Gauss gun sometimes sets player uranium ammo to -1

[SamVanheer]

When using the Gauss gun's secondary attack, the player's uranium ammo can be set to -1 if the player has only 1 unit of ammo left and holds the secondary attack key down.

The cause is here:

halflife/dlls/gauss.cpp

Lines 229 to 256 in c7240b9

	// during the charging process, eat one bit of ammo every once in a while
	if ( UTIL_WeaponTimeBase() >= m_pPlayer->m_flNextAmmoBurn && m_pPlayer->m_flNextAmmoBurn != 1000 )
	{
	#ifdef CLIENT_DLL
	if ( bIsMultiplayer() )
	#else
	if ( g_pGameRules->IsMultiplayer() )
	#endif
	{
	m_pPlayer->m_rgAmmo[m_iPrimaryAmmoType]--;
	m_pPlayer->m_flNextAmmoBurn = UTIL_WeaponTimeBase() + 0.1;
	}
	else
	{
	m_pPlayer->m_rgAmmo[m_iPrimaryAmmoType]--;
	m_pPlayer->m_flNextAmmoBurn = UTIL_WeaponTimeBase() + 0.3;
	}
	}
	if ( m_pPlayer->m_rgAmmo[m_iPrimaryAmmoType] <= 0 )
	{
	// out of ammo! force the gun to fire
	StartFire();
	m_fInAttack = 0;
	m_flTimeWeaponIdle = UTIL_WeaponTimeBase() + 1.0;
	m_pPlayer->m_flNextAttack = UTIL_WeaponTimeBase() + 1;
	return;
	}

When using secondary attack the weapon first uses up one unit of ammo, then the next time it checks it uses up another unit of ammo before checking if the player is out of ammo.

If the player only has 1 unit of ammo left to begin with then the first time it thinks while charging it will go from 0 ammo to -1.

To fix this an additional check is needed to prevent the ammo consumption from occurring:

		if (m_pPlayer->m_rgAmmo[m_iPrimaryAmmoType] > 0)
		{
			// during the charging process, eat one bit of ammo every once in a while
			if (UTIL_WeaponTimeBase() >= m_pPlayer->m_flNextAmmoBurn && m_pPlayer->m_flNextAmmoBurn != 1000)
			{
#ifdef CLIENT_DLL
				if (bIsMultiplayer())
#else
				if (g_pGameRules->IsMultiplayer())
#endif
				{
					m_pPlayer->m_rgAmmo[m_iPrimaryAmmoType]--;
					m_pPlayer->m_flNextAmmoBurn = UTIL_WeaponTimeBase() + 0.1;
				}
				else
				{
					m_pPlayer->m_rgAmmo[m_iPrimaryAmmoType]--;
					m_pPlayer->m_flNextAmmoBurn = UTIL_WeaponTimeBase() + 0.3;
				}
			}
		}