Prior to this commit, if the player was standing on coodinate with
x=0 or y=0, no missile would be created when casting a spell. This
is due to an off-by-one when doing bounds-checking.
When spawing quest items (e.g. blood stone), no unique seed is set
for the item. Therefor two quest items may share the same seed, this
happens deterministically for the Valor quest, since three blood stones
are spawned, each with item seed 0x00000000.
For this reason, if two or more such quest items with identical seed are
looted within less than 6 seconds, the 2nd, 3rd, etc loot actions are
ignored.
If the random number generator ends up giving X-Y coordinate pairs
that always are on bad tiles (e.g. solid, with object or with monster)
then after a total of MAXDUNX * MAXDUNY tries, it will still cast
phasing to teleport to the bad tile.
The item get record array tracks items being recently looted in an
effort to prevent the same item from being looted more than once.
Prior to this commit, the item get record array (and corresponding
item get record array length) variables were not cleared when
creating a new game. Therefore, the item get record array of a
previous game could remain in between games and prevent an item
from being looted (if it was looted in a previous), even if it was
never looted in the current game. In practice this almost never
shows up, since each item get record is valid for a total of 6
seconds before being cleared. So, you would either have to save
a game, quickly loot an item, when load the game and try to loot
the same item before 6 seconds pass. OR, you could use the demo
replay functionality to run test cases, and speed up execution to
run e.g. 10'000'000 logic ticks per second. Both would exhibit the
bug and prevent the item from being looted.
ref: diasurgical/devilutionX#2691
These bugs are related to time of access, where fields of e.g. a
player or monster struct is accessed upon missile impact (instead
of missile launch), and at this point, the monster may be dead, or
the player may have left the game, resulting in accessing garbage
data that may have been overwritten by other data (e.g. new monster
spawn or new player joining).
One way to resolve this issue is to store e.g. the damage in the
missile struct when lanuching the missing. This way, the missile
would have all information required to know its damage on imact
instead of having to rely on outside sources that may no longer
be present.
Without this BUGFIX, pathing towards and attacking a hostile
player with player index 0 (through 3) would trigger the speech
dialogue of a corresponding monster 0 (through 3), should they
have speeches activated. Given that the first 4 monster indices
are reserved for Golems, this BUG would trigger if a golem was
killed, and given the incorrect implementation of pseudo delete
of golems in DeleteMonsterList failing to reserve the golem
monster indices, and a new monster was spawned (e.g. by King
Leoric) thus taking a "golem" monster index. Given this scenario,
attacking a player could trigger a speech dialogue (well, that is
if the spawned monsters had speech dialogues activated).
MWVel velocity values are not rounded consistently (inconsistent use of
floor and ceil). The original formula is (for 16, 32 and 64 pixels of
movement, respectively):
vel16 = (16 << monsterWalkShift) / nframes
vel32 = (32 << monsterWalkShift) / nframes
vel64 = (64 << monsterWalkShift) / nframes
The BUGFIX comment contains updated monster walk velocity values for
the MWVel table, where the formala is calculated as above with consistent
rounding to nearest integer.
Also, correct minor typo in BUGFIX of M2MStartHit. The DevilX code
is correct in M2MStartHit (the Devilution comment used
`<=` rather than `<`).
Both were related to the special handling of golem monster numbers.
Having golems occupy the first 4 monster number slots feels like
such a lovely hack :P
The index used to access monster was incorrect for the fallen
one flee behaviour. The AI should make fallen ones flee from
the direction of the monster which got hit. Right now, it's
random as the wrong index is used.
Robin Eklind
qndel
Robin
Anders Jenbo
Martin Wolters
Yuri Pourre
Maxim
FluffyQuack