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*                                                                             *
*   Demo:   Shining Demo       Type:    Amstrad CPC Emulator DSK File         *
*   Author: Odiesoft           Webpage: http://www.odiesoft.de                *
*   Size:   1 * 194816 Bytes   Date:    2. March 2003                         *
*   File:   Odiesoft Demos - Shining Demo (1992).dsk                          *
*                                                                             *
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Title: Shining Demo
Year:  1992


Around Christmas 1992 an Amstrad freak with the alias "Shining" organized a
party in his basement and I went there with some other freaks from the South of
Germany. I remember that we had to drive in the car for a long time to get
there, so it was probably somewhere in central Germany, but I don't remember
anymore.

We were a lot of people (among them Marabu, Lovebyte (?), Prodatron, Alien,
Crown and Bad Error, as far as I can recollect) cramped in Shinings small
basement. Some people were smoking in the room, because it was too cold to go
outside. It was the first and last Party where I actually managed to stay awake
for 54 hours straight!

During these 54 hours I spent some time working on the first version of a
Dynablasters conversion that later became my biggest success: the CPC game
Megablasters. But at some point I was so tired that I just fell asleep as soon
as I resumed programming.

I still remember that I went outside for a night walk through the small town in
which Shining was living trying to stay awake for some more hours. When Marabu
drove back home taking Lovebyte and me along I fell asleep at the instant I
entered the car...

The demo itself was almost finished already when I got to Shinings place. The
only thing missing was a nice sound to accompany the demo. I used some
Soundtrakker sound for this job, but I don't know how had created the sound.

The idea of this demo was to create vertical color bars with different sizes.
Using a simple hardware trick it was rather easy. With a two line split I let
the CRTC (Central Ray Tube Controller - the CPCs graphics chip) copy two
horizontal screen lines along most of the screen. With some speed optimized
sprite routines I painted two sprites with a height of two screen lines into the
same two horizontal screen lines with different positions, that were controlled
by some pre-defined sinewave patterns.

Thus I display the same two screen lines over and over again, but every time
they are displayed againsome more graphics data is added to the lines. The whole
stairs-effect is based on this recursive adding of data to the same two lines.
The important point to that effect is that the sprite routine painting the
elements of the vertical color bars has to be fast enough, so that it is
finished drawing the elements when the electron beam of the CPC monitor has
finished drawing the current two lines on the screen. If it would be too slow
then the whole effect would start to flicker.

Since I'm not this good in creating hardware effects it took some time until I
got this demo running on all various CRTCs of the different CPC computers. Even
after releasing this part in the XMAS 1992 Demo I had to reprogram it, so that
it was CPC Plus and ASIC (the CPC+ CRTC) compatible.

When I was at the Euromeeting 2 in Reims/ France I had already created that
demo, because I showed it to Longshot from Logon System and he told me, that
Logon System already had created a demo with that trick, but they hadn't
released it (and as far as I know they never did!).

So when the Shining Demo came out in early 1993 with my part at the end it was
the first time such an effect was published on the CPC (as far as I know). Later
this kind of effect became very popular on the CPC and there were a lot of demos
that had far better versions of it. But it's like with the egg of Columbus:
sometimes you have to show people that something is possible and suddenly they
can also do it, even better...

Some years later I reused the code of this demo to create a cool Chessboard
effect. You can read the story to that on the page of the Chessboard zoomer, so
I won't recite it here again!


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*                                                                             *
* This program can be distributed freely and without the need of a written    *
* of a written permission by Odiesoft, as long as it is distributed free of   *
* charge!                                                                     *
*                                                                             *
* If you had to pay for this, you've been ripped off!                         *
*                                                                             *
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