Comments on: Weird Water

By: Benjamin Supnik

Benjamin Supnik — Sun, 04 Apr 2010 14:09:13 +0000

re: using noise for texture detail..the short answer is "yes". We have also looked at using a texture source for detail, as well as using noise sources for more complex modulation effects. There is no question that adding more detail on shader would provide scalability that simply having insanely huge textures wouldn't provide.

By: Anthony

Anthony — Tue, 30 Mar 2010 16:09:44 +0000

The water in x-plane is mostly excellent. it tends to fall down only in steep valley rivers. If we assumed that all sloping water is fast moving river water, could the reflections be disabled and replaced with a rapids texture with the direction running downhill, white water doesn't need any reflection. That would solve much of the weird water.

By: Anonymous

Anonymous — Sat, 27 Mar 2010 19:00:36 +0000

Raytracing should handle it very well. But yeah, obviously it's an entirely different beast that would require recoding everything. Not to mention the cost of maintaining raytracing structures and raytracing itself.

By: Anonymous

Anonymous — Sat, 27 Mar 2010 17:48:34 +0000

Not directly related to water rendering, but since you are using GLSL shaders, have you given any thought to baking several octaves of Perlin noise into a little (say 128x128xrgb) texture and modulating the intensity of the fragment color with that?

What this can very easily do is provide "fake" detail at a higher frequency than what's in the main terrain texture. When getting close to some terrain where you normally see single texels blown up to 100x100 on-screen pixels, instead it remains the same base color, but you avoid the "huge monotonous regions of interpolated color" problem. Since you don't need color in the noise texture, just intensity, one texture fetch can get you 3 octaves of noise in the rgb channels.

It doesn't pose a significant load on any modern-ish card; it's just one more sampler request at txCoord.xy*some_frequency, plus a modulation. It can make the terrain look a lot less bland close up.

Cheers,

- random new X-plane user (on Ubuntu64)

By: Christer Hellholm

Christer Hellholm — Wed, 24 Mar 2010 11:00:47 +0000

The problem you mentioned in your blog "Weird Water", will OpenRT or Real Time Raytracing have the same problem? I feel that OpenRT will solve your problem.

I'm, however, clear over that OpenRT will require huge horsepower from GPU boards.