third_party_mesa3d/docs/README.DJ

			Mesa 5.0 DOS/DJGPP Port v1.3
			~~~~~~~~~~~~~~~~~~~~~~~~~~~~



Description:
~~~~~~~~~~~~

Well, guess what... this is the DOS port of Mesa 5.0, for DJGPP fans... Whoa!
The driver has its origins in ddsample.c, written by Brian Paul and found by me
in Mesa 3.4.2.



Legal:
~~~~~~

Mesa copyright applies, provided this package is used within Mesa. For anything
else, see GPL.



Installation:
~~~~~~~~~~~~~

Unzip and type:

	make -f Makefile.DJ [OPTIONS...]

Available options:

     Environment variables:
	CPU		optimize for the given processor.
			default = k6
	SGI_GLU=1	build SGI's GLU instead of Mesa's.
			default = no
	GLIDE		path to Glide3 SDK include files; used with FX.
			default = $(TOP)/include/glide3
	FX=1		build for 3dfx Glide3. Note that this disables
			compilation of most DMesa code and requires fxMesa.
			As a consequence, you'll need the DJGPP Glide3
			library to build any application.
			default = no
	HAVE_X86=1	optimize for i386.
			default = no
	HAVE_MMX=1	allow MMX specializations, provided your assembler
			supports MMX instruction set. However, the true CPU
			capabilities are checked at run-time to avoid crashes.
			default = no
	HAVE_SSE=1	(see HAVE_MMX)
			default = no
	HAVE_3DNOW=1	(see HAVE_MMX)
			default = no

     Targets:
	all:		build everything
	libgl:		build GL
	libglu:		build GLU
	libglut:	build GLUT
	clean:		remove object files
	realclean:	remove all generated files



Tested on:
	CPU:		K6-2 (CXT) @500(412.5) MHz
	Mainboard:	ViA Apollo VP2/97 w/ 128 MB SDRAM
	Video card:	PowerColor EvilKing3 (Voodoo3 3000 PCI) w/ 16 MB SDRAM
	DJGPP:		djdev 2.04 + gcc v3.2.1 + make v3.79.1
	OS:		DOS and Win9x



FAQ:
~~~~

1. Compilation

   Q) I tried to run `make' and it exits because `gcc' complains it cannot find
      some stupid file.
   A) You need LFN support.
   A) When compiling for Glide (FX=1), pay attention to Glide path.

2. Dynamic modules

   Q) What are you mumbling about dynamic modules?
   A) You must have the DXE3 package (available on my site) installed in order
      to build the dynamic modules.

   Q) DXE3 modules give me headaches...
   A) The DXE3 modules are not compulsory. The static libraries are still built
      and you can use them in the old-fashioned, classic way... and learn to
      live with your huge executable size. For example:
	gcc -o OUT.exe IN.c -lglut -lglu -lgl

   Q) Okay, DXE3 modules are built. How can I use them?
   A) Build your export object file; then link it with your application.
      For example:
	dxe3res -o dmesadxe.c gl.dxe glu.dxe glut.dxe
	gcc -o dmesadxe.o -c dmesadxe.c
	gcc -o OUT.exe dmesadxe.o IN.c -liglut -liglu -ligl -ldl

3. Using Mesa for DJGPP

   Q) DMesa is so SLOOOW! The Win32 OpenGL performs so much better...
   A) Is that a question? If you have a Voodoo3/Banshee card, you're lucky. The
      Glide port is on my web page. If you haven't, sorry; everything is done
      in software. Suggestions?

   Q) I tried to set refresh rate w/ DMesa, but without success.
   A) Refresh rate control works only for VESA 3.0. If you were compiling for
      Glide, see Glide info. If not, sorry!

   Q) I made a simple application and it does nothing. It exits right away. Not
      even a blank screen.
   A) Only DMesa+FX supports single-buffered. The standard VESA/VGA drivers
      will always work in double-buffered modes. If/When I will find a way to
      use *REAL* hardware acceleration for a specific card, it might or might
      not support single-buffered modes.
   A) Another weird "feature" is that buffer width must be multiple of 8 (I'm a
      lazy programmer and I found that the easiest way to keep buffer handling
      at peak performance ;-).

   Q) My demo doesn't display text. I know I used the glut font routines!
   A) Then you probably use GLUT as a DXE. Well, there is no direct access to
      variables due to the way DXE works. Read the documentation. The author of
      GLUT took this into account for _WIN32 DLL's only; I don't want to modify
      his headers. The only workaround is to link GLUT the old way :-(

   Q) The GLUT is incomplete.
   A) See below.



libGLUT (the toolkit):
~~~~~~~~~~~~~~~~~~~~~~

Well, this "skeletal" GLUT implementation was taken from AllegGL project and
heavily changed. Thanks should go to Bernhard Tschirren, Mark Kilgard, Brian
Paul and probably others (or probably not ;-). GLUT functionality will be
extended only on an "as needed" basis.

GLUT talks to hardware via PC_HW package which was put together from various
pieces I wrote long time ago. It consists from the keyboard, mouse and timer
drivers.

My keyboard driver used only scancodes; as GLUT requires ASCII values for keys,
I borrowed the translation tables (and maybe more) from Allegro -- many thanks
to Shawn Hargreaves et co. Ctrl-Alt-Del (plus Ctrl-Alt-End, for Windows users)
will shut down the GLUT engine unconditionally: it will raise SIGINT, which in
turn will (hopefully) call the destructors, thus cleaning up your/my mess ;-)
NB: since the DJGPP guys ensured signal handlers won't go beyond program's
space (and since dynamic modules shall) the SIGINT can't be hooked (well, it
can, but it is useless), therefore you must live with the 'Exiting due to
signal SIGINT' message...

The mouse driver is far from complete (lack of positioning, drawing, etc), but
is enough to make almost all the demos work.

The timer is pretty versatile for it supports multiple timers with different
frequencies. While not being the most accurate timer in the known universe, I
think it's OK. Take this example: you have timer A with a very high rate, and
then you have timer B with very low rate compared to A; now, A ticks OK, but
timer B will probably loose precision!

As an addition, stdout and stderr are redirected and dumped upon exit. This
means that `printf' can be safely called during graphics. A bit of a hack, I
know, because all messages come in bulk, but I think it's better than nothing.
"Borrowed" from LIBRHUTI (Robert Hoehne).

Window creating defaults: 300x300x16 at (0,0), 16-bit depth, 16-bit accum,
8-bit stencil. However, the video mode is chosen in such a way that first
window will fit. If you need high resolution with small windows, set initial
position far to the right (or way down); then you can move them back to any
position right before the main loop.

The following environment variables can customize GLUT behaviour:
	DMESA_GLUT_REFRESH	- set vertical screen refresh rate (VESA3)
	DMESA_GLUT_BPP		- set default bits per pixel (VGA needs 8)



History:
~~~~~~~~

v1.0 (mar-2002)
	initial release

v1.1 (sep-2002)
	+ added 3dfx Glide3 support
	+ added refresh rate control
	+ added fonts in GLUT
	* lots of minor changes

v1.2 (nov-2002)
	* synced w/ Mesa-4.1
	- removed dmesadxe.h

v1.3 (jan-2003)
	+ enabled OpenGL 1.4 support
	+ added MMX clear/blit routines
	+ enabled SGI's GLU compilation
	+ added new GLUT functions
	+ added color-index modes
	+ added 8bit FakeColor (thanks to Neil Funk)
	+ added VGA support (to keep Ben Decker happy)
	* fixed GLUT compilation error (reported by Chan Kar Heng)
	* overhauled virtual buffer and internal video drivers
	* better fxMesa integration
	* revamped GLUT
	* switched to DXE3



Contact:
~~~~~~~~

Name:   Borca Daniel
E-mail: dborca@yahoo.com
WWW:    http://www.geocities.com/dborca/