In GK2, restoring a save game causes the segment manager to reset
in the middle of a kListFirstTrue call, which invalidates all
pointers and reg_ts to stored data. This means that when
kListFirstTrue tries to decrement the list recursion counter at
the end of iteration, it is writing to freed memory, potentially
resulting in heap corruption.
SCI3 added checks to prevent this from happening, but these checks
seem like they should have also been applied to some SCI2.1 games
as well (like GK2).
Since there should be no negative side-effect to this check, it
is applied universally to all SCI32 games.
Game scripts pass an extra argument which is never used in SSCI.
This happens e.g. when warping from room 620 to room 860 in
LSL6hires.
Adding a signature for kPalVarySetVary for SCI2.1early games only
does not work because KQ7 1.51 is detected as SCI2.1early but the
interpreter includes kPalVary code that matches SCI2.1mid.
Fixes Trac#9611.
This change invalidates earlier SCI32 save games, which separated
arrays and strings in an incompatible manner. Old save games
contain invalid references to a string segment which no longer
exists, and contain incompatible array structures that lack
critical type information.
These were introduced in SCI3, and are used by RAMA. We don't preload
videos, so we don't really need kPlayVMDSetPreload, but
kPaletteSetGamma may need an implementation.
With these two stubs, the main menu of RAMA is working again
On at least DC platform, the ShowStyleType enum is fit to a 4-bit
data size, so the 16-bit input value needs to be checked for
validity *before* it is cast to a 4-bit ShowStyleType.
This may come back in the future to deduplicate some gfx code,
but SCI32 had two different inlined ways of doing coordinate
conversions with different rounding methods, so CoordAdjuster32
didn't get used when the graphics system was rewritten.
At the moment, SCI32 code uses the mulru/mulinc methods from
helper.h for scaling up/down coordinates.
KQ7 2.00b, PQ:SWAT, Phant1, GK2, and Torin are all verified as
using the 'ignore' variant; SQ6 and QFG4CD are verified as using
the 'fail' variant. MGDX and Shivers could not be checked as they
have only Phar Lap Win16 executables, so took a guess based on
their release dates.
This commit implements all of the known plane transitions from
SCI2 through SCI2.1mid games. Because kSetShowStyle is always
called indirectly via the Styler game script, it is difficult to
find all the places where transitions are used. As such,
transitions that appeared to never be used have been added as
stubs which will trigger a game crash with a message to report
what was being done, so any missed transition types can be
identified quickly and then implemented.
Bitmaps in ScrollWindow and Robot code are managed by the kernel
and not by game scripts, although they must be able to be
referenced through a reg_t. To prevent incorrect GC of bitmaps
that are in use but not referenced by any game script, explicit
memory management of hunk entries can be enabled.
Remap would crash SCI2.1early games with 19 remap slots, and
did not actually work in most cases in SCI2.1mid+ games.
The SCI16 implementation was moved to its own separate file but
was otherwise touched as little as possible, so may still have
similar problems to the SCI32 code.
1. Split SCI16 and SCI32 code into separate files
2. Use -32 prefixes for SCI32 code and no prefix for SCI16 code,
where possible, to match other existing code
3. Avoid accidental corruption of values from the VM that may be
valid when signed or larger than 8 bits
4. Added documentation
5. Add missing remap CelObj calls
6. Inline where possible in performance-critical code paths
7. Fix bad `matchColor` function, and move it from GfxPalette to
GfxRemap32 since it is only used by GfxRemap32
8. Fix bad capitalisation in getCycleMap
9. Remove unnecessary initialisation of SingleRemaps
10. Update architecture to more closely mirror how SSCI worked
11. Clarify the purpose of each type of remap type (and
associated variable names)
12. Split large `apply` function into smaller units
13. Fix buffer overrun when loading a SCI2.1early game with remap
14. Remove use of `#define` constants
15. Warn instead of crashing with an error on invalid input (to
match SSCI more closely)
16. Change the collision avoidance mechanism between the RemapType
enum and remap kernel functions
17. Add save/load function
Most of the time, we get a bitmap to draw on it. Exposing a buffer
avoids consumers having to create their own all the time, and
encourages use of common drawing code exposed by the buffer.
This kernel call seems only to be used by KQ7 1.51 (which was
Windows-only) to send warnings to the user.
It was easy enough to do a basic implementation in the ScummVM
GUI rather than just make it an empty call, so now it is a thing.
Most SCI32 games draw a "fred" object to the screen when the game
first starts to benchmark video performance. When framerate
throttling is enabled (which fixes many/most timing-related bugs
and reduces system load caused by unnecessary graphics updates),
the game's performance check will think that video card is slow,
causing some "high-performance" game features to be disabled.
To avoid this, we simply disable throttling during benchmarking by
detecting the "fred" object.
Colin Snover
Willem Jan Palenstijn
Filippos Karapetis
Ori Avtalion