Celestia Forums

Hi,

I'm getting very jealous of seeing peoples posts with beautiful images of hi-res Earth textures (yes, you know who you are ), while I suffer here using the original distribution Earth texture and a 4K JPG version.

I thought it was time I downloaded a better quality Earth. The trouble is that with my hardware there's probably no point wasting bandwidth downloading textures that are just going to bring my hardware to a grinding halt. (eg. 128K, 64K, or even probably 32K)

So the reason for this post is to ask for other peoples advice (or experiences with similar H/w configuration) as to the maximum resolution and type of texture it would be reasonable to D/L and still maintain reasonable FPS and/or load times.

I have 1 desktop and 2 laptops (all windows) none of which is very spectacular as they were not purchased with Celestia or graphics performance in mind.

In order of apparent graphics capabilities from worst to best (in my experience):


According to what I've read in stickies, higher resolution (8K/16K) DDS format maps may actually work better than the 4K JPG I've currently got, but I'm not sure if my H/W will handle DDS. (The 3rd configuration above, does have options to "Force S3TC texture compression" and "Force FXT1 texture compression" which makes me think that it may handle DDS's. The other laptop also mentions texture compression but nothing about S3TC. SO even if the last one handles DDS, the other 2 probably wont.

So, my questions are basically:
1. What's the maximum resolution that I should download without wasting my time?
2. Is it worth downloading DDS format maps at all? - ie. which configs above would handle DDS?
3. If I was to upgrade my graphics and RAM (I suspect probably only practical on the desktop) to handle 64K or 128K maps, what specification is recommended?

I'd appreciate any advice from either people with similar HW as to what textures they have managed OK,
OR
from people using 64K/128K textures as to their machine specification and experiences with load performance, frame-rates etc.

Thanks in advance
CC

If at all possible, you should consider upgrading the main memory on whichever system(s) you use the most for Celestia, to 512 MB or maybe even 1GB. Most laptops can be upgraded, but you do have to be careful to get compatible memory sticks. (VT memory usage, for example, starts small but as you look at different locations it quickly grows until the system pages frantically.)

You probably should test your systems using a small DDS image. I'm not sure the OpenGL features you mention are relevant. There's a 170KB 512x256 DDS surface texture that can be used for Mars at http://www.lepp.cornell.edu/~seb/celest ... rs-512.dds
It is quite distinctive, so you'll know when you see it

( See http://www.lepp.cornell.edu/~seb/celest ... index.html
for more info about the RGB Mars Addon. )

Thanks Selden,
(very nice texture BTW.)

It works on System#1, so prob. will be fine on the others as well.
Does this mean I'll be able to use any of the VT maps ? (as they are made up of DDS's) -- or is something else required to be able to handle tiled VT's.
Of course, there'll still be a limit to the size I can use without upgrading my H/W. I was surprised you only mentioned upgrading system RAM. I would have thought that video memory would be a higher priority than system RAM for Celestia. In any case, the desktop will probably be 5x cheaper to upgrade than the laptops, and if I want to take advantage of all the new OpenGL2.0 rendering for atmosphere's etc, then I think a new graphics card will be required, and that might be difficult on the laptops.
Up to now, I've found it more convenient to do Celestia work on the laptops, but that might have to change post 1.5.

Actually, another question arises out of this. I noticed while trying this DDS out that it only works if placed in one of the top-level Celestia/textures subfolders, but NOT if installed as an extra. (if installed as an alt surface, then the SSC could exist in extras, but the texture can't, even if in a similar folder structure), so what are the implications of this for managing VT sets with lots of DDS's?
Sorry if this is a bit of a newbie question. I think I've seen the answer somewhere in the past, just can't remember where, and as I haven't used VT's before, I didn't really take too much notice.

regards
CC

Chuft-Captain wrote:Thanks Selden,
(very nice texture BTW.)

The map itself is by Frans Blok (see the Web page mentioned above). I just converted it for use with Celestia.

It works on System#1, so prob. will be fine on the others as well.
Does this mean I'll be able to use any of the VT maps ? (as they are made up of DDS's) -- or is something else required to be able to handle tiled VT's.

That means the DDS VTs should work.

Of course, there'll still be a limit to the size I can use without upgrading my H/W. I was surprised you only mentioned upgrading system RAM. I would have thought that video memory would be a higher priority than system RAM for Celestia.

I assumed you knew that Get the best Nvidia card you can afford, but even a bottom of the line 5200/6200/7200 would be just fine. If you don't upgrade the main memory, though, performance will be pathetic for large textures.

In any case, the desktop will probably be 5x cheaper to upgrade than the laptops, and if I want to take advantage of all the new OpenGL2.0 rendering for atmosphere's etc, then I think a new graphics card will be required, and that might be difficult on the laptops.

impossible, unfortunately I think Alienware has been the only company to produce laptops with replacable graphics cards.

Actually, another question arises out of this. I noticed while trying this DDS out that it only works if placed in one of the top-level Celestia/textures subfolders, but NOT if installed as an extra. (if installed as an alt surface, then the SSC could exist in extras, but the texture can't, even if in a similar folder structure)

That's certainly not my experience: so long as the Addon's directory structure is correct, all texture types (including VTs) work fine in the Addon's /textures/ folders. They don't have to be in one of Celestia's top level /textures/ folders.

so what are the implications of this for managing VT sets with lots of DDS's?
Sorry if this is a bit of a newbie question. I think I've seen the answer somewhere in the past, just can't remember where, and as I haven't used VT's before, I didn't really take too much notice.

Tch, tch.

Sorry: I'll have to point you toward the docs. There are too many details that have to be correct for me to spell them out here.

Of course, I'll point you to my pages but they include links to more docs on the MotherLode and elsewhere.
http://www.lepp.cornell.edu/~seb/celestia/textures.html

Thanks Selden,

I think I'll try downloading a 16K or 32K VT, although without upgrading I suspect even that might be a stretch with my current config.

Of course, there'll still be a limit to the size I can use without upgrading my H/W. I was surprised you only mentioned upgrading system RAM. I would have thought that video memory would be a higher priority than system RAM for Celestia.

I assumed you knew that Get the best Nvidia card you can afford, but even a bottom of the line 5200/6200/7200 would be just fine. If you don't upgrade the main memory, though, performance will be pathetic for large textures.

Do you see any value at all in increasing the RAM on the laptops ? - given that the graphics chip can't be upgraded as well.
IMO, it would significantly improve performance by reducing or eliminating swapping between disk and RAM for large textures, but I'd still have swapping between video RAM and system RAM but this would be less significant as it's orders of magnitude faster than disk.
So it seems to me that the bulk of the performance increase can be achieved from more system RAM.
Of course this wouldn't give any openGL2 enhancements but just improved performance, and laptop RAM is pretty expensive cf. desktop stuff.

Actually, another question arises out of this. I noticed while trying this DDS out that it only works if placed in one of the top-level Celestia/textures subfolders, but NOT if installed as an extra. (if installed as an alt surface, then the SSC could exist in extras, but the texture can't, even if in a similar folder structure)

That's certainly not my experience: so long as the Addon's directory structure is correct, all texture types (including VTs) work fine in the Addon's /textures/ folders. They don't have to be in one of Celestia's top level /textures/ folders.

Sorry, I made a stupid mistake. Work's fine if I get the folder structure right!

Tch, tch.

I always assumed my lowly system couldn't handle VT's.

Chuft-Captain wrote:Thanks Selden,

I think I'll try downloading a 16K or 32K VT, although without upgrading I suspect even that might be a stretch with my current config.

One advantage of VTs is that the individual tiles are relatively small, typically 512x256 or 1Kx512. The entire VT doesn't get loaded, only the tiles you look at. More main memory and/or paging file space helps since many tiles eventually will be loaded if you do much exploring.

So it seems to me that the bulk of the performance increase can be achieved from more system RAM.

Exactly.

Many laptop graphics chipsets don't have dedicated graphics memory. They map to a chunk of main memory instead, making it unavailable to the operating system. You'll have to check the specs of your systems to see if that's what they do. If so, more main memory will help that much more.

You'll have to decide how much it's worth to you. Investing the same money into that much better a graphics card for your desktop could be more rewarding emotionally.

Great.

Thanks for all the helpful advice Selden.
Sounds like even a 64K texture will work better than non-VT, as it will have a small memory footprint as long as you don't get too close to the object.


I think system#1 has shared graphics (16MB) (system RAM reduced to 240MB) and system#3 has a chip.
Unfortunately, from what I understand, increasing system RAM (although helpful with performance) won't result in a larger allocation to video memory - it will still only use 16MB.

regards
CC