Celestia Forums

I downloaded and installed RealisticEarth-v4-8kDDS.dss from CelestiaMotherLode. I believe it is a Don Edwards 8k texture. When I start Celestia v1.4.0pre6 and switch it to the 8k texture from normal and then back to the normal default texture the program crashes after 1 change. It does the same thing in v1.3.2. It also does it with a 4k texture of Jupiter, but not as quick and only after circling the image and changing textures back and forth a few times. However, it does not do it with virtual textures....I have one of Jestr's 32K Earth textures with 32k Normal Map and Night Map....it works fine regardless of how many times I switch back and forth.

I have an Nvidia Geforce2 MX/MX400 with 64MB....I believe it only displays textures of 2048. Is that the problem, or is it a bug with Celestia? Why would I be able to switch between the 32k and default OK, but not the 4k or 8k, if it were due to the 2k limitation?

Also, does Celestia choke on the images even if none are selected as alternate images? For example, if I run Celestia with all the default planet images and the default star database with galaxies turned off, Celestia should run smooth then, right? It seems to me that Celestia, even when higher resolution images aren't selected, will still run choppy as if you had selected them....almost like it is still reading the "potential" image files and not just the selected ones. Anybody else experience this phenomenon?

How big is the 8K DDS image texture file? (ibiblio isn't reachable right now, so I can't check, but I'm sure it's more than 40MB.)

That entire file has to fit into the memory of your grahics card. All of the other surface textures that you look at have to fit in, too. Celestia doesn't unload a texture when you're not looking at it. It stays in the card until Celestia exits.

If you add them all up, you'll discover you're trying to look at more than 64MB of surface texture images. That can't work. Celestia doesn't try to do anything graceful when it encounters this problem. What happens depends on the exact circumstances. Sometimes it'll draw a bare sphere if there's no room for its surface texture image.. In this case, it crashes.

A 4K texture is smaller (~12MB?), so it takes a little longer before you encounter a problem while it's loaded.

In contrast, Jestr's 32K VTs consist of many small image texture files. Only the ones that you're looking at need to fit into the grahics card. Since you can see only a tiny portion of a planet at a time at high resolution, only some of them get loaded into your card. Of course, if you actually try to look at the whole thing at the highest resolution you'll eventually run into the same problem.

This is one reason why some people buy 256MB cards and are anxiously waiting for 512MB cards to be available with reasonable prices.