[Dragon]

I will get straight to the point.
I would like to ask ,why there is no height maps in mediavps.
They improve the game look ,but the only places where I found them was TVWP normal maps pack and FSPort HTL Karnak maps. I know that the change is not as significant as with normal maps ,but I think they are still worth of effort. So I would like to know why they are not included into mediavps.
(on a side note 3.6.10 also miss HTL Typhon made by Trashman)

[Herra Tohtori]

Their proper use so that the parallax effect equals the perceived height difference from the normal maps is almost impossible, and when the parallax effect isn't in sync with the normal map it causes really weird stuff to happen.

It simply doesn't work very well at all with sharp transitions between high and low ground, which it what ships' surface detail usually consists of. So, it was deemed that they didn't offer enough benefits for the performance they took (in fact my personal opinion is that they degraded the quality on most cases) so they were taken away to save bandwidth and topics where users ask about weird stuff going on in their model surfaces. For example the Karnak's height maps caused a really strange thing where the textures changed locations in a way that was definitely not intended...

Also, TrashMan's Typhon was not qualified for the MediaVP's due to it's strange texture usage as well as other model issues (plus in a blind test, majority thought the retail model was the improved one). Personally I tend to also think that the retail model with GalEmp's maps looks better than TM's model. It should be available in FreeSpaceMods, though, so anyone who wants can install it as a replacement to mediaVP's.

[Dragon]

OK ,I never had problems with height mapping ,I think you can make a pack with all height maps made for FS2 textures and release it with "at your own risk" sign.
(or I can do it myself if I only know which mediavps were the latest ones to have height maps).
As for Typhon I will upload a simplified ,3.6.10 compatible version (availabe Typhon is a mod).

[DaBrain]

Parallax mapping only works for organic models.

I gave up trying to make it work for ships and fighters.
It might be used for asteroids in the next version, but that's about it.

There is no point in releasing the height maps. They weren't designed to be used with parallax mapping and will lead to terrible results.

[Aardwolf]

Their proper use so that the parallax effect equals the perceived height difference from the normal maps is almost impossible, and when the parallax effect isn't in sync with the normal map it causes really weird stuff to happen.

Why is it 'almost impossible' ? I don't really know what math is behind it, and although I could probably understand it I don't really care to, but... Couldn't you just use a single map, containing height values, to determine the texel that is going to be drawn, and then look up the normal vector in a normal map generated at load-time (if necessary)?

[Zacam]

Good luck with that.

[Herra Tohtori]

Why is it 'almost impossible' ? I don't really know what math is behind it, and although I could probably understand it I don't really care to, but... Couldn't you just use a single map, containing height values, to determine the texel that is going to be drawn, and then look up the normal vector in a normal map generated at load-time (if necessary)?

Because the perceived surface "altitude" variations caused by normal map are relative and those caused by parallax map are absolute.


Normal map "tilts" the surface into some direction, and the change of height depends not only on the angle of the tilt but the width of it; it's simple trigonometry. On the other hand, height map needs an absolute scale of lowest point and highest point (black and white) to know the parallax difference that the shader should utilize between those points, and "no parallax shift" always needs to be middle gray. Then there's the matter of model scale... on normal maps it's not a problem because everything is relative, but parallax maps are more troublesome. Is the height difference from lowest to highest point defined in game units? Or relative units depending on the model's size? What happens when the geometry in parallax and normal map do not match perfectly?

And this is why it is practical impossibility to make the height map's scale match the scale of perceived height variations on all places of the map.

The problem is further exacerbated by the fact that when you generate a normal map from the height map, it doesn't necessarily match the original height map. For example, normal map cannot deal with immediate contrast changes from black to white, so it generates a narrow transition area with maximal normal angle difference. And now there is a discrepancy already between what the normal map makes you think and what the height map thinks the surface geometry should be, and they start fighting each other and results are not good.

The general result is that parallax mapping for ships is not useable as such. Besides the general perceived surface geometry impression from normal maps alone is very effective and more than sufficient for ships.