private void initializeVertexBuffer() {
FloatBuffer vertexDataBuffer = BufferUtils.createFloatBuffer( vertexData.length );
vertexDataBuffer.put( vertexData );
vertexDataBuffer.flip();
vertexBufferObject = glGenBuffers();
glBindBuffer( GL_ARRAY_BUFFER, vertexBufferObject );
glBufferData( GL_ARRAY_BUFFER, vertexDataBuffer, GL_STATIC_DRAW );
glBindBuffer( GL_ARRAY_BUFFER, 0 );