FC Forums

I'm getting some strange lighting bugs in one of my worlds. Specifically, daylight is passing through several layers of solid stone and illuminating an area that ought to be pitch black. Has anyone else seen this? Do you know how to fix it? It seems persistent. It's remained the same after logging out and back in, switching Minecraft versions, and covering the lighted area twenty-five blocks deep in bedrock. I don't know what to do about it, and unfortunately it completely ruins an effect that I've spent several hours trying to get right.

Screenshotted for proof:

There are no light sources whatsoever in that room.

It used to be related to pieces of the chunk stack not being stored to memory and this was falsely associated with being aboveground. But I sort of thought that was fixed a long time ago...

It seems to happen often.
Edit for me at least

fr0stbyte124 wrote:It used to be related to pieces of the chunk stack not being stored to memory and this was falsely associated with being aboveground. But I sort of thought that was fixed a long time ago...

This happened today in Minecraft Version 1.4.7.

Oh, Jeb, being that guy...

Dammit Jeb, this is why you need unit testing!

Correction: Dammit Dinnerbone. I keep forgetting.
Also it looks like he is aware of the problem and is trying to fix it for 1.5. I still say it needs more unit testing, tho. They should make it a built-in option. Crowdsource some of that debugging.

Update: In an attempt to get rid of this, because IMO it really ruins the entire structure, I moved the whole thing with Single Player Commands in the hopes that it wouldn't happen somewhere else. The results are interesting:

The bugs still exist, but now they're nice and even. Any idea what's up with that?

It's interesting. The light spots have a level of 6, which matches with no natural light source. They're spaced 16 apart, so it's definitely chunk-based, and probably one of the corners. Another noteworthy thing is that it exists on the walls, as well, meaning it is a volumetric artifact. There is also the fact that the spacing is missing a spot at the corner.

In Anvil, chunks are divided into 16 block high pieces, so it makes sense that an artifact would form at repeated Y coordinates. And it appears that only the chunk sections which are completely empty suffer from it. If you can recreate the error, this time make part of the floor a few blocks higher. If my guess is right, the light level should increase as you get closer to the artifact source. You might also try going by the lighting on entities, though that is going to be less precise.

Something else I'd like you to check: does the light level change at different times, or is it constant throughout the day? I suspect the former, but just to be safe...

fr0stbyte124 wrote:It's interesting. The light spots have a level of 6, which matches with no natural light source. They're spaced 16 apart, so it's definitely chunk-based, and probably one of the corners. Another noteworthy thing is that it exists on the walls, as well, meaning it is a volumetric artifact. There is also the fact that the spacing is missing a spot at the corner.

In Anvil, chunks are divided into 16 block high pieces, so it makes sense that an artifact would form at repeated Y coordinates. And it appears that only the chunk sections which are completely empty suffer from it. If you can recreate the error, this time make part of the floor a few blocks higher. If my guess is right, the light level should increase as you get closer to the artifact source. You might also try going by the lighting on entities, though that is going to be less precise.

Something else I'd like you to check: does the light level change at different times, or is it constant throughout the day? I suspect the former, but just to be safe...

At night it's moonlight. For what it's worth, that's actually the ceiling. I'm looking up at it. There's light on objects down below, too, though. I'll try raising it, although that'll have to wait a few hours because I only have a few minutes right now. I'll get back to you on that.

I started seeing this bug as soon as Jeb's first update came out. It's Jeb's fault.

fr0stbyte124 wrote:It's interesting. The light spots have a level of 6, which matches with no natural light source. They're spaced 16 apart, so it's definitely chunk-based, and probably one of the corners. Another noteworthy thing is that it exists on the walls, as well, meaning it is a volumetric artifact. There is also the fact that the spacing is missing a spot at the corner.

In Anvil, chunks are divided into 16 block high pieces, so it makes sense that an artifact would form at repeated Y coordinates. And it appears that only the chunk sections which are completely empty suffer from it. If you can recreate the error, this time make part of the floor a few blocks higher. If my guess is right, the light level should increase as you get closer to the artifact source. You might also try going by the lighting on entities, though that is going to be less precise.

Something else I'd like you to check: does the light level change at different times, or is it constant throughout the day? I suspect the former, but just to be safe...

Wow. whats it like to have the mind of a coder? Anyways, you're right about the light increasing as you get closer to it. I have the same bug on all my worlds with a player-created enclosed space bigger than 1 chunk.

Can you tell what the block coordinate is at an artifact origin? (If you are using your feet coords, round down (even on negatives) to get the block coordinate.)

While attempting to determine the coordinate of the light source, I built a little hollow room on top of the larger structure: Much to my surprise, this removed that glitch area. Perhaps because it's a hollow area, rather than a solid thing? I don't understand.

What are you talking about? They're right there in your picture.

*Edit* Oh, the missing one. Interesting.

It may be there is some property regarding the top loaded chunk which determines whether the effect cascades downward or not.
It would help to know the dimensions of both boxes and their coordinates.

The center of the glitch was at (-400, -2191). I don't know how high it was, because it disappeared, but that ceiling is at y = 105. The box on top of the large building is 13x13x5. The large building is a bit more than 50 blocks across and 100 blocks long, I'm not certain exactly. Also, having measured, the glitches are not all sixteen blocks apart. In one direction they are, but in the other they're 17 blocks apart. I measured enough times that I'm pretty sure I'm not crazy. I'll put the world up for download if you want to mess around with it yourself.