ballisticfox
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Remaking 64k Textures.
🕑 Added 2023-06-20 00:29:11 +0000 UTCWell here's the first little dev diary/update thing.
Currently remaking 64k textures for RSS-Reborn, similar to what EVO and PRVE-64k have, this time I'm not reusing the same old textures PingoPete made back in 2016 for RVE64.
The reason I'm doing this is pretty simple, PingoPete cut out spots for the citylights, which just looks awful because you end up with random gaps in the texture, I tried recovering them through the alpha channel but the data's been lost so I have to remake them.
These will probably release in a day or two when I finish up with removing the leftover water
Dev Stuff:
This is the source of the textures, I believe it's the source of pretty much every Earth texture about on the internet, with a maximum color map resolution of 81k in 8 tiles.
https://visibleearth.nasa.gov/collection/1484/blue-marble
After combining the 8 tiles and resizing the image to 65536x32768 (64k) I can get to work.
Cubemaps are basically a different way of projecting square textures onto a sphere
Now the question is, how do we turn a equirectangular map (seen below)
Into 6 faces?
Well, first, let's project the image onto a sphere, because we know we can do that:
Then, let's move our camera inside of then sphere
This is basically what we need for a cubemap, just set the camera to orthographic to remove the perspective and rotate it around and that's what you get, but Blender is just too hefty and not specialized enough to do this task efficiently, so let's find a better way.
Thinking about this problem I realized that in a way, I am basically just using this texture as a panorama, projecting it onto a sphere a technically infinite distance away and taking pictures on it, luckily gimp has a filter just for this, Panorama Projection (in filters>map>panorama projection)
It's rather tricky to see when you can't move the canvas around, so you'll have to bare with me
Using this I can set the canvas to a square that is 1/4th the width and center, after adjusting the zoom a bit it becomes much more apparent this is the inside of a sphere.
Then I can set the Pan to 0, tilt to 0, and zoom to 25 (what I found to be the proper value via referencing the other textures) and we get our first cubemap face!
Then simply step up the Pan by 90 again until you get the four horizontal, then set it back to 0, and set the tilt to -90 (backwards I know) to get the northern and 90 to get the southern tiles.
After way too much screwing around with color to alpha to remove all of the water we get the beautiful textures seen above!
Anyways that's all for right now, my MTE Script development will be out in an hour or two, thanks for reading!
