This is just a little demostration on how to recycle hardware sprites on Amiga Computers.
This project takes advantage of the glorious ACE Engine by Kain at https://github.com/AmigaPorts/ACE
To get the executable just clone the project and compile it with m68k-amigaos-gcc from Bebbo.
If you dont have time to build your toolchain you can use my docker image:
docker run -it --rm -v #where you cloned the repo#:/data -w /data ozzyboshi/acedocker:20200311 /bin/bash
autoreconf -i
configure --host m68k
make
at this point you should have the executable built into your src directory.
Alternatively you can download the executable from the Github release page of this project.
Nothing special, just copy the executable somewhere in your Amiga machine and launch it from the CLI or double clicking on its icon from the Workbench. The project has been tested on real A600.
It's just a little demonstration on how to use Hardware sprites, each star in this demo is a sprite and 111 stars are drawn on the same frame.
The height of each sprite is 1 pixel, the width 16px.
As you may know old Amigas computers only have 8 sprites, we get 111 using a well known trick called "sprite recycling", all the sprites are concatenated one after another like a big sprite.
To use sprite recycling the only requirement the height difference of each sprite must beat least 1 pixel, this is why I ended up using 111 sprites.
The horizontal positions of the stars are generated randomly at boot time so each time you run the demo you get a different star pattern (even it's hard to notice on a first glance).
The stars are divided in 3 groups, the first one travels at slow speed, the second one at medium speed and the third one at high speed. You can adjust the speed just controlling how often the "moveStars" function is called.
At default, the stars moves behind a playfield containing a Vampire Italia logo (if you like Vampire accellerators please visit our forum at https://vampireitalia.forumfree.it/ ), pressing the 'O' keyboard button the playfield/sprite priority changes giving more priority to the stars.