¬¬  Hardware Scrollies .. Everything You Might Dream Of .. ¬¬

                

 Released   : 17/10/93
 Doc & Code : Binary Slave
 Last Minute: Living Nature

 Binary Slave presents his first source-code to Public Domain.

 It mainly consist of the so called Hardware scroll... .

 A Hardware scroll is a characteristic of the standard VGA-card.
 It does not take hudge CPU time just a few port writes and the rest
 is up to another VGA characteristic nl. Vertical retrace which does
 all the synchronisation.

 I will give you an idea/example how to make a hardware scrolly... .
 So you'll be able to make very fast scrollers (I sure hope so) on
 your PC even on an XT! Just like in some demos.
 All you need is some knowledge about programming pascal/assembly,
 graphic environments,image processing.

 The code is written in TP & ASM, and may easyly be converted into C
 language or similar languages. The complete source is given and you
 need at least TP version 6.0.

 I've chosen those languages for several reasons.
  Turbo Pascal : - one of the most popular languages...
                 - very easy to read/write/learn and understand some
                   techniques.
  ASM : For the fast actions... such page flipping/filling/drawing
        routines.

 It was not the intention to make a super fast scrolling, no, it is
 intended to make Hardware scrolling a fact and understandable to all
 coders, not just the asm-speed freaks (who already know the hardware
 scrollies).
 The speed of the actual scroll is not so important due to the
 synchronisations Learning to make smooth animations is perhaps more
 important than the speed of the animation!
 Also try not to make too much procedure calls because TP's internal
 memory management slows (due to the activation records) down the
 animation.

 The scrolling is performed in tweaked video mode, it is also perfectly
 possible that you make your scrollers in normal graphics mode (13H -
 320*200*256colors), but I think mode X has got its charms...

 Well if you find something interesting, or if you make some scrollies
 yourself with this source, I would be pleased if you upload them 
 at MN2.
 Also if you have an idea/comment please upload it at MN2 in the
 Binary Slave conference...
 Still having trouble?
 Leave a msg at MN2 and I'll see what I can do...

 Files:
 ------
 - Cijf.pcx
 - Multa-u.pcx
 - Multv-.pcx    {GFX files made by Wolf. My personal gfx man!}
 - Example.hdw   {"Modulated" scroll text}
 - Example.txt   {Scroll text}
 - Explain.doc   {This file}
 - Hscroll.exe   {Compiled example file}
 - Hscroll.pas   {Example source}
 - Meat.exe      {MN2 publicement file}
 - Meat.pas      {Source from this file}
 - Txt2scr.exe   {Converts example.txt 2 example.hdw ascii# 33 - 100}
 - Txt2scr.pas   {Source for this file


 Note:
   I don't have the official documents of the Vga, only some books.
   I'm not responsable for any faults in these docs!
   Take care with some ports because they might cause damage!
   The only method to learn such things is trail and error!
   Be sure you get the whole and correct source and D/L it from MN2!

 | MultiNet 2: +32 (0)50/36.33.96 [HST 24/24]             |
 | FidoNet   : 2:291/1800.12 [Bart Vanderostyne]          |
 | F A X     : +32 (0)50/34.73.79 [Write to Binary Slave] |

 Hi's and Ho's  to - D.H.
 -------------     - Tasmaniac
                   - Shadowlord
                   - Overlord 0f House
                   - Living Nature
                   - El Presidento

   Greetings to all wich I humbly forgot on the MN2 greetingslist...

<EOF>