A lod bias can be applied to textures when dynamic resolution is
enabled. A proper lod bias is calculated and applied for quality levels
HIGH and ULTRA.
Lod Bias is implemented in glslang, which mean it's ignored when
glslang is not used, which currently happens with OpenGL backends with
optimization turned off (which includes filament LITE). This may be
fixed in the future.
We were decrementing activeJobCount after removing the job from the
queue, which could cause other threads in the pool to preempt us before
the decrement, causing them to spin forever trying to get a non-existant
job, until the decrement actually happened.
Now we always decrement first and fix-up the count if we couldn't get
a job from the queues. The race is inverted, and doesn't cause threads
to spin a long time.
the gc usually runs for a very short amount of time, so the jobsystem
overhead is very significant compared to the actual work.
additionally this works around a scheduling issue that happens sometimes
on some devices where a thread could be "runnable but not running" for
many milliseconds.
On some GPU such as Adreno, the shader compiler flattens the early
exit condition, which becomes useless. We work around this by using a
two pass version of the algorithm using the depth buffer for
skipping "fast" fragments that have already been rendered.
This improves performance significantly, e.g. from 5ms to 1.3ms on
Pixel4.
Currently this mode is always enabled, which hurst performance on GPUs
that don't have this problem. This will be remediated later.
Now that FSR scaling is cheap enough on mobile, we use it for quality
levels MEDIUM to ULTRA.
MEDIUM and HIGH use the mobile optimized version, which has a slightly
lower quality, ULTRA uses the original version.
Additionally the RCAS sharpening pass can always be disabled by setting
the sharpen value to 0.
We used the "float" code with the "half" texture coords, turns out FSR
uses slightly different code for both.
We're now using the "half" code (using mediump float).
filament cannot use fp16, so we make the necessary changes for the
float version. Note that we are using mediump float, which ends up
using 16 bits floats anyways.
This provides 78% reduction in execution time (i.e. 4.6x performance
improvement). We see the EASU go from 4.2ms to 0.9ms.
The quality is slightly impacted.
Non sampleable buffers (Renderbuffers) are always rounded to 32 pixels
currently and on the backend side this buffer can end up being cached
as a sidecar buffer for MSAA. When it is created, it needs to be created
with the size of the texture it represents, not the size of the FBO,
which might be smaller.
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()`.
