railcraft functions

function fuelUsage($maxHeat, $heatLevel, $numTanks, $type)
{
  $temp = $heatLevel / $maxHeat;

  $base = ((6.4 - $numTanks * 0.08) / $type) * $numTanks;

  $fuelUsage = $base + $base * (8 - 8 * $temp);

  return $fuelUsage;
}

function increaseHeat($heatLevel, $numTanks, $maxHeat, $heatStep)
{
  $change = $heatStep;
  if ($heatLevel < 0.25)
  {
    $change += $heatStep;
  }
  if ($heatLevel < 0.5)
  {
    $change += $heatStep;
  }
  if ($heatLevel < 0.75)
  {
    $change += $heatStep;
  }
  $change /= $numTanks;
  $heatLevel += $change;
  $heatLevel = min($heatLevel, $maxHeat);

  return $heatLevel;
}