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  1. Minecraft: Java Edition
  2. MC-46082

Crashes when populating a chunk with empty (void) columns

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    • Icon: Bug Bug
    • Resolution: Fixed
    • Minecraft 1.8-pre2
    • Minecraft 1.7.4, Minecraft 1.7.5, Minecraft 1.7.9, Minecraft 14w21b, Minecraft 14w25b, Minecraft 1.7.10, Minecraft 14w28b, Minecraft 14w29a, Minecraft 14w29b, Minecraft 14w30a, Minecraft 14w30b, Minecraft 14w33c
    • None
    • Ubuntu 13.04 64-bit
      java version "1.7.0_51"
      Java(TM) SE Runtime Environment (build 1.7.0_51-b13)
      Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)
    • Confirmed

      Minecraft crashes when populating a chunk which has empty columns ("void columns"), i.e. colums with just air blocks, no bedrock, such as can for instance be generated by creating a Superflat world with preset 

      2;0;1;decoration

      I have attached the crash report. I don't have access to the Minecraft source code, but using the Minecraft Coder Pack for Minecraft 1.7.2 I've traced it to the following code in BiomeDecorator.java (method func_150513_a(BiomeGenBase), lines 160-166):

            for(var3 = 0; var3 < this.grassPerChunk; ++var3) {
         var4 = this.chunk_X + this.randomGenerator.nextInt(16) + 8;
         var5 = this.chunk_Z + this.randomGenerator.nextInt(16) + 8;
         var6 = this.randomGenerator.nextInt(this.currentWorld.getHeightValue(var4, var5) * 2);
         WorldGenerator var10 = p_150513_1_.getRandomWorldGenForGrass(this.randomGenerator);
         var10.generate(this.currentWorld, this.randomGenerator, var4, var6, var5);
      }

      It takes the height at a particular x,z coordinate and feeds the result (times two) to Random.nextInt(int). Unfortunately that method throws an exception when passed a value of zero.

      One way to fix this would be to change those lines to something like:

            for(var3 = 0; var3 < this.grassPerChunk; ++var3) {
         var4 = this.chunk_X + this.randomGenerator.nextInt(16) + 8;
         var5 = this.chunk_Z + this.randomGenerator.nextInt(16) + 8;
         int height = this.currentWorld.getHeightValue(var4, var5);
         if (height > 0) {
	         var6 = this.randomGenerator.nextInt(height * 2);
	         WorldGenerator var10 = p_150513_1_.getRandomWorldGenForGrass(this.randomGenerator);
	         var10.generate(this.currentWorld, this.randomGenerator, var4, var6, var5);
         }
      }

      The same would have to be done for the other loops in that method.

        1. crash-2014-01-25_17.33.43-server.txt
          3 kB
        2. crash-2014-01-25_19.58.57-server.txt
          3 kB
        3. crash-2014-02-22_10.51.54-server.txt
          3 kB
        4. crash-2014-02-22_14.29.12-server.txt
          3 kB
        5. crash-2014-07-11_14.34.04-server.txt
          3 kB
        6. crash-2014-07-16_12.07.32-server.txt
          3 kB
        7. crash-2014-07-17_20.29.06-server.txt
          3 kB
        8. crash-2014-07-23_15.21.20-server.txt
          3 kB
        9. CrashMap.zip
          90 kB

            TheMoogle Mog (Ryan Holtz)
            Captain Chaos Pepijn Schmitz
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              Created:
              Updated:
              Resolved:
              CHK: