HPAVC

home *** CD-ROM | disk | FTP | other *** search

/ HPAVC / HPAVC CD-ROM.iso / pc / FAQSYS18.ZIP / FAQS.DAT / MODEX.FAQ / text0000.txt < prev

Wrap

Text File | 1995-12-12 | 24.7 KB | 619 lines

Ok, this might be the last post for a while, its archived on x2ftp.oulu.fi thanks to jouni, anyway, I am off again for a few weeks.. X-Mode Frequently Asked Questions - By Zoombapup (Phil) 2-Oct-94 ====================================================================== Foreword -------- Hmm, whats new this time?? Well, I am off the net for a coupla weeks, which is kinda hard :) dont forget x2ftp.oulu.fi is now a good programmers site, if a little slow sometimes, in /pub/msdos/programming you can find all sorts. Basically, READ THE INDEX FILE before you ask about stuff, all jouni seems to post is answers to "where is this file or that file" he was kind enough to setup and moderate that site, least people could do is to do a LITTLE of the work themselves. Table of Contents ----------------- 1) What is this FAQ and why should I read it?? 2) What IS mode X? 3) How do you set mode-x? (asm source) 4) Source code reference list a) Information Sources b) Books & Other sources c) Source Code etc... 5) Simple Questions and answers (read it ok??) 6) Further helpful reading (Not necassarily Mode-X) Section 1 - What is this FAQ and why should I read it?? ------------------------------------------------------- This FAQ (Frequently asked questions file) is here to provide the reader with a brief outline of what Mode-X is and to provide some useful references for looking into it further. It is also an attemp by me to help cut down the posts on Comp.sys.ibm.pc.demos asking for information on Mode-X programming when that very same information is posted weekly (or seems like it). It is also a chance for the reader to find reference material that may take ages searching to do something specific in Xmode. If youre really desperate to find something, then maybe its a chance to learn how to use archie?? try telnetting to archie.doc.ic.ac.uk (or one closer to you), login as archie then try typing prog <filename> to search for a particular file (and dont forget to note the result!). Section 2 - What IS mode-X?? ---------------------------- Well, It has been mentioned that perhaps I should make it clear what is meant by Mode-X, well, it can really mean two things, the first is that it means a mode originally written about by Mike Abrash in Dr Dobbs journal (a US programmers magazine), it basically involved tweaking (reprogramming) some of the registers on the VGA display adaptor, in effect it gave a resolution of 320x240 with 3 pages for graphics, and he christened it Mode-X (because there was no bios mode for it). After this article it became easier for everyone to write the same type of things, using different resolutions, e.g. 320x200x4page etc.. the problem was, what would one call these modes?? as there are just about unlimited combinations, I think it would be better to refer to ALL tweaked VGA modes as Mode-X, and as far as I am concerned that is what mode-x means...... Anyway, back to the text:- Over to Themie Gouthias for that one..... (original author of Xlib) Mode X is a derrivative of the VGA's standard mode 13h (320x200 256 color). It is a (family) of undocumented video modes that are created by tweaking the VGA's registers. The beauty of mode X is that it offers several benefits to the programmer: - Multiple graphics pages where mode 13h doesn't allowing for page flipping (also known as double buffering) and storage of images and data in offscreen video memory - A planar video ram organization which although more difficult to program, allows the VGA's plane-oriented hardware to be used to process pixels in parallel, improving performance by up to 4 times over mode 13h - Loads of other neat tricks associated with having multiple pages of video memory to program with, and also smoother animations (PC Note that one :) ) Please note BEFORE you go flooding Themie with email about Xlib questions that he has taken a break from supporting it himself for a while and has left two other people in charge. (see ref) Section 3 - How to set up mode x -------------------------------- Here's the code needed to set up a tweaked 320*200*256-mode. It was in a text file by some unknown finnish author, It was translated by Saint/EMF (thanks Jani). --------------------------------------------------------------- 1. Set the BIOS mode 13h, which is the standard 256-color mode. mov ax, 0013h int 10h 2. Put the CHAIN4-mode of Sequencer off mov dx, 03C4h mov ax, 0604h out dx, ax 3. Clear the video memory (setting mode 13h clears only every fourth byte from each plane) mov ax, 0F02h out dx, ax mov dx, 0A000h mov es, dx xor di, di xor ax, ax mov cx, 8000h rep stosw Note: Parts 4 and 5 may need switching round, i.e. do part 5 first, then part 4... but it works anyway.... 4. Turn off the CRTC's LONG-mode mov dx, 03D4h mov ax, 0014h out dx, ax 5. Turn on the CRTC's BYTE-mode mov ax, 0E317h out dx, ax And now you are in tweaked mode! If you want also double the vertical resolution to 320*400*256, add this: mov ax, 4009h out dx, ax --------------------------------------------------------------- The last out is needed if you want to double the Y-resolution to 400 lines, so that each scanline has its own line in memory. The bits 0-4 in the CTRC register 09h define the number of times to display the scanline minus one. To get back to 200-line mode, out 4109h there, or if you want a 100-line mode, out 4309h. The same thing can be applied to the Mode X to get 480- or 120-line modes. Many Thanks to jani for this, I've only just decided to include it in the faq (I had it for months, but I didnt want to confuse beginners by supplying source like this, but WTH) -- Phil. Section 4 - Source Code reference list -------------------------------------- Alright, this is probably THE most important part, in that this is where you'll find all the source code and information you'll ever need to program proficiently in mode-x, so if you EVER post a question about HOW TO PROGRAM MODE-X after reading this list and getting the source etc, then YOU WILL BE SHOT AT DAWN :) a) Information Sources ---------------------- These sources are good for mode-x stuff.. Filename : xintro18.zip Where: simtel archives... usually Directory : I forgot to write it... should be /VGA will be confirmed. Author : Robert Shmidt (Ztiff Zox??) Simtel Stuff can be gotten from oak.oakland.edu Description: XDiscuss (now called Xintro :)) is a really good description of How modeX works, how the memory is organised in planar fashion, it includes a few graphics pictures to help visualise the memory organisation, really a must have to understand the mode. ---------------- Filename : Graphpro.lzh Where: wasp in pub/msdos/demo/ programming/source Author : Michael Abrash (Mode X guru) Description: This file is a collection of texts and sample source code to loads of graphics programming problems, mike was the first person to really describe Mode-X in a magazine (Dr Dobbs Journal), in this file he goes through a number of interesting routines etc, he also sets up a simple 3D polygon filling, lightsourced program called X-Sharp, all-in-all this file is A MUST HAVE! --------------------- Filename : Tweakxxx.zip Where : same place as xintro above Author: Robert Shmidt (again!) Description: Tweak is a utility that lets you mess around with the registers on youre VGA card, which is a real help when trying to come up with youre own Xmode, it enables you to test settings on the CRTC regs and play with loads of settings. ---------------------- Filename : Unchain.zip Where : probably most archives.... Author: Colin Buckley (with correct tabs, honest :) ) Description: Unchain is a utility to help people using turbo debugger to debug mode-x programs (because they screw TD's display up usually), it allows viewing of the pages in vid ram etc.... UPDATE: Unchain also works with BC,BP and loads of other products.. ------------------------ b) Books & Other Sources ------------------------ Nothing I know of in this category as yet, some non-specific graphics books are recommended in a FAQ in rec.games.programmer I suggest anyone interested in graphics programming read that newsgroup (or at the very least get the FAQ, I think its on ftp.uwp.edu - but I'll confirm this) NOTE: For those of you without a VGA reference for the registers the r.g.p FAQ has loads of them in, so look out for it!! Also you can READ comp.sys.ibm.pc.demos for a while, and you will usually pick up any info you need to do something that you cant get from the files below, only if you have read the newsgroup for a while and have not seen what you need posted should you post a question, PLEASE DON'T TIE UP THE GROUP especially with questions that have been answered over and over again.... c) Source Code -------------- Most of this stuff can be found on ftp.eng.ufl.edu in the directory pub/msdos/demos/programming/source NOTE: when I refer to wasp, I mean the above site, this was just the old name for the site. Wasp is probably THE best place to look for new source right now, as many other sites have had major space problems, but wasp CAN be very slow..... some other programming stuff can be found on archive.epas.utoronto.ca mainly soundcard info for the gravis ultrasound. (Nice SDK and stuff) but as always looking around is the order of the day... -------------- Filename: Xlib06.zip Where: wasp directory: /pub/msdos/demos/programming/source Author: Many contributors, originally by themie gouthias.. Decription: This really is THE source code to get to be able to use Xmode. the archive contains mainly C linkable assembler code that covers pretty much everything possible with Mode-X, all the code is copyright public domain, and is usually pretty fast. In the archive there are also demo programs to show what is possible and some useful doc's and further references. ALSO: Note that there are 2 new re-workings of Xlib in pascal called Xlib_tp5.zip and Xlibpas.zip available for pascal coders available on the net (ftp etc...) NOTE: If you have problems with the unit in Xlibpas not working be sure to set the compiler switches {$G+} and {$X+} which enable 286 code and extended syntax, then everything should run allright. ------------ Filename: stmik020.lzh Where: TBC (to be confirmed) directory: at a guess try ftp.uwp.edu somewhere... Author: Future Crew Description: This archive is FC's release of the screamtracker music interface kit (basically a mod player that you can use in youre demo's), whats interesting about it is that they have included the whole of thier MENTAL SURGERY demo, which has them setting a Mode-X variant, and also I believe setting up a VBI int... good to see how a well known (who am I kidding) group does things like the usualy horizontal stars.... All code in assembler. ------------ Filename: vlafont.zip Where: wasp (look for vlapak1.zip) directory: usual wasp programming dir.... Author: Draeden (of VLA) Description: This archive contains all the code and tools to incorporate a scrolly mode-X font routine, has sample code (including Y scale) and has a good re-working of Mode-X set code from Xlib, all code in assembler... Note: Generally try to get anything with VLA in the title, Draeden has released a load of code, and although he's made himself scarce for a while, the rest of VLA can be mailed, also he has done IMHO the best ModeX setting code for asm programmers... ------------ Filename: mx2_vla.zip Where: TBC Author: Draeden (of VLA) This is THE best working of Mode-X set code I've seen, really an update on the routines found in vlafont.zip, Its really a must have for asm programmers (especially tasm users), it provides loads of useful routines like mode setting (really flexible) and palette and other stuff like that. More stuff about VLA releases next time. Section 4 - Simple questions and answers ---------------------------------------- 1q) Is it possible to reset mode-x so that the addressing is linear like good old 13h but with the 4 pages still?? 1a) No, to the best of available knowledge no its not.... Note: Just to update this, there has been some discussion carried on and it seems that it IS possible on a very few VGA cards, but its so rare that it is practically useless, unless someone can get it to work on ALL vga cards 2q) Is it possible to set up my own mode, in some way?? 2a) Yes, but it is quite a tricky process, a utility to help you try tweaking the registers for this sort of thing is in the file section 3a) Information sources (tweak by Rob shmidt?) 3q) I have a (insert a crappy vid card name) VGA card, with 4meg memory can I still use ModeX? 3a) Yeah, basically ANY card 100% ibm (tm) VGA compatible can do it.. and why have you got 4 meg?? :) 4q) I want to be able to double buffer using a VBL is there one on the VGA and how do I use it?? 4a) There isn't a built in VBL on the vga, but you CAN set one up by re-synch-ing one of the timers (08h usually), there is an example in the newer Xlib (ver 06). Note: there are also VBL examples in mental-surgery by Future-Crew and in the demoVT example code *for thier magnificent modplayer* :) demoVT.arj (at least demoVT is on ftp.eng.ufl.edu) 5q) I want to do a font routine in 320x200x256x4 mode x, and I cant get hold of any fonts, the ones Ive got are scanned left to right top to bottom, and they make for a hard font routine, is there any fonts that I can use in a different format? 5a) Yes, you can get two utilities for fonts that are perfect for mode-x formats, one is in VLAFONT, mentioned elsewhere in the FAQ and another is in PCXTOOLS (which is also mentioned elsewhere), if you get either one, they hold the font data scanned from top to bottom, left to right (i.e. columnwise) which makes drawing them in mode-x much faster (dont need to keep setting the plane), also this layout lets you do things like move the start of the column in a sine wave (for a sin scroller) and other effects.. 6q) What sort of effects are possible in mode-x that are not possible in 13h? and why would I use them? 6a) Well, basically the effects available in mode-x over the normal mode 13h stem from the availability of off-screen video ram, this means that you have access to the 256k ram on youre card, rather than just the 64k that can be accessed by the PC (the pc address space for VGA use is only a 64k window), using off screen ram, it is possible to use VGA hardware to do scrolling (via the screen start address and pixel pan registers), fast vram-vram copies, double buffering (drawing to an offscreen page while you display another and then flipping these two *also called page flipping* there are MANY things that can be done with mode-x, but sadly coding for it is more complex as a result. NOTE: These techniques require a bit of practice, it would be wise to learn the in's and out's of normal mode-x BEFORE posting to newsgroups about "How do I?" questions, many times just looking at Xlib and other related sources will show you how to do these things. Section 4 - Further Helpful reading ----------------------------------- Newsgroups!! pretty simple really, read the graphics newsgroups, rec.games.programmer has some useful info on occasion alt.graphics, comp.graphics (I think), so get a list of newsgroups and take em all!! :) well, a few... Note: NEVER just go straight to a newsgroup you've never read before and post loads of questions, read it for about a month or so this gives you a chance to see what the group is about, and also to see if there's a faq posted, usually FAQ's are posted at least once a month... Reference Books --------------- General ------- Beginner: --------- -"Assembly Language from Square One", Jeff Duntemann, Scott Foresman IBM Comptuter Books. ISBN 0-673-38590-6. -"Assembly Language for the IBM PC", Kip R. Irvine, ISBN 0-02-359840-9 -"Mastering Turbo Assembler", by Tom Swan, Hayden Books, 1989. ISBN 0-672-48435-8. NOTE: Ive been told this is a good beginner book, might scan through it when I'm back at uni and do a review for newbie's... -"Assembly Language and Systems Programming for the IBM PC and Compatables", Karen A. Lemone, Little, Brown, & Co. ISBN 0-316-52069-1. -"Assembly Language Primer for the IBM PC/XT", Robert Lafore, Plume/Waite. -"Using Assembly Language", Allen L. Wyatt Sr., Que 1990. ISBN 0-88022-464-9. Intermediate: ------------- -"The Zen of Assembly", Michael Abrash, Scott Foresman Publ. plus "Zen of code optimisation" same author -"Assembly Language Primer for the IBM PC/XT" -"IBM Microcomputers: A Programmer's Handbook", Julio Sanchez and Maria P. Canton, McGraw-Hill. ISBN 0-07-054594-4. -"Programmer's Problem Solver for the IBM PC, XT, and AT", Robert Jourdain, Prentice Hall 1986. ISBN 0-89303-787-7. -"IBM PC ASSEMBLER LANGUAGE AND PROGRAMMING", Peter Abel, 1987, Prentice-Hall, hardcover (college text). ISBN 0-13-448143-7. Advanced: --------- -"80386: A Programming and Design Handbook", 2nd ed., Penn & Don Brumm, TAB Books. ISBN 0-8306-3237-9. -"80486 Programming", Penn & Don Brumm and Leo J. Scanlon, McGraw-Hill. ISBN 0-8306-3577-7. -"ADVANCED ASSEMBLY LANGUAGE", Steven Holzner and Peter Norton Computing, Inc., Brady Books/Simon and Schuster. ISBN 0-13-658774-7. Video Graphics -------------- Intermediate: ------------- -"Programmer's Guide to PC & PS/2 Video Systems", Richard Wilton, Microsoft Press. ISBN 1-55615-103-9. out of press now i believe.. supposedly good if you can find it.. Advanced: --------- -"Power Graphics Programming", Michael Abrash, Que Corporation. ISBN 0-88022-500-9 -"Programmers Guide to the EGA and VGA cards", 2nd Ed., Richard F. Ferraro, Addison-Wesley Publishing Co. ISBN 0-201-57025-4. I dont recommend this one.. -"Advanced Programmers Guide to the EGA/VGA", George Sutty and Steve Blair, Brady Books/Prentice Hall Trade. ISBN 0-13-729039-X. References/Specialized ---------------------- Intermediate: ------------- -"Undocumented DOS", Andrew Schulman, Raymond J. Michels, Jim Kyle, Tim Paterson, David Maxey, and Ralf Brown, Addison-Wesley. ISBN 0-201-57064-5. -"DOS Programmer's Reference", 2nd Edition, Terry Dettmann, QUE. ISBN 0-88022-458-4. Advanced: --------- -"386SX Microprocessor Programmer's Reference Manual", Intel Corp., McGraw-Hill. ISBN 0-07-881673-4. -"i486 Microprocessor Programmer's Reference Manual", Intel Corporation, McGraw-Hill. ISBN 0-07-881674-2. -"The Programmer's PC Sourcebook", Thom Hogan, Microsoft Press. ISBN 1-55615-321-X. -"System BIOS for IBM PCs, Compatables, and EISA Computers", 2nd Ed., Phoenix Technologies Ltd., Addison Wesley. ISBN 0-201-57760-7. -"PC Magazine Programmers Technical Reference: The Processor and Coprocessor", Robert L. Hummel, Ziff-Davis Press. ISBN 1-56276-016-5. -"Mastering Serial Communications", Peter W. Gofton, Sybex 1986. ISBN 0-89588-180-2. -"DOS Programmer's Reference", 2nd Ed. -"MS-DOS Programmer's Reference", MS Press. ISBN 1-555615-329-5. Also there is a PC programmers reference out there as a file, dosrefxx.zip which I can REALLY recommend, and also HELPPC21.ZIP which is good too, look for both on x2ftp.oulu.fi Note: the above taken from a faq I had.. some books are out of print. -------------- EGA/VGA a programmers reference guide by Bradley Dyck Kliewer ISBN: 0-07-035099-X Description: Pretty clear VGA technical reference manual, I prefer it to ferraro's (which I will post details on next time), it has all the info you need on all the vga's registers, very clearly explained, probably THE best vga reference for clarity, although perhaps not as exhaustive on the svga than other ref's. I'd say that this book is really an essential to all those who havent got a VGA reference... (my personal opinion) --------------- Introduction to Algorithms - by Thomas H Cormen ISBN: 0-262-03141-8 published by Mit press and McGraw Hill.. Description: A radically good book, covers pretty much ALL the algorithms needed in programming, although the title says introduction, it is not just an introductory level text, but covers a wide range of levels, it has timings, examples, discussion, and information to a mathematical level. IMHO this book is another must have, at least read it once, I think that it pays to have this book as a standard reference, really highly recommended.... --------------- Photorealism and Ray Tracing in C - Watkins, Coy and Finlay ISBN: 1-55851-247-0 published by M&T books... Description: I've been looking for a good book that deals with 3D math for a long time, given that math isn't my strong point, I wanted a book with clear descriptions, diagrams and useful examples, anyway, I accidentally ordered this book, (I dont program in C), but I've got to say, its been better for 3D math, than ANY 3D math book Ive seen to date! It also covers stuff like colour reduction, image enhancements and effects, anti-aliasing, and other useful topics.... Overall, a must have book for any graphics programmer.... pc ------------- Also It might be a good idea to get back issues of Dr Dobbs journal with the articles Michael Abrash wrote about Mode-X in, as you really need the pictures to appreciate his stuff. Footnote: Apparently Mike is now working for Microsoft, poor man, what a cruel twist of fate, that a man so into getting code to run as fast as possible should have to work for them!! Other magazine's, especially programmer based ones, PC Techniques have had some articles, and also game designer magazine, although these seem to have been deleted (they are magazine's on disk), try archie for GMD*.* GDM1.ARJ and GDM2.ARJ I know about, but they are a little too simple for my taste, may be helpful to newer games programmers. Also, for the more acedemic, or those who are at a good school etc, I would reccomend ACM Siggraph papers, and IEEE transactions on graphics, both of which are really leading the way, can be a bit heavy going, but some useful gems for us PC programmers too. -=END OF FAQ=- Written by PC (Phil... philc.... zoombapup etc )) please ask permission before re-printing somewhere else..... Oh, and If Ive forgotten anyone-anything, please feel free to write to me and ask for info to be included (not things like "please email me source to set mode-x in quickfortran"), or general questions that you feel arent answered here, or in the source files mentioned. One last thing, Take care y'all, and have a nice day! Zoombapup // CodeX :)