In low-light conditions, peak luminance sensitivity of the eye shifts
toward the blue end of the visible spectrum. This effect called the
Purkinje effect occurs during the transition from photopic (cone-based)
vision to scotopic (rod-based) vision. Because the rods and cones use the
same neural pathways, a color shift is introduced as the rods take over to
improve low-light perception.
This function aims to (somewhat) replicate this color shift and peak
luminance sensitivity increase to more faithfully reproduce scenes in
low-light conditions as they would be perceived by a human observer
(as opposed to an artificial observer such as a camera sensor).
The night adaptation can be controlled using a 0..1 factor for artistic
reasons: `ColorGrading::Builder::nightAdaptation()`.
* Use wide gamut color grading and gamut mapping
This change introduces a new API on ColorGrading to enable or disable gamut mapping at will. This feature is currently off by default and while useful and recommended, it isn't cheap and we need to figure out what we want our defaults to be especially on mobile targets.
Gamut mapping can be combined with luminance scaling to properly control hue skews.
* Small cleanup
* More precise Rec.2020 conversion
We now have an option for evaluating the bent normals from SSAO.
This is used to improve specular AO.
Currently these bent normals are not used for diffuse lighting because
they're "flat" (face normals), which is too distracting.
The bent normal buffer is stored in the SSAO texture, in a separate
layer. This is the first post processing effect that uses 2D array
in order to limit our sampler usage.
This CL also changes how we handle SPECULAR_AO_BENT_NORMALS when
material bent normals are not available: we're now using the "Cones"
algorithm with the regular normal, instead of Lagarde's approximation.
This can have a dramatic effect on SSAO and needs
to be adjusted based on the scene's scale/units.
The default value used to be about 6cm, and has
been changed to 5mm.
* 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
* Generalize luminance scaling in color grading
Previously the luminance scaling step was tied to a specific tone
mapping operator, called "EVILS" in the API. This was however
somewhat misleading as EVILS really is a color handling system
that's independent of what we call tone mapping.
This change splits the luminance scaling step from the tone mapping
step, allowing the use of luminance scaling (the LICH part of EVILS)
with any tone mapping operator.
As a result, the operator known as EVILS is currently mapped to the
linear operator and renamed to "RESERVED" until it is replaced by
a proper — configurable — operator.
* Update release notes
* Fix web build
* Add new sample app: image_viewer
This app shows how to load and visualize images. It's also useful to work
on color grading and other post-processing effects by just loading an HDR
or EXR image as a reference.
This change also adds a new exposure setting to the color grading LUT.
* Fix comments and build
* Fix Metal
* Use high precision for the UV coordinates
* Fix refactoring issue
This is still somewhat work-in-progress, but good enough to be useful.
Some caveats:
- large blurs don't work well with cascades
- the implementation uses more memory than it could
- use EVSM (exponential VSM), helps a lot with light bleeding
- don't apply shadow biases with VSM
- improve VSM user settings: added more controls, expose to java
- minor code cleanups:
- rename some structures
- remove unused parameters
- remove unused uniforms
If expecting a bool and receiving anything other than true or false,
this is invalid and should fail. This change triggered a unit test
failure which uncovered several actual problems.
* 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
The focal length slider now works over a remote connection. Also, the
slider for focus distance now controls the value in `ViewerSettings`
(which gets applied to Camera) rather than the value in
`DepthOfFieldOptions` (which is deprecated).
Shockingly there were no unit tests that did a simple write-then-read.
This is important because it's easy to forget details such as trailing
commas and the fact that uint8_t is a char.
* move the focus distance from DofOptions to Camera
The DofOption parameter is now deprecated, but will still work if the
focus distance is not set on Camera.
* A few new helper APIs on Camera
- getFocalLength() which returns the focal length used internally for
DoF computations.
- computeEffectiveFov() and computeEffectiveFocalLength() which can be
used to better simulate a real camera's FOV changes with the
focus distance.
Modified gltf_viewer so it uses the effective fov/focallendth when
DoF is active.
* simplify setLensProjection
We can call setProjection directly instead of converting to a fov
first, which ends up performing atan(tan(x)).
Also improve parameters names.
Currently the only NONE and MEDIAN are available options, at some
point we may add a "MAX" option which is cheaper.
There is no real practical uses for this option with these only two
choices, other than for debugging.
This fixes two different logcat messages that would occur when scrubbing
a slider in the UI:
- "Discarding message, message queue overflow."
- "Downloading model..." would repeat itself needlessly
This adds a WebSockets server to filament-utils-android.
Unlike my first attempt (#3599), this does not use a piping server and
is therefore much faster to use over a LAN. It also has lower user
friction because there is no need to touch a button in the app or
scan a QR code.
This adds libs/viewer to filament-utils-android and provides JNI
bindings for AutomationEngine.
This commit also changes the AutomationEngine to use PPM for screenshots
rather than PNG. The reasoning is that it is wasteful to include stb and
our two image-related libraries just to dump screenshots, especially for
a feature we might not use on Android.
Mathias Agopian
Romain Guy
Philip Rideout
Ben Doherty