Array Index out of Bounds

Hi, i was creating a voxel game and I used roboleary’s code for greedy meshing:

But the problem is, when i set the chunk width and height to not be equal, it throws an IndexOutOfBoundsException at

for(x[v] = 0; x[v] < CHUNK_HEIGHT; x[v]++) {

                        for(x[u] = 0; x[u] < CHUNK_WIDTH; x[u]++) {

                            /*
                             * Here we retrieve two voxel faces for comparison.
                             */
                            voxelFace  = (x[d] >= 0 )             ? getVoxelFace(x[0], x[1], x[2], side)                      : null;
                            voxelFace1 = (x[d] < CHUNK_WIDTH - 1) ? getVoxelFace(x[0] + q[0], x[1] + q[1], x[2] + q[2], side) : null;

                            /*
                             * Note that we're using the equals function in the voxel face class here, which lets the faces 
                             * be compared based on any number of attributes.
                             * 
                             * Also, we choose the face to add to the mask depending on whether we're moving through on a backface or not.
                             */
                            mask[n++] = ((voxelFace != null && voxelFace1 != null && voxelFace.equals(voxelFace1))) 
                                        ? null 
                                        : backFace ? voxelFace1 : voxelFace;
                        }
                    }

The Exception is at

voxelFace1 = (x[d] < CHUNK_WIDTH - 1) ? getVoxelFace(x[0] + q[0], x[1] + q[1], x[2] + q[2], side) : null;

thrown at the getVoxelFace method

The Exception goes like

“Index 64 out of Bounds for length 64”

When chunk width is 64 and height 128

Anyone know whats going on?