Enemy Visibility In Accordance To Lighting?

[woah]

I was just curious how the team plans to go about enemy visibility in accordance to lighting. Will there be preset areas of darkness as in the Thief series? Will the darkness intensity be based on the Doom 3 engine's dynamic lighting? I know there will be a light gem, but will the light gem be a representation of the model's visibility, or will the light gem's visibility factor be of itself with the assumption that the player model visibility will be adequate to the light gem's?

 

I also noticed that in Doom 3 there was never really any different intensities to light--there was hard black or plain light. Is this modifiable?

Edited July 12, 2005 by woah

[sparhawk]

The lightgem is a representation of the visual awareness that a real person would have. Of course a real person wouldn't need this, because it is pretty well aware about it's surroundings, but this is not so obvious in a game environment. The value that the lightgem shows is derived from the actual light the mode receives in a given frame.

 

As for D3 lighting. Of course you can have all kind of light intensities, but shadows will be hard always, because softshadows are way to performance intensive for current machines. There was a testmap with the T3 engine on TTLG which tried to create softshadows, but this was using 16 lightsources. Needles to say that such a map is not playable. Even though D3 is much more effecient then the T3 engine, this would be the same.

[Springheel]

Soft shadows just refers to the edges of the shadow itself, and yes, it's difficult to make the edges fuzzy. But shadows in D3 don't have to be full-black. It is possible to place soft ambient lights so that your shadows will be various shades of grey.

 

If you check out this thread: http://www.doom3world.org/phpbb2/viewtopic.php?t=10469 you'll see that there are plenty of shadows that are not pitch black.

[Fingernail]

You can achieve some fuzzyness, however, but using lightextures which are projected. They can be used to create, among other things, the shadows of grilled lights, irregular light beams, etc.

[Domarius]

But... aren't dynamic light sources the ones that cast hard-edged shadows?

 

If you put a normal light in a Doom 3 room, the fall-off is soft, like real life, it gets darker the further away you go from the light.

[Fingernail]

That's for all lights in D3. That's not softness. The EDGE of the shadow is still hard, but the darkness has a falloff like a gradient.

[sparhawk]

That's wrong. All the lights are using projection textures which create the soft falloff. You can use this also for a dynamic lightsource. IMO in D3 (the game) most of the lights were artificial lights and therefore had a very crisp and hard shadow as well, but this has nothing to do with them being dynamic lights or not.

[Fingernail]

Just FYI both sparhawk and I are referring to Domarius' post (I guess )

[sparhawk]

Yes. The last post from me at least.

[DopeFishhh]

I'm assuming that you are taking the thief route of visibility where, contrast is ignored and current player illumination is the deciding factor.

[Domarius]

Spar implemented an awesome light gem which also looks at the falloff texture to get the value of how lit the Thief is, so even though the falloff is done with a texture and the actual light is hard edged, as far as the light gem is concerned the fall off is real

 

Oh I see what you mean - you mean sillhouette instead of contrast right? Then the answer is yes. Guards won't see your dark form if you are in shadow but the background is bright (creating a sillhouette). You are in shadow and that's the end of it.

[Springheel]

Well, that remains to be seen, Dom. Silouhettes are on our list of things to explore...there's no guaruntee we'll be able to do them, but there are some ideas on the drawing board.

[DopeFishhh]

well assuming that you could figure out code to check silouettes you could use a line of sight check to optimise it's usage.

 

but there's another problem of that once you go the silouette route the light gem doesn't represent enough information. because you might be in darkness but when contrasted you can be seen easily. but the contrast will depend on a guards perspective, so how do you represent perspective based contrast? could modify the brightness of the gem as to indicate that you are contrasting, the more you contrast and the more directions you contrast in the brighter it gets.

 

or you could simply ignore it and require the player remember the bright spots around him and avoid contrasting.

 

oo, nightmare mode: no light gem

[sophisticatedZombie]

How about this: (creating new work for everyone)

 

The player chooses his/her getup in the store. Each cloak has a contrast value associated with it.

 

Each material can have either a sampled, or tagged constrast value assigned to it (black and white detection in the eye is more sensitive than color detection in low-light conditions). The clothing contast value is compared to the texture contrast valueif the surface beyond the player along the line of sight. The "light gem" could have an outer ring that shows the contribution to the light gem brightness caused by visible contrast with the most different of the surrounding surfaces.

 

Essentially, a simple way to do it would be to raycast out in the 6 directions of a cube from the player and see what the worst contrast would be (other than up?) and then have a second part of the light gem that included that information.

 

Perhaps even cloaks could be a piece of equipment. ie, switch from the green cloak to the brown cloak when going inside....

 

Ok, now I'm preparing myself for the fashion model jokes.

[OrbWeaver]

How about this: (creating new work for everyone)

 

Not only that, but it would make the game a lot more difficult - unnecessarily so in my opinion. There is such thing as too much realism.

 

One thing I have been wondering about visibility is the relationship between the light gem and r_shadows. If you have shadows turned off, will the light gem be affected or is the visibility code independent of that of the renderer?

[obscurus]

I hope no one would actually play the game with the shadows off, and I hope that the visibility code does depend somewhat on the renderer so that people don't have that sort of cheat available to them... That would utterly defeat the purpose of playing a shadowy stealth game... I do hope a computationally affordable method can be found to take sillhouettes into account... That would really make a difference to me at least

 

Don't forget about AMBIENT LIGHT people, that is the big advantage of lightmaps, they help to give you a more realistic set of shadows, because you can do a realistic global illumination calculation with radiosity or photon mapping. Downside is they aren't dynamic. I guess realtime radiosity is still a while away, but you can simulate it to a degree in Doom 3 with careful use of ambient lighting and non-shadowing fill lights. Unless your map is set deep underground, there will always be a tiny bit of ambient light in a room, even if there are no obvious light sources, so always make sure you adjust ambient lighting in each room to an appropriate level.

 

Does the Doom 3 engine allow you to trigger ambient light levels with a script, so if you doused a torch or switched an electric light off, you can change the ambient light level accordingly?

[Gildoran]

Yeah, D3 scripting is great... it would be very easy to do that.

Edited July 13, 2005 by Gildoran

[Domarius]

OrbWeaver - the answer is that the light gem would not be affected. Doom 3 still has the light data there, but the console command only stops the game from rendering it. The only thing it saves is video card load - so for me it doesn't show a performance increase because my video card is already running as fast as it can, it's my processor that is slowing the game down.

[sparhawk]

but there's another problem of that once you go the silouette route the light gem doesn't represent enough information. because you might be in darkness but when contrasted you can be seen easily. but the contrast will depend on a guards perspective, so how do you represent perspective based contrast?

 

Well, that's your problem (as the player). The lightgem does NOT tell you wether your are seen or not, or how good you can be seen from indidivudal AIs. the lightgem only tells you how bright you are lighted. This is the same as in RL when you look down your body and say to yourself "Damn! I'm standing in bright light, so I have to find a darker spot." It also won't tell you if you are standing out for individual, enemy positions.

 

The AI has enough disadvantages as it is, so if the silhouette can be properly coded than it will be one disadvantage less.

[sparhawk]

OrbWeaver - the answer is that the light gem would not be affected.  Doom 3 still has the light data there, but the console command only stops the game from rendering it.  The only thing it saves is video card load - so for me it doesn't show a performance increase because my video card is already running as fast as it can, it's my processor that is slowing the game down.

 

Actually if the new lightgem system will work properly, then it would mean that the lightgem reflects exactly what the player sees on the screen. If he disables shadows than there wont be any shadows. With the current lightgem this is different because it doesn't know what the renderer does.

[Bhruic]

the lightgem only tells you how bright you are lighted.

 

That's not the way the lightgem works/worked classically. Otherwise there would have been no reason for it to get brighter when holding a weapon, or running, because neither of those things are going to suddenly cause more light to fall upon you.

 

The light gem basically was an indication of how noticable you were.

 

However, in this case, I'd agree that there's no real way for the lightgem to factor in silhouette. Whether or not your silhouette is visibile is determined by the location of the guard looking for you, meaning that it is based on the individual, not something that can be represented in general.

 

Bh

[sparhawk]

Of course such factors (holding a wepaon, being near a wall) will also influence the lightgem. My major point though, was that it will NOT indicate how visible you are for a given AI.

[obscurus]

I'm sure this has already been asked somewhere, but will the player cast shadows, as in TDS, and will there be some kind of body-awareness similar to TDS? I really liked the way that was done (except for that strange delay when you walked). It would also be very good (IMO) if the AI responded to the players shadow, although I don't know if that is possible to code.. I would rather look at my hands and feet to see how brightly they were lit rather than have a lightgem, not that I ever pay a great deal of attention to the lightgem in Thief anyway.

[Bhruic]

Of course such factors (holding a wepaon, being near a wall) will also influence the lightgem. My major point though, was that it will NOT indicate how visible you are for a given AI.

 

I think I agree with you, but just to clarify, by "how visible", you are referring to the silhouette issue, yes? Because, otherwise, the lightgem should show how visible you are in general, which would also hold true for any given AI.

 

Bh

[sparhawk]

Yes. But also to other factors. If the lightgem would indicate visibillity to AI then it would also have to take into account line of sight and such stuff. But then there would be the problem, to which AI?.