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  1. Minecraft: Java Edition
  2. MC-46082

Crashes when populating a chunk with empty (void) columns

    Details

    • Type: Bug
    • Status: Resolved
    • Resolution: Fixed
    • Affects Version/s: 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
    • Fix Version/s: Minecraft 1.8-pre2
    • Labels:
      None
    • Environment:

      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)

    • Confirmation Status:
      Confirmed

      Description

      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.

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              • Assignee:
                TheMoogle Mog (Ryan Holtz)
                Reporter:
                Captain Chaos Pepijn Schmitz
              • Votes:
                40 Vote for this issue
                Watchers:
                14 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved:
                  CHK: