Page 2 of 4 - Introduction
Before we begin outright, we should remind ourselves briefly as to exactly why the API will be seeing point releases as of DirectX 10. The main reason for this move is the removal of cap (or capability) bits in the API. In the past, cap bits allowed for graphics vendors to basically pick and choose what features their hardware would support (albeit within some fairly strict guidelines to ensure compliancy to particular DirectX and Shader Model revisions). Although this left the likes of NVIDIA and ATI with plenty of room to develop and tout features that the other didn't have, it also had the side effect of creating development Hell for any game developers working on titles, leaving them to sort through a myriad of cap bits for different GPUs and configurations to ensure that they were supporting the right features for the right boards - More often than not, this simply meant that advanced features that only one graphics vendor supported were left out of the vast majority of titles altogether (Truform anyone?). The removal of this labyrinth was one of the main things developers were screaming out for when it came to discussing what was required of DirectX 10, and so it came to pass.
Of course, this removal of cap bits had to be offset against the ever changing and progressing world of GPU development, so the graphics vendors still needed a way to push the technology forward and allow new technologies to find their way into games. Thus, DirectX 10 will be seeing point releases, one of the main facets of which will be to facilitate the inclusion of new funtionality for compliant graphics hardware to make use of. This makes life easier both for developers (who can target DirectX 10, 10.1 etc rather than individual features) and consumers - How do you explain to the man on the street that yes, a Radeon X800 and GeForce 6800 are both DirectX 9 parts, but both support different Shader Models in their respective architectures. It isn't much fun, trust me. As DirectX 10 and its point releases will also have very little in the way of features that are only optional in the API, buying a graphics board compliant with a particular DirectX 10 version will ensure that it does everything it needs to do to satisfy game titles that use that level of technology. No more Vertex Texture Fetch-esque confusions this time around then.
The other question to answer (or not answer, such is the way these things work) before we start is - When will DirectX 10.1 be released? From what we've heard thus far, it appears that it may well become available not all that long after DirectX 10 itself. What isn't so likely however, is that we'll be seeing DirectX 10.1 capable hardware before or at the time of the launch of this new iteration of the API. The main reason for this will be the additional requirements necessary to support DirectX 10.1's WDDM 2.1 driver model, but we'll go into that a little more thoroughly in due course. In other words then, although we may see DirectX 10.1 pretty soon in the grand scheme of things, don't expect to be racing out to buy a DirectX 10.1 capable graphics board for the forseeable future.