In vanilla, Blinking lights + Lower and Change (into nukage) = ???

[Scypek2]

Doom Wiki says, blinking light sector types work by assigning a Thinker to the corresponding sector, and then setting the sector type to 0. So I thought, can't I make a sector that's both blinking and damaging, besides that one fast strobe + 20% damage combo? I made a blinking sector (type 13 synced fast blink) next to and above a typical damaging 5% nukage sector. I made action 37 sink the blinking sector into the damaging sector, to inherit the damaging property. And then once I touched that sector in vanilla, it crashed with a random 5-digit number reported as unknown sector type.

 

I made a test map with the same premise, but with blinking type 2 (non-synced fast blink) instead. It worked fine? The few times I tested it, at least. But when I introduced type 13 into the mix again, things started to get weird. Usually it would crash upon entering the blinking sector. One time the blinking sector worked as expected, damaging, blinking and not crashing the game, but the main sector's nukage became non-damaging. Then I tested it again, and this time the game crashed as soon as I entered the nukage, the corrupted sector type spilling out somehow.

 

blinknukageerror.zip

 

Here's my test map. The line in the front lowers the non-synced blinking light sector, the line on the right lowers the synced blinking sector that causes all sorts of trouble.

 

Anyone well versed in doom source code has any idea what's going on and why? Could it still be possible to achieve this very specific effect in vanilla? (Which might not be worth the effort, but it's interesting)

[kb1]

If I'm not mistaken, this *might* be fixed in Boom, but definitely won't work in vanilla. It goes something like this: Vanilla assumes that the blinking light thinker is a door and does a half-ass job transferring properties. (That's not strictly true - I can't remember the exact details, and can't look right now, but it's close enough for you to get the gist.) In other words, yep, it'll crash in vanilla. Boom does a bit better, allowing different types of actions on the same sector. (If someone can explain this more accurately, please do.)

[scifista42]

14 hours ago, Scypek2 said:

Doom Wiki says, blinking light sector types work by assigning a Thinker to the corresponding sector, and then setting the sector type to 0. So I thought, can't I make a sector that's both blinking and damaging, besides that one fast strobe + 20% damage combo?

 

I've seen it done in vanilla wads and seen it discussed on this forum before, it is possible. Try one of the raise-and-change-texture actions instead of lower-to-lowest-floor-and-change-texture, as the latter is known for causing crashes in other unusual scenarios too.

[Scypek2]

I tried the Raise By 24 action instead, and that appeased the fickle spirits of vanilla. Thanks @scifista42!

[kb1]

13 hours ago, Scypek2 said:

I tried the Raise By 24 action instead, and that appeased the fickle spirits of vanilla. Thanks @scifista42!

Be sure to test it in something like Chocolate Doom. In DOS, it's possible for code to do illegal actions (like write to unowned memory, or memory 'owned' by a different program), and not crash. But true 32/64 bit programs running in memory-protected operating systems (like Windows 95+) will typically catch such illegal memory accesses. In other words, if it works in Chocolate Doom as well as vanilla, you're most likely good to go.

[The_MártonJános]

On 8/8/2018 at 1:58 PM, Scypek2 said:

I tried the Raise By 24 action instead, and that appeased the fickle spirits of vanilla. Thanks @scifista42!

Uh, but does that change the (other) effect, too? As far as I'm concerned, it doesn't.

[EDIT] @Scypek2 oh, you mean the Walkover action?! Neat.
Also, good thing you mentioned the rising bridge puzzles, I personally believe that they are really underrated gems in Doom's mapping history.

Edited August 15, 2018 by Cell

[Scypek2]

It's the same action as in the rising bridge puzzles in E2M2 and MAP12. It changes the effect (to the one in front of the trigger linedef), and leaves blinking lights intact since they're their own thing after the map's initialized. Exactly as I intended.

[scifista42]

On 8/14/2018 at 8:01 PM, Cell said:

oh, you mean the Walkover action?!

Even the switch activated action changes both texture and effect. Just keep in mind that, both in case of walkover and switch activated action, the texture and effect are copied from the front sector of the action line, not from the neighboring sector of the action's target sector.

Edited August 16, 2018 by scifista42

[Scypek2]

On 8/14/2018 at 8:01 PM, Cell said:

Also, good thing you mentioned the rising bridge puzzles, I personally believe that they are really underrated gems in Doom's mapping history.

 

Yeah, occasional puzzles in doom maps are fun. Especially if they just lead to extra stuff, like both of those in the IWADs. I added a classic rising bridge puzzle to my Infernew contribution!