3 ms·

They talk about the bounces of light, which reminds me of radiosity global illumination[1]. I'm left wondering if this idea of going "from the camera to the lig

They talk about the bounces of light, which reminds me of radiosity global illumination[1]. I'm left wondering if this idea of going "from the camera to the light sources" is applied in any particular radiosity implementation, and which are it's differences in respecto to the basic form of the algorithm (that would be "from the light sources to the camera"). [1] https://en.wikipedia.org/wiki/Radiosity_%28computer_graphics%29 https://en.wikipedia.org/wiki/Radiosity_%28computer_graphics...

wlesieutre 11y ago
Radiosity doesn't track where light is coming from or going to, just the total amount of light hitting a face from any direction. It's built around the simplification that all surfaces are perfectly diffuse so that it can iterate through all the faces and exchange light with every other face. This has its advantages and disadvantages, the biggest advantage being that it's "view independent." Since there's no specular reflection, a surface looks equally bright from any direction, and you don't need to recalculate anything if you move the camera. The big disadvantage is there's no soecular reflection, so light bounces wrong off anything that should have been glossy. I'm not aware of any attempts to do it "backward," and I can't think of how that would work. The camera in radiosity is essentially an afterthought; you can calculate the entire scene without even having one, and the view you get afterward is more of a data visualization of that result than anything that involved the camera in a fundamental way.
- dr_zoidberg 11y ago
  Sounds about right. Not having the time to work on implementing this sort of thing (even as a toy project) leaves me at the point where I sometimes read about the algorithms but can't see through them into the details.

3 ms·

They talk about the bounces of light, which reminds me of radiosity global illumination[1]. I'm left wondering if this idea of going "from the camera to the lig

by dr_zoidberg 11y ago

wlesieutre 11y ago
Radiosity doesn't track where light is coming from or going to, just the total amount of light hitting a face from any direction. It's built around the simplification that all surfaces are perfectly diffuse so that it can iterate through all the faces and exchange light with every other face. This has its advantages and disadvantages, the biggest advantage being that it's "view independent." Since there's no specular reflection, a surface looks equally bright from any direction, and you don't need to recalculate anything if you move the camera. The big disadvantage is there's no soecular reflection, so light bounces wrong off anything that should have been glossy. I'm not aware of any attempts to do it "backward," and I can't think of how that would work. The camera in radiosity is essentially an afterthought; you can calculate the entire scene without even having one, and the view you get afterward is more of a data visualization of that result than anything that involved the camera in a fundamental way.
- dr_zoidberg 11y ago
  Sounds about right. Not having the time to work on implementing this sort of thing (even as a toy project) leaves me at the point where I sometimes read about the algorithms but can't see through them into the details.