Modern 64k intros typically use D3D or OGL but they still need to generate the meshes, textures and sound themselves. In the DOS days (mid/late 90s) this was no

Modern 64k intros typically use D3D or OGL but they still need to generate the meshes, textures and sound themselves. In the DOS days (mid/late 90s) this was no different except there also had to be all sorts of software rasterization code in there just to get the scenes rendered. OTOH there were plenty of effects done back then that were strictly 2d using clever lookup tables. The DOS 64k intros typically didn't link to any stdlib but would just provide their own implementation along with a few of the symbols that the C/C++ compiler (typically Watcom) would require. Combine that with a tiny DOS extender like PMODE/W and a compressor like UPX and you'd be off and running. A minimal intro (just showing a bouncing pixel or whatever) could be had with only just a few kilobytes. Nowadays intros typically rely on, as mentioned, D3D or OGL but also usually on the MSVC runtimes. Compression is still done using tools like UPX or kkrunchy but that actually's becoming difficult to do because virusscanners are usually flagging them as suspicious nowadays because of all the malware that also uses these compressors. Also, file size is not something that most people care about too much nowadays so the whole concept of the intro seems to have become less and less interesting over the years.