Switching default texture format to DDS: Difference between revisions
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=== ATI/AMD proprietary driver === | === ATI/AMD proprietary driver === | ||
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!Card | |||
!Driver | |||
!DDS ok | |||
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|ATI Radeon HD 6310 | |||
|14.6-1 | |||
|{{yes}} | |||
|ZLSA | |||
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=== ATI/AMD OpenSource driver === | === ATI/AMD OpenSource driver === |
Revision as of 15:14, 4 September 2014
Work in progress This article or section will be worked on in the upcoming hours or days. See history for the latest developments. |
Feedback needed - should Flightgear switch the defaults to dds format for terrain texturing?
What is this about?
The FG development team is considering to switch the format for terrain textures from png to dds. This would offer a number of significant advantages:
- dds is a compressed format, hence the download size of the FG base package may be decreased
- compressed dds can be directly used by many graphics cards, reducing also GPU memory consumption
- dds stores all texture resolution levels, i.e. no lower resolution levels have to be generated when the texture is used, hence it loads much faster into memory
- the resolution levels ('mipmaps') can be customized, allowing for some interesting effects at no performance cost
Practically all commercial simulations use dds for these reasons.
However, the dds compression algorithm is patented, which means that it is not readily available for OpenSource graphics drivers used by Linux distributions. Dependent on the specific hardware, this may or may not be a problem (modern graphics cards typically do not need the driver to process dds, for older graphics cards there are non-patented workarounds available which decompress the dds on the software level). The development team is concerned about making the Flightgear experience pleasant for all users, hence we would like to gather feedback how many users would be affected by a change in practice.
If there are no problems reported, FG will change defaults to textures in dds format with the 3.4 release, and then phase out the use of png textures.
What would we need?
Flightgear already provides the simple option to test a dds texture set. If you are running on Linux and use an OpenSource graphics driver, please take 5 minutes to help during your next FG session:
- Open the dialog under View -> Rendering
- Under 'Terrain texture scheme', change the default 'Region-specific' to 'Global alternative (DDS format)'
- Press 'Okay' - FG will reload the terrain
- Do you see proper textures on the terrain (they may look different and may also not fit the location perfectly)? If yes, you're fine. If you see monochromatic colors or other rendering artifacts, your system may have problems with dds.
- Change back to the texture scheme you like best
- Enter your experiences in the list below
Thanks for your help!
Tested hardware and graphis drivers
NVIDIA proprietary driver
Card | Driver | DDS ok | Reported by |
---|---|---|---|
GeForce GTX 670M | 310.19 | Yes | ThorstenR |
GeForce GT 540M | 331.82 | Yes | Gijs |
N13M-NS Optimus | 340.32 | Yes | Tom_ch |
GeForce GT640 | 343.13 | Yes | lumni1968 |
GeForce GTX 780 Ti | 340.52 | Yes | Avionyx |
GeForce GT 750M | 331.38 | Yes | Dutchguy |
NVIDIA OpenSource driver
Intel proprietary driver
Intel OpenSource driver
Card | Driver | DDS ok | Reported by |
---|---|---|---|
HD Graphics 3000 (i7-2600K) | 10.2.6 | Yes | cdesai |
ATI/AMD proprietary driver
Card | Driver | DDS ok | Reported by |
---|---|---|---|
ATI Radeon HD 6310 | 14.6-1 | Yes | ZLSA |
ATI/AMD OpenSource driver
Excerpts from the ongoing discussion
Here is my suggestion how to proceed:
Does that sound reasonable for everybody? — Torsten Dreyer (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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let's collect some some feedback until late November and restart this topic. We probably know by then what we do for the next release. — Torsten Dreyer (2014-09-03). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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Misc
I'd propose [...] this process:
I think we have an information management problem in relation to the user base - a frequent forum situation is that a user requests something that's already there, but the information is just not out. So if we even envision such a change, I would start spreading the relevant information basically yesterday. — Renk Thorsten (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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Challenges
"dds on an open source driver (radeon and intel) I was forced to use radeon at some time, and it was fun, the planes were pink :) once libtxc-dxtn installed, dds were loaded fine again, so it can be used on open source if you are ok to use the lib."
— Renk Thorsten (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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Another potential option would be to convert regions to .dds but keep both global-png and global-dds, but making that user-friendly would — Rebecca Palmer (2014-09-02). Re: [Flightgear-devel] Download size,
and hardware support (was .dds textures).
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On my system (Intel Ivybridge), DDS works with or without libtxc, but this may not be true of all Intel hardware. — Rebecca Palmer (2014-09-02). Re: [Flightgear-devel] Download size,
and hardware support (was .dds textures).
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You can specify the dependency on libtxc_dxtn, but then distributions like openSUSE cannot ship FlightGear anymore. libtxc_dxtn implements S3 texture — Stefan Seifert (2014-09-02). Re: [Flightgear-devel] Download size,
and hardware support (was .dds textures).
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Debian/Ubuntu's libtxc is libtxc-dxtn-s2tc, which claims to avoid the patent at a small cost in visual quality: — Rebecca Palmer (2014-09-02). Re: [Flightgear-devel] Download size,
and hardware support (was .dds textures).
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The dds textures seem to have some advantages over our png textures and using them is tempting. — Torsten Dreyer (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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We currently have regions-png, global-png and global-dds; as I noted earlier, switching to regions-dds, global-png and global-dds has the — Rebecca Palmer (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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Can we invert the logic in, say, preferences.xml so xxx-dds is enabled by default and switching to xxx-png has to be done in rendering options? — Torsten Dreyer (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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Changing the default (which is in preferences.xml) is easy: the problem is how do users with non-.dds-supporting hardware (if this exists) know — Rebecca Palmer (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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Conversion
Automatic conversion script is welcome indeed. Also I'm pretty sure that we have some people here ready to convert a PNG to DDS as soon as you say "Hey boys I created a new PNG file, can you convert this file for me please ?" :-)
— Clement de l'Hamaide (2014-09-02). Re: [Flightgear-devel] Download size,
and hardware support (was .dds textures).
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A few world about the conversion: once a png/rgb/jpg found, the script try to guess the suitable dds format: with or without alpha channel, — jean (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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Pros
I always got a loading problem with png textures, large textures take seconds to load and convert, and that ruin my close flight where you — jean (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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Contra
FG actually runs with dds textures, it just doesn't render anything reasonable, I believe you get monochromatic colors. But I don't expect the menu to be affected, it doesn't use textures.
— Renk Thorsten (2014-09-02). Re: [Flightgear-devel] .dds textures (was Unused and/or sourceless textures).
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If it's relevant, I recall having S2TC compression problems when running Flightgear, and updating this package to a newer version manually (outside of the main repos) fixed the issue. I'm on an Intel HD 3000, but I'm guessing that Intel HD 4000 doesn't have this problem, since it seems to have better OpenGL and OpenCL support.
— Saikrishna Arcot (2014-09-02). Re: [Flightgear-devel] Download size,
and hardware support (was .dds textures).
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