MipLevels = 13

Expanding and utilizing the engine via C++.
27 posts Page 3 of 3
chriscalef
Posts: 398
Joined: Mon Feb 09, 2015 7:48 pm
by chriscalef » Sat Apr 18, 2020 2:42 am
Sweet, thanks! :mrgreen:
Duion
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Joined: Sun Feb 08, 2015 1:51 am
 
by Duion » Mon Apr 20, 2020 5:51 pm
well there are some black areas on that texture map so im guessing it has alpha? but it doesnt seem to have any fading alpha so no banding should occur from DXT3
You are such amateurs, always use DXT1 if possible, if you cannot because alpha channel, delete alpha channel, since those textures are not supposed to have alpha, but even DXT1 can have alpha, just no gradients in it. DXT1 gives best performance, since it is half the size of DXT3 or 5.

And someone should go to the Flightgear developers and punish them for their development style crimes, but hey wait a minute, I just realized why they may do it that way, the reason is if you have an atlas texture with no textures right or left to it, you can tile the texture horizontally using the atlas texture without creating new polygons. So this may be the reason for that weird format, but I see they also have textures next to each other, which breaks this system again, so no idea, if they are genius or just stupid. The textures are also too small, should be at least 512 pixels or even 1024, think about upwards compatibility, which open source developers usually never care about, but a professional developers usually always keeps the high res versions.
marauder2k9
Posts: 418
Joined: Wed Feb 18, 2015 7:36 am
by marauder2k9 » Mon Apr 20, 2020 10:00 pm
well there are some black areas on that texture map so im guessing it has alpha? but it doesnt seem to have any fading alpha so no banding should occur from DXT3
You are such amateurs, always use DXT1 if possible, if you cannot because alpha channel, delete alpha channel, since those textures are not supposed to have alpha, but even DXT1 can have alpha, just no gradients in it. DXT1 gives best performance, since it is half the size of DXT3 or 5.

And someone should go to the Flightgear developers and punish them for their development style crimes, but hey wait a minute, I just realized why they may do it that way, the reason is if you have an atlas texture with no textures right or left to it, you can tile the texture horizontally using the atlas texture without creating new polygons. So this may be the reason for that weird format, but I see they also have textures next to each other, which breaks this system again, so no idea, if they are genius or just stupid. The textures are also too small, should be at least 512 pixels or even 1024, think about upwards compatibility, which open source developers usually never care about, but a professional developers usually always keeps the high res versions.
DXT1 is smaller for a reason, due to the finer details in the texture he posted he should use DXT3

if you look at this image, the pic on the left is the original image the one on the right is after DXT1 compression. The finer changes in color are completely removed under the compression. You have too many details in those textures that are close together such as the roof tiles. if you were to have them as DXT1 these details would be lost.

Image

This happens because DXT1 is only 4 bpp whereas DXT3 is 8 bpp

EDIT: Also just on that point about the Flightgear developers. They probably modeled whole cityscapes in one file with simple geometry plus, being a flight sim they would have probably thought most of your time would be spent yano flying! as far away from any of those textures as possible. Smaller textures actually look better from further distances. That's actually why mipmaps are used in a lot of games, its not to save on resources as using mipmaps actually use more resources because the engine is loading more textures than if you were to just use the default texture, but if you already start off with the smaller texture u don't really need them if these textures are specifically meant to be viewed from a distance.
chriscalef
Posts: 398
Joined: Mon Feb 09, 2015 7:48 pm
by chriscalef » Mon Apr 20, 2020 10:22 pm
if you have an atlas texture with no textures right or left to it, you can tile the texture horizontally using the atlas texture without creating new polygons
Ah, thanks, I didn't know that, and that explains why so often there are triangles that extend off the right side of the file. They do sometimes put two textures next to each other, but it's not the typical case, and there are definitely a lot of UVs that go into space on the right, so maybe they just know which is which somehow.

Re: going to yell at them, good luck with that, it's a bunch of part time volunteer people with mixed skill levels, same as every other open source project, and they have their own set of flame wars ongoing, feel free to go start one if you want but don't tell anybody you're with me. ;) :lol:
Duion
Posts: 1626
Joined: Sun Feb 08, 2015 1:51 am
 
by Duion » Tue Apr 21, 2020 1:52 am
I hardly ever found DXT1 to be an issue, it is only bad for normal maps or textures with alpha, if your low res textures look fine from the distance the few broken pixels due to DXT1 will not matter also.
chriscalef
Posts: 398
Joined: Mon Feb 09, 2015 7:48 pm
by chriscalef » Tue Apr 21, 2020 4:22 am
Yeah, DXT1 looks fine to me, all together it came out about half the size of the original png with mipmapping on board, so, yay! Thanks a lot.
Duion
Posts: 1626
Joined: Sun Feb 08, 2015 1:51 am
 
by Duion » Tue Apr 21, 2020 9:00 am
The compression on DDS files looks bad when you only look at filesize, the main advantage is that DDS files are not uncompressed in the GPU.

I wonder if the mip maps work or look good on such a small texture. If you have a front of windows on a 256 pixel wide texture, they will probably be destroyed and become only blur color after one or two mip map levels.
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