Originally posted by sgross
HDRI
I think, at this time it is not possible with a:m, Yves had described why in the a:m list.
The reason a real HDRI plugin is not possible is because HDRI requires High Dynamic Range bitmaps meaning that each color channel have way much more than 256 values as it is the case with normal bitmaps. A real HDRI would need to have the HDR bitmap data integrated in A:M and then a plugin would probably not be necessary. Donāt underestimate the implications of integrating HDRI in A:M. It is not just a simple issue of reading in the file since simply reading the file and converting it to standard bitmap data would loose the HDRI data. There is much more than simply reading the file in involved here.
Real HDRI is related to GI too and would need to be integrated with the current Photon Mapping implementation or at least with the final gathering step.
A possible plugin be a material HDRI environment mapping. This way the plugin could read a HDR file and compute an environment map. But that is far from true HDRI because of the missing interreflection, the missing indirect illumination and the environment mapping idiosyncrasies. Also, the HDR maps need to be manually pre-blurred in order to simulate dull surfaces. This technique have been used in the past in feature films (I think it was the first Jurasic Park) but with a lot of care and compositing.
Iāve been toying with the idea of a HDRI shader pluging for several months now. It would have to rely on several tricks that would need to be setup in the scene like a light positionned at camera position and a null object used to orient the virtual HDRI sky. But it would not work with reflective objects and the camera light would cause some illumination problems.
In short, developing a HDRI plugin is far from being a trivial task.
Yves Poissant