Local light probe

[cjlong1213]

Is your feature request related to a problem? Please describe.
Suggested by @romainguy #7413 (comment), we design the IBL by HDR Light Studio software but unfortunately all tested IBL images were not good.

I read the Local light probe from filament doc then try to test it but not find it.
We are going to test the Local light probe disscuss at this issue #644 (comment)
Does filiment implement the Local light probe feature?

Describe the solution you'd like
Test the "Local light probe" which can modify the IBL position and change the default IBL model from "infinity" to definite distance.

OS and backend
Android OpenGLES

[Nolram12345]

So is this basically about a local "reflection probe", similar to the global IBL, but which only affects a specific area? This would be immensely useful.

[jeanlemotan]

+1
No need for anything fancy, a simple API to set the probe per renderable would be sufficient. We can build octrees or octahedrons or any spatial lookups ourselves, we just need API to set the probe.

[Nolram12345]

I agree that a per-renderable option would be sufficient.

I think an optimal solution would be adding a "probe volume" or something like that - basically just a box that can either be manually assigned an IBL texture, or perhaps even allow for capturing the environment into an IBL cubemap and convolving it for ambient light. This would allow for approximating global illumination in a local space for basically no cost at all. Then just adding the ability to have a blending area between the global IBL and this local volume would basically function as an approximate, but sufficient global illumination system with a constant, very low render cost. This method has been used quite successfully, even in recent productions.
This would allow for properly shading spaces that are both interior and exterior, which has many applications, from archviz over product configurators to games.

[TheIronLefty]

+1
Most real-time applications that do not depend on static or real-time global illumination have some sort of application of this method for approximating indirect shadowing.