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*                                                                             *
*   Game:   R-Type Clone       Type:    Amstrad CPC Emulator DSK File         *
*   Author: Odiesoft           Webpage: http://www.odiesoft.de                *
*   Size:   1 * 194816 Bytes   Date:    16. May 2003                          *
*   File:   Odiesoft Games - R-Type (1992).dsk                                *
*                                                                             *
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Title: R-Type Clone
Year:  1992


From the first day I saw R-Type in an arcade I was possessed with the idea of
creating a horizontal scrolling space shoot'em'up game. At first I've tried it
with software scrolling hoping to be able to create a software parallax
scrolling. One such try was the interrupt Parallax scrolling program shown
somewhere else on this page, another try was a little more sophisticated, but
got lost during a disc crash, so it isn't being shown on my pages...

I soon had to admit that the CPC wasn't capable to create a decent parallax
scrolling with a decent screen size. So I've switched over to a different
approach and tried to create an R-Type clone using a hardware scrolling.

I once even considered buying a PC Engine, just because there was a very good R-
Type conversion for this video game system. (Later I wanted to buy a Nomad, the
Handheld version of the PC Engine, just to be able to play R-Type). But I never
bought neither of these two and when my brother got the conversion for the Amiga
I was satisfied with playing it there. It was as good as it gets.

I didn't really like the CPC conversion of the game. I've bought it when it came
out as a low budget game, because I've heard so many bad things about the game.
Unfortunately these bad reputation proved to be right. The CPC conversion was
done in Mode 1 with four colors. You can do a lot with four colors if you want
to (as later Siggi from Bollaware impressively demonstrated), but obviously the
guys from Activision didn't wanted to create a better graphics and just used the
graphics ported from the Spectrum computer.

The scrolling of the game was some weird 1 pixel Mode 1 scrolling. It was slow
and very unsteady. Also on the left side of the screen every now and then random
bytes were erased from the graphics, right before it was scrolled out of the
screen.

The game play was somewhat similar to the arcade. The enemies seemed to be the
same (as far I as I can tell. But my knowledge is limited, since I never really
advanced very far in the original arcade game) and the weapons were also all
there. But the ugly graphics and the slow speed made playing the game rather
strenuous. Never less I've played it a lot and even managed to advance to level
5 or 6. Since I had the game on tape and every new level had to be loaded in
separately I obviously was very patient with this game.

Anyway I thought the CPC can do better than that and with my R-Type clone I
wanted to prove it.

Please don't ask me why I've painted the star fighter the way it is. For some
reason that eludes me today I've painted a star fighting ship that looks like a
flying wale with mean looking eyes. Probably I wanted to convert this bend nose
of the original R-Type ship but wanted to do it inconspicuously or so. I don't
know. It just looks stupid!

Anyway I've advanced pretty far with that game. It was even playable with some
different waves of attackers, some huge background elements like the destroyed
star ship base and the lookout towers. The scrolling was interrupt controlled,
so sometimes when it got stuck for some reasons I wasn't able to discover it
suddenly scrolled in fast forward for some steps. It looks weird, but makes
sense, since the interrupt requests pile up until they can be processed. I also
was able to animate the own shots and the collision detection was working too!

So the game was about 60% finished and just needed some more graphics, enemy
ships and waveforms and some extra weapons. But once again I've felt that with
all those necessary additions the game would be come unplayable slow. I've
conducted some tests on an extra weapon that fires 7 shots at a time and ended
up having over 40 shots on the screen that all had to be animated individually,
which took way too much time.

Also the way I've conducted the collision detection was getting me into trouble.
I did on the screen collision detection, by testing whether or not any of the
bytes in the area where the ship or the shots were going to be painted next
contained anything besides an empty byte. It was the best collision detection
possible, since only a collision with a part of the ship with any other element
on the screen was tested and not a collision of a rectangular box around the
ship with the rectangular box of the enemy ship or shot which often results in
false collisions.

But that restricted the background graphics to a black void, since anything else
would have created a collision with the ship. So I couldn't even add some moving
stars or so into the background.

Also sometimes exploding ships or a collision with anything on the screen
resulted in the erasing of a part of the background graphics. Since when a
collision with a ship and the background was detected the ship is very close to
the background element, but the explosion of this ship may be bigger than the
ship itself resulting in the erasion of everything that is being engulfed in the
explosion.

It was a shame to abandon this project. Unfortunately I wasn't aware of any
tricks to increase the speed with which sprites and graphic elements can be
painted to the screen like avoiding loops or commands with long execution times.
Direct addressing was still a inexpressive term to most of the CPC users at that
time including me.

Besides the test game, two editors, one to create the backgrounds and one to
setup the waveforms of the enemies I've also already created one of the end-of-
stage enemies. Actually it was this huge enemy space ship with which I began
creating this game.

Before I started with all of the rest I first wanted to find out whether the CPC
was possible to paint and move such a big enemy ship on the screen. It is
obviously a copy of the middle-of-stage enemy in the 3rd (or 4th?) level of R-
Type, but it also bears a striking resemblance to the Battlestar Galactica from
the TV show of the same name.

This huge enemy ship was composed of three full screen images put together at
two vertical intersections. I probably wouldn't have been able to really include
this ship in the game since it already took up most of the memory. But I think
unfinished as it is it still looks quite impressive.

Just imagine how the CPC community would have responded to a game like this, if
I ever had finished it...


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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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