The Mesa 3-D graphics library
Copyright (C) 1995-1996 Brian Paul
Introduction
============
Mesa is a 3-D graphics library with an API which is very similar to that
of OpenGL*. To the extent that Mesa utilizes the OpenGL command syntax
or state machine, it is being used with authorization from Silicon Graphics,
Inc. However, the author makes no claim that Mesa is in any way a
compatible replacement for OpenGL or associated with Silicon Graphics, Inc.
Those who want a licensed implementation of OpenGL should contact a licensed
vendor. This software is distributed under the terms of the GNU Library
General Public License, see the LICENSE file for details.
* OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
Miscellaneous
=============
There is a Amiga Mesa WWW page: http://www.efd.lth.se/~d94sz/amesa
and the orginal Mesa WWW page: http://www.ssec.wisc.edu/~brianp/Mesa.html
Since the OpenGL API is used, OpenGL documentation can serve as the
documentation for Mesa's core functions. Here are a few sources:
Man pages: http://www.digital.com:80/pub/doc/opengl/
Spec doc: http://www.sgi.com/Technology/openGL/glspec/glspec.html
Author
======
Brian Paul
Space Science and Engineering Center
University of Wisconsin - Madison
1225 W. Dayton St.
Madison, WI 53706
brianp@ssec.wisc.edu
AMIGA PORT of MESA: THE OPENGL SOFTWARE EMULATION by Stefan Zivkovic
====================================================================
When I first read about OPENGL in the summer of 1995 I was happy and filled with
joy. A few days later I surfed to the mesa homepage but only to discover that
there was no Amiga version. In the beginning of 1996 someone released a AMIWIN
version so I took the archive home to try it out, but it stayed packed on my HD.
One day when I was home and playing around with my HD I saw the archive and
started to try to make it work. Without luck as it seemed that you needed
the AMIWIN Includes and LIBFILES. But I also discovered that it was possible
to port it with not to much effort (WRONG THERE) so I begun.
For the Amiga there is only three important files + one directory.
src/Amigamesa.c The mesa GL Amiga implementation
(ddsample.c with some Amiga code)
src-tk/Awindow.c The tk (and aux) machine specific code)
include/GL/Amigamesa.h The prototypes for Amigamesa
Amiga/#?
Installing
==========
If you have the big archive you just have to unpack is where you want it.
If you have the updatepackage you need the orginal mesa archive and then
you will nead lha in your path and run the installer script in /amiga
(or just unpack AMesa.lha yourself)
Compiling
=========
If you use SAS just execute mklib.amiga (will appear if you have installed it correctly)
For compiling with gcc you have to enter the command "make amiga-gcc". Via the
environment variable LOCALFLAGS you can specify additional optimizations (for instance -m68040).
To use CyberGfx you have to define ADISP_CYBERGFX in include/gl/amigamesa.h
(you nead the includes for it (ftp.phase5.de))
About the code.
===============
The Code is compiled with cpu=020 math=ieee
If you would like it different then use the /Amiga/scoptions read next statement
The code is by defult amiga standard graphics If you for some unknown don't want
this there is a define in top of include/gl/amigamesa.h
The common scoptions file is in /Amiga
Here exists a scoption that is used in the WHOLE package, change math here
and it will reflect in all dirs
In /Amiga/library there are previews of files to the shared-library version
(This doesn't work yet but should give you an idea of how to use it)
In /Amiga/Examples there should be some amiga-demo code,
but I've got no code yet so feel free to send me your own examples.
All tk actions in tkExec are not finished. But most of them is. (low priority)
Most of the examples work. (ALL?)
etc. etc.
Write your own OpenGL code
==========================
1. For a easy start, look at the examples in /book/ and modify them
The examples uses a portable layer toolkit Not amiga specific at all
Until The shared library is ready you have to define AMIGALIB when
using <GL/gl.h>
2. For a better amigaprogram just open a window (on your favourite screen) and
add a few lines in your source:
-----------------------------------------------------------------------------
/* ADD where you want it */
#include <GL/gl.h>
Init() /* sets up viewport and projections */
{
glMatrixMode (GL_PROJECTION); /* prepare for and then */
glLoadIdentity (); /* define the projection */
glFrustum (-1.0, 1.0, -1.0, 1.0, 1.5, 20.0);/* transformation */
glMatrixMode (GL_MODELVIEW); /* back to modelview matrix*/
glViewport (0, 0, 200, 200); /* define the viewport */
} /* ^ ^ ^^^ ^^^--- The size of the mesa/openGL window */
/* ADD In after you opened your window */
struct amigamesa_context *glcont;
glcont=AmigaMesaCreateContextTags(
AMA_DrawMode,AMESA_AGA,
AMA_Window,(unsigned long) test_window, // My Windowptr
AMA_RastPort,(unsigned long) test_window->RPort,
AMA_Screen,(unsigned long) test_window->WScreen,
AMA_DoubleBuf, GL_FALSE, // or GL_TRUE
AMA_RGBMode, GL_TRUE, // -"-
AMA_Left, test_window->BorderLeft, // offset from left edgr
AMA_Bottom, test_window->BorderBottom+1, // offset from bottom edgr
TAG_DONE,0);
// Neaded tags is AMA_RastPort,AMA_Screen if you supply AMA_Window
// it looks for RastPort and Screen in it so a Window_ptr will do.
if (glcont)
{
AmigaMesaMakeCurrent(glcont,glcont->buffer);
/* All your gl comands */
/*handle_window_events(test_window); or whatever */
AmigaMesaDestroyContext(glcont);
}
/* Don't forget to call glViewport() when you resize the window */
------------------------------------------------------------------------------
if you set doublebuff to GL_TRUE then you just switch buffer with
AmigaMesaSwapBuffers(glcont);
For more info on the internal of the Amiga port you can check the files
src/Amigamesa.c and include/GL/Amigamesa.h for tk check src-tk/Awindow.c
And info on how to write your own gfx-routines read include/GL/amigamesa.h for
more instructions.
THINGS THAT MAY GO WRONG
========================
Remember GL ALWAYS render with (0,0) in the BOTTOM left corner.
If you use SAS you have to use the latest version (v 6.57), there is some bugs
in the older version's you can get free upgrades on aminet.
WARNING The api has changed on AmigaMesaCreateContext() it is now called with
a taglist. Read /include/GL/amigamesa.h
Scoptions that should not be changed is Precision=MIXED, NoStackExtend, NoStackCheck.
It compiles but all examples crash everytime:
Set your stack high about 50kb or more.
Linking complains about not finding _glBegin(): or @glBegin():
You have compiled some code using the stack and some using registers as
parameter passing, You have to chose one of them and us it on both places.
The colors are really bad:
To emulate 24bit I alloc 255 colors in the beginning spread over the
palette and then use it. If you'd like better colors, buy a GFX-Card.
(And wait for gfx-card versions.)
Resizing is sometimes very very unhealthy.
Please keep in mind that since SAS pre 6.57 contains a few bugs thats could give you
problem please use the latest version of SAS (Aminet contains a uppgrade).
I have many users that repordet problems that disapered when thay upgaded SAS to 6.57
LATEST VERSION:
===============
http://www.efd.lth.se/~d94sz/amesa
TODO:
=====
Debugg.
Fix resizing bug.
FUTURE:
=======
A shared library would be nice. (I have started)
Faster and better. (You may have some nice idea?)
HISTORY:
========
Release:
0.8 This code worked with Mesa 1.2.6 and all makefiles also.
But when I released it, Mesa 1.2.7 was released and some changes were made.
It didn't work.
0.9 Makefiles is remapped to work with Mesa 1.2.7.
Double buffering works.
Implemented fast_poly_draw (big speed improvement).
tkExec a few more tests were done. (right & middle mousebutton is not
implemented)
1.0 I've put a common scoption file in /Amiga (thanks to Kamil Iskra).
Due to the common scoptions you can change CPU and math more easy ,and
compiler options set to default math=ieee, cpu=020 so that it works on
1200's and up
Many bugfixes (thanks to Daniel Jönsson).
Have fixed the smakefile name collision with AMIWIN version.
Mesa 1.2.8 Fixed.
Spellcorrection of the docs were made by Peter Sandén.
(Blame him, not me!)
All tk's windows are opened on a pubscreen named "MESA" if it exists.
1.1 Faster and more stable (Many thanks to Jorge Acereda (JAM))
Faster pen usage now it allocates 255 pens and use them (thanks to
Stefan Burström)
A few enhancements here and there.
Fixed a smake bug ignore=A only works in the latest SAS version. Now I
have changed it to IGN=ALL (Thanx to everyone who reported this one)
1.2 Removed math from smakefiles, SAS handles this better self. (Kamil Iskra)
Fixed a serious drawing bug (appeared when using GL_SMOTH).
Fixed a very flexible programming API for future gfx-board implementations
Added a BOOL AmigaMesaSetDefs(struct TagItem *tagList); usefull for future enhancements
***'API change: AmigaMesaCreateContext uses taglist se include/GL/amigamesa.h
Faster on doublebuffer rendering. (Now I convert whole double buffer c2p)
Easier to integrate future gfx-cards routines. Look in include/GL/amigamesa.h
tk toolkit fixed to work better. Thanks to Georg 'Wulf' Krämer
1.4 Uppdated to reflect Mesa 2.0
Small Bugfixes. Relesed With Mesa 2.0
1.5 A few bugs intruduced in 1.4 was fixed (a workaround SAS oml/slink bug)
Due to a bug in SAS (oml/slink) 1.4 didn't work, this version should work better.
1.6 I haved splitted amigamesa into amigamesa and ADisp_AGA.c
this ensures higer modularity, and becomes easier to se what is neaded to port
if you want to make your own gfx rutines.
ADisp_Cyb.c contains CyberGFX drawer rutines (Joerg Nilson)
It's also posible to use gcc now. (Joerg Nilson)
Now works with mesa 2.2.
Due to my lack of time this will be my last relese of mesa, If you are interested to take over and mainten the source
please feel free to do so, Just please let me know so I can put some info on my webpage.
Please contact me with suggestions and additional info.
You can reach me at:
d94sz@efd.lth.se
Or mail:
Stefan Zivkovic
Kämnärsv. 9L:225
226 46 LUND
Or Phone:
+46 46 150763
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