TDM´s Shadow System

[LEGION 4]

I just played Sons of Baltona and it never bothered so much until now that very often some textures seem to be too much bright and others may too much dark in shadows with no light sources. I´ve added a screenshot there you can see that the top and bottom are how they should be, I guess, but the walls and the beds/objects much too bright.

 

I played around with 'r_lightscale' but this affects only the dark places.

 

Is this still under development or will it be like this forever? Or is it somehow texture-related?

 

edit: the shot appears to be darker as in real on my screen.

Edited July 11, 2010 by LEGION

[Diego 198]

If I understood correctly, it's not a problem with the engine but with the laws of physics If it were completely dark everything would be pitch black, but if you add just a tiny bit of light, the whiter objects would pop out before the darker ones.

 

Edit: Except the lights! those have an evident shader problem.

Edited July 11, 2010 by Diego

[LEGION 4]

But the difference is too much, isn´t it?

[aidakeeley 30]

I'm pretty sure all the light textures are being worked on (See: Serpentine).

[New Horizon 507]

But the difference is too much, isn´t it?

Those lights are a material shader problem.

 

There's nothing wrong with the screen shot beyond the self lit glass in the lights. It's up to the map author to decide how much ambient light they want lighting their entire map, we make some suggestions on the wiki I believe, but the light level I'm seeing here doesn't look too out of the ordinary in your screen shot. On my laptop monitor it looks just right, and on my older CRT monitor...it's almost too dark to see anything. So I think it's ok. I've seen Thief 2 scren shots that looked far brighter than that.

[Serpentine 127]

As said, it's mostly just textures/material shaders.

That said, black isn't very attractive and you need a pretty high base brightness on stuff to keep the game from being annoyingly dark, you also have to take into consideration that the 'blacks' on 95% of the target audience will not be as good as they were 10 years ago when everyone had CRT's. In very low ambient light the contrast between lighter surfaces and solid colours increases quite dramatically, however the balance of "what is light and what is dark" is outside the scope of my "give a damn", making sure that say, walls and floors have similar brightness as to avoid "bad" contrasting in the same environment, well that's very important (i.e you can feel free to report it)!

 

It's one of those areas that realism is really quite bad in terms of enjoyable experience, the example looks fine to me. At the end of the day, perceived brightness/realism/your eyes/your monitor/your software config/your screenshot adjustment will all play a role, the best thing you can do is adjust your gamma in TDM to match what you would want (and when testing to release a map, make sure to test the defaults )

[Diego 198]

Precisely. There is nothing wrong with that image, but maybe realism isn't the best choice for darker scenes.

 

To make it visually more interesting, but actually less realistic, night scenes shouldn't necessarily be darker, but have a higher contrast. And a blueish tone also helps, because our eyes perceive blue better in low light conditions.

 

I did a really quick paintover on that image to illustrate. The blue tone is easy.. the contrast is tricky because you need at least some difference in light to create the contrast, so I just painted the windows and the glass on the door.

[LEGION 4]

Whoo, that´s a way too dark, at least at my screen. How did you get my shot, anyway? I wasn´t able to download the images so I had to make a screenshot of my originally own screenshot. I adjusted the gamma about 0.20 to get a version that´s bright enough to see the guard. I would appreciate a much more less bluish tone on outside night-sights, though.

 

Yeah, there is not much wrong (on the first image), but the white textures could be 10 or 20% more dark. I know nothing about shaders yet, but I´ll look into it, always learning here...

[Diego 198]

Yeah, it shouldn't be so dark.. lol but you get the idea

[OrbWeaver 618]

I think the reason the white beds may appear to be too bright is because of the constant level of ambient light throughout the entire room, which makes all of the beds "glow" at the exact same brightness no matter where they are in the room.

 

In real life a room would never be illuminated by a constant but low level of ambient light; in low-light conditions the room might be illuminated by radiosity but the light level would vary with distance from the indirect light sources.

[nbohr1more 2096]

Ambient Occlusion would help then? (I keep bringing up things that are speculated to be part of the upcoming HDR enhancement but the cooks won't talk about the soup before diner...)

[LEGION 4]

Hmm, HDR enhancement, it sure does sound tasty!

[nbohr1more 2096]

For this example, the AO maps in the textures would have to work via absolute distance\angle versus relative distances (the way I suspect it works)... but even relative angle\distance AO would look better... ?

[OrbWeaver 618]

It doesn't need AO, just more artistic placement of lights. Illuminating a scene with a constant ambient light (at any brightness) looks flat, boring and unrealistic.

 

Even if the scene is intended to be "unlit", because it is underground, night-time or whatever, it still needs a variety of positional light sources to look interesting. Diego's mockup is one example of this.

[LEGION 4]

What are AO maps? Google talks about maps for Anarchy Online...

[OrbWeaver 618]

What are AO maps? Google talks about maps for Anarchy Online...

 

Don't worry about it. It refers to a 3D rendering technique that is not, and almost certainly never will be, part of the Doom 3 rendering engine.

[nbohr1more 2096]

Ambient Occlusion

 

Yeah, anything that adds complexity to the look of the lighting would help. Orbweaver's description reminded me of AO that's all.

 

light level would vary with distance from the indirect light sources

[nbohr1more 2096]

Well then this discussion has been mooted (JC Denton):

 

7upMan, on 12 January 2010 - 05:07 PM, said:

 

By the way, there seems to have been on and off talk about implementing soft-shadows, which seems to be a problem in Doom 3. What is your opinion on this, would you be able to implement them?

The way right now soft shadows are being done for Doom 3 requires one extra rendering pass for shadows, which is slow as heck. I can attempt an entirely different approach with everything done on GPU, but it's a huge task.

 

Melan, on 12 January 2010 - 05:49 PM, said:

 

That is utterly beautiful! There seem to be some slight graphical glitches on Shot062 and Shot064 - the metal bits on the two towers look off. Otherwise, these are some exciting possibilities for TDM players.

 

[edit]Would I be able to enjoy this if I installed it on my doom3 install and loaded TDM?

 

Well, I certainly like criticism, but I don't think the metal on the tower looks off. In fact, it looks metallic now than before.

 

The modified interaction shader is just drop in thing. You just need to place it in the TDM folder.

 

New Horizon, on 12 January 2010 - 08:20 PM, said:

 

Overall performance is an issue for us, as TDM is not like vanilla Doom 3. Under the hood, tdm is a lot more intensive and our core audience generally have mid to low range systems....myself included.

 

At most, I think we would be quite happy with just the test.vfp changes, we would make them an option just as we do with Rebb's enhanced interaction shader. Auto eye exposure is cool and all, but doesn't really fit the flavor of TDM.

 

Can we download your test.vfp to try out on our own systems?

Wow! You almost wrote the feature off ! Well, you can give me a chance to implement it and you can test it on different machines and if then you find out that it's not worth the performance hit (which there should not be much) then I'd agree. In such a case, you guys have nothing to lose.

 

Here's what I can do to keep the performance impact low:

 

As it is, the lighting model is an extension of blinn-phong (my very own version that can't be found in any book or paper) and not something as math heavy as cook-torrance, but visually produce almost same effect. Also, the postprocessing the right now the TDM has, is my own and I know that I can fit the new one with nearly the same performance impact. I am ready to trim down the new version of postprocessing if need be. Also, it can be turned off through console and a parameter can be hooked in into the settings GUI, so that people can easily turn it off from the menu.

 

I can factorize/approximate my version of test.vfp and make it faster without much of a visual difference. As Serpentine said the contrast is little high between the bright and dark and it can be tweaked by changing one value in the test.vfp, but I can just hook in a postprocessing parameter so that the contrast becomes user configurable.

 

What automatic eye exposure can do:

When you are standing into a bright area and looking at dark corners but could see almost nothing unless you move out of the brightness and stare at the dark are few seconds longer. Or, when you are hiding into the shadows and you see lit areas slightly brighter. Also, when you are looking at a scene with parts bright and parts dark then the contrast will be dynamically shifted giving a nice visual contrast.

 

 

Serpentine, on 12 January 2010 - 07:48 PM, said:

 

As for AO maps, I think TDM 1.0 shipped with a single one, I dont know if it would be worth the effort, but maybe I should set up a scene and see.

 

Precomputed AO has advantages such as:

-For the fact that AO is constant at any time of day, it can be baked.

-The baked AO, if stored as a map can be applied based on direction of light with next to no performance loss.

-The baked AO can account for all the occluding geometry in the map as well as the normal maps and is accurate than SSAO.

-Character lighting looks far more superior with AO maps (than without them), with only drawback that, AO remains constant when character changes pose and the character does not cast soft-AO-shadows on surroundings.

 

If you could set up a room with AO maps that'd be really great! I have to change a line or two to apply AO based on direction of light. Also, AO looks very good with hemispheric ambient. A lot of current generation games use bake AO into their diffuse e.g. Rage does it for environment, crysis does it for characters (despite the fact that crysis has SSAO).

 

On a side note, I'd suggest to use specular map to store AO, specular, glossyness in R, G abd B channel respectively. We can get nice simulation of shiny as well as rusty surfaces with zero performance sacrifice. That also means the specular intensity should be a gray-scale map.

 

??

Edited July 11, 2010 by nbohr1more

[nbohr1more 2096]

Sorry to bring it up if it's contentious... ... I just find that segment compelling.

[ungoliant 120]

I think the reason the white beds may appear to be too bright is because of the constant level of ambient light throughout the entire room, which makes all of the beds "glow" at the exact same brightness no matter where they are in the room.

 

In real life a room would never be illuminated by a constant but low level of ambient light; in low-light conditions the room might be illuminated by radiosity but the light level would vary with distance from the indirect light sources.

 

this is gonna piss some people off, but i'm pretty sure the whole contrast of light and dark textures at low ambient light levels is due to (maybe not due to, but at least illustrated by) this perpetrator right here:

 

// TDM Ambient Method Related
{
	blend	add
	map textures/darkmod/xxx/something/source_diffusemap_d
	red global2
	green	global3
	blue	global4
}

[New Horizon 507]

This is for the'fast ambient' method. It is used by players with low powered machines. When this method is selected, the physical ambient light gets switched off and a texture blend is used instead of the ambient_world light. This reduces overhead. The two are nearly identical...except the fast ambient method doesn't calculate any normal maps. So, you're not pissing anyone off. It's a player chosen setting for better performance.

 

 

this is gonna piss some people off, but i'm pretty sure the whole contrast of light and dark textures at low ambient light levels is due to (maybe not due to, but at least illustrated by) this perpetrator right here:

 

// TDM Ambient Method Related
{
	blend	add
	map textures/darkmod/xxx/something/source_diffusemap_d
	red global2
	green	global3
	blue	global4
}

[ungoliant 120]

well thats what I thought too, and i use relatively high settings, but i was playing around with material shaders with different blend modes and noticed that a lack of this stage seemed to make a dramatic difference, so I assumed that ambient_world was influenced by this for everybody.

 

edit: anyway the point was, i figured that at a light level low enough that its only illuminated by ambient_world, that the contrast between dark and light textures is totally linear, where in the "real world" it seems that this should not be so. not really looking to press a "real world vs game world" issue here, but anyways...

Edited July 12, 2010 by ungoliant

[New Horizon 507]

well thats what I thought too, and i use relatively high settings, but i was playing around with material shaders with different blend modes and noticed that a lack of this stage seemed to make a dramatic difference, so I assumed that ambient_world was influenced by this for everybody.

 

What kind of difference were you seeing when you removed this stage? It should only be active when 'fast ambient' is selected in the menu. If it's somehow being activated with standard ambient, that could be a problem.

[ungoliant 120]

What kind of difference were you seeing when you removed this stage? It should only be active when 'fast ambient' is selected in the menu. If it's somehow being activated with standard ambient, that could be a problem.

 

rrrmmm... as i recall about 5 hours ago, the textures were just a whole lot brighter... (or darker?) before i added that stage to them.. but then again I've also had about 8 more beers at the bar since then. Just to be sure i went into my settings just now, and the ambient rendering option is indeed set to standard, not fast. If need be, I can re-experiment with the shaders tomorrow night to duplicate, but for now I must /passout and then /work10hourday