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Payware for FlightGear? Should it exist?

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Hi guys. I'm a developer of payware add-ons for X-Plane and have been hearing some buzz about FlightGear. One thing that caught my attention is that FlightGear is built on top of OpenSceneGraph and osgEarth, and my company's technology for volumetric clouds, skies, and 3D water effects integrates really easily into those sorts of systems. (See http://www.sundog-soft.com/ if you're curious.)

 

The problem is that this technology is not free and open source, but FlightGear is. So, a few questions before I explore things further:

 

1. FlightGear is under a GPL license, which means any add-ons that it links in must also be GPL (open source.) Payware for FG is a non-starter, unless a modified license to carve out add-ons has been discussed. Has it, to anyone's knowledge?

 

2. Hypothetically speaking - would you pay for an add-on to a free product if it were good enough?  My main concern is that users of a free / open source simulator could have an allergic reaction to add-ons that are not. 

 

3. Anyone have an estimate of the relative percentage of Linux / PC / Mac users of FG?

 

Thanks!

 

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I will, if you don't mind, forward your questions, which make all sense to me and I would also like to see answered, at the FlightGear forums...

 

It would be great to have SunDog effects in FG!


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I was hoping to get a take on it from a consumer perspective before posting it there, where all the developers hang out.

 

Bringing up closed-source software on an open source developer's forum could be considered trolling, and I don't want to be one of the those things!

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Ok, I understand. I will not post there - I agree with your point :-)

 

From a users perspective, should it be possible, I would have no problem in paying for Flight Gear add-ons, and judging from what it was possible to attain in X-Plane 10 ( SkyMaxx Pro ) with your technology, I would certainly love to see it available for FG too !!!

 

I was trying to search through the net because I believe I had an old link to an FNPT ( payed and expensive ) using Flight Gear as the base, but I couldn't find it... I will keep trying to find it...


Main Simulation Rig:

Ryzen 5600x, 32GB RAM, Nvidia RTX 3060 Ti, 1 TB & 500 GB M.2 nvme drives, Win11.

Glider pilot since October 1980...

Avid simmer since 1992...

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Personally I do not think it will work, attemps have been made and flightgear users didn't like it as this is the only true freeware flight simulator.

 

What they dislike even more, is if some kind of intrusive DRM get's implemented since the source is open. And due to this, those attemps failed.

 

There's a few threads about it on flightgear forums

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FG is an open source , and it is not charged , the payware add ons should not exists. 


Ryzen 5 1600x - 16GB DDR4 - RTX 3050 8GB - MSI Gaming Plus

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Should it exist ? Why not ?

 

But it's important to understand that the FlightGear license is about freedom, it's not about the price. You can also pay for a FlightGear DVD: http://shopping.flightgear.org/

 

The freedom will make it possible for future generations of the community to compile a 128-bit or 256-bit version of FlightGear, to use 32k x 32k textures with OpenGL 42.0, to adapt it for the operating system you will use in 20 years without starting everything from scratch, including the programming of the avionics of your favorite aircraft.

 

If you want to release a payware product for FlightGear, what will be your EULA ?

 

I don't know the percentage of Linux / PC / Mac users of FG, but it may be close to the X-Plane percentage.

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I think Linux % is much higher than on X-Plane.

Yes why not. There is SASL for X-Plane which is GPL too. Authors are usually saying that the plugin folder is GPL and all the rest copyrighted stuff.

You cannot link to GPL stuff but there are workarounds like for ex.

https://github.com/PhilippMuenzel/vascore-embedded

does in the CRJ etc. It's not trivial programming though.-

Good luck and bring it on.

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Hi guys. I'm a developer of payware add-ons for X-Plane and have been hearing some buzz about FlightGear. One thing that caught my attention is that FlightGear is built on top of OpenSceneGraph and osgEarth, and my company's technology for volumetric clouds, skies, and 3D water effects integrates really easily into those sorts of systems. (See http://www.sundog-soft.com/ if you're curious.)

 

The problem is that this technology is not free and open source

Actually, OSG is based on LGPL, and osgEarth should follow the same. So there's no licensing problem if FlightGear integrates those systems. However, FlightGear is licensed under GPL, and if it integrates with non-free software than it's no longer a GPL software.

 

So, a few questions before I explore things further:

 

1. FlightGear is under a GPL license, which means any add-ons that it links in must also be GPL (open source.)

Wrong. You can build any proprietary software to work on FlightGear. What shouldn't happen is FlightGear integrating proprietary software into it's code by default. So in this regard you're more than welcome to develop a proprietary add-on to the Sim, I even support this idea.

 

Payware for FG is a non-starter, unless a modified license to carve out add-ons has been discussed. Has it, to anyone's knowledge?

You license has nothing to do with FlightGears's license. You can launch a proprietary add-on for FlightGear with no problems.

 

And you may wonder: Can I launch a GPL payware addon?

 

Yes. FOSS (free and open-source software) doesn't mean "free as in free beer", but in freedom of speech. It can be purchased, but it's users should have the 4 freedoms: the freedom to modify any parts of the addon they want; the freedom to see the source code; the freedom to re-distribute the program; the freedom to re-distribute their modified program.

 

2. Hypothetically speaking - would you pay for an add-on to a free product if it were good enough?  My main concern is that users of a free / open source simulator could have an allergic reaction to add-ons that are not. 

 

3. Anyone have an estimate of the relative percentage of Linux / PC / Mac users of FG?

 

Thanks!

 

I personally would. This is totally a question of personal choice, a user can be against proprietary software and yet fly with FlightGear without your addon. The name "add-on" is self explanatory and doesn't inflict on the users' choice :)

 

3 - I think there's no possible way of knowing that. 

 

FG is an open source , and it is not charged , the payware add ons should not exists. 

Your statement only reflects the lack of knowledge most people have on the GPL license.

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