Those are common bit-depths used in imaging processing in general. For clarity to other readers "half" refers to a half precision, or 16 bit, floatiting point format. In any case these are just generalized descriptions of the characteristic of some format or piece of data, they do not describe a particular format in themselves. Terragen 2 already supports OpenEXR format which allows for up to 32 bit full floating point precision per channel, as well as other high dynamic range bit-depths (half, 32 bit integer, etc.). OpenEXR is widely supported in the effects industry and in other 3D and image processing software and is generally the preferred method of supporting higher bit depths in an interoperable way.
Support of OpenEXR, mentioned in the TG2 FAQ under "Will TG2 be able to save/export HDRI images?", inherently implies support of the bit-depths you mentioned. 8 bit is the standard for virtually every other commonly used image format, so it's really a given that TG2 supports it.
Hopefully that answers your question. Note that we will be overhauling our website before product launch with better descriptions and feature reviews for TG2. At this point, due to the Preview nature of the current releases, we are not as concerned about heavily marketing TG2's capabilities.
- Oshyan
