Is there a solution to graphics pop-in?

[futurefields]

Every game that features large maps has set draw distances on everything from which models to use, which textures to use, which shadow resolution to use etc... because computers can't render the whole map in full detail. The problem is it breaks immersion when you see it happening before your eyes which has become all too apparent in the post-programmable shader era in which the amount of up-close detail has increased tremendously but distance detail, while increasing, hasn't increased at the same pace and is still using the same technique of flipping between 2 or 3 different LOD models as the character/camera gets closer to the object.

Is there any solution to this rendering technique, or is graphical pop-in here to stay? Could tessellation be used instead to more discretely ramp up the detail on objects in a less obvious/intrusive manner, basically replacing the use of different LOD models? Or is tessellation way too expensive to be used in that manner?

 

[AFurryReptile]

It depends entirely on the game, but a lot of them will have a .ini file you can edit to even further increase the draw distance of different textures. Skyrim and STALKER are two that I can remember doing this for. Some games are starting to build-in the option to disable "texture streaming", like Hitman: Absolution.

I'm not sure tessellation would be a fix to this problem. First of all, it's taxing on the hardware. Second of all, it is dependent on the textures themselves; there was a tech demo I tried once, and when I dropped texture resolutions down really low, tessellation looks really crappy.

Honestly, I think this is just a hard problem to fix. Think of it this way:

You're in a game, and your face is placed against the floor. You're looking at a leaf with a 1024k resolution. For the sake of argument, let's say every last pixel your looking at is rendered. Now, step 50 feet away from that leaf on the ground. That leaf is, what, now 4 pixels large on your screen? It doesn't make sense to render that leaf at 1024k anymore - it would bring your system to a crawl. Through in a few hundred or few thousand more, and I think you'll understand why this problem has existed for a long time now. Unfortunately, all we can really do at this point is wait for better hardware...

 

[PrincessFrosty]

It's not really a "problem", it's a trade off. You have to remember that in the early days there was no LOD, LOD systems were brought in deliberately because they provide some benefits which outweight their costs.

You can easily render your entire world all at max detail with no LOD at all, you simply drop all your models into an engine and turn of LOD scaling, simple. The problem is that to get large worlds with lots of models you need to scale back quality on average, in order to achieve acceptable performance.

I think the question is better framed as "can we improved LOD systems to reduce their drawbacks" to which the answer I believe is yes. Tessellation does provide a smooth transition from higher to lower polygon models, the problem is that it takes some overhead of computational power to do that, which means again you're facing a trade off, are you happy to sacrifice some overall scene complexity to enable tessellation to help mask LOD transitions, it's not really a question with an objective answer.

What you have to realise is that at the heart of it, we have fixed speed hardware with which everything we do with is inherently some kind of trade off between complexity and speed, there's no magic bullets, any fancy LOD system you make will always come with some kind of graphics processing overhead.

It's worth noting that with modern consoles trying to join the big league running engines like the Crytek and unreal engines gamers have become used to an ever more aggressive LOD in order to obtain better graphics, that's more of a social trend among casual gamers than a technical problem.

If you're particuarly bothered by LOD pop in my suggestion would always be to set the draw distance and LOD distances as high as you can in games and then lower the overall quality of the scene by reducing texture size and disabling other features, maybe dropping the screen resolution, often you can mask LOD transitions by simply pushing the LOD boundary out far enough so the transitions are imperceptible but again it's all a trade off, you'll have to sacrifice quality in other areas to achieve that.

On average people tend to prefer to live with some minor pop in to allow for higher fidelity visuals up close, but it's subjective which is why its good to learn how to tweak game settings, in the ini/cfg files if necessary.

 

[JamesV]

Using tessellation on objects 'coming into view' would be a huge hit to performance. Instead of a 2D sprite of a tree miles distant, you'd have to process each of those trees individually on a per pixel basis (based on light, etc)... would make any game crawl.

I always bump up draw distance if the option is available through options or an ini file. What I wish you could do, is bump up the 'active' distance. For example, in GTA games, you have a circle of area around you that is 'active'; what I'd like to be able to do is double that distance so cars don't disappear behind you when you look in the opposite direction.

 

[BrightCandle]

Another reason for having level of detail is that using a reduced detail model or even a sprite can look more like its meant to at a distance due to the quantisation effect of rendering to pixels. Without level of detail its not uncommon to get pop effects and shimmering on distance objects. LOD is also a quality of image improver as well as a performance saver.

 

[futurefields]

I guess I'm focused more on the intrusive kind of pop-in, it's especially bad in non-GTA open world games, especially from Ubisoft. For example, the Assassin's Creed games on PC feature horrendous LOD effects, where objects manifest out of thin air often within 20-30 feet of the player character. Or Far Cry 3, where trees and foilage are constantly rearranging themselves as you walk around, even on Ultra settings. Or games like Saints Row, which seem to be permanently stuck on the equivelant of the lowest LOD settings in GTA4. Rockstar seems to have a much more elegant LOD system in place than other companies. Objects seem to fade in rather than just suddenly popping in, which makes it feel more organic.

 

[BrightCandle]

Games like arma show that you can have very complex scenes with vast visibility (literally miles) with little to no object pop. About the only noticeable change you see is the trees, otherwise you have a seamless world with realistic distances of visibility. It also runs terribly and is horribly CPU limited and the visibility setting is the most intensive in the settings.

 

[Midwayman]

Isn't the final solution ray traced rendering? I know a few years back they were talking about implementing it in hardware and how it would eliminate geometry complexity issues.

 

[magomago]

Isn't the final solution ray traced rendering? I know a few years back they were talking about implementing it in hardware and how it would eliminate geometry complexity issues.

They've been saying that since at least 1998 in my old PC Gaming Magainzes. I'm sure someone else will come along that is older than me and talk about how even ray tracing was discussed back in the 80s.

 

[Midwayman]

They've been saying that since at least 1998 in my old PC Gaming Magainzes. I'm sure someone else will come along that is older than me and talk about how even ray tracing was discussed back in the 80s.

Well, intel had hardware that was doing in based on larabee
http://techreport.com/news/17641/intel-shows-larrabee-doing-real-time-ray-tracing

Raytracing is old. I think the hardware effort being taken seriously was new.