Cpu ray tracing

[rotan1999]

Hi. I Don have a ray tracing gpu. What about ray tracing done by cpu? Is it possible? 

Will dcs support gpu or cpu ray tracing in the future?

[Glide]

Ray tracing by CPU is possible but not efficient enough for real time rendering in a flight sim.  Ray tracing in the GPU is "early days" with Nvidia having a clear lead in performance.  I'm guessing it will be quite some time before ray tracing is mature enough for DCS.

[Scott-S6]

Is ray tracing even useful for DCS? The only shadow fidelity we care about is the cockpit shadows and with only one light source they're easily faked.

The only place you'd really see ray tracing doing anything is on the deck of a carrier at night. Not worth implementing, imo.

[Eugel]

2 hours ago, Scott-S6 said:

Is ray tracing even useful for DCS? The only shadow fidelity we care about is the cockpit shadows and with only one light source they're easily faked.

The only place you'd really see ray tracing doing anything is on the deck of a carrier at night. Not worth implementing, imo.

Strictly speaking, Raytracing is useful for any kind of computer graphics as it is the most realistic form of rendering images.
And there are plenty of instances where you´d see it in DCS (sunlight through clouds, illumination at airfields or cities, explosions illuminating their surroundings, searchlights from a helicopter, but also the simple rendering of textures on aircraft where you don´t need any fake shadow maps and stuff like that)

It may take another 10 or 20 years or even more, but I´m sure, raytracing will come for any game.

[Hiob]

3 hours ago, Scott-S6 said:

Is ray tracing even useful for DCS? The only shadow fidelity we care about is the cockpit shadows and with only one light source they're easily faked.

The only place you'd really see ray tracing doing anything is on the deck of a carrier at night. Not worth implementing, imo.

Shadows go a long way in making a scenery look good/realistic. You may not care about that when doing mostly jet-stuff or dogfighting. But helicopter pilots or low level bomber may care a lot. I certainly do!

[Scott-S6]

56 minutes ago, Eugel said:

Strictly speaking, Raytracing is useful for any kind of computer graphics as it is the most realistic form of rendering images.
And there are plenty of instances where you´d see it in DCS (sunlight through clouds, illumination at airfields or cities, explosions illuminating their surroundings, searchlights from a helicopter, but also the simple rendering of textures on aircraft where you don´t need any fake shadow maps and stuff like that)

It may take another 10 or 20 years or even more, but I´m sure, raytracing will come for any game.

But lots of those can be easily approximated in an environment like DCS where there is usually only one significant light source. Light through clouds definitely does not require ray tracing and the shadows cast by an explosion are so brief (literally less than a single frame where the explosion is bright enough for them to be visible in daylight) that they are a great example of "who cares?". Cities don't need raytracing, static light sources against static terrain casts static shadows and there are many much simpler techniques.

There are other use cases where a good approximation is difficult and ray tracing makes a difference but this isn't it.

25 minutes ago, Hiob said:

Shadows go a long way in making a scenery look good/realistic. You may not care about that when doing mostly jet-stuff or dogfighting. But helicopter pilots or low level bomber may care a lot. I certainly do!

Shadows don't need ray tracing when there's only one light source. Lots of other methods are available.

It's very telling that there are so few examples of ray tracing actually making a difference, even in games where the lighting and shadows are far more visible. I have a 4090 so I can run max raytracing on everyrhing and most of the time it is highly underwhelming. First person games where you are moving with other characters that also have light sources is pretty much the only time that it's at all impressive.  Search and rescue with a group of helicopters using spotlights at night in cramped environments would be awesome but for most of DCS raytracing would do very little.

Edited December 11, 2023 by Scott-S6

[Hiob]

Ok.   No raytracing for you then. Luckily it is optional usually.

I can clearly see the benefits from a good implementation (CP2077 e.g.). Is it worth the performance penalty? Well, sometimes, sometimes not. Once I start really playing the game it doesn’t matter all that much (either game). But nevertheless, sometime I enjoy the eye candy and fly (or walk) around just to take in the nice scenery.

Would I sacrifice performance in DCS for that? Currently not, but that could change in the future. Let’s see where the development takes us.

 

[Eugel]

7 hours ago, Scott-S6 said:

 Cities don't need raytracing, static light sources against static terrain casts static shadows and there are many much simpler techniques.
Shadows don't need ray tracing when there's only one light source. Lots of other methods are available.

Of course, no one "needs" raytracing. But there is good reason CGI effects for movies are done with raytracing.
Even with a single light source, raytracing will look more realistic.
Yes, I don´t see it worth it in DCS at the moment. And as I said, it may take 20 years, but I´m sure, the hardware will get there to implement raytracing on full scale.

[Scott-S6]

1 hour ago, Eugel said:

Of course, no one "needs" raytracing. But there is good reason CGI effects for movies are done with raytracing.
Even with a single light source, raytracing will look more realistic.
Yes, I don´t see it worth it in DCS at the moment. And as I said, it may take 20 years, but I´m sure, the hardware will get there to implement raytracing on full scale.

You're completely missing the point, especially with that comparison to movies.

Cities don't need raytracing because the light sources and the buildings are static. You can create a shadow texture map with pre-rendered raytracing and then no raytracing is needed by the game during run time (which is what we're talking about here - realtime raytracing, not pre-rendered raytracing which has been widely used for environmental lighting and shadows for a long time). All realtime raytracing would add is dynamic shadows to vehicles moving about or reflections on their glass. Is that something that you're even going to see? 

8 hours ago, Hiob said:

Ok.   No raytracing for you then. Luckily it is optional usually.

I can clearly see the benefits from a good implementation (CP2077 e.g.). Is it worth the performance penalty? Well, sometimes, sometimes not. Once I start really playing the game it doesn’t matter all that much (either game). But nevertheless, sometime I enjoy the eye candy and fly (or walk) around just to take in the nice scenery.

Would I sacrifice performance in DCS for that? Currently not, but that could change in the future. Let’s see where the development takes us.

 

CP2077 is a great example. The environmental lighting could have be done without realtime raytracing using conventional techniques. All RT really did that couldn't have been done conventionally was the reflections on vehicles and the wet street at night and there are well established techniques to approximate that. It's far more novelty than anything else.

Now, a co-op horror game where one of you has a flashlight and the other has a gun would be a fantastic use of raytracing. It would be core to gameplay as you have to think about your positioning relative to each other and the environment. The player with the flashlight isn't really going to see it (you could even make RT optional for him) but for the player without it's going to look awesome.

Edited December 12, 2023 by Scott-S6

[Eugel]

2 hours ago, Scott-S6 said:

You're completely missing the point, especially with that comparison to movies.

Not sure what your point is, then.
You said it yourself, of course, most effects can be faked, that´s what video games have been doing for decades, but not faking it will always look better and more realistic, that´s what I wanted to point out with my comparison to movies.

It doesn´t matter if an object is static or not or how many light sources there are. Raytracing will look more realistic. 

Raytracing is more than just eye-candy reflections you see in Cyberpunk. It replicates what light does in real life. There are hundreds of instances where that would be amazing in DCS.

[Scott-S6]

34 minutes ago, Eugel said:

Not sure what your point is, then.
You said it yourself, of course, most effects can be faked, that´s what video games have been doing for decades, but not faking it will always look better and more realistic, that´s what I wanted to point out with my comparison to movies.

It doesn´t matter if an object is static or not or how many light sources there are. Raytracing will look more realistic. 

Raytracing is more than just eye-candy reflections you see in Cyberpunk. It replicates what light does in real life. There are hundreds of instances where that would be amazing in DCS.

The reason that the comparison to movies is bogus is because everything is prerendered. In games you have to make the differentiation between what you can prerender and what must be rendered realtime.

Streetlights in a city casting shadows on buildings and static street objects is completely pointless as an application for realtime raytracing - you can use raytracing in your environment modelling app to create pre-rendered lighting and shadow maps, getting the same effect without real-time raytracing (no need for GPU or game engine support, drastically less GPU load) and this has been done for a long time. This isn't "faking" it or approximating it, it simply doesn't need to be raytraced realtime since the light sources and objects are static.

Raytracing the shadows for a car moving on the street could be a use case for realtime raytracing as the alternative is to approximate those shadows. The question is - will you as a DCS pilot be able to tell the difference or even see those shadows?

The use cases for real time rendering are quite specific and many have little relevance to DCS. 

Edited December 12, 2023 by Scott-S6

[Hiob]

5 hours ago, Scott-S6 said:

CP2077 is a great example. The environmental lighting could have be done without realtime raytracing using conventional techniques. All RT really did that couldn't have been done conventionally was the reflections on vehicles and the wet street at night and there are well established techniques to approximate that. It's far more novelty than anything else.

Ok. When you say so...... 

[Brun]

6 hours ago, Scott-S6 said:

Cities don't need raytracing because the light sources and the buildings are static.

The most significant light source in DCS is the sun, and that's definitely not static. Neither are the cockpits which it casts shadows into, or aircraft it casts shadows from.

While I would agree that there are fewer benefits to ray tracing in DCS compared with other applications, it should at least make shadows more accurate and less prone to issues. It's also important to distinguish between ray traced direct shadows and bounced lighting from diffuse surfaces (aka global illumination or GI), the latter being what baking seeks to address. As far as ray tracing is concerned, they're independent of one another and direct shadows could be ray traced without the performance hit of calculating indirect lighting.

[Scott-S6]

5 hours ago, Brun said:

The most significant light source in DCS is the sun, and that's definitely not static. Neither are the cockpits which it casts shadows into, or aircraft it casts shadows from.

The sun only moves if the mission time isn't set to static. And I entirely agree that the cockpit is by far the most significant shadow/lighting effect.

Edited December 12, 2023 by Scott-S6

[Art-J]

Is such "static" mission time even a thing in DCS? Just curious - I've never experienced sun not moving in my 9 years of playing this sim.

[Eugel]

On 12/12/2023 at 8:14 AM, Scott-S6 said:

CP2077 is a great example. The environmental lighting could have be done without realtime raytracing using conventional techniques. All RT really did that couldn't have been done conventionally was the reflections on vehicles and the wet street at night and there are well established techniques to approximate that. It's far more novelty than anything else.

Novelty ? Raytracing has been around for 40+ years. I ran raytracing demos on my Amiga 500 in the early 90s.
All the "conventional" and "established" techniques you mentioned are just workarounds to get close to achieving the results of raytracing. And not because they are better or simpler, but because until very recently, computer hardware just couldn´t do it fast enough. 
We are just now entering a territory where hardware can do it in real time, so why settle for an inferior workaround ? 
Why bother developers with creating shadow maps, illumination maps, reflection maps that look maybe 80% as good as with raytracing, when you have the hardware to get the real deal automatically ?

Yes, Cyberpunk is a great example, there are plenty of videos that compare graphics with and without RT, and there are plenty of static objects that just look more realistic.
And it´s not just reflections and wet streets.

[Hiob]

14 minutes ago, Eugel said:

Yes, Cyberpunk is a great example, there are plenty of videos that compare graphics with and without RT, and there are plenty of static objects that just look more realistic.
And it´s not just reflections and wet streets.

I think arguing with him is futile. He obviously thinks about Raytracing only in the most simple of ways, like drawing shadows from multiple lightsources.

[SharpeXB]

On 12/13/2023 at 4:16 AM, Eugel said:

Raytracing has been around for 40+ years. I ran raytracing demos on my Amiga 500 in the early 90s.

Right. It just took an entire day to render one scene instead of getting it in real time at 60fps

DCS certainly needs better lighting and shadows, it’s the most dated effect you see here.