This adds a new class which allows to create type safe resource handle
types. At the moment, the engine uses ints pretty much everywhere for
providing handles to resources created by the specific subsystems. Since
all ints are the same to the C/C++ typesystem it is perfectly legal to
pass a sound handle to the graphics API as a buffer handle which will
obviously cause issues.
This adds a new type called "ID" which is a wrapper class for a generic
handle but with added type safety. An instance of this class cannot be
passed to a function expecting another type of handle which provided
compile-time type safety for these APIs.
As an initial test I converted the game sound handles to this new type.
I already found a bug in the mainhall system thanks to this new type.
The mainhall used the game sound handles as sound instance handles which
probably meant that that specific code never really worked right. I
removed the code since there was no better alternative for fixing it.
A conditional originally added to shield_add_strength() to make shields not recharge beyond the recharge limit forgot to check that the amount shields are changing by was positive (unlike a couple other conditionals added/modified around the same time), so a call to shield_add_strength() with a negative delta (e.g. when transferring energy from shields to weapons) when the current shield strength is at or above the recharge limit (i.e. full strength when a recharge limit isn't specified) would immediately return without doing anything. This would, of course, result in no change to shield strength... so if you had full shields and had drained your weapon batteries dry, you could get free energy by hitting the button to transfer energy from your shields.
This introduces a new mechanism for handling bit flags. Instead of using an int (or two, or three) to write bits into, this uses the std::bitset in a wrapper class that accepts an enum class as input. This means that certain classes of errors we've had a few of in the engine, where a coder used the wrong set of flags or checked them against the wrong variable (SF_STEALTH vs SIF_STEALTH, for example) can now be detected at a compiler level rather than not at all.
CasparKielwein