Unsupported format for non-raw create

[bourbonut]

Hi, I want to create several .ktx2 files with specific vkFormat.

• one with VK_FORMAT_ASTC_4x4_SRGB_BLOCK (supported)
• one with VK_FORMAT_R8G8B8A8_SRGB (supported)
• one with VK_FORMAT_BC7_UNORM_BLOCK (unsupported)
• one with VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK (unsupported)

$ ktx --version
ktx version: v4.4.0
$ tree .
.
├── skybox-ktx2
└── skybox-src
    ├── skybox-0.png
    ├── skybox-1.png
    ├── skybox-2.png
    ├── skybox-3.png
    ├── skybox-4.png
    └── skybox-5.png
$ ktx create --format VK_FORMAT_ASTC_4x4_SRGB_BLOCK --cubemap \
                                 skybox-src/skybox-0.png \
                                 skybox-src/skybox-1.png \
                                 skybox-src/skybox-2.png \
                                 skybox-src/skybox-3.png \
                                 skybox-src/skybox-4.png \
                                 skybox-src/skybox-5.png \
                                 skybox-ktx2/astc.ktx2
$ ls skybox-ktx2/
astc.ktx2
$ ktx create --format VK_FORMAT_R8G8B8A8_SRGB --cubemap \
                                    skybox-src/skybox-0.png \
                                    skybox-src/skybox-1.png \
                                    skybox-src/skybox-2.png \
                                    skybox-src/skybox-3.png \
                                    skybox-src/skybox-4.png \
                                    skybox-src/skybox-5.png \
                                    skybox-ktx2/rgba8.ktx2
$ ls skybox-ktx2/
astc.ktx2  rgba8.ktx2
$ ktx create --format VK_FORMAT_BC7_UNORM_BLOCK --cubemap \
                                 skybox-src/skybox-0.png \
                                 skybox-src/skybox-1.png \
                                 skybox-src/skybox-2.png \
                                 skybox-src/skybox-3.png \
                                 skybox-src/skybox-4.png \
                                 skybox-src/skybox-5.png \
                                 skybox-ktx2/bc7.ktx2
ktx create fatal: Unsupported format for non-raw create: VK_FORMAT_BC7_UNORM_BLOCK. See 'ktx create --help'.
$ ktx create --format VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK --cubemap \
                                    skybox-src/skybox-0.png \
                                    skybox-src/skybox-1.png \
                                    skybox-src/skybox-2.png \
                                    skybox-src/skybox-3.png \
                                    skybox-src/skybox-4.png \
                                    skybox-src/skybox-5.png \
                                    skybox-ktx2/etc2.ktx2
ktx create fatal: Unsupported format for non-raw create: VK_FORMAT_ETC2_R8G8B8A1_SRGB_BLOCK. See 'ktx create --help'.

I tried also ktx transcode without any success :

$ ktx transcode --target bc7 skybox-ktx2/rgba8.ktx2 skybox-ktx2/bc7.ktx2
ktx transcode fatal: KTX file is not transcodable.
$ ktx transcode --target etc-rgba skybox-ktx2/rgba8.ktx2 skybox-ktx2/etc2.ktx2
ktx transcode fatal: KTX file is not transcodable.

I'm not sure if I'm using the command line correctly. Do I need to install additional packages for bc7 and etc2 supports ?

[MarkCallow]

Sorry. libktx does not have etc2 or bc7 encoders. There is a long standing request for help to add a bc7 encoder in issue #587. I would like to see it happen and an ETC2 encoder too.

Only BasisLZ/ETC1S and UASTC formats can be transcoded. That is their purpose. Conversion between any other formats would require decoding (if encoded) followed by encoding, which would require the missing encoders.

[bourbonut]

Thanks for your response ! No worries, I found the CLI compressonator for BC7 encoder. I will make more searches for ETC2 encoder.

I hope the request in the issue #537 will be resolved.