QuakeC Globals

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QuakeC Manual 1.0 Copyright(C) 1996 by Ferrara Francesco (frank@aerre.it) ________________________________________________________________________________

       Table of contents
       

1. Introduction

       1.1     What is QuakeC
       1.2     Contributions

2. QuakeC Language

       2.1     Comments
       2.2     Names
       2.3     New types
       2.4     Definition of variables
       2.5     Definitions of constants
       2.6     Definitions of functions
       2.7     Function declaration
       2.8     Definition of a frame function
       2.9     Conditional construct
       2.10    Loop construct
       2.11    Function calls
       2.12    Logical operations
       2.13    Comparisons
       2.14    Operations on floats or integer
       2.15    Bitwise operations

3. Builtin functions

       3.1     Basic math functions
       3.2     Basic vector maths
       3.3     Sound emission
       3.4     Entity management
       3.5     Move Entities
       3.6     Fights and Shots
       3.7     Collision checking
       3.8     Server related functions
       3.9     Print messages
       3.10    Console 
       3.11    Debugging
       3.12    Precaching files

4. Defines

       4.1     Values: temporary entities
       4.2     Values: Sound Channel of entities
       4.3     Values: Sound Attenuation
       4.4     Values: Contents of level areas
       4.5     Values: Entity light effects
       4.6     Values: Existing Items
       4.7     Values: Behavior of solid objects
       4.8     Values: Type of movements
       4.9     Values: Entity can solid take damage
       4.10    Values: Entity dead flag
       4.11    Values: Spawnflags

5. Entities 6. Model pragma 7. Network protocol 8. Network Builtin functions 9. Tips & tricks 10. Basic Types 11. Compilation of QuakeC 12. Execution of QuakeC 13. Examples

       13.1    Looping between all monster
       13.2    Creating a new entities
       13.3    Setting point of view
       13.4    Teleporting
       13.5    Throwing your Eyes
       13.6    Radar


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 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.
       
       

2. QuakeC Language ________________________________________________________________________________

       Basic constructs of Quake-C

2.1 Comments


   // 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, 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:

   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...
   };


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.


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

Function: anglemod

       float anglemod (float angle)
       returns angle in degree, module 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

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

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

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: 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.

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

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

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. 


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 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
 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 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

   //  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 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' vector oldorigin; // only used by secret door float t_length; float t_width;

Doors

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

Miscellaneous

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;


5. 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.

Misc

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?

6. Model pragma ________________________________________________________________________________

(Derived from information 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

directory

$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

$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

$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).

7. 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.

SVC_SETVIEWPORT = 5; SVC_SETANGLES = 10; SVC_TEMPENTITY = 23; SVC_KILLEDMONSTER = 27; SVC_FOUNDSECRET = 28; SVC_INTERMISSION = 30; SVC_FINALE = 31; SVC_CDTRACK = 32; SVC_SELLSCREEN = 33; SVC_UPDATE = 128;

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.


8. 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.

9. 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 (tiger@ecis.com)

   // 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.

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 source he diffed from.

10. 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:

   .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 two tags, and you won't be in trouble.


11. 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



12. 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.


13. Examples ________________________________________________________________________________

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

13.1 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( (head.health > 1) && (head != self) && (head != self.owner)) { traceline(self.origin,head.origin,TRUE,self); if ( (trace_fraction >= 1) && (vlen(head.origin - self.origin) < dist) && (head.owner != self.owner)) { selected = head; dist = vlen(head.origin - self.origin); } } head = head.chain; } if (selected != world) { sprint (self.owner,"Pet attacking -> "); 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;

};

13.2 Creating a new entities

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"); };

13.3 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

};

13.4 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(self.health <= 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 & FL_ONGROUND;

remove(bdest); };

13.5 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);
       }

13.6 Radar

       if (cvar("temp1")==1)
       {
               local entity head,selected;
               local float min,dist;
               if (radar_time==0) radar_time=time;
               if (time>=radar_time) 
               {
                       min=2000;
                       head = findradius(self.origin,1000);
                       selected = world;
                       
                       while (head)
                       {
                               dist = vlen(self.origin - head.origin);
                               if( (head.health > 1) && (head != self) && (head != self.owner) && (dist<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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