code: private void renderLine(Graphic g, int numLine, int lineY)
      {
          final int lineWidth = surface.getLineWidth(numLine);
          for (int j = -amplitude; j < amplitude; j++)
          {
              final int lx = (int) (-offsetX + offsetX * j - x[numLine] - x2[numLine] + numLine * (2.56 * factH) * j);
              if (lx + lineWidth + decX >= 0 && lx <= screenWidth)
              {
                  surface.render(g, numLine, lx + decX, lineY);
              }
          }
      }
docs: Render parallax line.
  
  @param g The graphic output.
  @param numLine The current line number.
  @param lineY The line y position.