GLfract II Realtime 3D fractals

Here’s one of those little windows programs that doesn’t serve much purpose other than that it’s fun to play around with. GLfract II uses your video card to render heightmapped fractals in realtime in OpenGL. You can watch my video demo of it on Youtube.


Heightmapping doesn’t produce real 3D fractals but merely uses the colour information of the 2D (flat) images to produce a 3D representation of them, which basically tends to look like mountains an valleys. It is interesting though to see how easily a fractal can look like nature by combining such simple imaging techniques. Heightmapping is not a new imaging technique, it was for instance already used in old fractal software like Fractint and it’s still often used to make 3D landscapes. The latest software more advanced software for producing 3D landscape is Terragen 2.

Using GLfract II

Usage of GLfract II is fairly straightforward since there are only a few options to work with. Basically you just start the program and start clicking using the mouse and holding down the “Control” button on the keyboard. You can choose various different fractals (keyboard 1 to 5) and various render methods (L & P button). By invoking the command window (tab button) you can load and save files and do some settings.

For instance you can increase the complexity of the model with the “res number x number” command, but do not set the complexity too high or your computer will look like it’s stalled (but it won’t be because it’s merely rendering the image in the resolution you have set and won’t update the screen anymore untill it’s finished). I used 2048 x 2048 on my Geforce 8600GT, which is about as much as needed is for some highres exploration, the default setting is 400 x 400. Keep in mind that the overall performance also depends on the windows size. If you have a really fast video card you might want to increase the number of iterations (this increases the complexity of the fractal from which the 3D model is made), of course the higher the iterations setting the more CPU time it will cost. On complex models changing the number of iterations doesn’t show any more significant results.

Supposedly it is possible to load .map files, which are colour settings as it’s used in Fractint, but i didn’t have much success in loading my own maps, so i think that function doesn’t quite work right. But by loading the example files you can get some colours in there. All the commands available are listed in the readme so it’s wise to open that aswell when you run the program.


You don’t need a very fast 3D card to use it, i have tested it on a Nvidia Geforce 8600GT and an onboard Nvidia Geforce 6200  and both worked fine. However the faster the graphics card the more detailed you can make the 3D object using the “res” setting. You will of course need a fast CPU for calculating the fractals. Because this is how the program works: it uses your CPU to generate the fractal and then the heightmapped image which produces the 3D model which is then uploaded to the GPU (using OpenGL) and which point you can move the object around with further need of the CPU. It would be really cool if one day the program would be further developed to use the GPU for the fractal calculations using OpenCL (that’s a C not a G) or NVidia’s CUDA. I’m sure much  GPU accelerated fractal software will be coming out way in the near future though.

Video Demo

I have made a HD video in 720p of me just fiddling about with the software so you can see what it’s about, you’ll need to watch it on Youtube to see it in HD. The music is an old favorite of mine it’s an old amiga mod, the dance track is composed by Sqd, it’s an instrumental remix of the 1992 hit “Captain Hollywood Project” – “More And More” (Stone Cold-Cut Edit by Sqd). It seems the track has been released yet again in 2009, watch video. The music is available for free from the Amiga Music Preservation website for instance. You do need special software to playback mod tunes though, like Deliplayer or XMplay (which are the most accurate) or the DUMB plugin for Foobar 2000 (best quality) or the BASS plugin for Winamp.

Watch in 720p HD on Youtube:

Sidenote: Deliplayer was one of the most widely used software for playing back tracker music (called modules or mods) on the Amiga in the heyday of the popularity of the Amiga computer. Later a windows version was released, it was claimed to be the most accurate player for all the various tracker formats and indeed was regarded as such, while the software is now no longer developed or supported it is still the most accurate software for playing back tracker music on windows computers because no software that surpassed it has ever been produced.

The only software that remains that still is able to playback most tracker formats fairly accurate is XMplay. Much less accurate but also usable for a wide range of tracker formats are the DUMB plugin for Foobar 2000 and the BASS plugin for Winamp.

Links: (terragen 2) (GLfract II demo) (More and More 2009) (More and More 1992) (Sqd’s mods on Amiga Music Preservation) (XMplay & BASS plugin) (DUMB plugin)