15/03/2006 @23:28:07 ^00:39:47

Visplanes and large dropoffs

I've managed to waste the whole day trying and failing to work out why rboom segfaults when you go over a large dropoff (say, 0 to -31000). All I've learned is that it's not in the gameplay code as I first thought, it's in the renderer; specifically, the part that handles visplanes. If you compile it with rangechecking you get a R_MapPlane error instead (and then the thing segfaults somewhere else... damnit)

I've also learned that I still don't understand how the renderer works at all and also that I still don't know how to use a debugger properly. Damnit. I even managed, while typing that last paragraph, to spell "renderer" as "rendererer". It's one of those words like "banana" when you don't know where to stop.

This all came to pass since Andy's WAD (review somewhere in this post) was uploaded into /idgames this week. I mentioned the fault, which also happens in prboom stable, in the thread and another WAD in which it happens was posted in response.

It's all so very frustrating, very little I've tried to do these past couple of weeks has actually worked. Anyway I've played some maps:

Baron's Keep This is Agent "Mapper of the Year" Spork's first map. I can't imagine why he uploaded it to /idgames, except perhaps egotism, because it's dire. There are literally thousands of shells in piles of boxes, and barons and hellknights everywhere, usually in quite small rooms where they're hard to avoid. There are also ugly mazes with teleporters most of which are traps and instantly kill you and ends up in a mad circle-strafe around a crowd of cyberdemons. If you want a half-decent "my first map" with barons in the title, try "The Baron's Domain" (av46sp01.wad)

Endoomed A sequence of rather unmemorable rooms. The least unmemorable was the strobelit poisonous maze full of crushers. It's easier than it looked to start with as you get another megasphere every 10 seconds or so, though. I liked the look of large brick chamber with the spider, I like starkly lit grand chambers with high ceilings.

Haslam's Book Store of Doom Some guy who owns a book store made a map out of it. It's not bad, actually, there's quite a lot of room to run around, certainly a lot to shoot at, plenty of ammo and so forth. Lots of barrels around too, except they don't look like barrels. The one secret area is a right pain to find, I needed a map editor, so I'll spoil it: you have to get up on the shelves to the balcony with the rocket launcher and then run all round the edge on the bookshelves to the yellow door. When you fly off the end of the shelves (over a sign that says "Gunt/Hunt/Nautical", there's some shells on top of it) you should hear a floor descending. Oh yes there are also a number of invisible doors that you need to find to end the level, so maybe you should use the map cheat or an editor anyway just to get it over with. Anyway niggles aside this is actually a very fun map to play and the extra graphics aren't too annoying so give it a go.

The Apocalypse Project Man, look how long this has been in the archives, it has a three-figure /idgames frontend id. This is a whole episode of 9 maps that replaces Doom episode 1.

• Map 1: you start in a jail cell and break out by shooting the barrel. There follows a rather featureless maze of tunnels. There's a crashed spaceship, but that isn't the exit - that is behind a big throne with a baron on it. It reminded me of that bit in Ghostbusters 2 when Vigo spouts off about living in a castle of pain on a throne of blood. It always amuses me how in really old maps certain monsters like barons and cyberdemons are often given their own rooms with massive amounts of revenance and splendour. Now you get huge crowds of barons and they're just another species. Anyway I'm kind of wittering here.
• Map 2: This is a town or something, there's a bunch of buildings and you start in the open air, anyway. There's plenty of zombies around so watch out. Actually it was at this point that I realised I'd played these maps before, but I think it was the really crappy Doom 2 conversion on the D!1000 CD.
• Map 3 is a number of slime-filled sewers vaguely reminiscent of that part of Galaxia.wad. They collapse sometimes as you walk past them. The second half of the level has a large dark cave and a tunnel with a load of imps in ambush positions. It's very bland.
• Map 9 is directly led on from map 3, that is, map 3 has no real secret exit. I didn't get very far here as this was the map I mentioned above as having been pointed out for having reproducible R_MapPlane errors in it. I didn't see much of the map itself but it's basically one large cavern with some really massive height differences and huge staircases. It's kind of a shame it doesn't work in a way...
• Map 4 is a large featureless maze, similar to the computer core maze on E1M2 if anything. Monsters roam it constantly, and more come in from side areas as you trip hidden wires. This map is really quite annoying and I did it firmly with the help of the Overdetailed Map Cheat and I don't feel guilty at all!
• Map 5: you're in some kind of hell cavern, but you can't go anywhere except into passageway that leads out into another jail cell. The rest of this map is some kind of dungeon or torture chamber.
• Map 6 is a maze of grandiose marble hallways and stone rooms. There's another couple of barons on thrones too. The best part is right at the end where there's a spider and a crowd of 32 barons in a huge cavern; I don't think you're actually meant to fight them as there is a bypass mechanism but I still did!
• Map 7 is a huge chamber supported by pillars and with a central core. You get the red key from the core and then can open the side doors and get bogloads of guns and ammo. Then you can press a button and fight two spiderdemons and search for a while and find another key to exit. This one's okay for speedrunning.
• Map 8: finally another grand marble hall that's quite empty besides two barons. Kill them though and the huge wall descends to reveal an even bigger throne with a cyberdemon and a BFG on it. There's a bug in this level that means you can exit the map instantly, but doing a 100% kills run from a pistol start is quite entertaining.

So yeah I didn't hate it, well, I hated the mazes but not all of it, but nevertheless it's probably not worth the bother. A final note on the Doom 2 conversion: it's terrible and really lazily done. It's basically a search and replace on all the textures that aren't in Doom 1, and a search and replace on some species of monster - for example, barons have turned into arachnotrons. However no tweaking or bug-fixing appears to have been done afterwards; on map 6, where instead of getting two barons chasing you after you pick up the computer map, you get two arachnotrons stuck in the wall. Hilarious.