MC-7192The generation of "terrain" surface layer in Nether produces local straight artifacts/glitches (partial fix included)
This bug is very closely related to MC-6820, as the mistakes in the code are virtually the same.
What seems to be wrong
In Nether, due to the way the terrain surface features are made, the artifacts are very difficult to notice while playing, but using a map (with ability to see "slices") reveals similar artifacts as the same bug for the overworld generator produces. They are easiest to notice at levels just below the top bedrock as straight "cuts" in the hidden "basins" (of layer of one block air 
) just below the bedrock. See the attached screenshot of a map, the brighter brown blobs with straight east-west cuts. The cuts are exactly at chunk borders.
The bugged code is in ChunkProviderHell.replaceBlocksForBiome(int, int, byte[]), in almost begin of the method. However, this time I've replaced the MCP decompilation result with my own interpretations for some of the variable names:
this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d, d, 1.0D); this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d); this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d * 2.0D, d * 2.0D, d * 2.0D);
Note the difference in the order of Y and Z parameters between method calls.
What I expect
The blobs (and few other less easily seen features) should have curving/natural shapes and no artifical straight east-west cuts. Sorry, no good screenshot about it, but just imagine that bug-example screenshot having the blobs' south side cuts replaced with something similar to their north sides.
The fixed code would be:
this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d, 1.0D, d); this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d); this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d * 2.0D, d * 2.0D, d * 2.0D);
HOWEVER only the 3rd line is for this particular case, even if the first line has the same bug (and fix). The problem with the first line's fix is that it unfortunately reveals that the gravel-generation was based on a side-effect of that bug, and the first line fix makes slowsand always overwrite gravel. Full fix for that needs more knowledge on how the generateNoiseOctaves can be used and/or an additional adjustment later in the same method.
Example seed and coords:
8833675719584443437
270 126 -80
Environment
Windows 7 64-bit, java 7 64-bit
Linked Issues
Created Issue:
The generation of "terrain" surface layer in Nether produces local straight artifacts/glitches (partial fix included
This bug is very closely related to
MC-6820, as the mistakes in the code are virtually the same.What seems to be wrong
In Nether, due to the way the terrain surface features are made, the artifacts are very difficult to notice while playing, but using a map (with ability to see "slices") reveals similar artifacts as the same bug for the overworld generator produces. They are easiest to notice at levels just below the top bedrock as straight "cuts" in the hidden "basins" (of layer of one block airThe bugged code is in ChunkProviderHell.replaceBlocksForBiome(int, int, byte[]), in almost begin of the method. However, this time I've replaced the MCP decompilation result with my own interpretations for some of the variable names:
this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d, d, 1.0D);
this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d);
this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d * 2.0D, d * 2.0D, d * 2.0D);Note the difference in the order of Y and Z parameters between method calls.
What I expect
The blobs (and few other less easily seen features) should have curving/natural shapes and no artifical straight east-west cuts. Sorry, no good screenshot about it, but just imagine that bug-example screenshot having the blobs' south side cuts replaced with something similar to their north sides.The fixed code would be:
this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d, 1.0D, d);
this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d);
this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d * 2.0D, d * 2.0D, d * 2.0D);HOWEVER only the 3rd line is for this particular case, even if the first line has the same bug (and fix). The problem with the first line's fix is that it unfortunately reveals that the gravel-generation was based on a side-effect of that bug, and the first line fix makes slowsand always overwrite gravel. Full fix for that needs more knowledge on how the generateNoiseOctaves can be used and/or an additional adjustment later in the same method.
Environment
Platform/environment shouldn't matter, as the bug is in the java code.
(Windows 7 64-bit, java 7 64-bit, naturally unmodified Minecraft).
Attachments1
This bug is very closely related to
MC-6820, as the mistakes in the code are virtually the same.What seems to be wrong
In Nether, due to the way the terrain surface features are made, the artifacts are very difficult to notice while playing, but using a map (with ability to see "slices") reveals similar artifacts as the same bug for the overworld generator produces. They are easiest to notice at levels just below the top bedrock as straight "cuts" in the hidden "basins" (of layer of one block airThe bugged code is in ChunkProviderHell.replaceBlocksForBiome(int, int, byte[]), in almost begin of the method. However, this time I've replaced the MCP decompilation result with my own interpretations for some of the variable names:
this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d, d, 1.0D);
this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d);
this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d * 2.0D, d * 2.0D, d * 2.0D);Note the difference in the order of Y and Z parameters between method calls.
What I expect
The blobs (and few other less easily seen features) should have curving/natural shapes and no artifical straight east-west cuts. Sorry, no good screenshot about it, but just imagine that bug-example screenshot having the blobs' south side cuts replaced with something similar to their north sides.The fixed code would be:
this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d, 1.0D, d);
this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d);
this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d * 2.0D, d * 2.0D, d * 2.0D);HOWEVER only the 3rd line is for this particular case, even if the first line has the same bug (and fix). The problem with the first line's fix is that it unfortunately reveals that the gravel-generation was based on a side-effect of that bug, and the first line fix makes slowsand always overwrite gravel. Full fix for that needs more knowledge on how the generateNoiseOctaves can be used and/or an additional adjustment later in the same method.
This bug is very closely related to
MC-6820, as the mistakes in the code are virtually the same.What seems to be wrong
In Nether, due to the way the terrain surface features are made, the artifacts are very difficult to notice while playing, but using a map (with ability to see "slices") reveals similar artifacts as the same bug for the overworld generator produces. They are easiest to notice at levels just below the top bedrock as straight "cuts" in the hidden "basins" (of layer of one block airThe bugged code is in ChunkProviderHell.replaceBlocksForBiome(int, int, byte[]), in almost begin of the method. However, this time I've replaced the MCP decompilation result with my own interpretations for some of the variable names:
ChunkProviderHell.replaceBlocksForBiome(int, int, byte[])this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d, d, 1.0D); this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d); this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d * 2.0D, d * 2.0D, d * 2.0D);Note the difference in the order of Y and Z parameters between method calls.
What I expect
The blobs (and few other less easily seen features) should have curving/natural shapes and no artifical straight east-west cuts. Sorry, no good screenshot about it, but just imagine that bug-example screenshot having the blobs' south side cuts replaced with something similar to their north sides.The fixed code would be:
ChunkProviderHell.replaceBlocksForBiome(int, int, byte[])this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d, 1.0D, d); this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d); this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d * 2.0D, d * 2.0D, d * 2.0D);HOWEVER only the 3rd line is for this particular case, even if the first line has the same bug (and fix). The problem with the first line's fix is that it unfortunately reveals that the gravel-generation was based on a side-effect of that bug, and the first line fix makes slowsand always overwrite gravel. Full fix for that needs more knowledge on how the generateNoiseOctaves can be used and/or an additional adjustment later in the same method.
The generation of "terrain" surface layer in Nether produces local straight artifacts/glitches (partial fix included)
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This ticket is incomplete without the requested information, no response has been received within a reasonable time. If you are still experiencing this issue, we can reopen it at your request.
![[Mod] Ezekiel (ezfe)](../../../data/assets/gravatar/ezekielelin.jpeg){kind=small}
![[Bot] Arisa](../../../data/assets/gravatar/mustek2.png){kind=small}
Platform/environment shouldn't matter, as the bug is in the java code.
(Windows 7 64-bit, java 7 64-bit, naturally unmodified Minecraft).Windows 7 64-bit, java 7 64-bit
![[Mod] Neko](../../../data/avatars/users/92901.png){kind=small}
This bug is very closely related to
MC-6820, as the mistakes in the code are virtually the same.What seems to be wrong
In Nether, due to the way the terrain surface features are made, the artifacts are very difficult to notice while playing, but using a map (with ability to see "slices") reveals similar artifacts as the same bug for the overworld generator produces. They are easiest to notice at levels just below the top bedrock as straight "cuts" in the hidden "basins" (of layer of one block airThe bugged code is in ChunkProviderHell.replaceBlocksForBiome(int, int, byte[]), in almost begin of the method. However, this time I've replaced the MCP decompilation result with my own interpretations for some of the variable names:
ChunkProviderHell.replaceBlocksForBiome(int, int, byte[])this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d, d, 1.0D); this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d); this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, d * 2.0D, d * 2.0D, d * 2.0D);Note the difference in the order of Y and Z parameters between method calls.
What I expect
The blobs (and few other less easily seen features) should have curving/natural shapes and no artifical straight east-west cuts. Sorry, no good screenshot about it, but just imagine that bug-example screenshot having the blobs' south side cuts replaced with something similar to their north sides.The fixed code would be:
ChunkProviderHell.replaceBlocksForBiome(int, int, byte[])this.slowsandNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.slowsandNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d, 1.0D, d); this.gravelNoise = this.slowsandGravelNoiseGen.generateNoiseOctaves(this.gravelNoise, par1 * 16, 109, par2 * 16, 16, 1, 16, d, 1.0D, d); this.netherrackExclusivityNoise = this.netherrackExculsivityNoiseGen.generateNoiseOctaves(this.netherrackExclusivityNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, d * 2.0D, d * 2.0D, d * 2.0D);HOWEVER only the 3rd line is for this particular case, even if the first line has the same bug (and fix). The problem with the first line's fix is that it unfortunately reveals that the gravel-generation was based on a side-effect of that bug, and the first line fix makes slowsand always overwrite gravel. Full fix for that needs more knowledge on how the generateNoiseOctaves can be used and/or an additional adjustment later in the same method.
Example seed and coords:
8833675719584443437
270 126 -80
![[Mod] Pokechu22](../../../data/avatars/users/92931.png){kind=small}
(Closely related to MC-7192.)
The seed for the world of two first screenshots (with swamp and desert) is -807116175.
Bug as seen in 1.4.7
Attached screenshot (..00.18) shows the visual effect of the problem with unmodified 1.4.7: one block too little sand in a straight line form, often repeating in 16-block period. The problem may affect other than sand surface, too. Note, the area around had not yet been fully loaded/generated at the time of the screenshot, so ignore the missing stuff in the distance.
What I expect to be seen
The other screenshot (..01.53) shows the same world and the same location after applying the proposed code fix shown below.
Background/other info
Examples of the bug are quite easy to find in almost any world, given enough flying around. While mostly investigating this in creative mode, it should be just as valid for survival mode.
(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
The bugged part of code (as seen with MCP 7.26) is:
ChunkProviderGenerate.replaceBlocksForBiome(int, int, byte[], BiomeGenBase[]), 3rd line of the method:
this.stoneNoise = this.noiseGen4.generateNoiseOctaves(this.stoneNoise, par1 * 16, par2 * 16, 0, 16, 16, 1, var6 * 2.0D, var6 * 2.0D, var6 * 2.0D);
Fixed code
The fixed version swaps the latter two coordinate axes (Y and Z, I suppose):
this.stoneNoise = this.noiseGen4.generateNoiseOctaves(this.stoneNoise, par1 * 16, 0, par2 * 16, 16, 1, 16, var6 * 2.0D, var6 * 2.0D, var6 * 2.0D);
Added
One more screenshot and map snippet, from very old worlds, at the time when I first checked this and made the fixes. The map snippet should clearly visualize it is not about "basins", and the screenshot also shows it is (back then) not about basins, as it was between sand and dirt at the same level. (This difference is because back then the same bug could affect not only thickness, but also the material, if I remember it right. I did have to make changes to 3 more lines in that same method to get all the related things fixed, but with the new biome code, only 1 line is enough.)
Added more
The stone-gray screenshot is taken with a modified client, in order to reveal the full extent of the bug. I modified the world generator to create the ground at fixed height of 7, and for the replace method (which has the bug) to switch the surface stone layer into air instead of dirt or sand. This way the height variation on the ground is actually showing only the surface layer thickness function (and some further random features, like those small ponds, caves and ravines).
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
I'm going to make another entry about an equal bug for Nether, but FYI, the corresponding class and method for Nether has the same bug, and another similar, as it is basically an adapted copy of the older overworld generator (with its multiple bugs it had back then).
Something similar seems to still be there in version 1.7.5, although I couldn't find equal example; not as sharp edge, but it still has east-west "lines" and all the typical symptoms. See screenshot example-1.7.5.png. Seed 8833675719584443437, nether location around 270,-80.
Of course, the issue is still practically invisible in-game; I used Unmined to spot those.
Still in effect as of 15w47c. The same seed and coords as in my previous comment can be used: 8833675719584443437, nether location around 270,-80. (The layer/level for the unmined screenshot is 126). (As a refresh for anyone else wanting to check it.)
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. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. It will be reopened as soon as the requested information has been delivered.
Apparently fixed in 18w16a; the relevant code no longer seems to exist (reworked into a newer system, probably as part of creating the buffet type?)