mipMap=0 should not imply autogeneration about ktx-specification HOT 4 CLOSED

There's a more general notion within Khronos that file formats should just describe data without defining runtime behavior. I think in this particular case, the spec can be a bit more subtle like:

• numberOfMipmapLevels = 1 means that a file contains only the first level and the texture isn't meant to have other levels. E.g. this could be a LUT rather than a natural image.
• numberOfMipmapLevels = 0 means that a file contains only the first level and engines should generate other levels if needed. In other words, it describes intent rather than strict runtime behavior.

from ktx-specification.

If apps don't want auto generation they can avoid specifying numberOfMipmapLevels = 0. Auto-generation has been in KTX since the beginning and this is the first time it has been suggested it should not be in the file format. The discussion that led to its inclusion was a long time ago so I'm afraid I don't recall the reasons.

from ktx-specification.

Reviewed on 12/21 call

It was agreed that the spec rework suggested by Alexey above would be the correct approach. Ie

numberOfMipLevels=[0,1]

Specifies intent when only a single mip image is transmitted (0=Singleton, or 1=MipChain level 0) . The choice as to whether to autogenerate higher levels is left to the engine at runtime

from ktx-specification.

Fixed by PR #46.

from ktx-specification.