[1.9.5.2] Planet Shadow too large - finally found the cause of the problem

[Sirian]

I noticed this when trying to make a fix for the GEM mods planet images.

All images displayed here were taken with Distant Worlds' unmodded planet images and unmodded shadow.png



The effect is most visible at gas giants because of their giant size. You see a dark outline around the planet. This outline comes from the shadow.png image being superimposed over the scene. The outline is 12 pixels wide and ths about 3,21% too large. The outline is also visible at the left side of the planet, although it was easier to take a picture on the right side.



Here is an image of an ocean planet - enlarged to twice the original size - you can see the dark outline here too.



Another enlarged image, this time its a desert planet. Interesting here, either the shadow is ok on the upper left part of the image, or the bug is just not visible there.



Finally an image of a continental planet (actually a forest planet) There is a slim dark outline here too. Maybe the atmosphere of the planet makes the dark outline seem thinner here.

I observed the bug at barren planets too, but I have no images of it there.

[AstroCat]

Yes this is the problem with the game scaling we now have. Your images have to be the same size as the original game or the game does not scale them correctly. This effects many, if not all of the game .png files. I fixed this for GEM, in the GEM thread. I had to resize and rescale all the planets and overlays.

But it gets even more complicated when working with new shipsets, adding the engine exhausts and running lights. Often they have to be "offset" in the .png to appear correctly in game. And, even when you do get them correctly, on subsequent loads they might be shifted around by the game and appear out of align again, this especially happens with the engine exhaust .pngs.

It's a real pain, I really hope they fix this issue. It even effects things like the landscape images.

[Sirian]

I do not know if there is a misunderstanding on your side or not, so forgive if it isn't but:

There are the unmodded original planets of the game. I could understand if there were dark borders at modded planets, but this is the game as it ships.

[AstroCat]

Oh I know the game is not rendering/scaling correctly, modded or not. It just shows up more often with modded files.

[Sirian]

I finally found the problem that is causing this "bug". "Bug" because, since I found out what causes is, I do not see it as a bug anymore but a feature.

The problem is the planets atmosphere.

A continental planet has an atmosphere integrated into its image. This atmosphere needs to be obscurred by the planet shadow or else the planet will look like this:



Above image shows the continantal planet with the planet shadow scaled so it will fit the planets body perfectly. To obscure the atmosphere, the planet shadow needs to be larger than the planet. That causes the "too large planet shadow" effect we are encountering in mods and the original game.

This also means that this problem is unfixable unless either the atmosphere is removed from the planet image so it has no atmospheric glow anymore or an additional atmospheric glow sprite is added that has the planet shadow built into it.