GameDAILY.com

Code3Arena

TUTORIAL 7 - Cloaking
by AssKicka

Teach those bots a lesson, Predator-style !
Let's add a nice cloaking feature that also decrements the players health while cloaked.

1. ADDING A NEW ENTITY FLAG.

First we are going to add a new entity flag called FL_CLOAK that we will use to activate and deactivate our cloaking. Open up g_local.h and add the code bellow after line 32.

#define FL_NO_HUMANS       0x00004000     // spawn point just for bots
#define FL_CLOAK               0x00010000     // health cloaking

2. CREATING A NEW CONSOLE COMMAND.

Open up g_cmds.c and add the code bellow after line 1022

/*
=================
Cmd_Cloak_f
=================
*/
void Cmd_Cloak_f( gentity_t *ent ) {

	char *msg; // message to player

	ent->flags ^= FL_CLOAK;

	if (!(ent->flags & FL_CLOAK)) {
		msg = "Cloaking OFF\n";
		ent->client->ps.powerups[PW_INVIS] = level.time;
		// Removes the invisible powerup from the player
	}        
	else {
		msg = "Cloaking ON\n";
		ent->client->ps.powerups[PW_INVIS] = level.time + 1000000000;
		// Gives the invisible powerup to the player
	}

	trap_SendServerCommand( ent-g_entities, va("print \"%s\"", msg));
}

All we did here is create a new function that is called when you use the /cloak command that we will be adding bellow. This function will change the current state of FL_CLOAK, activate/deactivate the invisible powerup and print a relative on/off message to the player.

What the hell is "level.time + 1000000000" ? What we are doing is making the invisible powerup last for 1666 minutes. We don't really need it to last that long because we will be decrementing the players health until it reaches 10 and then auto deactivating cloaking.

Now we must add the /cloak console command and get it to call the function we created. Goto line 1095 and add the code bellow

else if (Q_stricmp (cmd, "setviewpos") == 0)
	Cmd_SetViewpos_f( ent );
else if (Q_stricmp (cmd, "cloak") == 0)
	Cmd_Cloak_f( ent );

3. MAKING THE CLIENTS HEALTH DECREMENT WHILE CLOAKED.

We will now make the players health decrement every second while cloaking is enabled. open g_active.c and goto line 397 in ClientTimeActions. This function will be called once every second, making it perfect for our cloaking feautre. Modify the existing code 

// count down health when over max
if ( ent->health > client->ps.stats[STAT_MAX_HEALTH] ) {
	ent->health--;

to match the following code :

if (!(client->flags & FL_CLOAK)) {
	// count down hea