2D Terrain generation using midpoint displacement

There are tons of early examples of interactive 3D depending on what techniques and technologies you want to consider.

DragonStrike is most like a flight sim, of which the Microsoft Flight Simulator series dates back to 1976-77(for 8080 and Altair!), with FS 3 and 4, from 1988-1989 being most like DragonStrike in terms of tech. Contemporary examples within other genres include: Arctic Fox. M1 Tank Platoon, F-15 Strike Eagle II, Midwinter, Carrier Command, Stunts, and Test Drive III. "Flight sim" style 3D, with wireframes, flat polys and some sprites, was considered the main way to do interactive 3D for a long time, with each renderer having to pick and choose which details to focus on - the most common compromise being to impose heavy distance fog in order to convey detail in screenshots.

In the arcade, flat-shaded, color 3D was done in Atari's I, Robot in 1983! One year later, a simplified raytrace model was used to prerender terrain lighting for Marble Madness - a subtle solution to a problem that otherwise would consume a lot of artist time. Most of the 80's in arcades was dominated by sprite-scaling games with pseudo-3D road engine hardware like Outrun and Space Harrier, though. Wolfenstein 3D and Doom are in many ways more in the pseudo-3D genre than the flight sims, since they exploit a very specific hack with raycasting that gives decent quality and flexibility.

Edit: Wolf3D style raycasting was purportedly used in Alternate Reality: The Dungeon in 1986. You wouldn't know it at a glance, though, since it's a slow-paced RPG where your view is glued to 90-degree angles and snapped to the horizontal center of the grid cells.

Yes, he basically rediscovered a generalization of Brownian motion (for r=sqrt2), which is self similar.

In fact his algorithm is one way to get a Brownian bridge.

I think that midpoint displacement is a well known technique. If that is a fractal or not depends on the definition of fractal that you prefer.

Anyway, it's a nice article. I like the graphs with the different values of the displacement decay powers. It's probably also well known, but the comparison is nice.

Yes, I think you could call it a fractal. The Wikipedia page linked to from the article says that this technique is also called a "random midpoint displacement fractal".

Diamond square is often swapped out for Perlin noise in terrain generators. They give very similar effects, but Perlin's method is a little more flexible along certain parameters(e.g. arbitrary offsets, zoom-in) while diamond square has more control over the nature of features at different scales, which can be used to make terrain more or less noisy.

Better terrain generators will use higher-order curves rather than straight lines (i.e., instead of picking an increment for the midpoint and adding a multiple of 1 - |x|, add a multiple of 1 + cos(x)) in order to avoid having visible "corners". And of course terrain generators usually work in two dimensions, which makes this slightly more complex.

But yes, the "pick your dimensionality, randomly adjust the height in the middle, then recurse" approach is very standard.

Looks very "Out of this world" like

You put a word in quotes that appears nowhere on the page.

It's a useful technique in the procedural generation toolbox. Hardly ridiculous at all.

Please don't post nasty dismissals, especially in response to others' work.

https://news.ycombinator.com/showhn.html