Descent 2 secret levels allow a player to rescue hostages that are not
counted in `total_hostages`, so a player can exit with more hostages
saved than were in the mine. Change the scoring logic not to penalize a
player for saving these unaccounted hostages.
Instead of passing a bare `int` named `secret_flag`, define it as an
`enum class : uint8_t` to name the two special values.
Rework the passing of this value, to deal with some confusing
inconsistencies when reading the code.
Before this change:
In D1:
- Multiplayer will always go to the secret level, regardless of which
exit door the player used.
In D2:
- Flying through a D1 secret exit in multiplayer shows the on-HUD error
"Secret Level Teleporter disabled in multiplayer!", and does not exit
the level. This is at best confusing, and at worst dangerous, since
D1 secret exits are only available during the countdown, so the player
has little time to realize that the normal exit must be used instead.
- Like D1, multiplayer will request to go to the secret level regardless
of the exit used. Unlike D1, the caller ignores the flag and always
advances to the next regular level.
After this change:
- No observable differences for the player in-game. The questionable D2
secret exit handling for D1 is retained.
- The code makes clearer that secret exits do not work in D2
multiplayer, by way of `#if defined(DXX_BUILD_DESCENT_I)` guarding the
existence of the parameter and all updates to it.
Iterating over it returns each side number in turn. This allows
converting many loops of the form:
```
for (int i = 0; i < MAX_SIDES_PER_SEGMENT; ++i)
```
to the compact form:
```
for (const auto i : MAX_SIDES_PER_SEGMENT)
```
The compact form brings the usual benefit of range-based for: delegating
iteration to the compiler prevents the loop body from skipping a step,
and makes clear in the code that this is the case.
A level can have a secret exit without having a mission entry describing
where to go when the secret exit is used. Switch from an assertion
failure in that case to a log message.
Change it from the level number on which the path was created to a
true/false flag. The previous logic only tested whether the number was
equal to the current level number.
This also fixes a bug where the action was not available on the first
secret level, since that level is `-1`, and the value was set to `-1` to
indicate that it should be enabled.
Add a helper to deduce the enum type of a value, and use an appropriate
std::underlying_type<T> expression for that enum type. This avoids the
need to repeat the type of the enum at the site of each cast, and moves
the casts into the helper to make the callers easier to read.
Previously, callers chose whether to use a fullscreen background image,
and the newmenu code inferred that callers without a background image
wanted a background box, while those with a background image wanted no
box. Change newmenu_layout to take a parameter specifying the caller's
intent, so that a caller can choose to have any combination of a
background image and a background box.
Previously, if the background failed to load, the kmatrix window was
immediately aborted. Change the logic so that a failure to load uses a
blank black background, but still shows the kmatrix window.