[Ham-Computers] RE: No Direct 3D

[Hsu, Aaron (NBC Universal)]

Direct3D is an API included with DirectX.  DirectX is a programming API
used to allow programs to interface with various I/O devices not
normally available under standard API's.  As far as I remember, the
primary purpose for DirectX is to allow game developers a way to bypass
Windows's regular (slow) API's with something that almost allows direct
access to hardware (Windows doesn't allow direct access to any device or
memory - everything must be through a handler of some sort).

Back in the day, game developers were accustomed to DOS proramming
models where you could directly access devices and memory locations.
Since Windows has control of devices and managed memory, any app that
tries to directly access a device would leave Windows in an unstable
state as Windows doesn't know that an app has modified something
somewhere.  The standard Window's API's at the time were too slow to
allow gaming, so some alternative method needed to be developed so that
game developers could write games for the Windows OS.  Hence DirectX.

These days, I believe DirectX is used as the primary programming API for
anything graphics or sound related (most graphics and sound apps I've
seen require it).  DirectX is currently at version 9.0c and I believe 10
is just around the corner.  As mentioned earlier, Direct3D is a function
within DirectX.  However, Direct3D is also a function that needs
hardware support - this also means it requires driver support.  If the
hardware doesn't support Direct3D, or the drivers for the video card
doesn't support Direct3D, then it won't be available.  I believe there's
Direct3D "emulation" mode where 2D functions are synthesized to created
3D effects, but this is *SLOW* as it requires Windows to do all the
calculations.

So, to summarize, Direct3D support requires DirectX, video hardware
support, and video driver support.  I believe there's a Direct3D
emulation mode if the video hardware/drivers don't have Direct3D
support, but I'm not positive.  Maybe someone else can provide an answer
to this (or maybe I should just Google it =P ).

BTW, the "alternative" to DirectX is OpenGL.  OpenGL is widely used in
the graphics industry and with some game engines as it isn't Windows
dependent.  I believe it's also available for the "nix" operating
systems.

73,

  - Aaron, NN6O



-----Original Message-----
Sent: Thursday, December 22, 2005 4:57 AM
Subject: [Ham-Computers] No Direct 3D

** snip ***

Where does Direct3D come from, the OS, Video board, or mother board
dirver CD's?

Dave, K3ASI