Make a fly-by based on a speedrun

[w23]

To achieve that one would need to parse *.dem files, extract player positions and play them. Some sad facts:

1. There is no publicly available specs on GoldSrc (most speedruns are made playing original HL, not Source) *.dem format that look legit.
2. Source *.dem format (https://developer.valvesoftware.com/wiki/DEM_Format) suggests that the file itself contains just network packets, and common sense tells me that those should contain only player commands (input) and not much else. If this is right, then there's no way to extract player position without implementing the rest of the engine. Oh my! (However, Source SDK sources contain DEM parser that suggests that there really is a way to extract just a player position without processing actual input, but I went no further in my preliminary investigation)

[Triang3l]

You can safely skip non-movement commands by skipping their length.

GoldSrc demo format shouldn't be very different from Quake's one.

[w23]

That would be the best way to do it, but I still have to figure out the DEM format, which I believe is rather different from Quake. I've recently stumbled upon Xash3D (http://hlfx.ru/forum/showthread.php?s=&threadid=3729), an open source GoldSrc clone, also made by our соотечественник. When I get some time for this project, I think I'll look into that.

[w23]

dem format references:

• https://github.com/stgn/netdecode
• https://github.com/jpcy/coldemoplayer/blob/master/compLexity%20Demo%20Player/demo%20parser/HalfLifeDemoParser.cs
• https://github.com/Traderain/Listdemo-