Message-ID: <ww01-BeVH8A2182@netaddress.usa.net>
Date: Thu, 22 May 1997 01:59:26
From: "Joseph Morris" <b52g AT usa DOT net>
To: opendos AT delorie DOT com
Subject: DirectX -- ugh
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While on the subject of Direct X, did you know that it isn't
possible to have Falcon 4 and Sonic the Hedgehog on the same
machine?

Both these are pure Win95 apps that use DirectX.
Sonic the Hedgehog cacks itself if the display mode is not set
to 256 colours.  If it is more than 256 colours it still dies.

On the other hand, Falcon 4 needs 65536 colours..
I've never tried it though.  It's faintly possible it will run
with 256 and dither them, but I doubt this.

In DOS, we can just change the screen mode and be done with it.
But in win95 you will have to find the display controls, change
them and cold boot the machine to change video mode.
Win95 is an abomination.

Also, the degree of abstraction that DirectX provides is suspect.
Many times I've seen would-be developers complaining that they get a
"Cannot create directdraw surface" error messages.

I have a feeling that DX doesn't provide a uniform display area
for 16-bit colour modes (see Falcon 4).

Because hardware manufacturers do not agree, there are many schemes
for 65536 colours, different ways of distributing the 16 bits.

5:6:5 (R G B)
1:5:5:5 (Alpha R G B)
5:5:5:1 (R G B Alpha)
..and many others.  Also the order is NOT NECESSARILY
Red Green Blue, and there will not be any way to tell!

Because the RGB Alpha technique is highly uncompatible with
the extended-Green schemes, it is up to the Application to handle
this, not directX.  It may be impossible to play Falcon 4 on some
types of video board.. (I've seen worse things with '95)

At least, that's what I've heard.

Looks like we will have a good advantage with OpenDOS, in terms of
simplicity, if we can get a standard, even if we stick with VBE 2.
If we do use hacked X drivers, PLEASE make sure the system is
outside the kernel, so the drivers can be usable on '95 and
MesSDOS systems.

I've just stuck with 32k colour mode for my latest.

Lastly, is there a 'Designed for OpenDOS' logo?
I want one.  :-)