Reactor Critical heeft een erg diepgaand, 11 pagina's tellend schriftwerk over DirectX 8.0 afgeleverd. Het artikel beschrijft de onderdelen van DirectX (DirectX Graphics, DirectX Audio, DirectInput, DirectPlay e.a. meuk) en geeft een uitgebreide beschrijving van nieuwe features zoals de vertex en pixel shaders. Hier een sampletje:
Pixel and vertex shaders are different in the way they are supported by hardware. The point is that the vertex shader will be supported on any computers with processors that support SSE or 3Dnow! (or maybe on all processor types), i.e. their "software emulation" will be supported. Nevertheless, even this kind of "emulation" may offer more advantages than the standard T&L operations pipeline (all the more so that it is controlled by the central processor) since one may not include in shaders the operations not needed at the moment.As for pixel shader support, it must be implemented in video chips themselves. It is unnecessary, however, to implement this support in the form of a processor unit. For example, GeForce and GeForce 2 GTS chips have a multitexturing unit with a wide range of shading and texture blending capabilities. Possibly, the pre-processor implemented in the drivers could be used to make these chips work with some pixel shaders (but, by far, not with all of them).
Shader support is important for hardware manufacturers since together with addition of new flags indicating the state of the rendering pipeline, it will enable them to introduce their own new features into the standard Direct3D 8 pipeline (similar to OpenGL extensions). And features are currently known to be one of the main driving forces in the market.
DirectX 7, together with the introduction of hardware transformation and lighting support into API has acquired a new type of device that supports it. This is T&L HAL (apart from standard HAL). Thus, with introduction of a shader architecture, DirectX 8 has acquired another type of device - Pure HAL. Pure HAL implies devices that fully support the specification of DirectX 8 shaders and, hence, have a minimum software interlayer between the software and hardware.
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