* WIP New tone mapper API
* Implement tone mapper constructors and destructors
* Add new genertic tone mapper
* Make the generic tone mapper available in our sample UIs
* Fix warnings and crashes
* Fix generic tone mapper and graph mappers in the UI
* Add Java APIs for ToneMapper
* Implement copy/move operators for GenericToneMapper
* New experimental tone mapper
The new tone mapper proposed in this change replaces Uchimura (see
below) and is composed of two distinct algorithms:
- The first is the customizable compression curve from Timothy Lotte
(from GDC 2015). The curve's default parameters were chosen to
match the overall appearance (contrast) of the ACES curves used
as our current default tone mapper. This was done to provide a
good migration path to making this new solution the default in
a future version of Filament.
The compression curve can be customized via its contrast, shoulder,
input middle gray, output middle gray, and maximum "HDR value"
(scene referred).
It is important to note that the compression is only applied to
the luminance of the input scene referred value.
- The second is a novel approach by Troy Sobotka called Exposure
Value Invariant Luminance Scaling (or EVILS). This solution works
on the largest chromatic channel of the input value as opposed
to mapping all RGB channels as we do in our other tone mappers.
The algorithm effectively scales all channel by a ratio that
depends on both the compressed luminance from the first stage
and the luminance of input value normalized by the largest
channel.
This new solution offers important benefits as it manages to
preserve chromaticity for high input values. It is also designed
to provide a desirable rolloff to white on overexposure. This
means that even without gamut mapping, this solution avoids many
hue skews (red to orange, blue to purple, etc.). The results
provided by this solution are much more natural and make using
other color grading tools much easier.
* Use std::pow instead of pow
* Fix Web builds
* Add new color grading feature: shadows/mid-tones/highlights
This feature can be used to color correct specific tonal ranges.
The tonal zones can be precisely controlled.
* Add the ability to set a ColorGrading LUT per View
In this change, material_sandbox allows to change the tone mapping
operator at runtime.
* Add Mathematica notebook used to explore white balance
The implementation is meant to reproduce the temperature/tint sliders
founds in Adobe Lightroom. The temperature can be offset from 2,000K
to 50,000K using a slider between -100 and +100 (-1.0 to 1.0 in our
API). The range of tint was modelled after the range used for the
temperature.
* Fix various issues
- A refactoring wrongly remamed the color grading pass
- Setting a View's ColorGrading to null selects the
default color grading options
* Implement white balance in ColorGrading
We were conflating two concepts in our comments about the roughness
remapping, which was confusing. Also changed the remapping so it
matches a log2 mapping in our default configuration.
By removing the Fresnel term (often ommitted from fabric/cloth BRDFs)
we can store the DG term for the cloth BRDF in the 3rd channel of the
existing DFG LUT.
* Add new Cloth NDF
Based on the work by Estevez and Kulla, also known as the "Charlie" sheen.
* Restore DFG computation to GGX
* New proposed approximation for Cloth DFG
* Add "Charlie" cloth DFG approximation to cmgen
* Switch to "Charlie" sheen for cloth shading
* Document the new cloth NDF and DFG approximation
