why are we skiping textur sizes?

[Star Lion]

I just noticed this, all the texturs here are eather 2k, 4k, 8k, 16k, 32k, or 64k.

But what about 2k, 4k, 6k, 8k, 10k, 12k, 14k, 16k, 18k, 20k, 22k, 24k, 26k, 28k, 30k, 32k, 34k, 36k, 38k, 40k, 42k, 44k, 46k, 48k, 50k, 52k, 54k, 56k, 58k, 60k, 62k, 64k?

Thees are all a powe of 2, and haveing all of these would provide a smoother transition in VT's

[Don. Edwards]

Because of the power of 2 rule. That means each texture is 2 times 2 not 2 plus 2. That’s why we have no 6k, 10k and so on. So this means that if you start with a 1024x512 texture times it by 2 gives you a 2048x1024 texture, and by times it by 2 again you get 4096x2048, and then again you get 8192x4096, and again you get 16384x8192. Each texture is a 2 times increase in size but in actuality 4 times the size of the previous texture. Here is a texture size table that everyone should find useful in understanding how textures are sized and how each increase in size is exponential over the last one.


I hope this answers your question. Now get ready for a quiz on the subject.
Just kidding.

[Star Lion]

hmm, I wonder when we will be able to use odd sised texturs? If Celestia could we would be abel to have a much smoother transition between textur sizes with VT's.
One other problem vith VT's is that you cant select what level textur you want to start with , is it just me or does the earth look blury right befor a textur levle change?

sorry, now I'm ramboling
thanks for clearing this up

[selden]

Starlion,

My understanding is that the graphics chips require textures that are a power of two on a side. Programs which permit other sizes have to rescale the images. Performance and resolution are improved because Celestia enforces the necessary sizes to begin with.

You are correct that Celestia should change resolutions at higher altitudes. Hopefully this will be fixed in a future release.

[steffens]

Well, maybe graphics hardware needs textures to be of powers of two, but as I understand it, there is the possibility to apply multiple textures to objects. So chances are, that we could see virtual textures of 6x3 tiles, 1024x1024 pixels each. I know that this is not possible with current VTs and I do agree that handling textures the "power of two" way might be much easier. A binary tree is just u nice structure...

steffens

[jim]

hmm, I wonder when we will be able to use odd sised texturs? If Celestia could we would be abel to have a much smoother transition between textur sizes with VT's.

My current texture folder gots already a size of 1,5GigaByte and will grow up further. I see absolute no sence to add 'between' levels. Celestia is busy enougth with the current textures.

One other problem vith VT's is that you cant select what level textur you want to start with , is it just me or does the earth look blury right befor a textur levle change?

If you read carrefull this forum you would know the solution. Change the 'TileSize' in the 'CTX' of your VT to the next lower value (e.g. 512 -> 256) and you get sharp textures by cost of perfomence (Celestia must load 4 times more textures).

Bye Jens

[Star Lion]

changed cxt file, and the texturs do look better
I dont notice any chang in fps rate, maby its my GForce FX 5900!