v4.0.0

Release Notes

Version 4.0.0

Significant Changes since Release Candidate 1

• Basis Universal has been updated to version 1.15.

• Errors in both ktx2check and ktxinfo causing bogus out of memory messages when there is no metadata or an empty value have been fixed.

• An issue in msc_basis_transcoder causing intermittent Javascript "Cannot perform Construct on a detached ArrayBuffer" errors has been fixed. NOTE: that msc_basis_transcoder is deprecated and will be replaced by the transcoder wrapper from the Basis Universal repository.

Known Issues in v4.0.0.

• toktx will not read JPEG files with a width or height > 32768 pixels.

• toktx will not read 4-component JPEG files such as those sometimes created by Adobe software where the 4th component can be used to re-create a CMYK image.

• Emscripten versions greater than 2.0.15 have an issue that causes the Javascript wrapper for libktx to fail. The downloadable package KTX-Software-4.0.0-rc1-Web-libktx.zip has been built with Emscripten 2.0.15. You only need to be aware of this if building the wrapper yourself with your own installed emsdk.

• Users making Basisu encoded or block compressed textures for WebGL must be aware of WebGL restrictions with regard to texture size and may need to resize images appropriately using the --resize feature of toktx. In general the dimensions of block compressed textures must be a multiple of the block size and, if WEBGL_compressed_texture_s3tc on WebGL 1.0 is expected to be one of the targets, then the dimensions must be a power of 2. For portability glTF's KHR_texture_basisu extension requires texture dimensions to be a multiple of 4, the block size of the Universal texture formats.

• Basis Universal encoding results (both ETC1S/LZ and UASTC) are non-deterministic across platforms. Results are valid but level
  sizes and data will differ slightly. See issue #60 in the basis_universal repository.

• UASTC RDO results differ from run to run unless multi-threading or RDO multi-threading is disabled. In toktx use --threads 1 for the former or --uastc_rdo_m for the latter. As with the preceeding issue results are valid but level sizes will differ slightly. See issue #151 in the basis_universal repository.

Changes since v4.0.0-rc1 (by part)

libktx

• Adapt for Basisu 1.15. (a0642fa) (@MarkCallow)

  • Use zstd included in basisu.
  • Regen reference images with updated ETC1S encoder and newer zstd version.

• git subrepo pull lib/basisu (c721133) (@MarkCallow)

  subrepo:
  subdir: "lib/basisu"
  merged: "5337227c"
  upstream:
  origin: "https://github.com/BinomialLLC/basis\_universal.git"
  branch: "master"
  commit: "5337227c"
  git-subrepo:
  version: "0.4.3"
  origin: "https://github.com/MarkCallow/git-subrepo.git"
  commit: "c1f1132"

• Point .gitsubrepo at correct parent. (02c43d5) (@MarkCallow)

• Minor reformat (#399) (a78c3b4) (@lexaknyazev)

• Handle PVRTC1 minimum 2 block requirement. Fixes issue #390. (#398) (2034ce7) (@MarkCallow)

• Fix: Handle metadata with empty values. (0265230) (@MarkCallow)

  Incidental to the main fix, fix memory leaks in texturetests.

• Fix: properly handle 0 length kvdata. (aee7a1c) (@MarkCallow)

• Fix error in example. (b7563ea) (@MarkCallow)

• 2 small fixes: (50000ca) (@MarkCallow)

  • Raise error in GLUpload on attempted upload of universal texture.
  • In ktx2check don't combine FLOAT & NORM when checking VK_FORMAT name.

Tools

• Copy all image attributes when resampling. (83518cd) (@MarkCallow)

• Skip mipPadding also when no sgd or kvd. Fixes #395. (#396) (fa739a2) (@MarkCallow)

• 2 small fixes: (50000ca) (@MarkCallow)

  • Raise error in GLUpload on attempted upload of universal texture.
  • In ktx2check don't combine FLOAT & NORM when checking VK_FORMAT name.

JS Wrappers

• Obtain HEAP references after resizing vectors. (5bf11d8) (@MarkCallow)

  Possible fix for issue #371.