These constants are not part of the standard. We instead use our own
constexpr definitions in the filament::math namespace, as part of
the scalar.h include.
Currently we're arbitrarily clamping environments to 16384 because both
the pre-filtering and SH algorithms can't handle very larger dynamic
ranges. Instead of clamping, we now tonemap, which is a little bit better.
--sh-window=band, -w band : this low-pass-filters the environment
such that bands above 'band' are zero. This can be used to reduce ringing
when the source environment has high frequencies
--noclamp : turns off clamping before processing the cube map
This is still work in progress.
For jobs with that do very little work, the jobsystem can introduce
a lot of overhead, we mitigate this by:
- don't wake-up worker threads when scheduling several very small jobs,
like when scheduling the per-face jobs.
- don't wait for per-face jobs to finish -- we only did that to avoid
a copy of the job's data.
- don't use multi-threading at all if the job has too little work. We
evaluate the work using the scanline length and number of samples.
We now never process mirroring or mipmaping with multithreading
it's just not worth it given the overhead of the jobsystem.
We also require 64 lines per job, below that, we only multithread per
face (6 threads). This should probably depends on the sample count,
but we don't have this facility yet.
Special case downsampling for mipmaping.
This alone improves performance by 2x for small cubemaps (e.g. 16x16).
This adds a utility function on IndirectLight populate the reflection
map from an environment at runtime. This performs some processing
similar to cmgen, albeit at a reduced quality.
