This flag was used in SSCI to read from VRAM instead of from the
back buffer when a mouse interrupt was received in the middle of
a back buffer update. Since ScummVM controls when mouse events
are received via polling, it is not possible to receive a mouse
event in the middle of back buffer updates, so this code is
unnecessary for the engine to work properly.
This also fixes Valgrind warnings about use of uninitialized
memory at the start of the game, caused by not filling the cursor
memory buffers because `_frameNowVisible` was false until the first
frame was rendered.
This happens e.g. on the About page in LSL7 because of an
interpreter problem where bitmap handles are destroyed and then
reused without a kFrameOut call to remove old screen items from
the visible plane list before a kIsOnMe call that causes the
engine to try to read from reused bitmap handles with different
contents and dimensions.
This replaces bad memory reads on the About page in LSL7 with an
assertion failure, until the problem with the About page can be
properly addressed.
This code branch, existing since at least SQ6 but apparently never
used by any SCI2/2.1 game, is in fact the algorithm used by SCI3.
This fixes (at least) doubled rendering of transparent surfaces
like the background of the inventory window and conversation
choices panel in LSL7.
In Phant2, when going to email on Curtis's office computer, a
screen item that contained a bitmap on the last frame was updated
to contain a view on the next frame. This crashed the engine when
it tried to reuse the old disposed bitmap instead of the new view
because the cel type was never changed from kCelTypeMem to
kCelTypeView.
The boost is intended to compensate for the darkness caused by the
black lines, so should not be applied when there are no black
lines. This fixes too-bright videos in at least LSL7.
In at least RAMA, when using the pocket computer to view a mail
and then pressing the "return" button, the ScreenItem containing
the VMD will be destroyed before the VMD player is told to close
the video, resulting in a use-after-free trying to access the
bitmap ID through the deleted ScreenItem.
Sometime during SCI2.1mid, the palette manager was changed to
save and restore the source palette, and to add in-game gamma
correction. Previously, only the vary start and target palettes
were saved, and gamma correction was only configurable in SSCI by
editing RESOURCE.CFG.
In PQ4CD, when leaving the shooting range through the front door,
some transition screen items will be generated that have invalid
dimensions. SSCI simply clips these rectangles to zero.
PQ4CD and several other games contain a hack in two renderer
methods to avoid rendering invalid screen items with zero or
negative-dimension target rects. This prevents PQ4CD from
crashing during the fifth phase of target practice.
This is most noticeable at the beginning of the game during
benchmarking, where the benchmarking loop used to cause the mouse
to get stuck for the duration of the benchmark.
SSCI's last resort comparison here was to compare the object IDs
of planes & screen items, but this randomly breaks (at least) the
"you have died" dialog at the end of Phant1, and text & buttons
in Hoyle5, even in SSCI itself.
This commit changes last resort comparison to use a monotonically
increasing ID instead, which keeps objects with identical priority
& z-index in creation order when compared.
Fixes Trac#9585.
Transition timings were originally chosen largely by feel in SQ6,
as there was little other evidence to determine the correct speed.
As additional games started being playable in ScummVM, it became
apparent that these speeds were not quite right.
Additional adjustments may be needed in the future, but these new
timings seem to be somewhat closer to expectations than before.
Colin Snover
Willem Jan Palenstijn