[WGEN] Create a Riverland

Hey Guys,
in my Worldgeneration-tests I created this small fail:
View attachment 11748
I hope anyone can do someting with the code:

Code:

public byte[] generate(World world, Random random, int chunkX, int chunkZ) {
    byte[] b = new byte[16*16*128];
    Random seed = new Random(world.getSeed());
    SimplexOctaveGenerator gen = new SimplexOctaveGenerator(seed, 8);
    SimplexOctaveGenerator gen2 = new SimplexOctaveGenerator(seed, 8);
    PerlinOctaveGenerator pln = new PerlinOctaveGenerator(seed, 8);
    gen.setScale(1/64.0);
    gen2.setScale(1/128.0);
    pln.setScale(0.00215D);
    for (int x=0; x<16; x++){
                for (int z=0; z<16; z++){
                    double noise2 = Math.max(gen.noise(x+chunkX*16, z+chunkZ*16, 0.5, 0.5)*16, gen2.noise(x+chunkX*16, z+chunkZ*16, 0.7, 0.5));
                    double noise1 = noise2 + Math.E;
                    double noise = Math.sin(noise1) * 3;
                    for(int y=21; y<48.0D+noise; y++) {
                        b[xyzToByte(x, y, z)] = (byte)(Material.GRASS).getId();
                    }
                    for(int y=1; y<32+noise; y++){
                        if(b[xyzToByte(x,y,z)] ==0)
                        b[xyzToByte(x,y,z)] = (byte)(Material.STONE).getId();
                    }   
                    for(int y=0; y<1; y++) {
                        b[xyzToByte(x, y, z)] = (byte)(Material.BEDROCK).getId();
                    }
                }
               
            }
    return b;
    }

PS: Can someone explain me what the thing with the D is. I saw is at other codes, but dont know what this mean!?

Empty2k12

 

The D makes sure java interprets it as a double, that way if you do any division in your code, it doesn't get rounded.