Table of contents

1. Introduction

2. QuakeC Language

3. Builtin functions

4. Defines

5. Entities

6. Global variables
7. Model pragma
8. Network protocol
9. Network Builtin functions
10. Tips & tricks
11. Basic Types
12. Compilation of Quake-C
13. Execution of Quake-C
14. Examples

1. Introduction

1.1 What is QuakeC?

QuakeC is a language similar to C.
QuakeC can be compiled with qcc (Quake C compiler) to produce progs.dat, a file that Quake can load at startup. In that file, Quake searches the engines for various things in the Quake World.
Monsters, players, buttons, weapons are the target of QuakeC, you cannot modify levels or graphics that you can modify with a external editor.
Major part of this document are copyright by Olivier Montanuy . All the informations contained in this document are related to Quake-C, a language developed by and for Id Software, so all those informations are copyright (c) 1996, Id Software.
To compile and use all the code you must have qcc.tar.gz take it from Id Software. You can edit and then compile with qccdos (the compiler) all the .qc files. You can rewrote all AI of the monster or create new entities.
I have only converted, corrected and added some stuff.

1.2 Contributions

Olivier Montanuy is the real compiler of this document, it was first rearranged to a TXT version by Francesco Ferrara. Many thanks to Olivier and Francesco.
For those who wants to, you can download the text version (zipped 28 Ko).

2. QuakeC Language - Basic constructs


// followed by comments, until the next line.
/* enclose a block comments */

Those comments are the same as in C++ (and many C languages).

2.2 Names

Names of variable, field, or function have a maximum size of 64 characters, must begin with A-Z,a-z, or _, and can continue with those characters or 0-9.

2.3 New types

You cannot define new types from the existing ones. In particular, you cannot define new structures, new objects, and you cannot affect a new name to a type (as does typedef in C).

These restrictions make Quake-C compare unfavourably even to Basic, and sure it's about time the Id Software guys hired someone that already wrote a compiler.

You can add only fields to the most important type in QuakeC entity.

2.4 Definition of variables

type variable1, variable2; eg: float a,b; Where type is one of the pre-defined simple types.
You can also affect default values to variables, for instance :
type variable1 = value; eg: float a = 2; Scoping of variables : There are two levels of scoping. By default all variables are global : they can be accessed by any functions, and they are shared by all the functions (and all the clients of a given network server, of course).

But inside the functions, by using the keyword local just before the declaration of a variable, you can make this variable visible only the function itself (i.e. it will be allocated on the stack).

Note that parameters of functions are treated like local variables : they are only visible to the function, but they can be modified.

2.5 Definitions of constants

Any global variable that is initialized by setting a value to it, is actually assumed to be a constant.

Since a constant is in fact represented by immediate values, you should NEVER attempt to modify a constant by giving it another value. Otherwise the program might have unpredicable results.

The constants are not saved to game files. Only regular variables are.

2.6 Definitions of functions

The general structure of a function definition is :
type (type param1, typeparam2, ... ) function = { ... code ... }; Don't forget the ";" after the brackets.

Here are some examples :
void() think = {...}; entity() FindTarget = {...}; void(vector destination, float speed, void() callback) SUB_CalcMove = {...};

2.7 Function declaration

If you want to use a function before defining it, you must declare it, otherwise the Quake-C compiler will not be able to use it.

The general structure of a function declaration is: type (type param1, typeparam2, ... ) function;

2.8 Definition of a frame function

Frame functions (also called States) are special functions made for convenience. They are meant to facilitate the definition of animation frames, by making them more readable.

Here is an example :
void() framename = [$framenum, nextthink] { ...code...}; It is strictly equivalent to :
void() framename = { self.frame= $framenum; // the model frame to displayed self.nextthink = time + 0.1; // next frame happens in 1/10 of second self.think = nextthink; // the function to call at the next frame ...code... };

2.9 Conditional construct

if( expression ) { statements } else { statements }

2.10 Loop construct

while( expression ) { statements } or do { statements }while( expression )

2.11 Function calls

Call a function :
function_name ( parameter1, parameter2,... ) The cannot be more than 8 parameters.

Return a value :
return( expression )

2.12 Logical operations

! // logical not && // logical and || // logical or Take care that in if() conditional expressions containing two or more logical clauses, all the clauses will be evaluated before the condition test (like in Basic, and unlike C).

That means that if one part of your condition is not always valid or defined, you had better decompose your if() into two successive if(). It should also make it faster.

2.13 Comparisons

<= < >= > == // equal, beware at the double = like in C. != // not equal, like in C.

2.14 Operations on floats or integers

* / - + Use parenthesis to remove ambiguities.

2.15 Bitwise operations

& // bitwise and | // bitwise or These operators treat floats like integers, so they are usually meant to be used with values made of bit masks.

3. Builtin functions

These are the built-in functions of Quake C. Since they are hard-coded in C, they cannot be redefined, but they are very fast.

3.1 Basic math functions

QuakeC code
Function: anglemod float anglemod (float angle) Returns angle in degree, modulo 360.
Function: rint float rint(float val) Returns val, rounded up to the closest integer value.
Function: floor float floor(float val) Returns val, rounded up to the integer below (like the equivalent function in C).
Function: ceil float ceil(float val) Returns val, rounded up to the integer above (like the equivalent function in C).
Function: fabs float fabs(float val) Returns absolute value of val (like the equivalent function in C).
Function: random float random() Returns a random floating point number between 0.0 and 1.0.
Function: ftos string ftos(float value) Float to string: converts value to string.

3.2 Basic vector maths

QuakeC code
Function: normalize vector normalize(vector v) Returns a vector of length 1. Gives the vector colinear to v, but of length 1. This can be useful for calculation of distance along an axis.
Function: vlen float vlen(vector v) Returns the length of vector v (never < 0).
Function: vectoyaw float vectoyaw(vector v) Returns and angle in degree. Vector to yaw : calculates the yaw angle (bearing) corresponding to a given 3D direction v.
Function: vectoangles vector vectoangles(vector v) returns vector 'pitch yaw 0 '
Vector to angles : calculates the pitch angle (aiming) and yaw angle (bearing) corresponding to a given 3D direction v.
Function: vtos string vtos(vector v) Vector to String : print a vector, as a string.
Function: makevectors void makevectors(vector angles) angle = 'pitch yaw 0' Calculate the vectors pointing forward, right and up, according to the provided angles. Returns result in the global variables : vector v_forward; // points forward vector v_up; // points up vector v_right; // points toward the right

3.3 Sound emission

QuakeC code
Function: sound void sound (entity source, float channel, string sample, float volume, float attenuation) source = entity emiting the sound (ex: self)
channel = channel to use for sound
sample = name of the sample WAV file (ex: "ogre/ogdrag.wav")
volume = 0.0 for low volume, 1.0 for maximum volume
attenuation= attenuation of sound
The entity emits a sound, on one of it's 8 channels.
Function: ambientsound void ambientsound(vector position, string sample, float volume, float attenuation) position = position, in 3D space, inside the level sample = name of the sample WAV file (ex: "ogre/ogdrag.wav")
volume = 0.0 for low volume, 1.0 for maximum volume
attenuation = attenuation of sound
An ambient sound is emited, from the given position.

3.4 Entity management

QuakeC code
Function: spawn entity spawn () Returns an empty entity.
Create a new entity, totally empty. You can manually set every field, or just set the origin and call one of the existing entity setup functions.
Function: remove void remove (entity e) Removes entity e from the world (R.I.P.).
Function: makestatic void makestatic (entity e) Make an entity static to the world, by sending a broadcast message to the network. The entity is then removed from the list of dynamic entities in the world, and it cannot be deleted (until the level ends).
Function: nextent entity nextent(entity e) Returns entity that is just after e in the entity list.
Useful to browse the list of entities, because it skips the undefined ones.
Function: find entity find (entity start, .string field, string match) start = begining of list to search (world, for the begining of list)
field = entity field that must be examined (ex: targetname)
match = value that must be matched (ex:
Returns the entity found, or world if no entity was found.
Searches the server entity list beginning at start, looking for an entity that has entity.field = match.
Example : find the first player entity e = find( world, classname, "player"); Take care that field is a name of an entity field, without dot, and without quotes.
Function: findradius entity findradius (vector origin, float radius) origin = origin of sphere
radius = radius of sphere
Returns a chain of entities that have their origins within a spherical area. The entity returned is e, and the next in the chain is e.chain, until e==FALSE. Typical usage: find and harm the victims of an explosion.
Example : e = findradius( origin, radius) while(e) { T_Damage(e, ... ) // Let God sort his ones! e = e.chain }
Function: setmodel void setmodel (entity e, string model) e = entity whose model is to be set
model = name of the model (ex: "progs/soldier.mdl")
Changes the model associated to an entity. This model should also be declared by precache_model. Please set e.movetype and e.solid first.
Function: lightstyle void lightstyle(float style, string value) style = index of the light style, from 0 to 63.
value = (ex: "abcdefghijklmlkjihgfedcb")
Modifies a given light style. The light style is used to create cyclic lighting effects, like torches or teleporter lighting. There are 64 light tyles, from 0 to 63. If style is not strictly comprised in these values, the game may crash. Styles 32-62 are assigned by the light program for switchable lights. Value is a set of characters, whose ascii value indicates a light level, from "a" (0) to "z" (30).

3.5 Move Entities

QuakeC code
Function: ChangeYaw void ChangeYaw() Change the horizontal orientation of self. Turns towards self.ideal_yaw at self.yaw_speed, and sets the global variable current_yaw.
Called every 0.1 sec by monsters.
Function: walkmove float walkmove(float yaw, float dist) Returns TRUE or FALSE.
Moves self in the given direction.
Returns FALSE if could not move (used to detect blocked monsters).
Function: droptofloor float droptofloor() Returns TRUE or FALSE.
Drops self to the floor, if the floor is less than -256 coordinates below. Returns TRUE if landed on floor. Mainly used to spawn items or walking monsters on the floor.
Function: setorigin void setorigin (entity e, vector position) e = entity to be moved
position = new position for the entity
Move an entity to a given location. That function is to be used when spawning an entity or when teleporting it. This is the only valid way to move an object without using the physics of the world (setting velocity and waiting). DO NOT change directly e.origin, otherwise internal links would be screwed, and entity clipping would be messed up.
Function: setsize void setsize (entity e, vector min, vector max) e = entity whose bounding box is to be set
min = minimum, for bounding box (ex: VEC_HULL2_MIN)
max = maximum, for bounding box (ex: VEC_HULL2_MAX)
Set the size of the entity bounding box, relative to the entity origin. The size box is rotated by the current angle.
Function: movetogoal void movetogoal (float step) Move self toward it's goal.
Used for monsters.

3.6 Fights and Shots

QuakeC code
Function: aim vector aim(entity e, float missilespeed) Returns a vector along which the entity e can shoot.
Usually, e is a player, and the vector returned is calculated by auto-aiming to the closest enemy entity.
&lt;TR&gt; &lt;TD&gt;&lt;XMP&gt;Function: particle void particle(vector origin, vector dir, float color, float count) origin = initial position
dir = initial direction
color = color index (73,75...)
count = time to live, in seconds .Create a particle effect (small dot that flies away).
color = 0 for chunk
color = 75 for yellow
color = 73 for blood red
color = 225 for entity damage
Function: checkclient entity checkclient() Returns client (or object that has a client enemy) that would be a valid target. If there are more than one valid options, they are cycled each frame.
If (self.origin + self.viewofs) is not in the PVS of the target, 0 (false) is returned.

3.7 Collision checking

QuakeC code
Function: traceline traceline (vector v1, vector v2, float nomonsters, entity forent) v1= start of line
v2= end of line
nomonster= if TRUE, then see through other monsters, else FALSE.
forent= ignore this entity, it's owner, and it's owned entities. if forent = world, then ignore no entity.
Trace a line of sight, possibly ignoring monsters, and possibly ignoring the entity forent (usually, forent = self). This function is used very often, tracing and shot targeting. Traces are blocked by bounding boxes and exact bsp entities. Returns the results in the global variables : float trace_allsolid; // never used float trace_startsolid; // never used float trace_fraction; // fraction (percent) of the line // that was traced, before // an obstacle was hit. Equal to 1 // if no obstacle were found. vector trace_endpos; // point where line ended or met an // obstacle. vector trace_plane_normal; // direction vector of trace (?) float trace_plane_dist; // distance to impact along direction // vector (?) entity trace_ent; // entity hit by the line float trace_inopen; // boolean, true if line went through // non-water area. float trace_inwater; // boolean, true if line went through // water area.
Function: checkpos CURRENTLY DISABLED. DO NOT USE. scalar checkpos (entity e, vector position) Returns true if the given entity can move to the given position from it's current position by walking or rolling.
Function: checkbottom float checkbottom(entity e) e = entity that is to be checked
Return TRUE or FALSE.
Returns TRUE if on the ground. Used only for jumping monster, that need to jump randomly not to get hung up (or whatever it actually means).
Function: pointcontents float pointcontents(vector pos) Returns the contents of the area situated at position pos.
Used to know if an area is in water, in slime or in lava.
Makes use of the BSP tree, and is supposed to be very fast.

3.8 Server related functions

QuakeC code
Function: changelevel void changelevel (string mapname) Warp to the game map named mapname. Actually executes the console command "changelevel" + mapname, so if you want to alias it...
Function: setspawnparms void setspawnparms (entity client) Restore the original spawn parameters of a client entity.
Doesn't work if client is not a player.
Function: stuffcmd stuffcmd (entity client, string text) client = player that is to receive the command
text = text of the command, ended by \n (newline).
Send a command to a given player, as if it had been typed on the player's console. Don't forget the \n (newline) at the end, otherwise your command will not be executed, and will stand still on the console window.
Examples : stuffcmd(self, "bf\n"); // create a flash of // light on the screen. stuffcmd(self, "name Buddy\n"); // name the player Buddy. Mostly used to send the command bf, that creates a flash of light on the client's screen.

3.9 Print messages

QuakeC code
Function: bprint void bprint (string text) text = text of the message
Broadcast a message to all players on the current server.
Function: centerprint void centerprint( entity client, string text) client = player that is to receive the message
text = text of the message
Sends a message to a specific player, and print it centered.
Function: sprint void sprint (entity client, string text) client = player that is to receive the message
text = text of the message
Sends a message to a player.

3.10 Console

QuakeC code
Function: localcmd void localcmd (string text) text = text of the command, ended by \n (newline).
Execute a command on the server, as if it had been typed on the server's console.
Examples :
localcmd("restart\n"); // restart the level localcmd("teamplay 1\n"); // set deathmatch mode to teamplay localcmd("killserver\n"); // poor server...
Function: dprint void dprint (string text) text = text of the message
Prints a message to the server console.
Function: cvar float cvar (string variable) variable = see console variables
Returns the value of a console variable.
Function: cvar_set float cvar_set (string variable, string value) variable = see console variables
Sets the value of a console variable.

3.11 Debugging

QuakeC code
Function: eprint void eprint (entity e) e = entity to print
Print details about a given entity (for debug purposes).
Function: coredump void coredump() Print all entities
Function: traceon void traceon() Start tracing functions, end them with traceoff()
Function: traceoff void traceoff() End traces started by traceon()
Function: break void break() Exit the programs. Never used?
Function: error void error (string text) Print an error message.
Function: objerror void objerror (string text) Print an error message related to object self.

3.12 Precaching files

Those functions are used to declare models, sounds and stuff, before the PAK file is built. Just follow this rule : whenever one of your functions makes use of a file that's not defined in Quake, precache this file in a function that will be called by worldspawn(). Then, the QCC compiler can automatically include in the PAK file all the files that you really need to run your programs.
And when the level starts running, those precache orders will be executed, so as to attribute a fixed table index to all those files. DO NOT USE those functions in code that will be called after worldspawn() was called. As a matter of fact, that could bomb Quake (restarting the level, without crashing the game).
Files can only be precached in spawn functions.

QuakeC code
Function: precache_file void precache_file(string file) file = name of the file to include in PAK file.
Does nothing during game play.
Use precache_file2 for registered Quake.
Function: precache_model void precache_model(string file) file = name of the MDL or BSP file to include in PAK file.
Does nothing during game play. Must be used in a model's spawn function, to declare the model file. Use precache_model2 for registered Quake.
Function: precache_sound void precache_sound(string file) file = name of the WAV file to include in PAK file.
Does nothing during game play. Must be used in a model's spawn function, to declare the sound files. Use precache_sound2 for registered Quake.

4. Defines

4.1 Values : temporary entities

Information copied from the DEM specifications // point entity is a small point like entity. 0 TE_SPIKE unknown 1 TE_SUPERSPIKE superspike hits (spike traps) 2 TE_GUNSHOT hit on the wall (Axe, Shotgun) 3 TE_EXPLOSION grenade/missile explosion 4 TE_TAREXPLOSION explosion of a tarbaby 7 TE_WIZSPIKE wizard's hit 8 TE_KNIGHTSPIKE hell knight's shot hit 10 TE_LAVASPLASH Chthon awakes and falls dead 11 TE_TELEPORT teleport end // large entity is a 2 dimensional entity. 5 TE_LIGHTNING1 flash of the Shambler 6 TE_LIGHTNING2 flash of the Thunderbolt 9 TE_LIGHTNING3 flash in e1m7 to kill Chthon

4.2 Values : Sound Channel of entities

CHAN_AUTO = 0; // Create a new sound CHAN_WEAPON = 1; // Replace entitie's weapon noise CHAN_VOICE = 2; // Replace entitie's voice CHAN_ITEM = 3; // Replace entitie's item noise CHAN_BODY = 4; // Replace entitie's body noise Those values are meant to be used with the function sound.

4.3 Values : Sound Attenuation

ATTN_NONE = 0; // full volume everywhere in the leve ATTN_NORM = 1; // normal ATTN_IDLE = 2; // [FIXME] ATTN_STATIC = 3; // [FIXME] Those values are meant to be used with the functions sound and ambientsound.

4.4 Values : Contents of level areas

CONTENT_EMPTY = -1; // Empty area CONTENT_SOLID = -2; // Totally solid area (rock) CONTENT_WATER = -3; // Pool of water CONTENT_SLIME = -4; // Pool of slime CONTENT_LAVA = -5; // Lava CONTENT_SKY = -6; // Sky

4.5 Values : Entity light effects

EF_BRIGHTFIELD = 1; // Glowing field of dots EF_MUZZLEFLASH = 2; EF_BRIGHTLIGHT = 4; EF_DIMLIGHT = 8;

4.6 Values : Existing Items

IT_AXE = 4096; IT_SHOTGUN = 1; IT_SUPER_SHOTGUN = 2; IT_NAILGUN = 4; IT_SUPER_NAILGUN = 8; IT_GRENADE_LAUNCHER = 16; IT_ROCKET_LAUNCHER = 32; IT_LIGHTNING = 64; IT_EXTRA_WEAPON = 128; IT_SHELLS = 256; IT_NAILS = 512; IT_ROCKETS = 1024; IT_CELLS = 2048; IT_ARMOR1 = 8192; IT_ARMOR2 = 16384; IT_ARMOR3 = 32768; IT_SUPERHEALTH = 65536; IT_KEY1 = 131072; IT_KEY2 = 262144; IT_INVISIBILITY = 524288; IT_INVULNERABILITY = 1048576; IT_SUIT = 2097152; IT_QUAD = 4194304;

4.7 Values : Behavior of solid objects

SOLID_NOT = 0; // no interaction with other objects // inactive triggers SOLID_TRIGGER = 1; // touch on edge, but not blocking // active triggers, pickable items // (.MDL models, like armors) SOLID_BBOX = 2; // touch on edge, block // pickable items (.BSP models, like ammo box) // grenade, missiles SOLID_SLIDEBOX = 3; // touch on edge, but not an onground // most monsters SOLID_BSP = 4; // bsp clip, touch on edge, block // buttons, platforms, doors, missiles

4.8 Values : Type of movements

MOVETYPE_NONE = 0; // never moves //float MOVETYPE_ANGLENOCLIP = 1; //float MOVETYPE_ANGLECLIP = 2; MOVETYPE_WALK = 3; // Walking players only MOVETYPE_STEP = 4; // Walking monster MOVETYPE_FLY = 5; // Hovering Flight // meant for flying monsters (and players) MOVETYPE_TOSS = 6; // Balistic flight // meant for gibs and the like MOVETYPE_PUSH = 7; // Not blocked by the world, push and crush // meant for doors, spikes and crusing platforms MOVETYPE_NOCLIP = 8; // Not blocked by the world MOVETYPE_FLYMISSILE = 9; // like fly, but size enlarged against monsters // meant for rockets MOVETYPE_BOUNCE = 10; // bounce off walls MOVETYPE_BOUNCEMISSILE = 11 // bounce off walls, but size enlarged against monsters // meant for grenades

4.9 Values : Entity can take solid damages

DAMAGE_NO = 0; // Can't be damaged DAMAGE_YES = 1; // Grenades don't explode when touching entity DAMAGE_AIM = 2; // Grenades explode when touching entity Most damageable entities have DAMAGE_AIM, so that when they chew on a grenade, it explodes. If you make an entity DAMAGE_YES, the grenades will bounce off it.

4.10 Values : Entity dead flag

DEAD_NO = 0; // still living DEAD_DYING = 1; // dying (helpless) DEAD_DEAD = 2; // really dead DEAD_RESPAWNABLE = 3; // dead, but can respawn

4.11 Values : Spawnflags

The spawn flags are bit fields, whose interpretation depend on the concerned entity. There is quite a bit of a hack, that could cause unexpected bugs in the Quake C code. DOOR_START_OPEN = 1; // allow entity to be lighted in // closed position SPAWN_CRUCIFIED= 1; // for zombie PLAT_LOW_TRIGGER = 1; // for func_plat SPAWNFLAG_NOTOUCH= 1; SPAWNFLAG_NOMESSAGE= 1; PLAYER_ONLY = 1; SPAWNFLAG_SUPERSPIKE = 1; // for spike shooter SECRET_OPEN_ONCE = 1; // secret door, stays open PUSH_ONCE = 1; WEAPON_SHOTGUN = 1; // weapon, shotgun H_ROTTEN = 1; // health, rotten (5-10 points) WEAPON_BIG2 = 1; // items START_OFF = 1; // light, is off at start. SILENT = 2; SPAWNFLAG_LASER = 2; // for spike shooter SECRET_1ST_LEFT = 2; // secret door, 1st move is left of arrow WEAPON_ROCKET = 2; // weapon, rocket H_MEGA = 2; // health, mega (100 points) DOOR_DONT_LINK = 4; SECRET_1ST_DOWN = 4; // secret door, 1st move is down from arrow WEAPON_SPIKES = 4; // weapon, nailgun DOOR_GOLD_KEY = 8; SECRET_NO_SHOOT = 8; // secret door, only opened by trigger WEAPON_BIG = 8; // weapon, super model DOOR_SILVER_KEY = 16; SECRET_YES_SHOOT = 16; // secret door, shootable even if targeted DOOR_TOGGLE = 32;

5. Entities

Part of this information is derived from the DEM file specs 1.0.2 by Uwe Girlich.

In Quake, monsters, players, items, and the level itself are all entities. There are three kind of entities, and you will all encounter them in Quake-C code.

Types of entities

Static entities

A static entity doesn't interact with the rest of the game. These are flames (progs/flame.mdl), lights, illusionary objects, and the like. It is never be necessary to reference such an entity, so they don't get an entity reference number.

A static entity will be created by the function :
makestatic() (it causes a spawnstatic message to be sent to every client).
A static entity cannot be removed, once created.

The maximum number of static entities is 127.

Temporary entities

A temporary entity is a short life time entity. For instance, Quake uses these entities for hits on the wall (point-like entities) or for the Thunderbolt flash (line-like entities), gun shots, and anything that is not supposed to last more than one frame.

A temporary entity will be created by sending a valid temporary entity message.
A temporary entity doesn't need to be removed, it disappears by itself.

Dynamic entities

A dynamic entity is anything which changes its behaviour or its appearance. These are ammunition boxes, spinning armors, player models and the like.

A dynamic entity will be created by the sequence : entity = spawn(); setmodel( entity, "progs/entity.mdl" ); setsize( entity, vector_min, vector_max); setorigin( entity, position ); It will have to be removed by the function : remove( entity ); The maximum number of dynamic entities is 449.

Definition of entity fields

These are the fields that are available in the entity objects (like self, other). Beware that this is not true object oriented programming : there is no protection when accessing those fields, and no guaranty on the validity of values. So if you put garbage there you will probably crash the game.

You can add custom fields (for instance, to store the ammo count of a new weapon you created) but those fields must not be situated among thoses that are common between Quake-C and Quake.exe. Otherwise, Quake.exe would have to be re-compiled. So those fields must be situated after the fake variable called end_sys_fields, in the field definitions.

Fields shared between Quake.exe and Quake-C.

These fields describe the most common entity fields. They are shared between the C code of Quake.exe, and the Quake-C code of PROGS.DAT.

Some of the fields are managed by the C code : you can read their value, but YOU SHOULD NEVER MODIFY THEIR VALUE DIRECTLY (there are special built-in functions for that).

Technical data
entity chain; // next entity, in a chain list of entities float ltime; // local time for entity float teleport_time; // to avoid backing up float spawnflags; // see possible values.
Appearance of entity
float modelindex; // index of model, in the precached list string classname; // spawn function string model; The name of the file that contains the entity model. float frame; This is the index of the currently displayed model frame. Frames must be defined by a $frame construct in the model file, and manipulated in the code as $xxx (where xxx is the name of the frame). float skin; This is the index of the model skin currently displayed. If your model has more than one skin defined, then this value indicates the skin in use. You can change it freely, as long as it remains in a valid range. For instance, it's used by the armor model to show the yellow, red or green skin. float effects; This is a flag that defines the special light effects that the entity is subject to. This can supposedly be used to make an entity glow, or to create a glowing field of dots around it.

Position in 3D
vector origin; // position of model // origin_x, origin_y, origin_z vector mins; // bounding box extents reletive to origin // mins_x, mins_y, mins_z vector maxs; // bounding box extents reletive to origin // maxs_x, maxs_y, maxs_z vector size; // maxs - mins // size_x,size_y,size_z vector absmin; // origin + mins and maxs // absmin_x absmin_y absmin_z vector absmax; // origin + mins and maxs // absmax_x absmax_y absmax_z vector oldorigin; // old position vector angles; // = 'pitch_angle yaw_angle flip_angle' Quirks: setting the angles on a player entity doesn't work.

Situation of the entity
float waterlevel; // 0 = not in water, 1 = feet, // 2 = waist, 3 = eyes float watertype; // a content value entity groundentity; // indicates that the entity // moves on the ground Since groundentity is used nowhere in progs, it's meaning is just a wild guess from a similar field in messages.

Movement in 3D
vector velocity; // = 'speed_x, speed_y, speed_z' vector avelocity; // = 'pitch_speed yaw_speed 0', // angle velocity vector punchangle; // temp angle adjust from damage // or recoil float movetype; // type of movement float yaw_speed; // rotation speed float solid; // tell if entity can block the // movements.
Monster's Behavior
entity goalentity; // Monster's movetarget or enemy float ideal_yaw; // Monster's ideal direction, on paths float yaw_speed; // Monster's yaw speed. string target; // Target of a monster string targetname; // name of the target
Automatic Behavior
float nextthink; // next time when entity must act void() think; // function invoked when entity // must act void() touch; // function invoked if entity is touched void() use; // function invoked if entity is // used void() blocked; // function for doors or plats, // called when can't push // ### RWA, addition ### entity other; // entity that triggered event on // 'self' vector movedir; // mostly for doors, but also used // for waterjump string message; // trigger messages float sounds; // either a cd track number or sound // number string noise; // sound played on entity noise // channel 1 string noise1; // ... string noise2; string noise3; Information by Abducted :
When you want an entity to do something specific, after a certain delay (exploding, disapearing, or the like...), you set next thing to that delay (in seconds), and set think to the function to execute.

Information by Greg Lewis :
It seems that the touch function is called before the field is checked, so you can set this type in the touch function, and it will immediatly be taken into account.

Player/Monster stats and damage status
float deadflag; // tells if an entity is dead. float health; // health level float max_health; // players maximum health is // stored here float takedamage; // indicates if entity can be // damaged float dmg_take; // damage is accumulated through // a frame. and sent as one single float dmg_save; // message, so the super shotgun // doesn't generate huge messages entity dmg_inflictor; // entity that inflicted the damage // (player, monster, missile, door)

Player inventory
float items; // bit flags float armortype; // fraction of damage absorbed by armor float armorvalue; // armor level float weapon; // one of the IT_SHOTGUN, etc flags string weaponmodel; // entity model for weapon float weaponframe; // frame for weapon model float currentammo; // ammo for current weapon float ammo_shells; // remaining shells float ammo_nails; // remaining nails float ammo_rockets; // remaining rockets and grenades float ammo_cells; // remaining lightning bolts float impulse; // weapon changes When set to 0, the player's weapon doesn't change. When different from zero, this field is interpreted by the Quake-C
impulse command as a request to change weapon (see ImpulseCommand).

Player Fight
entity owner; // Entity that owns this one (missiles, // bubbles are owned by the player) entity enemy; // personal enemy (only for monster entities) float button0; // fire float button1; // use float button2; // jump vector view_ofs; // position of player eye, relative to origin float fixangle; // set to 1 if you want angles to change now vector v_angle; // view or targeting angle for players float idealpitch; // calculated pitch angle for lookup up slopes entity aiment; // aimed antity?
float frags; // number of frags string netname; // name, in network play float colormap; // colors of shirt and pants float team; // team number float flags; // ?
Fields used only by Quake-C (User defined)
These entity fields are used only by Quake-C programs, and are never referenced by the C code of Quake.exe. So you can do whatever you want with the values, so long as it's compatible with what other Quake-C modules do.

If the fields defined here are not suitable for you, you can define new fields, by adding them at the end of the defintion of fields. As a matter of fact, the number of fields in an entity (hence the size of all the instances of entity objects) is determined by Quake-C: in the PROGS.DAT header, a value named entityfields indicates to Quake.exe the size of the entity object.

Beware however that the more field you add, the more each entity will suck memory. Add just one float (4 bytes) and it will take, in memory, 4 bytes time the number of entity.

The best is to share fields between distinct classes of entities, by reusing the same position for another kind of field. If the Quake C Compiler was a real object-oriented compiler, that would be done very safely by single-inheritance (multiple-inheritance would be a deadly mistake). You will also notice that id software has made quite a lousy usage of most of the fields, defining much more than were actually needed, since they are only used by a few entities.

World fields
string wad; // name of WAD file // with misc graphics string map; // name of the map being // played float worldtype; // see below worldtype is 0 for a medieval setting, 1 for metal, and 2 for a base setting.
These fields might soon become global variables, so don't rely too much on them.

Quake Ed fields
string killtarget; float light_lev; // not used by game, but // parsed by light util float style;
Monster Behaviour
Those functions are called when these specific events happen : void() th_stand; // when stands iddle void() th_walk; // when is walking void() th_run; // when is running void() th_missile; // when a missile comes void() th_melee; // when fighting in melee void() th_die; // when dies void(entity attacker, float damage) th_pain; That function is executed when the monster takes a certain amount of damage from an attacker (a player, or another monster). Will usually cause the monster to turn against the attacker.

Monster state variables
entity oldenemy; // mad at this player before // taking damage float speed; float lefty; float search_time; float attack_state; float pausetime; entity movetarget; Player Only float walkframe; float attack_finished; float pain_finished; // time when pain sound // is finished float invincible_finished; float invisible_finished; float super_damage_finished; float radsuit_finished; float invincible_time; // time when player cease // to be invincible float invincible_sound; float invisible_time; // time when player cease // to be invisible float invisible_sound; float super_time; // time when quad shot expires? float super_sound; float rad_time; float fly_sound; float axhitme; // TRUE if hit by axe float show_hostile; // set to time+0.2 whenever a // client fires a weapon or // takes damage. Used to alert. // monsters that otherwise would // let the player go float jump_flag; // player jump flag float swim_flag; // player swimming sound flag float air_finished; // when time &gt; air_finished, start // drowning float bubble_count; // keeps track of the number of bubbles string deathtype; // keeps track of how the player died
Object stuff
string mdl; // model name? vector mangle; // angle at start. 'pitch roll yaw' vector oldorigin; // only used by secret door float t_length; float t_width;
vector dest; vector dest1; vector dest2; float wait; // time from firing to restarting float delay; // time from activation to firing entity trigger_field; // door's trigger entity string noise4; float aflag; float dmg; // damage done by door when hit
float cnt; // counter void() think1; vector finaldest; vector finalangle; // // triggers // float count; // for counting triggers // // plats / doors / buttons // float lip; float state; vector pos1; vector pos2; // top and bottom positions float height; // // sounds // float waitmin; float waitmax; float distance; float volume;

6. Global variables

These variables are accessible in every functions.
Quake C function are not supposed to modify them directly.
Variable : world
the server's world object, which holds all global state for the server, like the deathmatch flags and the body ques.

Variable : time
float time; // in seconds The current game time, a floating point value in seconds. Note that because the entities in the world are simulated sequentially, time is NOT strictly increasing. An impact late in one entity's time slice may set time higher than the think function of the next entity. The difference is limited to 0.1 seconds.

Variable : frametime
float frametime; // in seconds No idea what this can be. Used only when jumping in water.

Variable : self
entity self; The entity that is subject to the current function.

Variable : other
entity other; The object concerned by an impact, not used for thinks.

Variable : force_retouch
float force_retouch; // counter Force all entities to touch triggers next frame. this is needed because non-moving things don't normally scan for triggers, and when a trigger is created (like a teleport trigger), it needs to catch everything.
It is decremented each frame, so it is usually set to 2 to guarantee everything is touched.

Variable : mapname
string mapname; Name of the level map currently being played, like "start".

Variable : deathmatch
float deathmatch; // a boolean value, 0 or 1 True if playing deathmatch.

Variable : coop
float coop; // a boolean value, 0 or 1 True if playing cooperative.

Variable : teamplay
float teamplay; // a boolean value, 0 or 1 True if playing by teams.

Variable : serverflags
float serverflags; // bit fields Propagated from level to level, and used to keep track of the completed episodes. If serverflag & ( 1 << e) is true, then episode e was already completed. Generally equal to player.spawnflags & 15.

Variable : total_secrets
float total_secrets; // counter Number of secrets found by the players. Affected only by trigger_secret.

Variable : found_secrets
float found_secrets; // counter Number of secrets found.

Variable : total_monsters
float total_monsters; // counter Total number of monsters that were spawned, since the begining of the level.

Variable : killed_monsters
float killed_monsters; // counter Store the total number of monsters killed.

Variable : parm1...parm16
float parm1; // items bit flag (IT_SHOTGUN | IT_AXE ) float parm2; // health float parm3; // armorvalue float parm4, parm5, parm6, parm7; // ammo float parm8; // weapon float parm9; // armortype*100 float parm10, parm11, parm12, parm13, parm14, parm15, parm16; Those parameters seem to be a bit of hack. They are used when a client connects. Spawnparms are used to encode information about clients across server level changes.

Functions that are mandatory in Quake-C

These functions must be defined in Quake C, since they are invoked by Quake under certain conditions.
void main(); Only used for testing progs.

void StartFrame(); Called at the start of each frame.

Behavior of players
void PlayerPreThink(); Called with self=player, for every frame, before physics are run.
void PlayerPostThink(); Called with self=player, for every frame, after physics are run.

Management of network game clients
void ClientKill(); Called when a player suicides.
void ClientConnect(); Called when a player connects to a server, but also, for every player, when a new level starts. It is used to announces the new player to every other players.
void PutClientInServer(); Call after setting the parm1... parm16.
void ClientDisconnect(); Called when a player disconnects from a server Announce that the player has left the game.
void SetNewParms(); Called when a client first connects to a server. Sets parm1...parm16 so that they can be saved off for restarts.
void SetChangeParms(); Call to set parms for self so they can?

7. Model pragma

(Derived from informations published by Steve Tietze)

Here are a few definitions that are commonly found in the Quake-C code defining the behavior of animated models (monsters, players, etc...).

Most of this information is not interpreted by the Quake-C compiler, but it's useful for the program modelgen that generates the models.
Model name
$modelname name name is the name of the model file defining the object.
ex: $name armor

$cd dir Specify the directory where your model file (.MDL) is located.
ex: $cd /evil/models/armor

Special animation flags
$flags rotation This field is not interpreted by Quake-C, but it's useful for the program modelgen that generates the models.
Rotation of the object.
ex: $flags 8
Possible values for the flags : 8, the object keeps rotating, like armors.
Other values are not known yet.

$origin x y z This field is not interpreted by Quake-C, but it's useful for the program modelgen that generates the models. Location of the object within the bounding box, in the quake editor.
ex: $origin 0 0 8

Scale factor
$scale number This field is not interpreted by Quake-C, but it's useful for the program modelgen that generates the models. Number comes from the texmake number that is generated.
You can use different values if you want.
ex: $scale 4

$base object This field is not interpreted by Quake-C, but it's useful for the program modelgen that generates the models. Object is the name of a model file, that will be used as a kind of starting position, for animation.

Skin file
$skin skinfile This field is not interpreted by Quake-C, but it's useful for the program modelgen that generates the models. Skinfile is the name (without extension) of the .lbm file that defines the skin of the object, as generated by the program texmake.

Frame definitions
$frame frame1 frame2 ... This defines several animation frames of the object.
For every animation frame defined, you must also define a Quake-C function, that will be called during this animation frame. For instance : $frame walk1 walk2 walk3 walk4 void() man_walk1 = [ $walk1, man_walk2 ] { ... some code ... }; void() man_walk2 = [ $walk2, man_walk3 ] { ... some code ... }; void() man_walk3 = [ $walk3, man_walk4 ] { ... some code ... }; void() man_walk4 = [ $walk4, man_walk1 ] { ... some code ... }; In the brackets, the first parameter defines the name of the frame (as found in the model file), and the second parameter defined the function that is to be executed in the next frame (by setting the value of self.nextthink).

Most of these functions do nothing special, but some can be very complex (for instance, the functions that are called when the monster tries to see a player).

8. Network protocol

Quake-C is not supposed to handle a lot of network messages, since most are already handled in C.

However, builtin functions have not been built for every kind of messages in the Quake protocol, so you migth end-up composing protocol messages in Quake-C. I highly recommend that you build a single function to handle a given message type, because the structure of those messages might change, and then all your code would have to be checked for bugs.

By that way,
Id Software didn't even bothered to write a function to generate temporary entites, though they keep using this message. It's still a long way to ISO 9001, I'm afraid.

Definitions related to protocol messages

Values : How messages are sent
MSG_BROADCAST = 0; // unreliable message, sent to all MSG_ONE = 1; // reliable message, sent to msg_entity MSG_ALL = 2; // reliable message, sent to all MSG_INIT = 3; // write to the init string Use unreliable (but fast) messages, when it's of no importance that a client misses the message.
Examples : sound, explosions, monster deaths, taunts....
Use reliable messages when it's very important that every client sees the message, or a game incoherency might happen.
Examples : shots, player deaths, door moves, game ends ... and CD track changes!.

Values: Type of message
These are some of message types defined in the Quake network protocol.

Some message structures

Here are some of the messages defined in the Quake network protocol.
Beware, the structure of those messages might change in future version (Satan forbids!).

Message : Set View Position
msg_entity = player WriteByte (MSG_ONE, SVC_SETVIEWPORT); WriteEntity( MSG_ONE, camera); This message is meant for a single client player. It sets the view position to the position of the entity camera.

Message : Set View Angles msg_entity = player WriteByte (MSG_ONE, SVC_SETVIEWANGLES); WriteAngle( MSG_ONE, camera.angles_x); WriteAngle( MSG_ONE, camera.angles_y); WriteAngle( MSG_ONE, camera.angles_z); This message is meant for a single client player. It set the orientation of it's view to the same orientation than the entity camera.

Message : Temporary Entity
WriteByte (MSG_BROADCAST, SVC_TEMPENTITY); WriteByte (MSG_BROADCAST, entityname); WriteCoord (MSG_BROADCAST, origin_x); WriteCoord (MSG_BROADCAST, origin_y); WriteCoord (MSG_BROADCAST, origin_z);
Message : Set CD Track
WriteByte (MSG_ALL, SVC_CDTRACK); WriteByte (MSG_ALL, val1); // CD start track WriteByte (MSG_ALL, val2); // CD end track
Message : Final Message
WriteByte (MSG_ALL, SVC_FINALE); WriteString (MSG_ALL, "any text you like\n");
Message : Sell Screen
WriteByte (MSG_ALL, SVC_SELLSCREEN); Shows the infamous sell screen (like you needed it to understand).

Message : Inter Mission
WriteByte (MSG_ALL, SVC_INTERMISSION); Shows the inter mission camera view.

Message : Killed Monster
WriteByte (MSG_ALL, SVC_KILLEDMONSTER); Increase by one the count of killed monsters, as available to the client. Can be displayed with showscores.

Message : Found Secrets
WriteByte (MSG_ALL, SVC_FOUNDSECRET); Increase by one the count of secrets founds.

Message: Update Entity
This message has a rather complex structure. I already generated some valid update messages, but since the message structure seems highly susceptible to change in the next versions of Quake, I would recommend that you never use such messages : as a matter of fact, Quake itslef is very capable of generating all the required messages... unless you start creating deathmatch cameras or the like.

9. Network Builtin functions

Beware : when generating messages, you had better respect the format of the existing messages. Otherwise the game clients might not be able to interpret them (and will likely crash).

The functions below all write to clients (players connected via the network, or the local player).

Global variable for network messages

Variable : msg_entity
entity msg_entity; If you want to send a message to just one entity e, then set msg_entity= e and send the message with flag MSG_ONE, instead of MSG_ALL.
Never used. Maybe it doesn't even work.

Builtin functions for composing network messages

Function : WriteByte

void WriteByte(float to, float value)

         to = see messages

Function : WriteChar

void WriteChar(float to, float value)

         to = see messages

Function : WriteShort

void WriteShort(float to, float value)

         to = see messages

Function : WriteLong

void WriteLong(float to, float value)

         to = see messages

Function : WriteCoord

void WriteCoord(float to, float value)

         to = see messages

Function : WriteAngle

void WriteAngle(float to, float value)

         to = see messages
This function writes a single byte, that represents 256*(angle/380).

Function : WriteString

void WriteString(float to, string value)

         to = see messages
This function writes a string, terminated by \0 (the null character in C).

Function : WriteEntity

void WriteEntity(float to, entity value)

         to = see messages
This function writes an entity reference, taking two bytes.

10. Tips & tricks

Here are some characteristics of Quake-C that you had better be aware of.
The names of variable and functions must be unique.
The names of functions, variables and fields must be unique. For instance, you cannot define a variable with the same name as a field. However, local variables can be defined more than once (they had better!).

Composition of function is not supported
Since all the functions use a single parameter marshaling area, and a single global variable to store their reture result, you should NEVER try to call a function within another function call.
Example : printing the coordinate of entity self sprintf(self, vtos( self.origin )); will fail miserably (sending the message somewhere in hell), so it should be replaced by : text = vtos( self.origin ); sprintf(self, text); Unfortunately, this also applies to operators : sum = anglestovec( 45) + anglestovec( 90); will fail an should be replaced by : sum = anglestovec( 45); sum = sum + anglestovec( 90); Actually, Quake-C is rather lame as a compiler, and you will probably make hundred of little mistakes like that, that the compiler will not warn you of. But remember Quake-C was built for "performance", not ease of use. And also that it wasn't designed by people from the MIT. Remember also that you got it for free... you can always get gcc (the Gnu C Compiler) for the same price ;-)

You cannot initialise variable with default values.
If you give a default value to a quake-C variable, this variable will be considered as a constant. And since the value of constants is not supposed to change, your program may not work properly after that.

Coordinates are relative to the world.
All the geometry (coordinate positions, directions, angles) are relative to the world. They are never relative to a given object. To know the direction an object is facing, you have to require calculation of the v_front vector (respectively v_right and v_up for the right, and the top).

Frequently Asked Questions about Quake-C

How do I change the viewpoint?
You would like that a given player sees through the eyes of another entity. This commonly happens at the end of the level (all players see through a camera), or when the player head is severed (gibbed), or when a player is invisible (he only exists as his eyes).

But the example above work by changing the player entity, and what you want is probably just to see through a camera (Duke3D) or a missile (Descent).

This operation is known in the Quake network protocol as a setview message. But nowhere it's defined in Quake-C, and there's no function to change the view port. So the solution is to encode a set view port message, followed by a set view angles message (to take the orientation of the camera).

This works fine, except that if, for some reason, the entity you are using as a camera was not previously declared to the client, then the view port will be set to '0 0 0', which is usually somewhere in the void.

How do I teleport a player into another server
A trick by Steven Lang ( // In the slipgate touch function // other = entity that touched if(other.classname == "player") stuffcmd(other, "connect server.address\n"); // send command When the slipgate is touched, the entity jumps to another server.

Trouble : the player stats and weapons won't be preserved, and the player would be dumped to the console if the other server was full or not available.
That's why John Carmack, will rewrite the code of Quake.exe to implement his Quake World proposal, and advanced server with all kinds of goodies... permission lists, ability to block an IP, etc. (info from quake-c list).

How do I manipulate strings in Quake-C ?
Well, you can have any kind of strings, as long as they cannot be changed.

"In Ford we trust" (Brave New World).

Mind you, pr_comp.c, defines only operations = == != on strings.

How to read string variables, or text messages ?
Well, if you know, tell, that would make a nice addition to this specs.

How do I move an entity in Quake-C ?
You have better not touch it's position, else some stuff in the C code might not be valid anymore. So you call the setposition() built-in function.

How to change the velocity of an entity (make it bounce off walls) ?
Information by Greg Lewis.
It seems that an entity's velocity can't be changed in the Touch function of the entity.
Making the calculations there will be of no use. So just set entity .movetype to MOVETYPE_BOUNCE, entity.nextthink to 0.1 (to let it bounce off), and set entity.think to the name of a function that, when called 0.1 second later, will set entity.velocity to the right direction.

How to calculate the direction a player is facing?
Assuming the player is self, the entity field self.angles contains the orientation angles of the player (as set by moving the mouse).

Then the function makeverctors( self.angles) will calculate three vectors, that point in the direction the player is facing, but also to the right of the player (strafing direction) and to the direction the player is standing.

Note that those vectors are normalised to 1, so if you want to know what lays 100 units in front of the player, use self.origin + 100 * facing.

How to send a message to a client when he logs in ?
It has been noticed that using a sprint() in function ClientConnect just plain doesn't send any message at all. Maybe the client is not ready to receive messages at this point.

Doug Keenan has reported he could send such a text message by putting the sprint() close to the begining of the ClientConnect function. It doesn't work at the end, apparently.

Writing Quake-C code

Here are some suggestions that you should really consider when writing Quake-C code. Well, there are no obligations, but that would make life simpler for others when they read your code (and thus for you when you read theirs).

I assume here that you want to develop code that others can re-use, or that can be mixed seamlessly with codes written by others.

(If you are reinventing the whole world all by yourself, you hardly need any help or counsels. By the way, the first command is +light).

1. Please put comments in your code
Of course, the real gurus don't need comments. They understand raw Quake-C, even compiled. They can even imagine all the parts of your code before they read them. Even before you write them. But actually, they seldom read your code. Only normal people do.

2. Please tag the begining and end of your modifications, if you are fixing a code from someone else
Also put a date, and put a reason for the fix.
Example : // Patch by Nezu The Unworthy 8/3/96 // Gimme a chance to win a deathmatch if( != "nezu") self.frag = self.frag - 10; // Patch End
3. Creating new elements
Each time you create a new function, a new variable or a new field, please give it a name that will not conflict with function or variable defined by others.
A rather sure way to do this is to prefix every name with some abvreviated module name, or you initials, or whatever rare combination of three or four letter.
Example : void() NTU_think = // Nezu The Unworthy starts thinking { = 1; // turn red and boil };
4. Implementing new functions
Each time you implement some set of related functions, you should create a new Quake-C module, and give it a name different from the existing ones.
Please do not use one of the module names used by Id Software, this would be confusing. Try to be original, else we might end-up with two hundred modules called impulse.qc.

5. When you want to distribute some modified Quake-C programs :
Include a file_id.diz file explaining in 5 lines what your patch does, and where it should be stored in the archives (this file is to be read by system administrators).
Include a readme.txt file explaining in details what your patch does, how it does it, and what common files you had to modify.
Include the .qc modules that you created from scratch.
For the modules you modified, please let them pass through the utilities diff (see below), so that the original file can be patched the utility patch. Even if it has been modified since. Do not distribute modified .qc modules. Future versions of Quake will contain different code, and all your work would then be lost.

6. Compile and distribute
You should compile and distribute a version of your code, as a single PROGS.DAT file, to be used by those who just wanna have fun. Don't forget them, they largely overnumber the people who directly deal with Quake-C.

7. Upload your Quake-C patches to the primary quake ftp site at
Maybe if it's good enough it will also appear in the Quake-C code repository.

Using Diff and Patch

Information by Jeff Epler

You can find a DOS version of diff and patch on all the major ftp archives, for instance Simtelnet (mirrored at

For a Win32 (Windows95 and NT) version, see and

The full documentation for diff and patch is available on, but here are some shortened instructions :

To make a diff :

To patch with a diff :

11. Basic Types

Simple Types

Type : void
An empty result, mostly used for definition of procedures (i.e. functions that return no result at all).

Type : float
A floating point value.

Floats are also used to store booleans (TRUE, FALSE) or integer values linke counters, or bit flags. Valid syntax: 12 1.6 0.5 -100 Invalid syntax: .5 A parsing ambiguity is present with negative constants. "a-5" will be parsed as "a", then "-5", causing an error. Separate the - from the digits with a space "a - 5" to get the proper behavior.

Type : vector
A vector, made of 3 float coordinates.
Used to represent positions or directions in 3D space.
Valid syntax : '0 0 0' or '20.5 -10 0.00001'

Note the simple quotes around the vector. Do not use double quotes, they are reserved for strings.

If you declare a vector foobar, then you can access it's x, y and z fields with : foobar_x, foobar_y, foobar_z.

Type : string
Represents a character string.
Used to indicate file names, or messages to be broadcast to players.
Valid syntax: "maps/jrwiz1.bsp" or "ouch!\n".
Use \n for newline.

Type : entity
The reference of an entity in the game, like things, players, monsters.
For instance, this is the type of the entities self and other.

The entity type is a structured type, made of fields.
A description of each field is available.

Field types

Countrary to the other types, the entity type is a reference to an instance of a structured object, that contains many informations of totally different kinds.

To access all these informations conveniently, they are stored as fields of the entity object, and each field is given a name and a type, that makes it distinct of the others.

Some of the fields do not store value, but instead they store the function to be executed in certain conditions. They are called the methods that can be aplied to the object.

If Quake-C was an object oriented programming language, those method functions and would be distinguished from the other fields. And, above all, you would be able to create new object types, with their own fields.

As Quake-C stands currently, all the field definitions are definitions of entity fields. So anywhere in your code you could add definition of new fields, and the compiler would interpret them as an extension of the entity definition.

Here are all the possible definitions of entity fields, with their types :
Reserved field types (beware of the hack!)

In the first file read by the Quake-C compiler, defs.qc, there must be a definition for the entity fields, and world fields. This definition is hard coded. You had better not touch it, or you will have to recompile Quake itself.

The globals are defined before the special definition void end_sys_globals;. The entity fields are defined before the special definition void end_sys_fields;.

It's not important if you don't understand the nonsense above. It's an ugly hack. Just don't modify defs.qc before those two tags, and you won't be in trouble.

12. Compilation of Quake-C

The language is strongly typed and there are no casts.

Source files are processed sequentially without dumping any state, so if a defs file is the first one processed, the definitions will be available to all other files.

Error recovery during compilation is minimal. It will skip to the next global definition, so you will never see more than one error at a time in a given function. All compilation aborts after ten error messages.

Names can be defined multiple times until they are defined with an initialization, allowing functions to be prototyped before their definition. // in headers void() MyFunction; // the prototype // later void() MyFunction = // the initialization { dprint ("we're here\n"); }; Beware of the Quake-C compiler

13. Execution of Quake-C

Code execution is initiated by C code in quake from two main places : the timed think routines for periodic control, and the touch function when two objects impact each other.

Execution is also caused by a few uncommon events, like the addition of a new client to an existing server.

There is a runnaway counter that stops a program if 100000 statements are executed, assuming it is in an infinite loop.

It is acceptable to change the system set global variables. This is usually done to pose as another entity by changing self and calling a function.

The interpretation is fairly efficient, but it is still over an order of magnitude slower than compiled C code. All time consuming operations should be made into built in functions.

A profile counter is kept for each function, and incremented for each interpreted instruction inside that function. The "profile" console command in Quake will dump out the top 10 functions, then clear all the counters. The "profile all" command will dump sorted stats for every function that has been executed.

14. Examples

These are examples taken from the QuakeC patch archives. Two of them are made by Ferrara.

14.1 Looping between all monster

float() Pet_FindTarget = { local entity client; local float r; local entity head, selected; local float dist; dist = 10000; selected = world; head = findradius(self.origin, 10000); while(head) { if( ( &gt; 1) &amp;&amp; (head != self) &amp;&amp; (head != self.owner)) { traceline(self.origin,head.origin,TRUE,self); if ( (trace_fraction &gt;= 1) &amp;&amp; (vlen(head.origin - self.origin) &lt; dist) &amp;&amp; (head.owner != self.owner)) { selected = head; dist = vlen(head.origin - self.origin); } } head = head.chain; } if (selected != world) { sprint (self.owner,"Pet attacking -&gt; "); if (selected.classname == "player") { sprint (self.owner,selected.netname); sprint (selected,self.owner.netname); sprint (selected," sent one of his minions after you!\n"); } else sprint (self.owner,selected.classname); sprint (self.owner,"\n"); self.enemy = selected; FoundTarget (); return TRUE; } if (self.goalentity != self.owner) { self.goalentity = self.owner; self.think = self.th_run; } self.ideal_yaw = vectoyaw(self.owner.origin - self.origin); self.nextthink = time+0.1; return FALSE; };

14.2 Creating a new entity

void(entity myself) ActivateHolo = { local entity newholo; newholo = spawn(); newholo.solid = SOLID_NOT; newholo.movetype = MOVETYPE_NOCLIP; newholo.origin = myself.origin; newholo.angles = myself.angles; newholo.colormap = myself.colormap; setmodel (newholo, "progs/player.mdl"); newholo.classname = "holo"; newholo.owner=myself; newholo.frame=13; newholo.nextthink = time + 8; newholo.think = RemoveHolo; myself.currentammo = myself.ammo_cells = myself.ammo_cells - 10; myself.items = myself.items | IT_HOLO; stuffcmd (newholo.owner, "bf\n"); sprint(newholo.owner,"holograph activated\n"); };

14.3 Setting point of view

void(entity me, entity camera) NezuSetViewPoint = { // Set view point msg_entity = me; // target of message WriteByte (MSG_ONE, SVC_SETVIEWPORT); // 5 = SVC_SETVIEWPORT; WriteEntity (MSG_ONE, camera); // view port // Also set angles, otherwise it feels strange // NezuSetViewAngle(me, camera.angles); WriteByte (MSG_ONE, SVC_SETVIEWANGLES); // 10 = SVC_SETVIEWANGLES WriteAngle(MSG_ONE, camera.angles_x); // tilt WriteAngle(MSG_ONE, camera.angles_y); // yaw WriteAngle(MSG_ONE, camera.angles_z); // flip };

14.4 Teleporting

void() Teleport_to_bomb = { local entity oldself,bdest; bdest=spawn(); bdest.origin = self.telebomb.origin + '0 0 27'; // Blow up the bomb... oldself=self; self=self.telebomb; GrenadeExplode(); self=oldself; // Teleport to the bomb's old location if( &lt;= 0) { remove(bdest); return; } // Recreating the "teleport_touch" function here, once again spawn_tfog (bdest.origin); spawn_tfog (bdest.origin); spawn_tdeath (bdest.origin,self); setorigin (self,bdest.origin); self.teleport_time = time + 1; // Longer teleport recovery time self.flags = self.flags - self.flags &amp; FL_ONGROUND; remove(bdest); };

14.5 Throwing your eyes

if (self.impulse == 254) { local vector v; eyes = spawn(); setmodel (eyes,"progs/eyes.mdl"); eyes.movetype = MOVETYPE_BOUNCE; eyes.solid = SOLID_BBOX; eyes.effects = eyes.effects | EF_DIMLIGHT; msg_entity = self; WriteByte (MSG_ONE, SVC_SETVIEWPORT); WriteEntity (MSG_ONE, eyes); WriteByte (MSG_ONE, SVC_SETVIEWANGLES); WriteAngle(MSG_ONE, self.angles_x); WriteAngle(MSG_ONE, self.angles_y); WriteAngle(MSG_ONE, self.angles_z); makevectors (self.v_angle); if (self.v_angle_x) eyes.velocity = v_forward*600 + v_up * 200 + crandom()*v_right*10 + crandom()*v_up*10; else { eyes.velocity = aim(self, 10000); eyes.velocity = eyes.velocity * 600; eyes.velocity_z = 200; } eyes.avelocity = '300 300 300'; eyes.angles = vectoangles(eyes.velocity); setsize (eyes, '-3 -3 -3', '3 3 3'); setorigin (eyes, self.origin); } if (self.impulse == 253) { local vector v; msg_entity = self; WriteByte (MSG_ONE, SVC_SETVIEWPORT); WriteEntity (MSG_ONE, self); WriteByte (MSG_ONE, SVC_SETVIEWANGLES); v = vectoangles(eyes.origin - self.origin); WriteAngle(MSG_ONE, v_x); WriteAngle(MSG_ONE, v_y); WriteAngle(MSG_ONE, v_z); remove(eyes); }

14.6 Radar

if (cvar("temp1")==1) { local entity head,selected; local float min,dist; if (radar_time==0) radar_time=time; if (time&gt;=radar_time) { min=2000; head = findradius(self.origin,1000); selected = world; while (head) { dist = vlen(self.origin - head.origin); if( ( &gt; 1) &amp;&amp; (head != self) &amp;&amp; (head != self.owner) &amp;&amp; (dist&lt;min) ) { min=dist; selected=head; } head = head.chain; } sound (selected, CHAN_AUTO, "radar.wav", 1, ATTN_NORM); radar_time = min / 600; radar_time = radar_time + time; } }

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