Maratis Chess

Today I have studied a bit the uci interface.
UCI compatible chess engine are standalone programs that works with commands throught stdin / stdout.
I will need two half-duplex connection between maratis and the chess engine process.
Lua can't handle a half-duplex interprocess connection so I need to implement, two lua functions
1 - lua function for sends commands from maratis to the other process throught the stdin of the receiver
2 - lua function that receive the stdout of the other process

Do you think that's gonna be painfull?

it should not be too complicated.
you can add a function using the script context.

after a lot of work between nigth and morning I have created a plugin that can interact with an external program throught the stdin/stdout

here is the code...
The tricky part was finding a way to create a fullduplex communication system between two process throught stdin/stdout

Hope this helps someone

#include "ChessEngineInterfacePlugin.h"
#include <MEngine.h>
#include <sys/types.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <poll.h>

#define READ 0
#define WRITE 1

int infp, outfp;
char buf[4096];
struct pollfd ufds;

/** Interprocess comunication throught stdin/stdout */
pid_t
popen2(const char *command, int *infp, int *outfp)
{
    int p_stdin[2], p_stdout[2];
    pid_t pid;

    if (pipe(p_stdin) != 0 || pipe(p_stdout) != 0)
        return -1;

    pid = fork();

    if (pid < 0)
        return pid;
    else if (pid == 0)
    {
        close(p_stdin[WRITE]);
        dup2(p_stdin[READ], READ);
        close(p_stdout[READ]);
        dup2(p_stdout[WRITE], WRITE);

        execl(command, command, NULL);
        perror("execvp");
        exit(1);
    }

    if (infp == NULL)
        close(p_stdin[WRITE]);
    else
        *infp = p_stdin[WRITE];

    if (outfp == NULL)
        close(p_stdout[READ]);
    else
        *outfp = p_stdout[READ];

    return pid;
}

int readChessEngineOutput(){
    int rv;
    rv = poll(&ufds, 1, 1);
    if (  rv > 0 ){
        read(outfp, buf, 4096);
        printf("%s",buf);
    }
    return 0;    
}

int sendCmdToChessEngine()
{
    printf( "write to chess engine" );
    write(infp, "uci\n", 4);
    return 0;    
}

int initChessEngine()
{
    if (popen2("./Linux/rodent-32-ja", &infp, &outfp) <= 0)
    {
        printf("Unable to exec sort\n");
    return -1;
    }
    *buf = '\0';    
   ufds.fd = outfp;
   ufds.events = POLLIN | POLLPRI;

   printf("Chess engine link started");
   return 0;
}

void StartPlugin(void)
{
   MEngine * engine = MEngine::getInstance();
   MScriptContext* script = engine->getScriptContext();

   initChessEngine();

   script->addFunction("initChessEngine", initChessEngine);
   script->addFunction("readChessEngine", readChessEngineOutput);
   script->addFunction("commandChessEngine", sendCmdToChessEngine);
}

void EndPlugin(void)
{
    close(infp);
    close(outfp);
}

Hi heartseed!
Thanks for the consideration !!!

(You re an artist! So you can help me with graphics!!! XD)

Thanks for trying the game! At the moment it works only on linux, bring it to windows and macosx soon...
Actually I'm a coder and I'm pretty confident with maratis system.
Before of maratis I used many other engines so I'm not so new to game ambient...
At the state of art the game took me about 12 hours.

I haven't uploaded yet the latest version, cause it works only on linux at the moment.
I will finish it on linux, then port it to windows and then to macosx.

The pre-pre-pre-alpha version haven't the AI integrated yet.
Lua based AI are too weak beacuse lua is a bit slow for intensive computation.
So I have integrated C based strong AIs with UCI.

I will upload tonight the 0.1 version I'll try to port it on windows.
I haven't done it yet on windows cause I have to compile C plugin on windows,
I'm not sure if windows has all the library that I used in C
or if they are linux-specific libraries.

The problem of making a game is that we always overthink about what to do
we are atracted by big titles and we want to make big-title-games too...
in the end we finish with too much work to do and... give up...
I think that you should go with simple projects espacially if you are all alone to work on it...

Anyway hope you'lll give a try to my game soon
I'll upload it asap!

Actually I love maratis cause you can do more with less...
If you use complex libraries, it's painfull to learn everything, even simple things takes a lot of work...
maratis is very easy and usually most common things has a lua function,
and anyway having a tool like the maratis editor makes the job done faster.

All libraries in maratis are already togheter: audio, graphics and physics... this make it a complete game engine

So why do I like maratis?
-cause is _easy_ ,
-is fast for _prototyping ideas_
-no complex setup, just download the zip e start lua code
-perfectly compatible with blender ( which works good on linux )
-easy plugin system to extend the game engine with new funcitons
-good builtin editor

Last edited by SadWolf (2013-08-29 20:36:25)

It was a long time ago when I used it. Hopefully it is much better. It looked like Doom 95 then. hehe

I am going to play around with this and add another board style (maybe several) and perhaps an environment? We will see.

First one:

Need to get my normal map working though.

Last edited by Tutorial Doctor (2013-12-07 04:47:03)

That is the thing about Maratis, Marstis meshes can't be edited directly. Id have to have the original 3d files, and then open them in blender. Also, each one would have to be rigged because Maratis only accepts armature animation and not key frame animation.

I thought about using ASSIMP, but I have not been able to get an animated collada file out of Blender (I think the ASSIMP importer can handle animated collada files, but I'm not sure if Maratis can).