[MC-6820] The generation of terrain surface layer produces local straight glitches (fix included) Created: 10/Jan/13 Updated: 14/Aug/20 Resolved: 09/Sep/13 |
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| Status: | Resolved |
| Project: | Minecraft: Java Edition |
| Component/s: | None |
| Affects Version/s: | Minecraft 1.4.6, Minecraft 1.4.7, Snapshot 13w07a, Snapshot 13w09b, Snapshot 13w09c, Minecraft 1.5, Minecraft 1.6.1, Minecraft 1.6.2 |
| Fix Version/s: | Minecraft 13w36a |
| Type: | Bug | ||
| Reporter: | Markku | Assignee: | [Mojang] Jeb (Jens Bergensten) |
| Resolution: | Fixed | Votes: | 7 |
| Labels: | overworld, terrain, world-generation | ||
| Environment: |
Platform/environment shouldn't matter, as the bug is in the java code. |
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| Confirmation Status: | Confirmed | ||||||||||||||||||||||||
| Game Mode: | Creative | ||||||||||||||||||||||||
| Description |
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(Closely related to The seed for the world of two first screenshots (with swamp and desert) is -807116175. Bug as seen in 1.4.7 What I expect to be seen Background/other info (Note, this same problem has been around since a loooong time ago, and I submitted a bug report and (almost) the same fix back then. Apparently it was never fixed back then and the soon after implemented changes to terrain generation just made it less noticeable, or the bug has crawled back in.) Bugged code Fixed code Added Added more As can be seen, there are a lot of straight long east-west steps, exactly at chunk borders. Most of the effect is normally hidden by the random variation in the height of ground. That is, the visual effect of this bug is hidden below random noise of the normal ground level function. One would not detect that bad signs if all the dirt/sand would be digged away in a normally generated map, but the effect is still there. Uh oh, there is even more |
| Comments |
| Comment by [Mojang] Jeb (Jens Bergensten) [ 09/Sep/13 ] |
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Thanks for the research. I actually found the same problem while I was investigating how the noise patterns worked. Should be fixed in the 1.7 snapshots. |
| Comment by [Mod] Ezekiel (ezfe) [ 10/Jul/13 ] |
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Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. |
| Comment by Markku [ 28/Feb/13 ] |
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Added 'example_in_137.png'. Seed "137" (defaults), location about 20, 240. (Easier to type in and get to than the mycelium one). |
| Comment by Markku [ 26/Feb/13 ] |
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Added stripes_on_mycelium.png, example from issue |
| Comment by Adam Navigato [ 26/Feb/13 ] |
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Yup, this is the exact problem I had. exept mine destroyed half my mushroom biome. |
| Comment by Markku [ 11/Jan/13 ] |
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After analyzing the source code a bit more, I figured that there is a specific piece of code just to create "basins" (i.e. areas where stone is seen directly), and it indeed works by detecting when the surface layer thickness function returns negative values. After a bit of flying around, I was able to find a proper natural looking basin even when that fix was in effect (and thus the basin had no straight edges). So, while the fix does change the surface layer thickness all around (and thus locations of basins will not match before and after the fix), basins will still exist, and the straight edges will not. |
| Comment by Markku [ 11/Jan/13 ] |
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Added one more screenshot, this one with a bit modified client in order to reveal the full extent of the bug. |
| Comment by Markku [ 10/Jan/13 ] |
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In that particular location (of my screenshot) it indeed hides it all. Which should indicate that at that position, there shouldn't be any "basin" to start with. I can try and find a spot with a "real" basin (when generated with my fixed code), but do not hold your breath, as it is actually possible that no basins should exist at all, as they could be just a side effect of this bug. Note, there is a better way to create such basins than swapping to coordinates. Namely, just increase the variation range for the surface layer thickness a little bit (to the lesser direction) and clip at 0. |
| Comment by Tails [ 10/Jan/13 ] |
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Alright reopening. |
| Comment by Markku [ 10/Jan/13 ] |
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Older example and map snippet. |
| Comment by Tails [ 10/Jan/13 ] |
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Well as far as I can tell your fix does not only remove the straight line, but the hole basin itself. Looking at the original generation of the basin, it extends beyond those straight lines. |
| Comment by Markku [ 10/Jan/13 ] |
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It sure is a bug. Or really silly joke from the developer who swapped the two coordinate parameters. Back when I first checked it out, there were 3 similar code lines in that location. The two other lines had parameters in the order x, y, z, but this one bugged line had (and still has) the parameters in the order x, z, y, and they all called the same method. Also, if the "feature" was indeed a intended, those "basins" would have natural edges, not straight steps repeated at every chunk edge and running sometimes for more than 30-40 blocks. I still have somewhere some even worse screenshots (but I can not redo those worlds any more as the terrain generation changes made old seeds useless), once with "combs" of more than 10 such stripes in a row. The problem was much more stronger back then. The Note, basins can be indeed a feature, but the straight edges are definitely not. Or does those stripes in my screenshot look like a "basin"?!? Also, the screenshot in the wiki-article has nice natural looking random curves along top and bottom of the picture, but the right and left sides are showing symptoms of those straight edges. Straight edges are possible even normally (just random luck...), but when they are long, and repeat exactly at chunk borders, luck has nothing to do with it. (I can not say yes or no for that wiki screenshot, as I would need to be at the spot, looking at F3-coordinates... But the screenshot I provided for this bug report does have the glitches exactly at chunk edges (as can be noticed from the F3 data)). Note, minecraftwiki is written mostly by people who do not "read the source code" (and btw, I do, although decompiled only), and they make often incorrect assumptions. For example, that section about basins seems to be lacking any references (to developers or claims of reading source code) that would validate what is written. Unless wikitext provides credible sources/references, it should not be used as an authority. |
| Comment by Tails [ 10/Jan/13 ] |
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That's not a bug, it's a world gen feature, a so called "basin". Threrefore duplicate of |
| Comment by Markku [ 10/Jan/13 ] |
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This is NOT a duplicate of that whole chunk stripes. Look more carefully at the screenshots provided, this bug only affects the surface layer locally. It does NOT affect e.g. trees etc. and typically does not continue for long distances, like that other bug does. Also, this same bug has been around for a very long time, well before that striped chunks -bug appeared. (Oh, and I DID use the search, and did see/find that other bug, and after few seconds could easily realize it is different issue.) |