The introduction sequence of the movie "The Terminator" has facinated me ever since I first saw it. It was always a dream of mine to convert this effect into a CPC demo.
At first I had the idea of using sprites for the characters that were scrolling across the screen in two directions, but it turned out that this would be too slow. I had to accept that I had to be content to scroll the text in just one direction, because the CPC wasn't capable of supporting a overlapping scrolling in two different directions. So I used a byte-by-byte scrolling to move the text from right to left over the screen. I've used a CRTC register 3 trick to simulate a byte-by-byte scrolling. Later I was told that this looks bad on a green screen, so I've put in the Tunnel demo as a special green screen part.
I've spent a lot of time on the color fading effect used in this demo. I made sure that the colors didn't fade out to black, but to the correct background color - like in a correct alpha-blending, even though I didn't knew that it was called this at that time! That is if the text to be faded out was currently in front of one of the big ODIESOFT characters it faded out to the colors used in this character. I've seen some demos on the CPC or even the Amiga with its 65536 colors that faded out to the color black regardless whether there were different colors in the background or not.
As you may know at the end of the Terminator introduction sequence when the two parts of the "The Terminator" text connected in the center of the screen, the whole text was moving along the z-axis into the back of a virtual space, so that the viewer was able to read the text as a whole. As you can imagine the CPC's processing power was far to inferior to accomplish this with an text that was many times the screen size in width. Again I had to reduce my ideas to a simpler form of presenting the whole "Odiesoft" text to the users. I used some sort of laser beam that was moving from left to right and painting the Odiesoft text onto the screen. It looks dumb, but it was the best idea I was able to come up with.
The text at the start of this demo was similar to the prologue of the original Terminator movie. I rewrote it to fit to the computer and CPC theme of this demo: "The Amstrad rose from the mass of computer systems. His war to exterminate every other system has raged for decades, but the final battle would not be fought in the future. It would be fought here, in our present. Tonight...". This passage was intended to sound gloomy and ominous - and to be honest it still gives me the willies...
I liked to use passages of books, parts of poems or citations of famous people in my demos. Even though I wrote just three or four demos which actually contained some citations - often I didn't find a suitable citation for my demos. Obviously I didn't have Internet access at that time!
This time it wasn't an Amiga demo that triggered the creation of this effect - it was the Super Nintendo Game "Super Castlevania IV"!. A friend of mine had a Super Famicom/ Super Nintendo and lots of games. Super Castlevania IV was one of it.
Since he was pretty good at playing all the games on the Super Nintendo he once played the whole game through and I was watching it. Castlevania IV had a lot of cool effects like areas were the whole screen turned around its center point, zooming enemies and backgrounds...
One of the levels started in a tunnel which realistically rotated around the player. To say the least: I was speechless! This tunnel effect looked so cool I just had to try to convert it to the CPC.
I had many ideas how to create it, e.g. by using a single line hardware split, using fast software routines or using a color switch effect... the last method was the first and only I've tried out. (I always wanted to use the hardware line splitting of the CPC+ to create a better version of this routine, but never did!)
Since the CPC doesn't have enough nuances of the same color to satisfy my need for different gradations for the tunnel I used a green screen and the possibility to use all 26 colors as different hues of green to enhance the visual impact of this effect.
The result looked okay, but not really satisfying. I intended to try out the other two possibilities I had in mind, but I was kept busy with other things and never got to work on that again.
Since I used a CRTC register 3 scroll trick for the Terminator scroll and these scrolling tricks always look bad on a green screen I added the rotating Tunnel as special green screen part to the Terminator scroll.
Later I got the idea that I could switch between two or three screens to create the impression of a right or left scrolling tunnel. But this idea also didn't make it into reality. Too bad!