/ (NOBODY): Code helper function
//
gentity_t *findradius (gentity_t *from, vec3_t org, float rad)
{
	vec3_t	eorg;
	int		j;

	if (!from)
		from = g_entities;
	else
		from++;

	for (; from < &g_entities[level.num_entities]; from++)
	{
		if (!from->inuse)
			continue;
		for (j=0; j<3; j++)
			eorg[j] = org[j] - (from->r.currentOrigin[j] + (from->r.mins[j] + from->r.maxs[j])*0.5);
		if (VectorLength(eorg) > rad)
			continue;
		return from;
	}

	return NULL;
}



void G_HomingMissile( gentity_t *ent )
{
	gentity_t	*target = NULL;
	gentity_t	*blip = NULL;
	vec3_t  dir, blipdir, temp_dir;

	while ((blip = findradius(blip, ent->r.currentOrigin, 2000)) != NULL)	{
		if (blip->client==NULL)			continue;
		if (blip==ent->parent)			continue;
		if (blip->health<=0)			continue;
		if (blip->client->sess.sessionTeam == TEAM_SPECTATOR)
			continue;

		if ((g_gametype.integer == GT_TEAM || g_gametype.integer == GT_CTF) &&
			blip->client->sess.sessionTeam == ent->parent->client->sess.sessionTeam)
			continue;
		//in old code,this ent->parent->cliend-> was blip->parent->client->,
		//so didn't work in CTF and team deathmatch.Now it will work.

		//if (!visible (ent, blip))
		//	continue;

		VectorSubtract(blip->r.currentOrigin, ent->r.currentOrigin, blipdir);
		blipdir[2] += 16;
		if ((target == NULL) || (VectorLength(blipdir) < VectorLength(dir)))
		{
			//if new target is the nearest
			VectorCopy(blipdir,temp_dir);
			VectorNormalize(temp_dir);
			VectorAdd(temp_dir,ent->r.currentAngles,temp_dir);	
			//now the longer temp_dir length is the more straight path for the rocket.
			if(VectorLength(temp_dir)>1.6)
			{	
				//if this 1.6 were smaller,the rocket also get to target the enemy on his back.
				target = blip;
				VectorCopy(blipdir, dir);
			}
		}
	}

	if (target == NULL)	{	
		ent->nextthink = level.time + 10000;
		// if once the rocket lose target,it will not search new enemy any more,and go away.
	} else {
		ent->s.pos.trTime=level.time;
		VectorCopy(ent->r.currentOrigin, ent->s.pos.trBase );
		//for exact trajectory calculation,set current point to base.
			
		VectorNormalize(dir);
		VectorScale(dir, 0.3,dir);
		VectorAdd(dir,ent->r.currentAngles,dir);
		// this 0.3 is swing rate.this value is cheap,I think.try 0.8 or 1.5.
		// if you want fastest swing,comment out these 3 lines.

		VectorNormalize(dir);
		VectorCopy(dir,ent->r.currentAngles);
		//locate nozzle to target

		VectorScale (dir,VectorLength(ent->s.pos.trDelta)*1.1,ent->s.pos.trDelta);
		//trDelta is actual vector for movement.Because the rockets slow down
		// when swing large angle,so accelalate them.

		SnapVector (ent->s.pos.trDelta);                      // save net bandwidth
		ent->nextthink = level.time + 100;	//decrease this value also makes fast swing.
	}
}