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Author Topic: rapidly cycling material type (0.27.176.38a)  (Read 423 times)

BurnedToast

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rapidly cycling material type (0.27.176.38a)
« on: February 19, 2008, 04:50:00 pm »

I did a clean install of 0.27.176.38a, and made a new world. I embarked on an island and extended the embark area all the way to the deepest part of the ocean possible (~50 levels down, wow). When I use 'k' to view the ocean floor, some of the types very rapidly cycle between 'wet' material types, so fast I can hardly make out what they are saying though it seems there are alot of different gems and such in there. It only seems to be the very very deep parts of the ocean doing this, the land and shallow ocean parts don't have any of these messed up spots that I can find.

I've heard of this bug before, but it's always been someone who tried to overwrite the old version or who was using mods - mine is a clean, unmodded, no utilities used at all install. The only thing I've done is change some init options, and I am using a different tileset.

I regenerated the world in a new folder, new clean install with zero changes to anything (not even the init) and the bug reproduced - there are bugged squares at the bottom of the ocean in the same places.

If you want to try and reproduce it on your own, the seed is 2303250742, the location is here:

Otherwise I can send you a save if you want, just let me know which files you need and where to mail it to. In either case, the bugged squares are easiest to find along the left edge of the map in the deepest square of water.

If anyone else has a moment to try it reproducing it to see if it's just my computer, that would be nice. It's a 0 reject and pretty quick generating world so it shouldn't take too long.

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MOOMANiBE

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Re: rapidly cycling material type (0.27.176.38a)
« Reply #1 on: February 19, 2008, 07:35:00 pm »

I used his seed and picked the same location, and I can confirm the very, very strange ultrafast swapping of materials when k-highlighting parts of the bottom of the ocean.

However, I created a separate world to see if it would happen there, and so far my two tests have yielded no similar results. I'll try one more time, just for the heck of it.

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Toady One

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Re: rapidly cycling material type (0.27.176.38a)
« Reply #2 on: February 19, 2008, 09:27:00 pm »

Okay, I'll note it down.
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Keldor

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Re: rapidly cycling material type (0.27.176.38a)
« Reply #3 on: February 20, 2008, 12:32:00 am »

I also had this problem with a similarily shore-with-deep-water fort.  Come to think of it, it sounds like a buffer overflow issue.  Check your memory allocation, in particular the terrain map and whatever was allocated immediately before the terrain map.  Another hint is that the data in the overlapping buffer has some apparently constant data, as well as stuff that's changed every frame.

By the way, DON'T try to mine out the flashing tiles, or even any in the region.  So long as nothing touches the affected tiles, whatever data that is overwriting the terrain map will be safe.  If you were to ever mine these out, you'd be destroying that data, which at best would 'only' corrupt things, but more likely, given that it's changing, it could hit a pointer in a linked list or something which would quickly give you a crash to desktop via invalid memory access.

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Draco18s

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Re: rapidly cycling material type (0.27.176.38a)
« Reply #4 on: February 20, 2008, 02:07:00 am »

Reminds me of my old assembler class when you'd write data to the "program" section of memory which causes the CPU to execute the data resulting in awesome (random crap on screen and a lot of beeping (the writing of ASCII 0x07: system beep).
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Toady One

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Re: rapidly cycling material type (0.27.176.38a)
« Reply #5 on: February 21, 2008, 06:48:00 am »

Fortunately, it wasn't anything dramatic.  [SOIL_OCEAN] just wasn't putting on the regular soil flag for the stone, so when it tried to pull up the soil type for the ground, it failed and defaulted to a random stone for the map material.
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