Back in the early 2000s, I was part of a Polish online group of Assembler enthusiasts called New Age Assembler Group or NAAG (now defunct). Some of our works made it to the broader demoscene. For example, in June 2002 we released our only zine that can still be found here.
Here is a collection of graphical effects written originally for DOS in x86 Assembly language. Some of these effects were published on Demozoo, a demoscene site.
The effects are all implemented in 16-bit Assembly and use real mode. I have some better effects in 32-bit protected mode Assembly in a new repository.
This collection also contained effects written in C, but I have made a separate repository for them.
To compile and run the graphical effects, there are many options. You can use a retro PC with DOS, a virtual machine running DOS, or a PC emulator such as DOSBox or PCem.
For my development purposes, I use a VirtualBox VM with Win98. I also have a Pentium II PC for testing the "final product".
Secondly, you need some assembler. Back in the days, I used compilers from Borland, legally or not. Luckily, they seem to have become abandonware. For example, here you can download Borland Turbo Assembler 5.0.
Once you have the assembler installed, open the attached makefile and replace the paths to TASM and TLINK with your own.
Then, simply run make:
c:\legacy > c:\tasm\bin\make.exe -f makefile
At this point, you should have around 19 COM files.
Press any key to quit. In asmshade, you can press [space] to cycle between different display modes, and [escape] to quit.
If you are using DOSBox, it may be that some effects run too slowly. It is possible to accelerate them to some degree by repeatedly pressing [ctrl + shift + f12], which will increase the number of "cycles" in DOSBox.
The effects rely on vertical retrace for timing. Unfortunately, in VirtualBox this feature seems to be broken, and the effects run very very fast. I will implement a better mechanism based on the PC timer, when the time permits.
The code is really ancient 16-bit Assembly, but it makes use of some 32-bit instructions, eg. to accelerate copying display buffers. It also relies on the mathematical coprocessor.
It seems that a 386DX PC with a VGA video card is required just to start. I did the original development on a Pentium 133 Mhz PC, but I have never run these effects on anything slower.
Regarding the memory, all effects use the tiny memory model, but allocate some additional segments. 256 kB of free conventional memory should be enough.
The reason for publishing these programs here is solely because I think they may still have some educational, fun or nostalgy value for some people.
I am the only developer of the programs. Licensing information can be found in COPYING.