Lightening the edge of the water

[AntonioNoack]

Light Blue Coastlines

Description

The coast line water looked dirty, because the sand texture was blended with the water, and apparently, the world ground at z ~ -32 has a different color.

This PR adds a light-blue shine to coasts, so they look tropical rather than dirty.

Before this PR:

After this PR:

Implementation explanation:

I wanted to lighten the coast, so I had to find out where the coast is. Luckily, the depth texture is already available to that shader, so you can calculate the depth difference between the geometry and the background. Then just multiply that by cam_dir.z, and you have the water depth.

Remaining issues:

Please don't merge this yet, this doesn't work with MSAA yet.

I don't understand/know WGPU well enough yet to understand that error :/.

[CLAassistant]

All committers have signed the CLA.

[Uriopass]

Depth is different from distance so it actually looks weird at an angle but I have found out other games also do that trick and nobody seems to care so I'm ok with that.
The MSAA thing is from a time where I tried something similar, should probably not be a very complicated fix, it's about having the proper pipeline layout for the water shader

[Uriopass]

Fixed it.
Thanks ! Looks nice.