class Game_System def draw_line(bitmap, x1, y1, x2, y2, colour) w = (x1 - x2).abs h = (y1 - y2).abs sx = 0 sy = 0 if (x1 < x2) sx = 1 else sx = -1 end if (y1 < y2) sy = 1 else sy = -1 end err = (w - h).to_f while(true) bitmap.set_pixel(x1, y1, colour) break if ((x1 == x2) && (y1 == y2)) e2 = (2 * err).to_f if (e2 > -h) err -= h x1 += sx end if (e2 < w) err += w y1 += sy end end end end