How to do correct movement

[SteveC]

To get the bots to move correctly in my plugin, http://forums.bots-united.com/showthread.php?t=3366 , I used the following function;

void CBasePlayer:: ProcessUsercmds( CUserCmd *cmds, int numcmds, int totalcmds,
int dropped_packets, bool paused )

To get to this you need to get the CBasePlayer pointer, which I did with the following code;

// entity index
iBotIndex=ENTINDEX(pEdict);
// base entity
pBaseEnt = CBaseEntity::Instance(pEdict);
// get the player entity
if ( pBaseEnt && pBaseEnt->IsPlayer() )
{
pPlayerEnt = static_cast< CBasePlayer * >( pBaseEnt );
}
if (!pPlayerEnt) return false;

Where pEdict is the bot edict_t, pBaseEnt is a CBaseEntity pointer, and pPlayer is the CBasePlayer pointer. I can't remember which files I needed to include to get this to work, but I think it was 'cbase.h' as it links to most things.

[SteveC]

To build the CUserCmd I used the following code;

// look
if (pClosestEnemy)
{
// look at enemy
Vector vAim=vClosestEnemy-pBaseEnt->EyePosition();
VectorAngles(vAim, mBotCmd.viewangles);
}
else if (tFront.fraction<0.5f)
{
mBotCmd.viewangles.y+=90.0f+((float)rand() / RAND_MAX) * 180.0f; // turn 180 (ish)
}
else if (tLeft.fraction<0.5f)
{
mBotCmd.viewangles.y+=22.5f+((float)rand() / RAND_MAX) * 45.0f; // turn +45 (ish)
}
else if (tRight.fraction<0.5f)
{
mBotCmd.viewangles.y-=22.5f+((float)rand() / RAND_MAX) * 45.0f; // turn -45 (ish)
}
// forward
if (pClosestEnemy)
{
mBotCmd.forwardmove=0.0f; // stop to shoot at enemy
}
else
{
mBotCmd.forwardmove=200.0f;
}
//shoot
if (((float)rand() / RAND_MAX)>0.97)
{
mBotCmd.buttons|=IN_ATTACK;
}
else
{
mBotCmd.buttons&=~IN_ATTACK;;
}
//jump
if (((float)rand() / RAND_MAX)>0.97)
{
mBotCmd.buttons|=IN_JUMP;
}
else
{
mBotCmd.buttons&=~IN_JUMP;
}
// issue the command
pPlayerEnt->ProcessUsercmds(&mBotCmd,1,1,0,false);

[SteveC]

The most critical part to get them to turn, and move the way they are facing is to use this line of code;

// this changes the fixangle from absolute (which isn't coded for) to none
// note: has to be run here because it doesn't work in the addbot routine?!?!?
if (pPlayerEnt->PlayerData()->fixangle!=FIXANGLE_NONE) pPlayerEnt->PlayerData()->fixangle=FIXANGLE_NONE;

As the comment says the bots by default use FIXANGLE_ABS, but the HL2 movement code isn't coded to support that type, so I change it to FIXANGLE_NONE. However I haven't worked out exactly where it needs to be changed, so I check it each frame before issuing the movement command. A bit of a bodge I know .

I think that's everything to get the correct movement, with full animation, physics interaction, and possibly ladder use.

I'll post my full code sometime tomorrow probably, just incase I've missed something.

[Cheeseh]

How did you manage to compile with CBasePlayer ? The server & plugin builds are different and don't allow having cbasePlayer/CBaseEntity defined because there are hundereds of compile errors when I try. When I also contacted Alfred (valve) he said you cannot access these in plugins and so did botman, so please share your 'secret'

(ps: I'm sure all of us would be intrigued to know)

[SteveC]

I'm no C++ linker expert (if you know someone who is, let me know ), so I don't know what I did that is special. I think the main difference between my plugin and the sample one is that I included cbase.h.
I cannot access all the functions of the CBasePlayer, I get compile errors with many, and if include baseplayer.cpp in the project then all hell breaks loose as you say.
One thing I did find was that the class CBotManager is a friend class to CBasePlayer, I think that means you can then access private variables of CBasePlayer. However there is no CBotManager defined anywhere in the SDK, so I define one, but it doesn't seem to help much so I don't know if just defining a class of the right name is enough to become the friend. It could be useful in the future, but you don't need it to do what I'm doing now.

Also I found out how to use the Vector class routines (includes the pesky fast sqaure root), you just need to include the mathlib, but then I got exceptions because it wasn't initialised. Initialising it lets it all work, but surely it must be already initialised for the main engine? I just found it a bit strange.

Anyway attached is the source for the current build now it's been tidied up. There are still many problems to solve, like how to find enemies.

[stefanhendriks]

very interesting. I already had my own way of 'moving to a direction'. I am particularry interested in the aiming part of the bot. I want to do it as much the 'less hacky' way as possible.

I'll see if i can access cBaseEntity without hacking to much around. The above code looks a lot less hacky then the one i saw before... unless i am mistaken of course.

[SteveC]

No hacking in the code, well not intentionally anyway. The worst thing is casting the CBaseEntity to the CBasePlayer, but that was copied directly out of valves code.

I hope it works for you too, otherwise I've no idea what I've done to get it to work. o_O

[stefanhendriks]

well, i wonder if it will still work after a change in CSS, or that you have to recompile or whatever. Because that is my main concern, the continuity of a project

[@$3.1415rin]

looks like the only problem would be if a mod would change the CBasePlayer class, but as I already wondered in HL1, why shouldnt this be done by inheritance ? I mean, if nobody would change it, everything would be fine, but in HL1, almost everyone did ...

[SteveC]

Am I correct in assuming that it would only be a problem if they changed the number/definitions of the functions, they can change the content of the functions and it would be fine? Also you can still get to alot of stuff from the CBaseEntity, but I guess they could change that too, if they were really determined.