So the Windows7 beta has a cool new feature for backgrounds (desktop wallpapers) where you can set a rotation of several pictures and it phases from one to another on a timescale you set.
So I had a cool idea that if I could get my hands on pictures of the earth rotating in even spaced sequences that I could generate a sort of slowly animated background that rotates over a long period of time, even maybe in sequence with the actual rotation (over 24 hours)
Anyway getting the pics proved impossible, the few sets I found were either too infrequent (like quaterly shots) and were too low resolution, I wanted it for my 30" monitor which runs at 2560x1600
So I decided to make my own, heres how I did it. It took some investigation and some hacks to get the quality up but it worked a treat.
1) Download Celestia, a fantastic free simulation app - http://www.shatters.net/celestia/
2) The earth skin in Celestia is really low res so goto visibleearth.nasa.gov and aquire a high res picture of earth that is laid out flat, I grabbed the 48.7Mb TIFF [url="http://visibleearth.nasa.gov/view_rec.php?id=2431"]from here[/url]
3) Celestia needs images in .png format, so edit the image and save as 100% quality .png file, I used [url="http://www.paint.net/"]Paint.net[/url] which is free, the image ends up about 50mb.
4) Go to your Celestia install folder and in there find the /Celestia/textures/medres/ folder, replace the old earth.png with your new one, keep a backup of thje original if you want to undo the change.
5) While you're in the Celestia folder also go to /Celestia/data/ and rename "spacecraft.ssc" to "spacecraft.ssc.org". This file contains the data for several satalites orbiting earth, I couldnt find a way to distable them inside Celesitas menu so renaming this file just stops Celestia from loading the data, you can rename it back afterwards, it's only a white spot that rotates around but I wanted mine perfect
6) For best quality you want to force AA and AF, go into your control panel and if with Nvidia create a profile for Celestia, for ATI just force AA and AF for now, and revert back aftwards, I forced 16xAA and 16xAF
7) Down fraps for free [url="http://www.fraps.com/"]here[/url], install it then run it, go to the "screenshots" tab and set a record key (I used numpad + as it wasnt a shortcut key for Celestia also) then tick the "Repeat screen capture every x seconds" and set X to 1, this will make fraps take screenshot at regular intervals, for the best quality set the type to BMP, this is completely uncompressed (2560x1600 shots come out at 12mb each)
Run Celestia, configuire this to how you like it, theres a few things you'll want to do to get the best image pictures:
- Set "Toggle full screen" mode from the "Render" menu, also pick your monitors native resolution from the "Select Display Mode" menu.
- In the "Render" menu go to "View options" and untick anything you dont want displayed such as "markers" and set the information text to "none" to remove the HUD stuff, I also got rid of Athmospheres because thats another seperate layer for earth which spoils the particular image I used since it already had clouds etc
- Use [ and ] keys to decrease/increase the distance stars are rendered at, I increased a fair bit to get a fairly dense stary background which looks nice
- Turn of Anti-Aliasing in the "Render" menu, this will just cause problems with the AA you forced previously
- Use mousewheel to set distance, use right click-drag to set angle, if you left drag and take the earth off centre then just press the C key to re-centre.
- If when animating the camera is roating about the earth causing the stars to also rotate then just press the F key to enter follow mode, this fixes the stars and just rotates the earth.
Use spacebar to pause/unpause roation and use K and L keys to decrease and Increase the speed, I set mine fast at first to get an idea of what it would look like from all angles, tilted to get the best angle then set it slowly.
All thats left is to set the time speed using the [ and ] keys so its rotating slowly (approx 80 sec full rotate I made mine out to be) and make a mental note of when you start the image capture, I waited until a particular part of a continent was right at the edge of the globe. Hit the record key (numpad + in my case) and let it rotate, press again when finished.
You should find yourself with approx 80 images if you used the same rotate speed as me, or less if you used a faster one. I renmaed mine all to keep them in order as just 1.bmp. 2.bmp etc, copy them all to a seperate folder somewhere safe and then in windows 7 just go to the background properties and select that folder, tick all the images, make sure shuffle is unticked and set the cycle speed, I set 1 minute. And you're done!
Here's a jpg compressed at 100% qality in paint.net, I dont know if it's identical but either way I couldn't host a 12mb BMP It's 1Mb (down from 12mb) it's the first frame I did, it's in 2560x1600, you can see the AF and AA did a nice job of cleaning up the high res source image.
(apologies this forum wont fit the image width, heres the link to the full image on imageshack, you may need to click to zoom full size - http://img4.imageshack.us/img4/1982/74174584.jpg)
This is the whole set of 87 images packed into 67mb, all uncompressed and full quality 12mb bmp files - http://www.mediafire.com/?giwddlnn2jm