Virtual textures.

General discussion about Celestia that doesn't fit into other forums.
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ElChristou
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Virtual textures.

Post #1by ElChristou » 03.08.2008, 16:30

Folks, this is a comment I have from the very beginning but as I wasn't a big VT user, I never dare to post. Now that I'm taking the time to build some nice VT using Fridger's tools, I must ask:

Is there a way to change a bit the moment in which Celestia move from a level to another? Perso I find it too visible, somewhat later would be quite better.
Is this possible?
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selden
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Re: Virtual textures.

Post #2by selden » 03.08.2008, 16:47

The easiest way is to specify a different value of TileSize in the .ctx file.

If you use a TileSize that corresponds to the number of pixels in each tile, when a new resolution level is loaded, the visible resolution improves. This is because the lower resolution level was being displayed past the point where its resolution matched the screen resolution. Its pixels were being blurred across several onscreen pixels. It's generally best to specify a TileSize pixel value which is half the width of the tiles. If you have tiles which are 512x512 pixels, specify a TileSize of 256. The next level of tiles will be loaded when you have reached the point where the resolution visible on screen matches the resolution of the lower resolution tiles.
Selden

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ElChristou
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Re: Virtual textures.

Post #3by ElChristou » 03.08.2008, 17:33

Cool! I didn't knew on could override this basic rule!
Tx, things are much better now, even if the FPS drop a bit...
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ElChristou
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Re: Virtual textures.

Post #4by ElChristou » 05.08.2008, 12:36

A thought about VT versus the low, med and high res texture architecture in Celestia:

With a 64k VT, one actually possess the best of highres map. The only problem is that depending on the config, such VT can be a bit heavy, for example, for a quick browsing it can be boring to have some loading time during the rotations or zooms. Now, what if Celestia was able to use let's say the two first levels as low res, the four first levels as medres and the whole set for highres? With one VT set the user could use the resolution levels of textures to truncate the data depending on his needs... I wonder if this make sense... :?
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rthorvald
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Re: Virtual textures.

Post #5by rthorvald » 05.08.2008, 13:56

ElChristou wrote:With a 64k VT, one actually possess the best of highres map. The only problem is that depending on the config, such VT can be a bit heavy

This is what i did:
I used a 64k png set with 1024x1024 tiles in my hires folder, and a 2k singular map in the lores. For the medres, i made a lores version of the 64k png set, which i made by reducing all the tiles to 25% (512x512 for the equatorial tiles), then converting to DDS.

So, i have a medium version that loads much faster of the full VT for MedRes... Works great.

- rthorvald
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ElChristou
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Re: Virtual textures.

Post #6by ElChristou » 05.08.2008, 14:39

Yep, many solutions are possible. What I was thinking about was to not have other low or medres files. Only one Highres 64k VT used for all levels...
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rthorvald
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Re: Virtual textures.

Post #7by rthorvald » 05.08.2008, 15:27

ElChristou wrote:Yep, many solutions are possible. What I was thinking about was to not have other low or medres files. Only one Highres 64k VT used for all levels...

Well, since each level is loaded depending on your distance to the planet, what you want is an override function that does not load higher levels if the HiRes option aren?t selected. But that will still load two 1024 high-quality tiles when you are on LoRes... Instead of for example a single 1024x512 map, which is often preferable. So it really does not make too much sense... It limits the options.

- rthorvald
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ANDREA
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Re: Virtual textures.

Post #8by ANDREA » 06.09.2008, 14:23

rthorvald wrote:I used a 64k png set with 1024x1024 tiles in my hires folder, and a 2k singular map in the lores. For the medres, i made a lores version of the 64k png set, which i made by reducing all the tiles to 25% (512x512 for the equatorial tiles), then converting to DDS.
So, i have a medium version that loads much faster of the full VT for MedRes... Works great.- rthorvald
Runar, what do you think on using as medres the levels1-4 only of the full 64k VT version? :?
Could it avoid me the resizing of all the textures up to level5?
Thanks a lot for your opinion.
Bye

Andrea :D
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