Function CheckUnderflow

src/viewport.cpp:3046–3052

* Check for underflowing the map. * @param test the variable to test for underflowing * @param other the other variable to update to keep the line * @param mult the constant to multiply the difference by for \c other */

 * @param mult  the constant to multiply the difference by for \c other
 */
static void CheckUnderflow(int &test, int &other, int mult)
{
	if (test >= 0) return;

	other += mult * test;
	test = 0;
}

/**
 * Check for overflowing the map.