Talk:Phantom fireball explosions

Is this referring to the random "poof" (normally heard from a fireball hitting something) that one occasionally hears on MAP08? I have occasionally tried to track this down (on the rare times I have a save game a fraction of a minute before one occurs), but could find no place on the map (with the volume set very low) where it occured quieter than usual, leading me to postulate it was a fireball or weapons discharge that somehow escaped the confines of the map and was hitting a wall at ±32768. Be helpful if someone created this article ^_^. --Splarka (talk) 10:04, 15 September 2006 (UTC)

Your last hypothesis is reasonable, though I seem to remember it happening on MAP16 as well.  The next time it shows up in one of my walkthroughs (as it occasionally has), I will certainly look for evidence with IDDT and report the result here.    Ryan W 02:57, 15 January 2007 (UTC)

Evidence, believe it or not!  Watch E1M2 in this demo, turn on IDDT, and keep your eye on the entrance to secret #3 (the lower end of the green stairway leading to the chainsaw).  An imp shoots a fireball at the player, misses, and the projectile hits the west wall of the chamber — and passes right through!  Then, as the player is descending the staircase to the exit room, he hears the fireball hit a solid object.

That ±32768 number has a bibliography, I know, but is there a simple explanation for why the impact would be heard at full volume, as in this case?  (Nothing actually strikes any of the walls near the player, even from the back.)  Does the distance calculation overflow somehow and wrap around to a small number, so the engine concludes that the point of impact is nearby?

If the no-clipping phenomenon shown here is at all general (i.e. it doesn't depend on some pixel-perfect coincidence — is it just the noclip bug?), it at least explains why I reflexively associate phantom explosions with MAP16.  The large teleport trap in that level is full of monsters with projectile attacks, and I usually let them fight quite a bit before I attacked them.    Ryan W 15:03, 4 March 2007 (UTC)

Time to write the article? ^_^ --Splarka (talk) 03:17, 5 March 2007 (UTC)

D'OH! I wrote up a rather lengthy reply last night and apparently forgot to hit "Submit" after previewing. *kickself*

The gist of it was I hex edited the e1 demo above and a savegame generated from it so that we can experiment with that particular fireball. Interestingly, I cannot reproduce the phantom explosion sound when I -know- I'm in (roughly) the same place the player was at the same time the fireball hits -32768. The fireball undoubtedly explodes, but I can't hear it except in the original unedited demo file! I am tempted to play around some more with the demo to reproduce the bug, but I can't figure out what would make it such a specific and rare occurrence... Zack 16:10, 26 September 2008 (UTC)

For an even more blatant instance of the noclip part of the hypothesis, watch Xit Vono fight the first two barons in E2M4.  Dio mio.    Ryan W 21:36, 24 September 2008 (UTC)

Sprite limit could be a cause

I think that one cause for this could be the visible sprites limit bug. The original Doom engine has a sprite limit. If there are more things that are in the map, they may become invisible, or flicker. Perhaps this could be a cause in the phantom fireballs?

I've checked this with IDDT on (the visible sprite limit doesn't affect the pretty green triangles), and nothing out of the ordinary is showing in the map area. However, if you IDCLIP out of MAP08 (due to a sound bug) in Doom 1 or Doom 2 and shoot any non-hitscan projectile, after about a minute you hear a poof of it hitting something several thousand units away. This most likely is similar to the phantom fireball explosions (some projectile escaping the confines of a level at some point). --Splarka (talk) 11:36, 13 January 2007 (UTC)