I think you best hope is using OpenGL occlusion query to get pixel coverage. There isn't going to be an easy solution for what you want though, it won't be fast and it won't be straight forward to code.
Paul Martz has been doing work on occlusion querry so perhaps his work once open sourced may be a use, or guidance. On 6/22/07, Oliver Schoenborn <[EMAIL PROTECTED]> wrote:
It could be either extreme: any pixel seen, or whole object has to be seen. But just being in view frustum is not enough (could be wholy or partially occluded by other objects). Thanks, Oliver Robert Osfield wrote: > Hi Oliver, > > How exactly would you define being "look at"? Any part of the model > in the view frustum, any pixel on the objects seem? > > Robert. > > On 6/21/07, Oliver Schoenborn <[EMAIL PROTECTED]> wrote: >> I would like to change the color of a geode in one scene view (call it >> B) based on how "often" a geode is visible in another scene view (call >> it A). I.e., the longer the geode is being "looked at" in A, the >> brighter its corresponding geode gets in B, up to some saturation value. >> If I only had a small number of such geodes I could use IntersectVisitor >> but I have a large number of them (about 1 million), so I'm looking for >> better ways. >> >> I suppose a fragment shader might work, if two conditions are met: >> >> 1. Textures (as 2D arrays) can be written to by one shader, and read >> from by another >> 2. A shader only gets called for a fragment if fragment is visible -- >> not occluded by anything else. >> >> Any easier way? Any comments on above greatly appreciated. >> Oliver >> >> _______________________________________________ >> osg-users mailing list >> [email protected] >> http://openscenegraph.net/mailman/listinfo/osg-users >> http://www.openscenegraph.org/ >> > _______________________________________________ > osg-users mailing list > [email protected] > http://openscenegraph.net/mailman/listinfo/osg-users > http://www.openscenegraph.org/ -- Oliver skype: schoenborno _______________________________________________ osg-users mailing list [email protected] http://openscenegraph.net/mailman/listinfo/osg-users http://www.openscenegraph.org/
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