mipgen can now emit basis-encoded KTX2 files. Both the desktop and
web "suzanne" samples use this as a test for compressed textures.
This PR does not add KTX2 support to glTF, but it's on the way.
`BasisEncoder` has a builder style API that calls the basis encoder to
create KTX2 files. This hides some low-level BasisU features that we are
not using, like file I/O and mipmap generation.
`Ktx2Reader` is an easy-to-use API for creating Filament textures from
KTX2 files. Its API primarily consists of these two methods:
bool requestFormat(Texture::InternalFormat format);
Filament::Texture* load(const uint8_t* data, size_t size);
The first method is used to build an ordered list of formats that are
supported by your hardware. The second method consumes the contents of a
basis-encoded KTX2 file and attempts to produce a Filament texture with
a preferred format.
IMPORTANT: Our tools still let you use KTX1 for non-compressed images
because it is useful for HDR, but you can no longer use KTX1 for
block-compressed data.
Partial fix for #4771.
Changes:
- Remove the strange header-only variant of libs/image
- Rename KtxBundle => Ktx1Bundle
- Move image/KtxUtility => ktxreader/Ktx1Reader
- Add unit test for Ktx1Reader and test stub for KTX2.
Notes:
- Ktx1Bundle does not depend on Filament and is used by cmgen
and mipgen to generate KTX files.
- Ktx1Reader has a dependency on Filament and should therefore live in
a separate library, which it now does.
Block compression is currently only used when we invoke mipgen for the
suzanne demo. This PR makes it easy to disable.
Block compression is still enabled in our CMake build, but other build
systems can simply omit BlockCompression.{h,cpp} from imageio (as well
as the two third_party libs) and it will "just work".
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.
With KTX, we should simply create the specified output folder and put
the KTX file(s) in there. There is no need to create a subfolder of the
output folder.
This change also allows users to pick a custom name for their KTX file,
because we only use the "deployment" name when generating filenames.
Filament will now allow incomplete mipmap chains for the IBL and
map the roughness to the available chain.
This allows to create roughness cubemaps with a minim size for
roughness==1, instead of always mapping it to 1x1.
cmgen will now use 16x16 cubemaps for roughness==1, which
improves the quality of rough objects significantly.
The beauty of this is that there is no asset or API change. Old assets
will continue to work like before.
When processing very high dynamic range environments, the importance
sampling code falls appart, it becomes a user choice to decide if
prefilter importance sampling is better or worse than just regular
importance sampling -- both are usually bad.
--ibl-no-prefilter gives the user this choice.
Clamping is now disabled by default in cmgen, there is a new option
to enable it "--clamp".
Automatic SH windowing is also enabled by default and can be controled
with the "--sh-window" option. Accepted parameters are "no" to disable
windowing, "auto" for automatic windowing or a number to specify the
cutoff band.
auto windowing only works for 1, 2, and 3 bands.
--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.
The conversion factors from radiance to irradiance where wrong.
The bug above was found while refactoring the code to be clearer. Now
the method that computes the coefficients for the shader calls the
regular SH code and applies all the appropriate factors on that.
With this change the options "--sh-shader" and "-sh=3 -i" won't
produce the same result because --sh-shader includes the lambertian
diffuse. "--sh" now always produces actual SH coefficients.
- RGB_11_11_10 is exported in a RGBA PNG file where the 4 channels are
used as a uint32 storing a RGB_10_11_11_REV pixel.
We use the .rgb32f extension, and those PNG files contain garbage
when seen in a PNG viewer.
- This is now the default for the -x option.
- compressed KTX files don't encode RGBM, which means they can't
support HDR, unless an HDR compression scheme is used.
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.
this adds a new --type (-t) parameter that is
used to specify cmgen’s output.
faces: outputs cube maps separate faces (default
and current behavior)
equirect: outputs an equirectangular image
ktx: outputs a ktx file
--format=ktx now implies —type=ktx
- internal cross storage is now always horizontal
and seamless.
- source cross images are now always converted to
internal format, conversion includes rescaling
and sampling if scaling down.
- vertical cross is supported again
- fixes#283
- replace hardcoded constants
- cmgen now creates reflections maps for all input
assets by default instead of just for equirectangular
images.
- equirectangular decode doesn't mirror -- that's
done by the mirroring code now.
- mirroring can be turned of with --no-mirror
- option --mirror is gone
- faster mirroring code (do it before generating
mipmaps)
- added labels to faces of debug.png environment
- added a debug equirectangular image in third_party
(creative commons license)
