Q3 -changing the bot view angle

[gumstic]

Hi,

I'm trying to change the way a bot views in quake 3. I'm not sure whether the code I'm fiddling with is the right stuff.

ai_dmq3.c has a function to find an enemy and is also where some code is set for the bot viewing area (to see an enemy).

Does anyone know how to change this, because it seems a bit harder than I thought...



...a Q3Mod noob

[^misantropia^]

Counterquestion: why do you need to change the view angle? There may be different solutions, depending on what it is you are trying to accomplish.

[gumstic]

Ok,

The bot normally has a view angle of 90 degrees for detecting enemies, right?

I'm trying to make the non-view-angle (outside the 90 deg.) to be like a special "detection area" that the bot will use with specific fuzzy rules (events) to act upon when an enemy moves within this non-viewable area of the bot.

This will create more interesting "human-like" actions that the bot can make if being i.e. approached from behind.

Hope this sounds a bit more logical...

[^misantropia^]

Ah, you mean field of vision. A quick 'n' dirty solution:

1. Set the FOV for all bots to 360.
2. When a bot detects the player:
2a. Calculate the angle between the two, and
2b. Pick a course of action depending on the outcome of 2a.

Let me know if you need clarification or pointers.

[gumstic]

Hm, sounds feasible, but wouldn't that just switch (upon some detection) to a specific angle, or not? I may have something confused here...

Or should I be thinking at a "line" angle pointing strait to a direction the bot detects a player (around the 360 deg.), that way setting specific angles to reactions the bot would take for each case.

Am I on track ?

[^misantropia^]

Yeah, but allow me to explain a little as I took a shortcut with point 2a. You'll want the angle relative to the bot's current (2D) view angle. So if:

1. the player is at position (5, 5)
2. the bot is at position (10, 10), and
3. the bot is looking straight to the north (0 degrees clockwise), then
4. the player is at a 225 degree angle to the bot (south west), and hence not visible

Not visible, but perhaps audible. For extra spice, you can take other variables into account, like the distance between the player and the bot, the players view angle, direction and velocity. I hope I've made it a bit clearer, but if not, don't hesitate to say so.

[gumstic]

Excellent! I'll try it out and hope it works.

Thanks

[gumstic]

Ok, I'm trying to change the "fov" for the bots, but don't seem to be that simple.

The only logical place I see to add this "view feature" (board topic) is in the ai_dmq3.c
file within the "BotFindEnemy" function, but there's no "fov" here. The only thing that
could possibly be modified is:

Code: Select all

//check if the enemy is visible
vis = BotEntityVisible(bs->entitynum, bs->eye, bs->viewangles, f, i);
if (vis <= 0) continue; 

BotEntityVisible is declared as: (int viewer, vec3_t eye, vec3_t viewangles, float fov, int ent).
So this means the "f" is poiting to the "fov", but is a little confusing and I don't fully
understand it and also whether I'm working in the right spot or not .

Any help appreciated...

[^misantropia^]

Patch the InFieldOfVision() function in ai_dmq3.c so that the fov is always 360. Thousands of refactoring consultants are crying out in horror now, but don't let that bother you.

[gumstic]

oh, yes I'm sure of that, but if we think that it has been written quite a long
time ago, I will just lay back refactoring.

Ok, I tried changing the InFieldOFView to always see 360. I think its working. Now for
my next step I added the following to the "findEnemy" function, but don't think it works
correctly. It notes the Print output once for 270 (which is a test degree), but not
sure if it works properly.

Here's what I messed with:

Code: Select all

//check if the enemy is visible
		vis = BotEntityVisible(bs->entitynum, bs->eye, bs->viewangles, f, i);
		if (vis <= 0) {
            BotAI_Print( PRT_MESSAGE, "AGENT SAYS: Enemy is detectable.\n"); //gmod	
		continue; 
		}
		detect = findradius (detect, bs->enemyorigin, 270);
		if (detection = 270) 
			BotAI_Print( PRT_MESSAGE, "AGENT SAYS: Enemy is detected at 270.\n"); //gmod

Now, findradius is a function that calculates the radius between 2 objects (hopefully)
and so I just set that to get some feedback from the screen if it matches when the
player is 270 deg. towards the bot.

Making any sense

[^misantropia^]

Code: Select all

if (detection = 270)

Classic error. You are doing assignment instead of comparison here (that is, you're setting detection to 270). This is what you are after:

Code: Select all

if (detection == 270)

I take it findradius() is a function you wrote? Could you post its source?

[gumstic]

That's right, it's a plugged-in function sitting in the g_utils.c file in the Game project and the code is originally from the book "Mod programming in quake III arena" (by Shawn Holmes), here it goes:

Code: Select all

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;
}

[gumstic]

I don't seem to get any sign that this is working...

one question: how could I display a variable to the screen. I'm trying with this
radius but, I can only get the memory address output. What should I put to get the
actual value of the variable output ?

thx

[AnthonyJ]

I'm trying with this radius but, I can only get the memory address output.

... and that is why its not working. The findradius function doesnt return you a distance to another entity, its for finding any entities that are within the radius. The return value is the pointer to the entity it found.

I'd suggest you avoid using functions like that which you don't understand - either write your own function which does what you want, or try to understand the what the findradius func does, and use that the way it was intended.