communication between two plugins

[commonbullet]

I was wondering how could I establish communication between an amxx plugin and a metamod plugin - more precisely, an amxmodx plugin sets the game rule and a metamod bot should be aware about what's going on in the match.

It's been suggested that I could use engine messages, but I lack of understanding the mechanism.

I guess those messages have fixed sequences of parameters for each type of "event". I couldn't find where/how they are set in hlsdk, all I found was about SVC_TEMPENTITY.

Can I use a custom sequence of parameters and just return supercede?
Otherwise, if I would only be able to use existent messages patterns, wouldn't that be confused with 'real' engine messages.

I'd appreciate any information you could provide.

[KWo]

If You are using "standard" AMX X / AMX natives, they are using HL messages only AMX X / AMX with its plugin can hook, because metamod blocks them to intercept by other mm plugins.
Example:

static cell AMX_NATIVE_CALL cs_set_user_team(AMX *amx, cell *params) // cs_set_user_team(index, team, model = 0); = 3 params
{
    // Set user team
    // params[1] = user index
    // params[2] = team
    // params[3] = model = 0

    // Valid entity should be within range
    CHECK_PLAYER(params[1]);

    // Make into edict pointer
    edict_t *pPlayer = MF_GetPlayerEdict(params[1]);

    int model = params[3];

    // Just set team. Removed check of 1-2-3, because maybe scripters want to create new teams, 4, 5 etc?
    *((int *)pPlayer->pvPrivateData + OFFSET_TEAM) = params[2];
    if (model != 0)
        *((int *)pPlayer->pvPrivateData + OFFSET_INTERNALMODEL) = model;
    
    // This makes the model get updated right away.
    MDLL_ClientUserInfoChanged(pPlayer, GETINFOKEYBUFFER(pPlayer)); //  If this causes any problems for WON, do this line only in STEAM builds.

    // And update scoreboard by sending TeamInfo msg.
    char teaminfo[32];
    switch (params[2]) {
        case TEAM_UNASSIGNED:
            strcpy(teaminfo, "UNASSIGNED");
            break;
        case TEAM_T:
            strcpy(teaminfo, "TERRORIST");
            break;
        case TEAM_CT:
            strcpy(teaminfo, "CT");
            break;
        case TEAM_SPECTATOR:
            strcpy(teaminfo, "SPECTATOR");
            break;
        default:
            int team_nr = (int)params[2];
            sprintf(teaminfo, "TEAM_%i", team_nr);
    }
    MESSAGE_BEGIN(MSG_ALL, GET_USER_MSG_ID(PLID, "TeamInfo", NULL));
    WRITE_BYTE(params[1]);
    WRITE_STRING(teaminfo);
    MESSAGE_END();
    
    if (params[2] == 1)
        MF_SetPlayerTeamInfo(params[1], params[2], "TERRORIST");
    else if (params[2] == 2)
        MF_SetPlayerTeamInfo(params[1], params[2], "CT");
    else
        MF_SetPlayerTeamInfo(params[1], params[2], NULL);

    return 1;
}

As You can see cstrike.cpp uses MESSAGE_BEGIN...MESSAGE_END scheme. Using this function casues metamod bots wouldn't get the teaminfo message, because metamod doesn't allow it to send to other mm plugins. But if You would write Your own function in sma script

cs_set_user_team2(id, team, modelname[]); 
{
    // Set user team
    // params[1] = user index
    // params[2] = team
    // params[3] = modelname

    // Valid entity should be within range

    if (!is_user_connected(id))
        return PLUGIN_HANDLED
    
    set_pdata_int(id, OFFSET_CSTEAMS, team, OFFSET_LINUX)

    // And update scoreboard by sending TeamInfo msg.
    new teaminfo[32];
    switch (team) {
        case TEAM_UNASSIGNED:
            strcpy(teaminfo, "UNASSIGNED");
            break;
        case TEAM_T:
            strcpy(teaminfo, "TERRORIST");
            break;
        case TEAM_CT:
            strcpy(teaminfo, "CT");
            break;
        case TEAM_SPECTATOR:
            strcpy(teaminfo, "SPECTATOR");
            break;
        default:
            int team_nr = (int)params[2];
            sprintf(teaminfo, "TEAM_%i", team_nr);
    }
    EMESSAGE_BEGIN(MSG_ALL, GET_USER_MSG_ID(PLID, "TeamInfo", NULL));
    EWRITE_BYTE(params[1]);
    EWRITE_STRING(teaminfo);
    EMESSAGE_END();

    // This makes the model get updated right away.
    set_user_info( id, "model", modelname )
    
    return PLUGIN_CONTINUE;
}

I hope that example describes clearly what You need to do in AMX X to inform bots about the info You are sending to other AMX X plugins.

[commonbullet]

Thanks KWo, I understand now why engine messages should be sent instead.

But wouldn't these messages be confused with "real" game messages anyway?
I mean, suppose csflags plugin (an amxx plugin that adds "capture the flag" gameplay to cs) would send a message every time a flag is captured so bots (metamod) would be aware of the event. If it used an existent message like teaminfo or whatever, wouldn't that cause some mess in game?

[KWo]

Everytime You want to send a HL message You need to know what it is for the game. If it's only some visual effect meesage, it cannot destroy the gameplaying. If it's changing something for players (because HL messages sent by AMX X can hit players; they only cannot hit other mm plugins - including mm bots) - and You know what is happening for them - just the same will happen for bots.
Hint
Test first the plugin normal way (with HL messages sent normal way by AMX X) on CZERO bots. Metamod doesn't block (it just cannot) sending the messages to them. If everything is OK - You can try to convert the plugin to use emessages.

More than likely the bots will not react on Your flags at all, since they don't know what such flags are for (there is no code in bots to react on such things, I guess)...

[commonbullet]

Originally Posted by KWo

More than likely the bots will not react on Your flags at all, since they don't know what such flags are for (there is no code in bots to react on such things, I guess)...

I'm planning to code something in bot part to hook those messages and see if I manage to make them "skilled" to play csflags. (that's why I can't use csbots).

So, if it used a visual message just like you said (mostly tempentity messages), bots should still be able to distinguish those messages from "real" engine messages. I suppose these messages should contain a special value in a parameter so bots would know they're coming from csflags plugin (?).

[KWo]

They will not know where this message is coming from, so You don't need that extra info include there (even no way to tell that). I wish You good luck with this, but I don't think You will be finally happy. The bots are really stupid and You need to put also the "AI" to the code so they can react on the messages You are going to send them. They don't have eyes, they are using tracelines and tracehulls to "see" obstacles or objectivities.

[commonbullet]

About the amxx->metamod plugin communication, I've done some tests and it works fine so far.

Originally Posted by KWo

I don't think You will be finally happy. The bots are really stupid and You need to put also the "AI" to the code so they can react on the messages You are going to send them. They don't have eyes, they are using tracelines and tracehulls to "see" obstacles or objectivities.

To make things worse, I've no experience with bot coding. But it's not so hard, at least at the level you're assuming, I hope.

Luckily csflags plugin stores lots of information in the flags entities (I was trying to avoid abusing from global variables in amxx).

So basically I would add some "objectives waypoints" (thoses flags are fixed just like in dod), and try add some "extra behavior" to an existent bot; I wouldn't have to code the hardest parts ...

[commonbullet]

Just in case someone faces the same problem in counter-strike - CZCareer messages are very useful for this purpose since they have no effect in multiplayer matches. The first argument must be a string, then you may format the message as you like.