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PostPosted: Sun, 16-07-17, 7:47 GMT 
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https://celestiaproject.net/forum/viewt ... =3&t=17733


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PostPosted: Sun, 16-07-17, 14:12 GMT 
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sjohn / john71 wrote:
https://celestiaproject.net/forum/viewtopic.php?f=3&t=17733

As I anticipated, your crashes are not rooted in a 32bit -> 64bit issue.

What I strongly recommend to you in this situation is to consider textures including so-called mipmaps, i.e. instead of single textures, a set of textures, each being smaller by a factor of two than the previous one.

Wiki has a well readable introduction here:
https://en.wikipedia.org/wiki/Mipmap

OpenGL can handle these in the sense that dynamically, far away bodies are properly filtered to use an appropriate mipmap instead of the full texture! There is a large amount of literature about this technique in the net. Mipmaps may be generated with various tools, including --I recall-- the so-called NVIDIA texture tools.

Let me know if you need help there. But it's quite easy with the Nvidia texture tools. The DXT format naturally involves mipmaps. Hence all you need to do is to download the NV tools and compress (via nvcompress) all your 8k PNG textures into DXT format. There is a flag that may suppress generation of mipmaps during the conversion of PNG->DXT. Note that VT tiles automatically show mipmap behaviour...

While still developing Celestia (i.e.> 7 years ago) I did plenty of respective experiments with mipmaps. Here is such a thread of mine from 2004 ;-)
https://celestiaproject.net/forum/viewt ... 68&p=37872

Yet, my personal preference is still to switch to 16k VT tiles throughout and to optimize things with my tools, notably using DXT5nm instead of PNG for the normal maps! The resulting quality and resolution is excellent and the display speed is hard to beat. No problems with crashes at least in celestia.Sci.

Fridger

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PostPosted: Tue, 18-07-17, 4:42 GMT 
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if you are using a MS windows OS then use the directX dds format

my opinion is well known , so use what is BEST for YOU

and use the driver from your 3d card's website and NOT the one that win10 auto update will keep reinstalling
( unless MS has made peace with AMD and Nvidia in their war with them )

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PostPosted: Tue, 18-07-17, 18:54 GMT 
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Thanks for the advice! By the way, can I use dds for bump maps?

I started to use dds dxt5 files with mipmaps and there is some improvement.


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PostPosted: Tue, 18-07-17, 19:02 GMT 
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i would not use "bump maps"

Use a Normal map instead , for a planet texture use the "texturetools"

the normal tool converts the projection for a SPHERE!!!!! and not a flat plain ( like the gimp and PS tools do
also do not use "crazy bump " or like tools , they really do not work

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PostPosted: Tue, 18-07-17, 20:57 GMT 
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OK, but is it possible to have a dds normalmap?


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PostPosted: Tue, 18-07-17, 21:52 GMT 
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just do not compress it or if you do a very small amount

Cosmographia uses dds for a lot of things and celestia uses the same cmod code
Attachment:
Screenshot_20170718_175027.png
Screenshot_20170718_175027.png [ 571.69 KiB | Viewed 70 times ]

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PostPosted: Wed, 19-07-17, 7:21 GMT 
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sjohn wrote:
OK, but is it possible to have a dds normalmap?


@sjohn / john71:

While most of my previous writitng in this thread was about that issue ;-), how about reading this old tutorial of mine explaining in detail the importance and advantages of using DXT normalmaps.

http://www.celestialmatters.org/?q=node/10

For really excellent results, normalmaps need very smooth 16bit elevation map input AND need to be in the dedicated normalmap (nm) format dxt5nm.

Note this is crucial. dxt5nm is NOT equal to dxt5!!
Note also what I emphasized previously in this thread and JohnVV repeated:
t00fri wrote:
My tools moreover optimize the dxt5nm rendering and project the normal map correctly on spheres rather than incorrectly on plane surfaces!

John Van Vliet wrote:
..use the "texturetools" . The normal tool converts the projection for a SPHERE!!!!! and not a flat plain


How about having a look (again?) onto my previous two 16k examples utilizing exclusively DXT format for every texture including the normalmaps.
viewtopic.php?f=11&t=908#p14911

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PostPosted: Wed, 19-07-17, 21:08 GMT 
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Fridger: thanks for your help, but not everybody is a scientist! :)

I personally find your otherwise excellent programs hard to use without a GUI. So I use GIMP instead. Sorry. :o

DXT5nm (mipmaps generated) graphic files really work using the NormalMap parameter (but not BumpMap). Unfortunately under OpenGL 2.0 it produced very strange digital artifacts, so I decided to use png for the time being.

I have to admit that NormalMap is better than BumpMap.

I discovered CloudNormalMap, which is fantastic, very realistic!

Hey guys I have only used Celestia since 2014...I cannot know everything!

But thanks for your excellent help and advice!


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