My fault

src/minecraft/net/minecraft/src/NoiseGeneratorPerlin2.java

@@ -60,6 +60,10 @@ public class NoiseGeneratorPerlin2 extends NoiseGenerator
         return ((var8 & 1) == 0 ? var9 : -var9) + ((var8 & 2) == 0 ? var11 : -var11);
     }
     
+    private double floor(double value) {
+    	return value < 0 ? Math.floor(value) + 1 : Math.floor(value);
+    }
+
     /**
      * pars: noiseArray , xOffset , yOffset , zOffset , xSize , ySize , zSize , xScale, yScale , zScale , noiseScale.
      * noiseArray should be xSize*ySize*zSize in size
@@ -91,7 +95,7 @@ public class NoiseGeneratorPerlin2 extends NoiseGenerator
             for (int var30 = 0; var30 < par8; ++var30)
             {
                 var31 = par2 + (double)var30 * par11 + this.xCoord;
-                double var78 = Math.rint(var31);
+                double var78 = floor(var31);
 
                 if (var31 < (double)var78)
                 {
@@ -105,7 +109,7 @@ public class NoiseGeneratorPerlin2 extends NoiseGenerator
                 for (var37 = 0; var37 < par10; ++var37)
                 {
                     var38 = par6 + (double)var37 * par15 + this.zCoord;
-                    double var40 = Math.rint(var38);
+                    double var40 = floor(var38);
 
                     if (var38 < (double)var40)
                     {
@@ -146,7 +150,7 @@ public class NoiseGeneratorPerlin2 extends NoiseGenerator
             for (var37 = 0; var37 < par8; ++var37)
             {
                 var38 = par2 + (double)var37 * par11 + this.xCoord;
-                double var40 = Math.rint(var38);
+                double var40 = floor(var38);
 
                 if (var38 < (double)var40)
                 {
@@ -160,7 +164,7 @@ public class NoiseGeneratorPerlin2 extends NoiseGenerator
                 for (int var44 = 0; var44 < par10; ++var44)
                 {
                     double var45 = par6 + (double)var44 * par15 + this.zCoord;
-                    double var47 = Math.rint(var45);
+                    double var47 = floor(var45);
 
                     if (var45 < (double)var47)
                     {
@@ -174,7 +178,7 @@ public class NoiseGeneratorPerlin2 extends NoiseGenerator
                     for (int var51 = 0; var51 < par9; ++var51)
                     {
                         double var52 = par4 + (double)var51 * par13 + this.yCoord;
-                        double var54 = Math.rint(var52);
+                        double var54 = floor(var52);
 
                         if (var52 < (double)var54)
                         {