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[MODDING] Your first Sauerbraten MOD, Tutorial 1

by liquido on 11/15/2007 17:05, 77 messages, last message: 06/29/2010 07:30, 67688 views, last view: 05/18/2024 21:19, closed on 06/29/2010 09:29

[MODDING] Your first Sauerbraten MOD, Guide 1
---------------------------------------------
by liquido (jose.tapadas@yahoo.com)

(btw: i'm new to this forum :) ]

»»» [1]: INTRO:
===============

After googlin', searching and looking on the documentation I've noticed that there is a lot of spread information and nothing that a noob (must like me) could get as a platform to start coding for this great game engine, so I decided to write this guide so a modder-to-be could have some base to start on.
ATTENTION: Basic C/C++ knowledge required (if you don't know much don't worry!)

»»» [2]: THE TOOLS:
===================

Well as you know the Sauer is coded in C/C++ so in order to change something on it we need:

1. A C/C++ compiler:
Assuming you are using windows I recommend MinGW - Minimalist GNU for Windows, which has the Linux GNU tools all included on a win32 package
2. A C/C++ IDE (in order to help you browse through the code of Sauer and your mod.
3. Sauerbraten source code and engine (http://sauerbraten.org/)

To get all of this CodeBlocks has a package with all included:

Code::Blocks IDE, with MINGW compiler, Filesize: 13,597,181 Bytes | Version: 1.0rc2
download »» http://prdownloads.sourceforge.net/codeblocks/codeblocks-1.0rc2_mingw.exe?download

Now you need to configure the compiler so you can access it from any location and not only the MiniGW dir, so open Control Panel > System > Enviroment Variables search for "PATH" choose edit and add on the end of it ";C:\Program Files\CodeBlocks\bin".

»»» [3]: YOUR FIRST COMPILED SAUER:
===================================

On Sauer folder we have a well organized dir-structure so, with a little bit of inspection you can easily figure that we have a bi(nary) folder (with the game executable) and a src (source code folder). On this folder we wanna focus on 3 folders engine, fpsgame, rpggame.
It's not hard to figure that "engine" contains the Sauer game-engine (which contains the game physics, graphical rendering, etc..), fpsgame and rpggame contains both the fps and rpg game modes (or MOD's) which are included on Sauerbraten package.
Lets prepare a modding workspace on our engine, start by creating a new folder called "modgame" and copy into it all of the contents of the folder "fpsgame". We are going to mod the fps mode of Sauerbraten. Go inside your new folder and open all the .CPP and .H files with CodeBlocks. Go to "Search > Replace" and replace "fps" for "mod" on ALL FILES of that folder (when i say ALL I say ALL or it won't work!), save your progress and close CodeBlocks.
Still inside "modgame" rename "fps.cpp", "fpsserver.h" and "fpsrender.h" to "mod.cpp", "modserver.h" and "modrender.h".
Go back to the ..\src\ and go into mingw folder. Now create a copy of the "lib" folder and rename it to "lib.mingw", copy this folder into the ..\src\ folder. Copy the "MakeFile.mingw" into ..\src\ and "make.mingw.bat" into your Sauerbraten main dir (i.e. C:\Program Files\Sauerbraten).
Let's take a breath here to explain things:

* as you have noticed we are creating a new gamemode called "mod", based on the fps gamemode included on Sauer.
* on Sauer, fps and rpg modes, the gamemode binary is coded on "gamemode.cpp" (fps.cpp and rpg.cpp) and all the features are divided in something we call module coding, modules, weapons features on weapons.h, client features on client.h, all of them included on fps.cpp or rpg.cpp.
* if you are into the oo programming you will find interesting that all of the entities, actions and stuff on Sauer are divided into C/C++ classes which makes it very simple to develop.
* if you are not realy into OOP just forget (for now) the * above.
* the make file is something very usefull when programming very large projects with multiple files and compiler flags so it's a script who makes it for us.

We have created a mod workbench based on the fps game mode so lets include it on our makefile as a group ou files to compile, open the MakeFile.mingw and add just before of:

rpggame/rpg.o

the line:

modgame/mod.o \

To remove a compiling error on Sauerbraten scroll up and remove the line which adds:

engine/crypto.o \

(a feature removed from the cube time)

Save the MakeFile and close it. You are now ready to compile your mod and Sauer.
Run the "make.mingw.bat" and you should see somthing like this:

------------

C:\Program Files\Sauerbraten>cd src

C:\Program Files\Sauerbraten\src>mingw32-make all -fMakefile.mingw
g++ -O3 -fomit-frame-pointer -Wall -fsigned-char -Ienet/include -Iinclude -Ishar
ed -Iengine -Ifpsgame -o ../bin/sauerbraten-mingw.exe shared/tools.o shared/geom
.o engine/3dgui.o engine/bih.o engine/client.o engine/command.o engine/console.o
engine/cubeloader.o engine/grass.o engine/lightmap.o engine/main.o engine/mater
ial.o engine/menus.o engine/normal.o engine/octa.o engine/octaedit.o engine/octa
render.o engine/physics.o engine/rendergl.o engine/rendermodel.o engine/renderpa
rticles.o engine/rendersky.o engine/rendertext.o engine/renderva.o engine/server
.o engine/serverbrowser.o engine/shader.o engine/sound.o engine/texture.o engine
/water.o engine/world.o engine/worldio.o fpsgame/fps.o modgame/mod.o rpggame/rpg
.o -Lenet -Llib.mingw -lstdc++ -lenet -lmingw32 -lSDLmain -lSDL -lSDL_image -lSD
L_mixer -mwindows -lfmod -lz -lopengl32 -lglu32 -lws2_32 -lwinmm
strip ../bin/sauerbraten-mingw.exe

C:\Program Files\Sauerbraten\src>PAUSE
Press any key to continue . . .

-------------

Which means that everything went right!
Create a .BAT file called "mod.bat" on Sauer's main folder with the line :

bin\sauerbraten-mingw.exe -gmod

Save it.
This -gmod tells Sauer to run the game "mod".
Run it and....voila, your first mod!
Not very exciting because it's exacly the same that the fps mode but just have patience, you have compiled your first early-stage pseudo mod!

»»» [3]: YOUR FIRST MOD:
========================

Ok, lets do a actual MOD to the game.
Go to your mod's source folder (\src\modgame) and find a file called "weapon.h", open it!
As you can see from the first comment line:

// weapon.h: all shooting and effects code, projectile management

So this is the file where you find all the event handling, modeling and mumbojumbo when we are talking about weaponery stuff on Sauer. Search for the function:

void shoot(modent *d, vec &targ)

As you imagine this is the function which handles what to do when you fire your weapon on your game, so let's do some little moding.
On Sauer (and on most game engines, quake, source, doom, you name it!) we have something called entities which is basically everything that is interactive within the game, being it monsters, pick-ups, lights and even yourself the player, and on this shoot function we pass modent *d, which is a pointer to the entity who shoot's the weapon (so *d = (points) to ourselves for what we are concearned) and the vector &targ to the target of our shooting craziness. So lets mess up..cof...mod a little bit, scroll down until you find the line:

if(d->gunselect) d->ammo[d->gunselect]--;

Which is pretty much self explainatory, you d (ourselves) shoot go to the weapon ammo slot and dec. (--) by one ammo piece. Change it to:

if(d->gunselect) d->ammo[d->gunselect]++;

And this obviously will increase the ammo everytime you fire.
Save "weapon.h", run the "make.mingw.bat", then run your "mod.bat" and start shooting...free ammo on every trigger press!
I know this is very basic but it's a very important step on your journey as a modder ;)
Congratulations your first (micro) Sauerbraten MOD is complete.

Cumps, liquido... ;]

[keywords: mod, modding, Sauerbraten, tutorial, coding, develop, guide, noob, compile]

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#1: ..

by MovingTarget on 11/15/2007 17:36

Hehe, nice tut man! I started out pretty much the same way, except I didn't touch the makefiles! I just open src/mingw/sauerbraten.cbp in code::blocks, and click build/build. Nice little guide though!