Removing the player entity has all sorts of nasty effects, such as
softlocking the game because many inputs require there to be a player
present, such as opening the quit menu.
The most infamous glitch to remove the player entity is the Gravitron
Fling, where the game doesn't see a gravity line at a specific
y-position in the current room, and when it moves the bottom gravity
line it moves the player instead. When the gravity line gets outside the
room, it gets destroyed, so if the player gets dragged outside the room,
they get destroyed, too. (Don't misinterpret this as saying anytime the
player gets dragged outside the room, they get destroyed - it's only the
Gravitron logic that destroys them.)
Also, there are many places in the code that use entity-getting
functions that have a fallback value of 0. If it was possible to remove
the player, then it's possible for this fallback value of 0 to index
obj.entities out-of-bounds, which is not good.
To fix this, entityclass::removeentity() is now a bool that signifies if
the entity was successfully removed or not. If the entity given is the
player (meaning it first checks if it's rule 0, just so in 99% of cases
it'll short-circuit and won't do the next check, which is if
entityclass::getplayer() says the indice to be removed is the player),
then it'll refuse to remove the entity, and return false.
This is a change in behavior where callers might expect
entityclass::removeentity() to always succeed, so I changed the
removeentity_iter() macro to only decrement if removing the entity
succeeded. I also changed entityclass::updateentities() from
'removeentity(i); return true;' to 'return removeentity(i);'.
Otherwise, this would result in the game updating an entity twice, which
isn't good. This is most noticeable in the Gravitron, where many
Gravitron squares are created and destroyed at a time, and it's
especially noticeable during the part near the end of the Gravitron
where the pattern is two Gravitron squares, one at the top and bottom,
and then two Gravitron squares in the middle afterwards. The timing is
just right such that the top one of the two middle ones would be
misaligned with the bottom one of the two when a Gravitron square gets
outside the screen.
To do this, I changed entityclass::updateentities() into a bool, and
made every single caller check its return value. I only needed to do
this for the ones preceding updateentitylogic() and
entitymapcollision(), but I wanted to play it safe and be defensive, so
I did it for the disappearing platform kludge, as well as the
updateentities() within the updateentities() function.
It's treated like a bool anyway, so might as well make it one.
This also necessitates updating every single instance where it or an
element inside it is used, too.
This removes the variables obj.nblocks, as well as removing the 'active'
attribute from the block object. Now every block is guaranteed to be
real without having to check the 'active' variable.
Removing a block while iterating now uses the removeblock_iter() macro.
Not sure why this function is here. It makes sense if you know that the
game will only do certain moving platform things if you already have a
moving platform in the room, however apparently this function has
absolutely nothing to do with it.
This function's sole purpose was to make sure obj.nentity was in sync,
and that obj.nentity-1 pointed to the last 'active' entity in
obj.entities. But now that obj.nentity is removed and we use
obj.entities.size() instead, it is no longer necessary.
This removes the variables obj.nentity and obj.nlinecrosskludge, as well
as removing the 'active' attribute from the entity class object. Now
every entity you access is guaranteed to be real and you don't have to
check the 'active' variable.
The biggest part of this is changing createentity() to modify a
newly-created entity object and push it back instead of already
modifying an indice in obj.entities.
As well, removing an entity now uses the new obj.removeentity() function
and removeentity_iter() macro.
Also when we switch everything to not use 'active', we'll need this
macro to remove entities while iterating forwards through the vector one
at a time.
Ok, once we switch everything over to not use the 'active' system, it's
easier to read removeentity(t) than it is to read
entities.erase(entities.begin() + t).
This moves the setenemyroom() function onto the entity object itself, so
I can more easily change all 'entities[k].' to 'entity.' in
entityclass::createentity() later.
Additionally, I've had to move the rn() macro from Entity.h to Ent.h, or
else entclass::setenemyroom() won't know what it is.
This moves the setenemy() function onto the entity object itself,
instead of having to give the indice of the entity in obj.entities. This
makes the code more object-oriented so later I can simply change all
'entities[k]' to 'entity.' in entityclass::createentity().
This commit removes all global args from functions on the entityclass
object, and updates the callers of those functions in other files
accordingly (most significantly, the game level files Finalclass.cpp,
Labclass.cpp, Otherlevel.cpp, Spacestation2.cpp, WarpClass.cpp, due to
them using createentity()), as well as renaming all instances of 'dwgfx'
in Entity.cpp to 'graphics'.
I ran the game through Valgrind to catch various issues.
One thing caught my attention -- map.resumedelay. This is
used by The Tower/etc to add a delay before the game is
resumed (probably for camera controls delaying it) for
spawning the player. This variable was uninitialized. Notably,
if I explicitly set it to 592851 or similar, it reproduces the
bug, even if I cannot reproduce it with my typical compilation
flags. So fixing this by initializing it to 0, alongside some
other Valgrind warnings, should fix the problem entirely.
