Enabling Automatic Mipmap Generation Causes Validation Error about ktx-software HOT 1 CLOSED

createInfo.generateMipmaps sets up the texture to request the mipmaps to be generated by the client application at runtime. This is indicated in the created ktxTexture2 object and in a file by setting levelCount == 0. However as generating mipmaps for block compressed textures is not widely supported in hardware the specification says this is not allowed for block-compressed textures. This includes the universal formats as, at file creation, we cannot know to what format they will be transcoded.

The only issue I see here is that ktxTexture2_CompressBasisEx does not return KTX_INVALID_OPERATION when generateMipmaps is set in the input ktxTexture2. We should probably also rename generateMipmaps to runtimeMipmap to reduce confusion.

Do not set generateMipmaps. Instead create your own mip levels before compression, passing each to the ktxTexture2 object with ktxTexture_SetImageFromMemory.

from ktx-software.