Oldschool demo effects, once popular in the DemoScene, now in C#

Look ma no frameworks!

A project of dubious value to recreate some classic demo effects in C#, mainly ones you don't see very often or that are hard/impossible to find in C#. Done entirely in GDI+, no frameworks or OpenGL, just oldschool pixel pushing.

• this is a mess.
• no, really.
• we use reflection to pull out all demo classes that inherit from iDemo. Thus the interface's only purpose is to allow me to identify which classes are effects and which aren't. Once we have the classes, we create an instance of them and invoke the necessary methods. So that part is at least kind of extensible.
• the problem is that all drawing is done from the DrawScreen class, so each effect class needs delegates to that class. Not so extensible
• we roll our own texture methods. Stick a texture in the resources file, then read the pixel values into a [,] array, stick them wherever you want and live with the bounds checks.
• we avoid frameworks (except GDI+) because the old method of demo coding was to do your own drawing [mov cx,[blah]; rep stosb; lol].
• that being said, we use a standard cast-a-picturebox-to-a-bmp but then we use the FastBitmap class which uses pointers to manipulate the pixels.
• None of these effects are originally mine though all have my work in them. Most are collected from the internet over many years and translated from whatever language (usually C or some flavor of pascal with embedded asm, much from HornetArchive) into C#. I'll take credit for the translation, optimization and getting them to work, but otherwise full credit for the original algorithms goes to the original authors (whoever those were). I've listed my sources when I could remember them.
• Caveat: in the old demoscene, figuring out who or what group actually came up with an effect first was not easy to determine. In most cases the PC demoscene reused older effects that had originated in the Amiga scene. Still, don't be a l4m3r. Give credit where it's due if you didn't come up with everthing yourself. Quoting from the Hornet Archive reveals how common this practice was --> Space Port 2 BBS intro source by PSI : Sources to a BBS intro with ADlib music, scrollie, and star field all in 1993 bytes - The Adlib player in this BBS intro has been ripped and used time and time again by many people. Simple and easy to use. Kudos to those who have credited the source of where they got their player.
• I don't do copper bars. There is no way to do those in managed code, and not really a way to do them in assembly. Those were peculiar to the Amiga copper chip and drawing the bars is not how these were done. Even in assembly the closest I can get is to wait for [in al,dx; and al,08h;] and change the palette. It produces some cool effects but not really the same thing.
• FASM is fun if you have a jones for this kind of thing in assembler.
• Greets: http://dbfinteractive.com/ which is one of the best sites for demo code.

• bobs
• rotozoomer
• plasma clouds
• tri-layer plasma
• xor
• waving landscape
• dot tunnel
• fractal
• vector balls
• shadebobs
• floorcasting
• porky ball
• voxels
• water

Effect	Image
Voxels. Not common. The examples I could find were from the mid-90's and very mysterious. This is adapted from a 1998 QB example by Toshihiro Horie.
Dot landscape like Fake Demo from 93. Also not a very common effect.
Vector balls. Adapted from Tumblin/Bodies In Motion, 1994.
Bobs.
Plasma clouds. I cheat by drawing the map once and then color cycling.
Shadebobs. Uses angle arrays but not a heat structure so theres no cooling. To get around that we switch patterns. Loosely adapted from Flightcrank's example.
Rotozoomer. Adapted from TDEC by W.P. van Paassen.
Tri-layer plasma. Create a palette with a lot of black, then don't draw the black pixels.
XOR effects are simple and look very demo-y.
Fractals. No matter how much you optimize the routine, you eventually run into the escape time algorithm which won't budge. I even looked at this one in ILDASM but couldn't see much that would help.
Dot tunnel, adapted from an example by StoneMonkey in Freebasic. I'm going for the kind of look Xography had in their Crystal 2 BBS ad, for which no source exists. They've got some movement logic that eludes me.
Simple floorcasting. A very Amiga-y effect. Seen in Megademo by Dexion, 89. I should note that this one is actually my own work. The formula double fvs = (horiz / (y - midHeight)) / scale; was actually supposed to be part of a checkerboard but I screwed something up.
Porky ball. I'm not sure what these were called.
Water effect. Very common, even in C#, but still a great effect. This is adapted from an example by Cristian Tratz.

aka crap that was 'new' when Reagan was president

Effect	Image
Parallax stars. The screenshot looks like wtf
3D stars. The screenshot also looks like wtf
Rotating box-o-dots. This is an ancient way of doing 3D rotation manually. My box looks borked, possibly because I'd originally done this at mode 13 resolution. Oh well.
Sphere. I got this algorithm from somewhere but it was so stupidly common there's no telling where
Fire. My fire in ASM looks amazing. My fire in .NET looks like ass
Mod player! Seriously why would you want to do this? But here's how. Be warned, it's kind of a janky process. I got sharpmod from here https://github.com/jaredthirsk/sharpmod then compiled it, and made sure it and naudio (it's included, don't use the one on nuget) were in my build directory along with the mod I wanted to play. Song: starlit deception by necros, who is an amazing mod author. Find his stuff on modarchive.org ftw