Hi David, Pretty clever solution, but yes it does sound difficult to implement as a general case. To be honest I've don't think I've seen a real time ocean simulation with geometric wake formations, they usually just use texture overlays. I thought the overhead was too great. Perhaps I'm behind the times :)
Regards, Kim. -----Original Message----- From: [email protected] on behalf of David Spilling Sent: Mon 11/05/2009 20:44 To: OpenSceneGraph Users Subject: Re: [osg-users] osgOcean release Kim, For very large > expanses of ocean the problem I forsee is the time it takes to update the > vertices and primitive sets. > However, since the FFT technique is tileable it would be possible to only > update 1 tile and then translate > them into position using a shader. This would rule out any surface > interactions "Surface interactions" in terms of locally modifying the vertex heights? Tileable FFT doesn't definately rule it out : you can use the following approach: 1) render a FFT derived heightfield into a texture 2) RTT local heightfields (wakes and so on) attached to some object , as if you were the camera. 3) Use a vertex shader operating on a screen-aligned grid (i.e. projective grid approach) and some vertex texture operations to sample the FFT heightfield for the correct world position, and also to sample the RTT texture of "local" vertex heights. Unfortunately, the possibility of this type of technique makes providing some sort of overall osgOcean architecture that can act as a framework for all techniques very tricky, IMHO. (you get entangled in too many overall scenegraph issues) David
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