Hi Harash, J.P.
J.P. Delport wrote: > > I'm not sure your shader is doing a proper mean. For the GPU to do > mean/sum you need to do what is called a reduction. Search for reduction > on www.gpgpu.org. This is different from doing per pixel operations like > changing luminance e.g. > The posted code seems to be similar to the luminance computation in the HDR example (quick overview over the code). Using mipmaps one can compute an average or arithmetic mean value, I am not aware if reduction is really needed here. Maybe reduction means exactly the same. To compute it I would do the way, you described here: using UnitInMipmapOut to crete a mipmap with the average value in the highest level. What do you mean, that the values are not the same? In order to get the computed value out of the mipmap you have to access the last mipmap level in your shader. Take a look into brightpass/tonemap shader, where the last level with scene luminance is accessed. Also make sure that in the last level you access not on (0,0) position, but on (0.5,0.5), because otherwise you will get interpolated values. It is actually better to disable GL_LINEAR filtering for the textures used by the unit. art ------------------ Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=20803#20803 _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
