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Propeller blur shader

An exciting "new" option in FlightGear, that includes reflections, lightmaps, the particle system etc.. A lot is yet to be discovered/implemented!

Re: Propeller blur shader

Postby property_tree » Fri Nov 25, 2022 9:58 pm

Thorsten.
You seem like a very logical person, and seem to have some pride in your logic.

But logic is one of the least meaningful personality traits...ever.

Consider a sudoku puzzle and a 'cookie clicker' like idle/grind game.

One is a logic puzzle, the other is, well, a grind game where you raise a number by clicking on a cookie, and the only purpose of the game is to make the number raise.

But:
Effectively they're the same.

Just like how, if you had enough time and resources, you would eventually reach a billion cookies, even if you only clicked the cookie every year.
The sudoku puzzle would also be inevitably solved, since it's logical.

The application of logic is useful, but one of the greatest traps for intellectuals is the worship of it.
When logic is one of the least essential things, ever. I know it's being 'meme'd like a bulwark or wellspring of some energy that keeps 'evil away' (bigots for example are usually depicted as crude troglodyte like fools)

But in reality. While useful, it's superfluous, and, for the most part, inevitable.

You can keep humanity running with food, water, copulation and birth and shelter.
Housecats also run physics integration in their insane feline minds without even knowing what a 'number' is, but they still lead the trajectory, and swat a bird out of the air.

What I'm getting at is:
If you pretend, and I do think you are pretending...that you do not 'understand' the notion of making a mathematical computer pixel construct, more 'lifelike' by emulating the equipment and its quirks of physical devices, the traditional counterparts.
Then, well.

Why should I bother with someone like you?
Yes, you're logical. But logic is virtually inevitable. If someone applies logic to a problem that is solved with logic, then it will be solved. There is no creativity in logic, only logic.
This means that there's a chance that someone out there, who is also logical, perhaps not as much as you, but without this kind of insufferability attached to it.
Making you completely surplus to requirement, and remaining in a lowered state of "logic" (by shunning a logical ace like you, cause, again, logic is useful...) is still something less damaging to my being, and a whole more tolerable than this.

As for the computer built in the 40s. I was talking about concepts, not hardware, that was the entire point. I wish I had the examples on hand...but, all i can say is that there were computational concepts invented way way before any hardware that was capable of building it.
But that's beside the point.

I'm too turned off by "My eyes are not cameras so they don't have lens flare" as a response to "to some people it feels more realistic if their virtual rendering looks like a movie would look if it were recorded by a physical camera on physical film, something you can build IRL and recreate and verify physically"

Sure, in the simulation, you're simulating 'reallife' won't contest that.
But again.
"A cartoon that looks more real ho ho ho how absurd"
The point behind that, too, was emulating physical hardware. And I'm sure you know that.
Otherwise...you'd be pretty damn dense to not understand that.

And that actually, with your otherwise penchant for logics, would lower my opinion of you even further right now.
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Re: Propeller blur shader

Postby Thorsten » Sat Nov 26, 2022 10:42 am

The application of logic is useful, but one of the greatest traps for intellectuals is the worship of it.


Blabla. Sorry - no bearing at all on the problem.

When logic is one of the least essential things, ever.


Not when you dealing with a computer, then it ain't. Which we do in this forum and thread - which happens to be about coding. So a frontal assault on logic doesn't get you anywhere except over the edge of this discussion in a hurry.

You can keep humanity running with food, water, copulation and birth and shelter.


You can not, on the other hand, code a flight simulation or a propeller blur shader with food, water, copulation, birth and shelter (you missed out heating by the way).

Why should I bother with someone like you?


You're discussing with me - if you don't want to bother, just stop it. I'm not keeping you engaged, I'm not forcing you to read through what I write.

Yes, you're logical. But logic is virtually inevitable. If someone applies logic to a problem that is solved with logic, then it will be solved. There is no creativity in logic, only logic.


You have a very very wrong picture of what logic is, how science or math fundamentally works and how inevitable it all is.... I really can't stress this point enough here.

I'm too turned off by "My eyes are not cameras so they don't have lens flare" as a response to "to some people it feels more realistic i


I can't help it . It's certainly true that art appears to some people 'more realistic' or 'better' - yet it still isn't. It remains art. 'Realistic' isn't an art term that's up for opinion - it's a defined term which we can judge by comparison with reality. If you don't like this fact, then... well, be unhappy.

And yes, I find the claim that one cartoon looks 'more real' than the other absurd - for obvious reasons. Whereas I can well relate to the statement that some ways of doing cartoons look more visually pleasing than others.

At its core, your argument seems to be of the type Your points seem well researched and I see no easy way I could win this discussion with arguments, but I still think my opinion on the matter is very important and I don't want to change it in the face of arguments, so I'm disputing the validity of arguments as such and go for opinions instead, so things like expertise, knowledge or background research become irrelevant, at which point the discussion is much more fun and my opinion highly relevant.

Sorry, not interested. :D
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Re: Propeller blur shader

Postby erik » Sat Nov 26, 2022 12:35 pm

To be honest I'm really glad FlightGear kept away from movie-scenes or Disney-style look.

It makes the difference between this being realistically pleasing versus these images being way too dark and quite depressive otherwise. Overcompensating isn't good for mental health.

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Re: Propeller blur shader

Postby MariuszXC » Sat Nov 26, 2022 11:05 pm

Sigh..

Could we agree that what we are doing here is using 3D art to make a 2D image look as realistic as we can?
Plus a whole bunch of physics calculations supporting said 3D art..

@Eagle: how is progress on the visual side of things?
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Re: Propeller blur shader

Postby TheEagle » Sun Nov 27, 2022 12:49 am

Well, since my last post I'm stuck with the non-working compositor lighting … so I've commented it out for now. The blur is pretty good now I think - all that is left to do is to blend the alpha based on the view- and blade-angle, add reflections … and fix the compositor lighting ! :mrgreen:
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Re: Propeller blur shader

Postby MariuszXC » Sun Nov 27, 2022 9:28 am

Splendid :)

And I advanced things in fuel system on my end. Need to add emergency transfer and update logic on hi-lo sensors a bit and hopefully this part will be ready.
Back to work...
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Re: Propeller blur shader

Postby Thorsten » Sun Nov 27, 2022 10:21 am

@property_tree - I reported your post for moderation as it exceeds the limits of civilized discussion.

Could we agree that what we are doing here is using 3D art to make a 2D image look as realistic as we can?


I think the general distinction has merit (and I'd invite folks to think about it) - some things we do are physics. We can compute light intensities, solve approximate scattering equations etc.

Other things are art - we don't compute the impact of raindrops into puddles, we just mimic them.

Occasionally we hit on discussions like 'at what distance do we still see (and need to render) a 100 W bulb?' - and we could go both ways, we could create an artistic impression of a town at night, or we could compute the answer based on the sensitivity of the eye.

It's generally true that art can look stunning - we use it to bring out the essentials of a scene, make it larger than life (I know some of that in practice, as I make movies and often aim in post-processing to give a scene just that, this 'larger than life' or 'more real than real' appearance so that people say 'wow'.

When creating ALS< I have intentionally not chosen that path, but tried to be close to reality when it could be done. Often hazy or rainy scenes look bland and unassuming then - but they do so in real life. Lights look fainter than on stunning photographs - but the camera has a much wider opening than the eye and 'sees' night scenes differently.

So I see much merit in computing things when an effect is inserted into the ALS framework - because most of the rest in there is the result of a computation in one form or the other, and doing everything the same way leads to a visual consistency that is hard to achieve otherwise.


Having said that - a shader is a piece of code - applied math - so on that level you also have to compute 'art' - the difference is to what degree your calculation is based on physics results or not. But also note that if you do not need to compute physics in the shader - if you have a way of obtaining the answer, you can put something into the shader that (approximately) reproduces or parametrizes the answer - which is computationally much cheaper.

So that's (for me) the appeal of the multiple propeller geometry approach - because it contains all the right answers (reflection, progressive blur, shade,...) by construction, and it is conceptually elegant. Still, I am at a loss why it comes out so slow... (if I had a bit more time on my hands, I'd simply try toying with it myself, alas...) All these features are much harder to get with a fragment shader.
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Re: Propeller blur shader

Postby Ysop » Sun Nov 27, 2022 10:32 am

Good to read, that there is progress all around :-)

Not extending the topic too much, but realism is the way to go for a simulator.

Feedback on current development state:
Image

Those two rings do not appear IRL. It should be rather a big ring in the middle of those. Mayby at least making the rings less distinct?

Image
I am still not convinced, that brain makes something like this out of it, but I never was really paying attention to the aspect and currently no time for a reality check. We should organize a trip to the nearest airfield for you :)
(You might want to correct the positions for the scissors as well, screenshot from current next)

Debugging time here...
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Re: Propeller blur shader

Postby Thorsten » Sun Nov 27, 2022 10:35 am

I am still not convinced, that brain makes something like this out of it, but I never was really paying attention to the aspect and currently no time for a reality check.


The bright and dark sectors somehow mimic a reflection condition,but that should change brightness rather than transparency - the bright areas get fully transparent and that is just not as for a real propeller.
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Re: Propeller blur shader

Postby TheEagle » Sun Nov 27, 2022 1:13 pm

@Ysop: thanks for the feedback ! About the two rings - I don't like them too much either, something must be going wrong in my interpolation logic (the (most inner quarter radius part of the disc)'s alpha is computed for each pixel by linearly interpolating between 1 for the hub and whatever alpha value comes out of the calculation for the 0.25 station). And that there are two rings is simply due to the fact that the prop blur disc is two-sided and I can't figure out how to get the backside to cull correctly.
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Re: Propeller blur shader

Postby Gijs » Sun Nov 27, 2022 1:49 pm

Hi all,

Just a short heads-up to say that I've cleaned up some of the recent posts in this topic that were not in line with the forum rules. Please let's get back on the topic of improving TheEagle's propeller blur shader and leave any personal quarrels out from now.

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Re: Propeller blur shader

Postby Thorsten » Sun Nov 27, 2022 4:26 pm

and I can't figure out how to get the backside to cull correctly.


You should be able to set the surface one-sided in the modeling software, but you can also do a normal vs. view direction check inside the shader and drop fragments which face the wrong way.
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Re: Propeller blur shader

Postby S&J » Sun Dec 11, 2022 1:56 pm

So was the topic cleaned up and property_tree banned ?

He's been conspicuous by his absence.
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Re: Propeller blur shader

Postby Gijs » Sun Dec 11, 2022 3:52 pm

Yes, at his own request.
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