(entid) - Wake a sleeping object.
_phys.IsAsleep(entid) - Check whatever object is rested.
_phys.HasPhysics(entid) - Returns true if entity has a physics object.
_phys.ConstraintSetEnts(constraint, entity_1, entity_2) - Set Entities for constraint.
_phys.ApplyForceCenter(entid, force) - Pushes an object from the center. force is vector3.
_phys.ApplyForceOffset(entid, force, worldpos) - Pushes an object from the center. force and worldpos are vector3.
_phys.ApplyTorqueCenter(entid, force) - Apply torque to the object. force is vector3.

_TeamAddScore(teamid, score) - Add score for a team.
_TeamSetScore(teamid, score) - Set score for a team.
_TeamNumPlayers(teamid) - Get the number of players on a team.
_TeamCount() - Returns the number of teams _TeamScore(teamid) - Returns the total team score.
_TeamSetName(teamid, name) - Sets the name of the team.

Utilities

_util.PlayerByName(name) - Returns playerid of player with name.
_util.PlayerByUserId(playerid) - Returns playerid.
_util.EntsInBox(min, max) - Returns entities contained in a box. min and max are vectors.
_util.DropToFloor(ent) - Drops entity to floor.
_util.ScreenShake(pos, amp, frequency, duration, radius) - Shakes screen.
_util.PointAtEntity(ent1, ent2) - Point one entity towards the other.

All these function are only used when making SWEPs, check SWEP part.
_WeaponScriptedAssign(weapon, script) Assign a script to a scripted weapon.
_SWEPSetSound(weapon_index, action, sound) Sets SWEP sound.
_SWEPUseAmmo(weapon_index, clip[0|1], amount) Takes ammo from SWEP gun.
_SWEPUpdateVariables(weapon_index) Re-reads all the 'fetch' variables. You should call this if you have changed the accuracy etc.
_SWEPRunString(weapon_index, string) Runs a Lua string in the weapon's Lua instance.
_swep.GetClipAmmo(weapon_id, clip[0|1]) Get amount of ammo in a clip.
_swep.SetClipAmmo(weapon_index, clip[0|1], clip) Get amount of ammo in a clip.
_swep.GetDeathIcon(weapon_index) Gets death icon name.

_WeaponSetModel(weapon_name, model_type, model_name) Sets weapon model.
_WeaponSetSlot(weapon_name, slot, pos) - Sets weapon slot.
_WeaponSetSound(weapon_name action, sound) - Sets weapon sound.
_WeaponSetFOV(weapon_name, fov) - Sets a weapon's draw FOV.
_WeaponFlipHands(weapon_name, bool) - Flips a weapon's hands.
_WeaponSetDamage(weapon_name, damage) - Sets the damage that a bullet from this gun does.
_WeaponSetup(weapon_name, anim_prefix, clip_size_1, clip_size_2, default_ammo_1, default_ammo_2, primary_ammo, secondary_ammo) - Sets animation prefix.

'Deprecated'

_IsLinux() Would return true if running on a Linux server