[MC-77761] Ocean related biomes don't generate correctly in custom worlds

Since the bug of the water generating around Ocean Temples was fixed, I made a world to take a look, I discovered that no water generated, actually, a forest did. I tested this with Deep Ocean biome and the Frozen Ocean biome. At first I left the Ocean Monument to 'yes' in the customization menu. That's when it happened. Water level was set to '1'. In the pictures are the seeds of the worlds I tested on. In the FrozenOcean biome a kind of Forest/Taiga something appeared to form.
Deep Ocean Seed: -2237070983244950429
FrozenOcean Seed: 70814820975513480898
UPDATE: It seems that this bug does not affect 1.8.2-pre6 and earlier.

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Comments 19

bob 2015-02-19T17:25:21Z

The bit about snow generating isn't a bug; that's just the level decorator treating the frozen ocean as a big island due to the low water level. However the rest is.

Daniel Cruz 2015-02-19T17:33:17Z

Yeah, because as of I know, Deep Oceans generate gravel.

bob 2015-02-19T17:36:18Z

I was talking about the frozen ocean. The deep ocean generation in the screenshot is strange and I agree that its also a bug.

bob 2015-02-19T17:37:17Z

Maybe the generator only generates gravel below water to prevent gravel islands?

Daniel Cruz 2015-02-19T17:39:26Z

Perhaps? Ley me try with more water level.

9 more comments

Daniel Cruz 2015-02-19T17:53:36Z

Actually, its a bug. I tested this same configuration in the 1.8.2-pre6 and it generated as expected.

bob 2015-02-19T18:14:04Z

I've worked out why no gravel is generated: the sand and gravel decorators only generate below water:

WorldGenSand.java

/* 23:   */   public boolean generate(World paramWorld, Random paramRandom, BlockPos paramBlockPos)
/* 24:   */   {
/* 25:22 */     if (paramWorld.getBlockState(paramBlockPos).getBlock().getMaterial() != Material.water) {
/* 26:23 */       return false;
/* 27:   */     }
/* 28:25 */     int i = paramRandom.nextInt(this.radius - 2) + 2;
/* 29:26 */     int j = 2;
/* 30:27 */     for (int k = paramBlockPos.getX() - i; k <= paramBlockPos.getX() + i; k++) {
/* 31:28 */       for (int m = paramBlockPos.getZ() - i; m <= paramBlockPos.getZ() + i; m++)
/* 32:   */       {
/* 33:29 */         int n = k - paramBlockPos.getX();
/* 34:30 */         int i1 = m - paramBlockPos.getZ();
/* 35:31 */         if (n * n + i1 * i1 <= i * i) {
/* 36:34 */           for (int i2 = paramBlockPos.getY() - j; i2 <= paramBlockPos.getY() + j; i2++)
/* 37:   */           {
/* 38:35 */             BlockPos localBlockPos = new BlockPos(k, i2, m);
/* 39:36 */             Block localBlock = paramWorld.getBlockState(localBlockPos).getBlock();
/* 40:37 */             if ((localBlock == Blocks.dirt) || (localBlock == Blocks.grass)) {
/* 41:38 */               paramWorld.setBlockState(localBlockPos, this.blockType.getDefaultState(), 2);
/* 42:   */             }
/* 43:   */           }
/* 44:   */         }
/* 45:   */       }
/* 46:   */     }
/* 47:44 */     return true;
/* 48:   */   }
/* 49:   */ }

Line 25 allows sand & gravel to generate only underwater (MCP+own mappings). I'm guessing this kind of thing is also used to not generate trees, grass etc underwater.
I guess this is so that islands look natural if the terrain is suddenly forced up.
I tried this in both 1.8.1 and 1.8.2 and they generated the same natural waterless terrain when customised. If I've missed the point, sorry, I'll test further.
EDIT: The ocean monument thing is still a bug by the way.

Daniel Cruz 2015-02-19T18:28:17Z

So, you mean its normal?

bob 2015-02-19T18:56:52Z

Idk for all versions. The only way to check would be to test all versions since 1.8 ish

Daniel Cruz 2015-02-19T19:10:46Z

Well, for the 1.8.2-pre6 it made the gravel and stuff and I think for 1.8 too.

bob 2015-02-19T19:40:59Z

1.8.1 didn't have gravel... Its a bit of a mess.

bob 2015-02-19T19:45:19Z

I will test ~~all~~ versions from 1.8 onwards with sealevel=1 and biome=ocean on seed 4292011213696392089

bob 2015-02-19T19:52:51Z

It seems I opened a world by accident at some point rather than re-creating it.
1.8, 1.8.1 and 1.8.2 pre 6 all generate gravel
1.8.2 pre 7 doesn't so I now agree that this is probably a new bug
I don't know what was going on with the code but the ocean biomes probably have their own gravel generator hidden somewhere.

Daniel Cruz 2015-02-20T14:48:29Z

Confirmed for 1.8.3.

michael 2015-02-20T15:16:45Z

Ok, I'm a bit confused by your description. Does "Water level was set to '1'." actually mean you made a customized world and set the sea level to 1? In that case this is working as intended, that's the purpose of the sea level option.

Daniel Cruz 2015-02-20T15:47:20Z

But is the forest generation with such low water level normal?

bob 2015-02-21T09:43:57Z

Edit: nvm

bob 2015-02-21T09:46:41Z

The third to last image (BUG.png) shows the weird new generation compared to the old.

wobst.michael 2016-10-20T22:35:01Z

Is this still an issue in the most recent versions (i.e. 1.10.2, or 16w42a) of Minecraft?