will it run faster if i use dds files instead of jpg files??

[cyf]

will it run faster if i use dds files instead of jpg files in celestia??
P4 1.5Ghz
384MB SD RAM
Geforce4MX440 64MB DDR AGP8X card

[Psykotik]

To a GeForce user, I can say definitely yes. But you will loose some details.

[selden]

DDS files are a lot faster, since they're used directly by the hardware and don't have to be decompressed. Usually the reduction of the color palette isn't noticable at all.

[Rassilon]

If I were to use DDS with my addons I could not use compression as the dds compressor is worse than the jpeg one...It leaves dirty squares similar to low jpeg compression...The drawback of uncompressed dds files is that they range 8-10 megs for a 2048 x 1024 size texture...

They do load faster but will gobble up memory more than a jpeg...

[cyf]

then which texture should i use,dds or jpg/png??
when i use 4K earth dds texture,it runs very slow in celestia.

[Guest]

A 4k jpg will run just as slow for you then...Use a smaller texture size...

[Guckytos]

Well just yesterday i was out testing the load times of jpg versus dds files in celestia.

Hardware:
800 MHz Athlon
386 MB Ram
ATI 8500LE 64 MB
about 800 MB free Harddisk
win 98SE

first i started Celestia put myself in normal orbit around the planet and the switched the resolution and time it with a watch.
Earth:
Type Resolution Time until shown
jpg 8k 35 seconds
dds 16k 15 seconds

Mars:
Type Resolution Size Time until shown
jpg 8k 5 MB 55 seconds
dds 16k 90 MB 10 seconds

So the result is dds loads a whole lot faster on a slow machine than a jpg file. But you need really a lot more space on the harddrive.

and i found that flying from planet to planet in Highres seemed sometimes really slow, perhaps the system ran out of virtual memory?

Anyways, these are the results of my small test.

BTW: The moon in 16k dds highres really rocks!!

[Harry]

Well just yesterday i was out testing the load times of jpg versus dds files in celestia.

Your test made me curious, so I tested this on my own system (900 MHz Athlon, 256 MB). First with a 2048x1024 texture, time measured with a script using the preloadtexture command:

Code: Select all

JPG  0.5s
PNG  0.6s
DDS  0.05s


Yes, DDS needs 1/10th the time here - admittedly my system (slow CPU, fast disk) favours them, but still impressive.
Now with 8192x4096 things get even worse, because JPG/PNG need ~100 MB memory (which isn't initially available), while DDS only needs ~16 MB:

Code: Select all

JPG: 23s
PNG: 27s
DDS: ~0.9s !


And as a nice side effect Celestia is still usable (with 25 fps) while displaying this texture as a DDS, which is not the case with JPG/PNG ( << 1 fps). Faster systems with more memory (system memory as well as graphics card memory) may show very different numbers, but DDS should still win.

Now excuse me while I convert my textures to DDS...

Harald

[Guckytos]

Thanks Harry,

Now we have some really measured times. Hope you had fun converting your textures.

Just to clarify my timing method: I took the time from pressing the change resolution keys until Celestia did reaction to a zoom in command, after the texture was loaded.
Like pressing Shift + R, then scrolling the mouse wheel and waiting 'til the picture zoomed in.
So mine was just a ballpark method.