1.7+ lighting bug / black spots

Therefore it's important to attach seeds and coordinates.

Indeed. I think I encountered one yesterday in 13w36a, but I believe I was playing on AMPLIFIED world type... I'd actually rather have black spots on that than even more lag. But a problem is a problem, I just have no idea where that was.

From MC-30734 (AMPLIFIED world):

Seed: -3027881170886549624
Coordinates:
X = 15,700000
Y: 122,713
Z: 256,81216

in a cave (Normal world):
Seed: -7754467900641174952
Coordinates:
X 1415
Z 462

in a ravine (Normal)
seed: -7754467900641174952
Coords.:
X: 1946
Z: -65

Still present.

Yep. After it was fixed, these were more rare, but as more snapshots came out they started getting more frequent.

I really hoped this was fixed but it is back again! Added a picture of a black tree.

Still present in 1.7.8.

The real thing is that I never experience it. Maybe it's a distinct computer version or java or something?

Theoretically, we need to try and isolate where the glitch/bug occurs, and what Enviornment it happens on most often.

I believe that would speed up the bug fixing.

(NOTE: This also occurs on Console Edition MineCraft)

Confirmed for 14w21b.

Will be fixed in the next snapshot : https://twitter.com/SeargeDP/status/490077428316790784

If so, then this ticket is a duplicate of / caused by MC-7508

Duplicate of MC-7508

Well, read the last comments in MC-7508.

Still an issue in 14w30c (world newly generated with 14w30c). See attached screenshots. Please re-open.

@unknown in https://twitter.com/SeargeDP/status/492327454867226624:

And there we go, 14w30c is released and contains even more bugfixes. But probably also some more black patches, so we can lure trees back in

@Kumasasa, that tweet is gone. But this is a good one
https://twitter.com/SeargeDP/status/491938604827295744

Seen both dark and light patches, more dark as of late (1.8-pre3).

I have discovered an instance where the black spots can be triggered.
1) Create a world with the seed 5161024099533940428
2) Teleport your player to -5 80 443
3) Place a block below where you are floating, place a torch on the block's north face.

You will find that numerous black spots appear in the nearby trees.

Still occurs in 1.8.1-pre2.

Whenever I look at my building, this always occures.

Still occurs in 1.8.7 (frequently)

At Minecon Jeb said he tried to fix this issue but failed however he did say he would like to fix it

1.9 also has this glitch

( We haven't known about this bug in 1.9 yet . You wrote about prerelease ) Pleas , fix it in 1.9 release . PLS ;(

Affects Version/s - Minecraft 15w40b (prerelease 1.9)

Affects Version/s - Minecraft 15w41b (prerelease 1.9)

Affects Version/s - Minecraft 15w42a (prerelease 1.9)

Affects Version/s - Minecraft 15w47b (prerelease 1.9) and the previous releases.

Reproducible missing lighting updates in Survival 15w51b and 1.8.8. To reproduce, create new world with this custom preset expected to produce a uniform light level 8: 3;minecraft:bedrock,54*minecraft:stone,minecraft:iron_block,minecraft:stone,minecraft:log,2*minecraft:dirt,minecraft:grass,6*minecraft:air,minecraft:lit_pumpkin;1

An easier way to reproduce this issue in survival (also see screenshot 2015-12-27_22.29.36.png ) is to create a new world using custom presets. For example this preset should produce light level 9 over the superflat world:
3;minecraft:bedrock,57*minecraft:stone,minecraft:log,3*minecraft:dirt,minecraft:grass,4*minecraft:air,minecraft:lit_pumpkin;1

and this one should produce lightlevel 8 (the one used in screenshot using seed 000188):
3;minecraft:bedrock,54*minecraft:stone,minecraft:iron_block,minecraft:stone,minecraft:log,2*minecraft:dirt,minecraft:grass,6*minecraft:air,minecraft:lit_pumpkin;1

In survival the player will spawn on top of the lit_pumpkin ceiling; to see the black spots the player should break the pumpkins and fall the 6 blocks to the grass, there they will see a reproducible pattern of zero-light areas. Move over to each dark area and F3-debug will show light 0 and sky 15. Some areas are light 0 and sky 0. Placing and removing blocks or light sources on the ground will update the light level but not the sky level. Placing and removing blocks on the ceiling will correct the zero sky levels.

The issue also exists on the lit_pumpkin ceiling itself, but is harder to see: occassional hostile mobs will spawn on the rare zero light level blocks. The issue occurs in both 1.8.8 and the latest snapshot. My PC is Windows 8 and I use the standard launcher from minecraft.net with the built-in java runtime.

EDIT to note that the zero sky level (not the zero block level) blocks can be seen in my screenshot as a slight shade (not black) on the lower left.

1.8.8 Minecraft vanilla creative showing zero block light level where level 14 was expected. A creeper was found to have spawned on that block. This world was generated using a custom preset to generate a layer of lit_pumpkin.

confirmed for 1.9pre-1

Confirmed for 1.9 stable

A few deductions I've made (Jeb probably already considered these, but just in case)...

1. Because mobs can spawn in the dark spots (Marcus mentioned, I confirmed), even on SMP, it seems to be server-side (in SMP).

2. Block light levels are updated on triggers (not periodically), which leaves a lot of possiblilities, but...

3. Marcus also mentioned some are sky light levels, which are updated over time as the day/night cycle continues, which means the light level update is either not running for certain air blocks or that it is giving a false result consistently until related data is updated.

4. Both cases rely on the same data, so that's one chokepoint for finding the issue, though it can branch out again from there to anything that is altering (or SHOULD be altering) the block data.

5. To narrow that down a bit more, the PHYSICS of the blocks in the areas are perfectly fine. That is to say...the issue is not that there is a phantom solid block, etc. The issue probably lies in the state of a more specific data set than the one that keeps track of which blocks are where.

There are so many ways of doing things beyond this point that I can't make any further deductions without seeing the source, and I don't really feel like trying to go through obfuscated decompiled code to find something this complex lol (I really don't feel like looking at obfuscated code at all, and haven't...so far). Not sure if any of that helps, but maybe someone can expand on it or correct anything I may have wrong.

Lastly, a couple very broad areas that could affect many systems including the light levels...
...skipped or cut-off frames, ie frames belonging to a cyclic executive or similar task sheduling system (if the relied-on data was supposed to be updated there...but this is not likely, as the sky light levels would have to be skipped consistently if they stay there through the entire day cycle, which I have not confirmed....do you know if they do, Marcus?)
...data synchronization
These are both broad categories that could affect any number of things in a game, and may or may not have anything to do with the issue.

Edit: A few more bits that may or may not be helpful:
1. Sometimes the block renders as black when the (glitched) light level is 0 and the sky light level is high, even though it is supposed to use the higher value, and sometimes it renders the sky light level.

2. Placing a solid block on the dark face of a glitched block seems to extend the glitch to the same face of the new block. I extended one on side face and it extended until 2128, a chunk boundary but not a region boundary (80 blocks or 5 chunks from the nearest chunk boundary at 2048...interestingly, this was at a height of 80, which matches the block distance from the region boundary, but...that's probably not related...?)

3. Noticed edges of a glitched areas were at a chunk boundaries (in their found state, not after adding blocks as mentioned in #2), but not necessarily in a single chunk (some extend through multiple chunks). There are some exceptions though...I think I noticed an organic shape in one area...

4. Glitched areas don't seem to extend to region boundaries (at least in their found state), though they COULD have an effect if the area would normally extend beyond them...this would have to be tested at a region boundary though, and finding a dark spot on a region boundary is no simple task.

5. Watched affected areas as they loaded on an SMP server; they all seem to have boundaries matching edges areas that are loaded at a time. I'm not saying "chunks" because one of them is directly ABOVE unaffected blocks (flat vertical wall, glitched on side face), and visibly loaded AFTER the lower portion of the wall. Are chunks no longer full height, or do chunks load in sections from bottom up? If they're not explicitly being loaded in vertical sections, are they loading partially due to multiple chunk loading threads, or possibly packet transmission sections (would assume full chunks for each packet, but...)?

6. Added block adjacent to a glitched area, was fixed, relogged, broken. Removed block, fixed, relogged, broken. Added block JUST inside glitched area (glitched top, added to top face), still glitched, relogged, FIXED (interesting...). Same behavior for 1 block further inside (moving horizontally, placing on top face which is glitched). Same behavior for 1 block above as well, so probably any within area...HOWEVER it only seems to fix the glitched area for a certain distance, maybe the distance the "fixing block" would alter other blocks' light levels...?

...this is getting long and turning into a debugger's ramble. I think I should stop here.

@unknown please stop editing you comment over and over again, as each time you edit it, you'll send a mail to all people watching this ticket, use the preview button instead

The single block with the dark bottom face is showing the glitch in the 16x16x16 block area directly BELOW it. You can also see the one fixed 16x16x16 as the light section on the vertical 1x1 tower.

My apologies...each edit was after more tests were done, and I assumed a post edit would not send mail (personally I don't think it should; only new posts...that's one of the reasons to have an edit button). I'll avoid it from now on as best I can. This system doesn't seem to have mail or pm capabilities (unless I'm just not seeing them), or I would've sent you a mail instead of posting this.

Since I'm posting this apology anyway, I'll include a link to a video that proves this lighting glitch is affecting 16x16x16 areas, not full height chunks - https://youtu.be/f-1ql9vngag

And I almost forgot to test with a fixed 16x16x16 ABOVE a glitched 16x16x16, shown in the picture attached. If you look at the picture AFTER watching the video it makes sense. Also...I thought that "attach files" would include them in this post...sorry again...

SIDE RANT
More importantly, I'd say that edits sending mails should be changed at the very least; it discourages people from doing further testing and posting their findings. I realize for some, or even MOST issues, the entirety of the information can be posted in one go after all testing is done, but I think it's reasonable to say that this issue is not one of those, since it's been around for many years even after Jeb specifically targeted and attempted to fix it. If you want some real tests that show actual useful information, the system should not have something in place that discourages the posting of such information, even if it was found shortly after a previous post was made (I know this is not your fault and that you just have to deal with it as part of your moderator job FV...my condolences). I may even go so far as to say that if you don't like it...unsubscribe! (Again, I'm assuming mods cannot unsubscribe, so sorry about that; just meant for those who can.)

Also, a mail system should be added, so that you don't get UNRELATED SIDE RANTS LIKE THESE in the threads, taking up space!

Lastly, I didn't even notice that preview button until you said it existed...plenty of horizontal space down there for it to actually say "preview" but guessing that's atlassian's fault (but thanks for bitbucket, atlassian...very useful).

...and when you attach a file, it has you put in some description text, but neither the file nor the description text link to each other anywhere...? That will result in some extremely confusing posts. That's no good.
END SIDE RANT

Sorry one last time FV...just angry at the system, not the mods.

I cannot reproduce this bug in 1.9. If you once lightened that area up, will it then become dark again, after reloading the chunks?

Reloading with f3+a, no, reloading by unloading it server side, yes

In my case, the area remains glitched after a client reload (f3+a) and/or a server reload (leaving area and returning and/or logging out and logging back in. I don't think I did an f3+a in the video I posted, but I did test it just now. The video covers most of the other points.

I haven't done any thorough testing on underground areas yet, but I'm betting they are still 16x16x16 block areas.

My observations of some lighting glitches: they seem to occur if a light source is removed, such as a torch. They seem to be incorrect calculations of sky light in that area.

Go into a forest, place a torch on the ground then remove it. Trees in the vicinity will have lighting issues underneath them. Place an opaque block on the ground, then remove it. Nearby lighting issues will be fixed when the block is placed.

From this observation, it appears that when a light source is removed, the calculation of light intensity in that area appears to be skipping a calculation of sky light that is not being skipped when a block is placed or broken. This may also happen when trees or terrain is generated in new chunks.

The lighting issues will not always go away on their own. A common place to find lighting issues is on overhangs, such as a tree on the edge of a cliff or overhanging terrain. Lighting underneath the tree will often be incorrect. It is possible to stand in that darkened area and examine the light levels in the Debug screen. When you do this, you will find that the Sky light is much lower than expected. These dark areas are not generally aligned with chunk boundaries, so this is not the same issue as the one where cubic chunks with just air blocks are not saving lighting information.

1.9.4

As can be seen in the picture there is a block square on the floor.

Two images are:

2016-05-18_23.48.21.png
2016-05-18_23.42.18.png

The light properties are this:

Light: 15 (0 sky, 0 block) - for the day time square

Light: 15 (15 sky, 0 block) - for the night time larger area

Mobs do not spawn on these spots.

Still happens n 1.10 but much, much rarer.

Confirmed for 1.10.2 and 16w33a.

Affects Version 1.11.2

I find them regularly under many (if not all) birch trees, even if not completely black, but significantly darker than they should be. Placing a torch and breaking it fixes it, but it might come back when sleeping the night.

Some people have fixed this issue by walking into it placing water or replacing a block

for me the issue stands no matter what I do

still an issue in 1.12. this is one of the oldest bugs in minecraft please fix it.

For some reason, it doesn't happen in my gameplay

Still happening in my gameplay...

Could you show inages with the F3+G debug render on? it’s likely a different issue (MC-80966).