int vertexCount = input.capacity() / 3;
for (int i = 0; i < vertexCount; i++){
BufferUtils.populateFromBuffer(temp, input, i);
// offset and scale vector into -128 ... 127
temp.multLocal(127).addLocal(0.5f, 0.5f, 0.5f);
// quantize
byte v1 = (byte) temp.getX();
byte v2 = (byte) temp.getY();
byte v3 = (byte) temp.getZ();