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.
This adds support for decoding HDR files, dropping them into the remote
web page, and sending them over the wire. However the decoded results
are not yet passed into IBLPrefilterContext, that will be subsequent
PR.
Rename KtxLoader to KTXLoader.
The remote UI has been tweaked a bit, so that it shows a more helpful
message when disconnected.
Static JNI lookups were causing issues with multiple libraries.
We now do the lookups when we need them as they are effectively
just hashmap lookups and we do them only in places where the
work we need to perform will be much larger than a simple hash
map lookup anyway.
This chane also manually registers filament-utils JNI bindings
to get rid of unnecessary symboles. We should do the same for
other Filament libraries (the symbols are pretty long and
we now have many of them).
