Khronos Ratifies KTX 2.0
KTX is the industry group's container file format for storing GPU-ready texture data. KTX 2.0 adds support for Basis Universal compression to the specification. These KTX 2.0 compressed textures can then be used by OpenGL, Vulkan, and other APIs. With KTX 2.0, Khronos is also introducing the KHR_texture_basisu extension for glTF for allowing glTF to contain KTX 2.0 textures.
The Khronos Group is also publishing KTX-Software as open-source tools around dealing with KTX 2.0 compressed textures.
Run-time 3D assets have typically used JPG or PNG compressed images to transport textures with reduced file sizes. However, these formats cannot be processed directly by GPUs and must be decompressed into full size images in GPU memory, consuming precious memory space and bandwidth and resulting in poor rendering performance and high power consumption— which is particularly problematic on mobile devices. GPU compressed texture formats enable compact in-memory textures, with optimized memory access for faster, more efficient rendering. However, it is not practical to use GPU texture formats in widely-distributed glTF assets, as the highly fragmented GPU texture format landscape would make them unusable on many target devices.
Basis Universal compression technology from Binomial solves this problem by defining a ‘universal’ compressed texture format that can be efficiently transcoded at run-time into a natively-supported GPU format on the target device. Basis Universal provides developers two compression options that combine selected modes of the Khronos-defined ETC1 and ASTC GPU texture formats with RDO encoding and LZ-based supercompression for compact texture file sizes. The ETC1S mode can achieve significantly smaller transmission and memory sizes than JPEG and PNG textures. The UASTC mode delivers higher quality textures than ETC1S, particularly suitable for normal maps, while still achieving smaller file sizes and significant memory savings.
More details on KTX 2.0's ratification at Khronos.org.