Improve opaque leaves textures

[Wuzzy2]

Partial fix of #3001.

I updated all leaves textures so they look fine in Opaque Leaves mode. I edited the color of the transparent pixels but didn't change any other pixel. So the leaves in Fancy Leaves and Simple Leaves mode should NOT change at all. My technique was simply using the base texture and then rotating, copying and shifting it around until I filled the whole image and adding it to the background and then combine the whole thing. This works surprisingly well. :-)

There is one limitation: The blueberry bush with berries node still is bad. I swear I fixed the textures, but in Minetest, black pixels show up although both textures have no black pixels (even in the transparent ones). So my guess is Minetest has a problem with the texture overlay because this node uses an overlay. What should I do?

EDIT: Blueberry bush with berries fixed.

Screenshot: https://i.imgur.com/JYi3MTi.png

How to test: Test all leaves in Fancy, Simple and Opaque Leaves mode. Please also compare it with the previous texture and judge if it looks better than before.

Warning: Be careful when optimizing the leaves textures in future, don't accidentally throw away the transparent pixel color.

[Wuzzy2]

OK, I managed to find a workaround for the blueberry bush with berries node: For the default_blueberry_overlay.png, I used colors from the new default_blueberry_leaves.png for the transparent pixels. It would be better if leaves don't use any overlay at all but I didn't want to introduce new textures in order to not break texture packs.

[Wuzzy2]

Hmmm, I just noticed the bush leaves and apple leaves now look pretty similar in Opaque mode. Should I revert those back to the previous one?

[appgurueu]

Thanks for this. It's definitely a massive improvement:

Hmmm, I just noticed the bush leaves and apple leaves now look pretty similar in Opaque mode. Should I revert those back to the previous one?

I don't think that's an issue. I've always thought of bush and apple leaves as closely related (differing mostly in sparseness), similar to how acacia bush and acacia tree leaves are very similar (duh, they could even be the same node IMO).

Either way, this can be bikeshedded later on. No need to delay this improvement (or to go with uglier textures for better distinguishability). Why would you want to distinguish bush and apple leaves anyways? Most of the time it is clear anyways from whether the leaves are, well, up on a tree or down on a bush.