Saturday, January 12, 2008

Water: What's Coming Now

Beta 16 should be out relatively soon and includes what are probably the last of the water improvements for X-Plane 9.0. (All future water improvements will be in free patches or future releases.) Here's what made it into this particular version:
  • Water wave patterns now follow the wave settings in the weather-water screen.
  • "Fetch" data from the DSFs (information about whether water is subject to ocean waves or not) is used to modulate wave patterns - go to KSAN and set the wave height fairly high. Notice how the waves die out to ripples in some of the bays.
When I last blogged about water, I hadn't realized that we already have "fetch" data in the DSFs (and have since 820). Bear in mind that the fetch data in the current DSFs is not very good - I am sure you'll find plenty of strange cases where there are ocean waves inland, or calm areas in the ocean. The algorithm just isn't that good. New fetch data only comes with new global scenery.

The physics engine is not synchronized with the visual waves, although they both use the same wave height from the weather screen. The physics engine isn't using fetch yet. I may be ale to address this in a future beta, but I'm not sure.

What I have had to punt on (for now - remember, a ton of new features come to X-Plane in the form of free patches!) is the issue of reflectivity, sparkle, and water color from various view angles. As I explained in my previous post, the way the wave pattern is filtered with view-distance causes the water to look unrealistically calm from far away. Now that we can haev taller waves this is less of an issue (set very high waves to avoid the reflective look as much as possible) but it's still there.

I have some possible technology ideas on how to address this problem, but we don't have enough time left in this build to go all the way with them.

One final note on water: Windows users witih Radeon HD hardware can work around the corrupt reflective water issue by running the sim with --no_fbos.

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