1. Coursework 2 support

please download a quake 1 (darkplaces) tarball from: here and an ioquake tarball from here.
choose the latest dates for ioquake and darkplaces respectively
these are source archives of the same versions installed in the Labs
unpack them by typing the following commands:
tar jxf filename.bz2

2. Coursework Quake 1 texture modifications

download the improved textures for darkplaces (quake 1) engine from here
move this file into your folder $HOME/.darkplaces/id1
- where $HOME is /home/u01234567
now extract this texture file by opening up a command terminal and extracting the archive:
```
$ tar zxf textures.tar.gz
```
now run the system installed darkplaces engine to see the new textures appear:
```
$ q1
```

3. Modifying the Darkplaces game engine

extensive modifications have been made to the original Quake game engine - the result is darkplaces
downloading and unpacking the darkplaces source tree (see previous slides)
firstly build the GLX darkplaces engine, by:

$ cd darkplaces-20071120
$ make cl-release

confirm that you can run this executable (remember you must turn your Desktop effects off). You can run the executable by:

$ cd $HOME
$ ./darkplaces-20071120/darkplaces-glx

now navigate to the file: darkplaces-20071120/cl_particles.c and open it up in an editor
move to line 170 and here you will see some configuration values which control the particles in darkplaces
- enable some of boolean values by changing 0 ’s to 1 ’s and now by trial and error try adjusting some of the values of particle variables
- see if you can introduce your own gore variable and make it increase various particle effects, more blood, more smoke, greater length of time before bullet holes disappear etc
- feel free to modify darkplaces in any other way

4. Some previous modifications to original Quake (not darkplaces)

these notes might be useful to gain a flavour of how to modifify quake
- note they do not directly apply to darkplaces

5. Introducing gore into the original quake engine (not darkplaces)

firstly add a console function: in the file r_main.c

void R_Gore_f (void)
{
  if (gore) {
    gore = false;
    Con_Printf("gore off\n");
  } else {
    gore = true;
    Con_Printf("gore on\n");
  }
}

add new command to the file r_main.c inside the function: R_Init
```
Cmd_AddCommand ("gore", R_Gore_f);
```
add a boolean variable (external declaration) to common.h
```
extern qboolean gore;
```
declare and initialise the variable inside common.c
```
qboolean gore = false;
```
inside the function

void COM_InitArgv (int argc, char **argv)

add a test for the presence of the command line option -gore

  ...
  if (COM_CheckParm ("-gore")) {
     gore = true;
  }
  ...

6. Now for the fun... modify R_ParticleExplosion2 (not darkplaces)

void R_ParticleExplosion2 (vec3_t org, int colorStart, int colorLength)
{
  int i, j;
  particle_t *p;
  int colorMod = 0;
  int multiplier=1;


  if (gore)
    multiplier = 2;
  for (i=0; i<512*multiplier; i++) {
    if (!free_particles)
      return;
    p = free_particles;
    free_particles = p->next;
    p->next = active_particles;
    active_particles = p;
    p->die = cl.time + 0.3;
    p->color = colorStart + (colorMod % colorLength);
    colorMod++;
    ...

    p->type = pt_blob;
    for (j=0 ; j<3 ; j++) {
      p->org[j] = org[j] + ((rand()%32)-16);
      if (gore)
        p->vel[j] = (rand()%512)-256;
      else
        p->vel[j] = (rand()%1024)-512;
      }
    }
  }
}

7. Quake II

Quake II takes place in a science fiction environment
in the single-player game, the player is a human soldier
- known only by his alias, ’Bitterman’ taking part in ’Operation Alien Overlord’
- a desperate attempt to protect Earth from alien invasion by launching a counter-attack on the home planet of the hostile cybernetic Strogg civilisation
- most of the other soldiers are captured or killed almost as soon as they enter the planet’s atmosphere, so it falls upon the player to penetrate the Strogg capital city alone and ultimately to assassinate the Strogg leader, the Makron
- further reading

8. Technical aspects of Quake II

unlike Quake, where hardware accelerated graphics controllers were supported only with later patches, Quake II came with OpenGL support out of the box
the latest version is 3.21
- contains numerous bug fixes and new maps designed for multiple players death-match
Quake II uses an improved client server network model introduced in Quake
- the game code of Quake II, which defines all the functionality for weapons, entities and game mechanics, can be changed in any way because id Software published the source code of their own implementation that shipped with the game
Quake II uses the shared library functionality of the operating system to load the game library at run-time - this is how mod authors are able to alter the game and provide different gameplay mechanics, new weapons and much more
- originally just the shared library source code was released, eventually the code which loads the shared library game was released
technically Quake II is harder to modify than Quake as you have to be extremely careful where to add new variables
- are they declared in the shared library?
- or in the parent loader?
- or both?
full source code to Quake II version 3.19 was released under the terms of the GPL on December 21, 2001. Version 3.21 followed later.
since then several Third-party update projects to the game engine have been created
- the most prominent of these are projects focused on graphical enhancements to the game such as Quake2maX, EGL and Quake II Evolved
source release also revealed numerous critical security flaws which can result in remote compromise of both the Quake II client and server
most 3rd party engines include fixes for these bugs
the most popular server-side engine modification, R1Q2, is generally recommended as a replacement for the 3.20 release for both clients and servers
- the most widely used engine modifications as of 2006 appear to be R1Q2, AprQ2 and EGL, with a large majority of users still using the original 3.20 release
in July, 2003, Vertigo Software released a port of Quake II for the Microsoft .NET platform, using Managed C++
- it became a poster application for the language, showcasing the powerful interoperability between .NET and unmanaged C++ code

9. Ports

ports of Quake II were released in 1999 on the Nintendo 64 (ported by Raster Productions L.L.C. ) and PlayStation (ported by HammerHead Ltd.) console platforms
in both cases, the core gameplay was largely identical;
- however, changes were made to the game sequence,
- split-screen multiplayer replaced network or Internet play
SGI port was made in 1999 by Philip Nemec
- in 2002, the game was ported to the Amiga PowerPC platform by Hyperion Entertainment
there was also an unofficial port for the Sega Dreamcast,
- another port to Xbox, named Quake2X, and an unfinished port to Playstation 2 via homebrew coders

10. Nintendo 64 port of Quake II

the Nintendo 64 version, unlike the PlayStation version, had completely different levels and multiplayer maps which had never been seen before
this version also had new lighting effects, mostly seen on gun fire, and also used the expansion pack to offer extra graphical detail

11. Xbox 360 port of Quake II

ported version of Quake II was included in the box of Quake 4 for the Xbox 360 on a bonus disc
a direct port of the original game, and does not feature any graphical improvements, other than it may render in 480p and 720p
it does allow for System Link play for up to 16 players,
- split-screen for 4
- co-operative play in single player for up to 16 players or 4 with split-screen alone

12. Quake 2

has some of same weapons as Quake 1, and some new ones
- pistol, shotgun, super shotgun, Machine gun, Chaingun, Hand Grenade, Grenade Launcher, Rocket Launcher, Hyper Blaster, Railgun, BFG10K
- players can also throw grenades
recall that Quake had
- axe, shotgun, double-barreled shotgun, nailgun, supernailgun, grenade launcher, rocket launcher, thunderbolt
generally accepted that the multiplayer component of Quake 2 is much better than the single player game

13. Quake 2 Mods

there are so many, capture the flag, new skins, maps, deathmatch maps etc

14. Question

which of the three quake game engines begat this game engine?
- screencapture

Index

1. Coursework 2 support
2. Coursework Quake 1 texture modifications
3. Modifying the Darkplaces game engine
4. Some previous modifications to original Quake (not darkplaces)
5. Introducing gore into the original quake engine (not darkplaces)
6. Now for the fun... modify R_ParticleExplosion2 (not darkplaces)
7. Quake II
8. Technical aspects of Quake II
9. Ports
10. Nintendo 64 port of Quake II
11. Xbox 360 port of Quake II
12. Quake 2
13. Quake 2 Mods
14. Question
Index

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