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 search the engines for various things in the Quake World.
Monsters, player, 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 idsoftware, so all those informations are copyright (c) 1996, id software.
To compile and use all this info you must have qcc.tar.gz take it from idsoftware. You can edit and than compile with qccdos (the compiler) all of 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 he is the real compiler of this document, I have rearranged it to a TXT version. Thanks Olivier.
Those comments are the same as in C++ (and many C languages).
2.2 Names
Names of variable, fields, or functions have a maximum 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 structure, 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, 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 a 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 not function correctly.
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:
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.
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...
};
Controlling the flow of execution in Quake-C
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 integer
* / - +
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.
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
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.
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: other.target)
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.
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
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
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.
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
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
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
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
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.
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.
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 solid take damage
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
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 need not be removed, it disapears 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
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 other
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; // soudn 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 nextthink 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?
Deathmatch
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 > 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'
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.
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.
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.
However, Doug Keenan (doug.keegan@tamu.edu) 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(self.name != "nezu")
self.frag = self.frag - 10;
// Patch End
3.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
{
self.skin = 1; // turn red and boil
};
4.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.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 ftp.cdrom.com.
Maybe if it's good enough it will also appear in the Quake-C code repository.
Using Diff and Patch
Information by Jeff Epler (jepler@cse.unl.edu)
You can find a DOS version of diff and patch on all the major ftp archives, for instance Simtelnet (mirrored at
ftp://oak.oakland.edu/pub/simtelnet).
For a Win32 (windows95 and NT) version, see diffutils.zip and patch.zip.
The full documentation for diff and patch is available on www.ai.mit.edu, but here are some shortened instructions:
To make a diff:
. start with yourdir/ with an entire working set of .qc files, and v101qc/
with the virgin qc files from id.
. diff -ur --new-file v101qc yourdir > patchfil
To patch with a diff:
. copy everything in v101qc (or yourdir if you want to add these patches to
your already-customized setup) to newdir
. change to newdir
. patch -p1 < patchfil
. Look for any "rejected" patches and apply them by hand using your
favorite 2-window text editor. These should be few or none if the author
kept his changes well-structured or you patched from exactly the same
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:
.float field_name;
.string field_name;
.vector field_name;
.entity field_name;
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
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.
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.
