I'm afraid I can't recall the interpolation method used for generating the normals from the gerstner model, it is detailed in the book. I personally didn't use the gerstner approach since I had already built an FFT simulation for the wave surface and wanted to use that for the the normal computation instead. The extrusion of the parallelpepids is done within the vertex shader, you store the length of the extrusion as a texture coordinate for each vertex. So inside the vertex shader you have something along the lines of: newVertex = oldVertex + (gl_TexCoord[0] * refractionVector); That way you can differentiate between vertices that lie on the water surface and those that need to extruded downward. Finally, everything in the screen shot is simulated, no real world objects. Sorry the screenshot was deliberatly small as I didn't want to bloat peoples inboxes. Regards, Kim.
________________________________
From: [EMAIL PROTECTED] on behalf of Ümit Uzun
Sent: Tue 04/11/2008 12:35
To: OpenSceneGraph Users
Subject: Re: [osg-users] MAX to COLLADA or which format ?
Hi Kim,
Thanks for detailed explanation. I grasp the method of sun-beams and I will
read in ShaderX5 too. But could you clarify me at some point before I have
started to search about this topic?
I will create my own water surface and waves algorithm. And then with using sun
light I will calculate the reflection and refraction angles for every vertex
point. Then I will use this interpolated refraction angle and vertex position I
will create a grided parallelepiped volume which is going downward this point
under the sea with attenuating the glowing degree. But At that point I can't
understand the creation of this parallelepiped volume creation on
FragmentShader. How this grid of parallelepiped volumes geometry can be
interpolated ?
And I like so much your posted screen shot :) This is I think VENUS submarine
and I have some question about it. Is there all simulation environment or with
pilot cabin? I can't realize joysticks, another screen which is showing above
the water surface and sonar gauge are real objects or simulated environment.
Thanks for your advices Kim.
Best Regards.
2008/11/4 Kim C Bale <[EMAIL PROTECTED]>
Hi Umit,
Rendering God-rays is pretty easy. The approach I used is described in
the book ShaderX5, although I have to say it's quite badly written.
Basically you model the god-rays as a grid of parallelepipeds
positioned at the ocean surface, relative to the position of the camera. To
create the god-ray geometry you then need to extrude the base points downward
along the angle of refraction from the sea surface.
In order to compute the angle of refraction you'll need to create a
simulation of the ocean surface itself. The technique described in ShaderX5
details a Gerstner wave surface partially computed on the GPU. Using this you
can interpolate between the vertex normals to get the normals you need to
compute the refraction angles. Finally, you render these god-rays into a FBO
and then render that texture to the screen with additive blending. A final
stage which would look nice is to apply some sort of blur to the rays texture
so the edges aren't quite so crisp.
You can see the effect in the attached screenshot.
Regards,
Kim.
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ümit Uzun
Sent: 31 October 2008 15:42
To: OpenSceneGraph Users
Subject: Re: [osg-users] MAX to COLLADA or which format ?
Hi Kim,
2008/10/31 Kim C Bale <[EMAIL PROTECTED]>
Hi Umit,
Yes, I am employed on the VENUS project, how on earth do you know that?
I have searched on internet and so know VENUS project and your MSc
student Franclin Foping and another student Philip Apery who worked same
project before. I have read these student thesis and implement in my animation.
(caustics, fish motion, aquatic floara, silt on sea bed, water refraction and
so on...) Now I only want to much realistic fish motion as I said. So I
learned that I should try different tools like animetk or just like it.
I want to ask another question about god-rays. Did you implement
god-rays to VENUS? I want to create god-rays in my simulation, so is there any
advices and searh path you can give me?
Thanks for all advices Kim.
Best Regards.
Umit Uzun
I, personally haven't worked with any flocking algorithms, it's
a feature I haven't got round to adding yet. However, I did supervise an MSc
student project on flocking using OSG. In order to simulate fish body motion he
used an animated vertex shader to distort the model with a dampened sine wave
(as you mentioned). With a bit of tinkering this should provide nice results
with minimal effort. However, if you want more accurate movement I think it
would have to be modelled, but then of course you have the problem of loading
the animation into the OSG..
Hope that's of use.
Kim.
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of
Ümit Uzun
Sent: 31 October 2008 12:02
To: OpenSceneGraph Users
Subject: Re: [osg-users] MAX to COLLADA or which format ?
Hi Kim,
Thanks so much for reply. I remember, you have worked on VENUS
project. In this project how can you achieve fish motion modeling? Do you use
only shaders to give special motion mathematics on each skeletal model or do
you use sophisticated tools?
I mean, I want to model school of fish by using Reynold's
Flocking Algorithms and fish motions. At this point Do I have to model each
fish motion by using shaders (for example sinusoaidal travelling wave to
modeling fish waving) ? Or there is another way to to it except osganimation
toolkit?
Thanks for advices.
Best Regards.
Umit Uzun
2008/10/31 Kim C Bale <[EMAIL PROTECTED]>
In my experience the feelingsoftware collada exporter gives the
most reliable results when exporting models from Max. However, as far as I know
there is no way of getting any animation information out of max and into the
OSG.
I've noticed that the animation toolkit (osgATK/osgAnimation I
forget the name), mentioned recently in the forum had a Blender
importer/exporter that does support animation. Perhaps that is worth taking a
look at.
Hope that is of help.
Kim.
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of
Ümit Uzun
Sent: 31 October 2008 10:06
To: OpenSceneGraph Users
Subject: [osg-users] MAX to COLLADA or which format ?
Hi Folks,
I follows mail list and I know there was a discussion about
converting animated MAX format to any format which osg can understand. I
searched the all archive and want to ask same question again around the
different content.
As I said, I have animated MAX format models and want to export
another format in animation too. But after searching, I understand that I only
can do this conversion in COLLADA format. Is it right ? And if right how should
I achive? I found colladamax exporter
http://www.feelingsoftware.com/content/view/65/79/lang,en/ There is anyone who
used this exporter? I am asking because of leading me to right way.
And Does using COLLADA formatted animated model useful or not
on simulation project? I have never use collada format before, so I don't know
anything about the efficiency.
Any advices would be appreciated with glad.
Best Regards.
Umit Uzun
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--
Ümit Uzun,
Environmental Tectonics Corporation Turkey
ODTU Teknokent
Gumus Bloklar A Blok
Zemin Kat Bati Cephe Suit 1
06531 ODTU
Ankara, Turkey
Tel: 90 (312) 210 17 80
Fax: 90 (312) 210 17 84
E-Mail: umituzun84<at>gmail<dot>com
Website: http://www.etc-turkey.com <http://www.etc-turkey.com/>
<<winmail.dat>>
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