diff options
Diffstat (limited to 'engines/sci/engine/script_patches.cpp')
| -rw-r--r-- | engines/sci/engine/script_patches.cpp | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/engines/sci/engine/script_patches.cpp b/engines/sci/engine/script_patches.cpp index bfa0b338c5..d847644b77 100644 --- a/engines/sci/engine/script_patches.cpp +++ b/engines/sci/engine/script_patches.cpp @@ -7823,6 +7823,63 @@ static const uint16 qfg4SetScalerPatch[] = { PATCH_END }; +// In QFG4, the kernel func SetNowSeen() returns void - meaning it doesn't +// modify the accumulator to store a result. Yet math was performed on it! +// +// The function updates boundary box properties of a given View object, prior +// to collision tests. IF (collision detection is warranted, and IF those tests +// are true), THEN respond to the collision. +// +// SetNowSeen() was inserted in the middle of the IF block's list of conditions. +// That way it can be short-circuited, and it runs before the tests. +// +// Problem: void functions make no promise about their truth value. After the +// call, acc will be *whatever* happened to already be in there. This is bad. +// +// "(| (SetNowSeen horror) $0001)" +// +// Someone wrapped the func in a bitwise OR against 1. Thus *every* value is +// guaranteed to become non-zero, always true. And the IF block won't break. +// +// In later SCI2 versions, SetNowSeen() would change to return a boolean. +// +// Whether a lucky confusion or ugly hack, the wrapped void IF condition works. +// When an object leaks into the accumulator. SSCI doesn't mind OR'ing it, too. +// ScummVM detects unsafe arithmetic and crashes. ScummVM needs proper numbers. +// +// "Invalid arithmetic operation (bitwise OR - params: 002e:1694 and 0000:0001)" +// +// We leave the OR wrapper. When the call returns, we manually feed the OR a +// literal 1. Same effect. The IF block goes on evaluating conditions. +// +// Wraith, Vorpal Bunny, and Badder scripts are not affected. +// +// Applies to at least: English CD, English floppy, German floppy +// Responsible method: +// (ego1, combat hero) Script 41 - xSlash::doit(), xDuck::doit(), xParryLow::doit() +// (ego1, combat hero) Script 810 - slash::doit() +// (Revenant) Script 830 - revenantForward::doit() +// (Wyvern) Script 835 - doRSlash::doit(), doLSlash::doit(), tailAttack::doit() +// (Chernovy) Script 840 - doLSlash::doit(), doRSlash::doit() +// (Pit Horror) Script 855 - wipeSpell::doit() +// (Necrotaur) Script 870 - attackLeft::doit(), attackRight::doit(), +// headAttack::doit(), hurtMyself::changeState(1) +// Fixes bug: #10138, #10419, #10710, #10814 +static const uint16 qfg4ConditionalVoidSignature[] = { + SIG_MAGICDWORD, + 0x43, 0x0a, SIG_UINT16(0x00002), // callk 02 (SetNowSeen stackedView) + 0x36, // push (void func didn't set acc!) + 0x35, 0x01, // ldi 1d + 0x14, // or (whatever that was, make it non-zero) + SIG_END +}; + +static const uint16 qfg4ConditionalVoidPatch[] = { + PATCH_ADDTOOFFSET(+4), // + 0x78, // push1 (Feed OR a literal 1) + PATCH_END +}; + // script, description, signature patch static const SciScriptPatcherEntry qfg4Signatures[] = { { true, 0, "prevent autosave from deleting save games", 1, qg4AutosaveSignature, qg4AutosavePatch }, @@ -7831,6 +7888,7 @@ static const SciScriptPatcherEntry qfg4Signatures[] = { { true, 7, "fix consecutive moonrises", 1, qfg4MoonriseSignature, qfg4MoonrisePatch }, { true, 10, "fix setLooper calls (2/2)", 2, qg4SetLooperSignature2, qg4SetLooperPatch2 }, { true, 31, "fix setScaler calls", 1, qfg4SetScalerSignature, qfg4SetScalerPatch }, + { true, 41, "fix conditional void calls", 3, qfg4ConditionalVoidSignature, qfg4ConditionalVoidPatch }, { true, 83, "fix incorrect array type", 1, qfg4TrapArrayTypeSignature, qfg4TrapArrayTypePatch }, { true, 83, "fix incorrect array type (floppy)", 1, qfg4TrapArrayTypeFloppySignature, qfg4TrapArrayTypeFloppyPatch }, { true, 320, "fix pathfinding at the inn", 1, qg4InnPathfindingSignature, qg4InnPathfindingPatch }, @@ -7844,6 +7902,12 @@ static const SciScriptPatcherEntry qfg4Signatures[] = { { true, 633, "fix stairway pathfinding", 1, qfg4StairwayPathfindingSignature, qfg4StairwayPathfindingPatch }, { true, 800, "fix setScaler calls", 1, qfg4SetScalerSignature, qfg4SetScalerPatch }, { true, 803, "fix sliding down slope", 1, qfg4SlidingDownSlopeSignature, qfg4SlidingDownSlopePatch }, + { true, 810, "fix conditional void calls", 1, qfg4ConditionalVoidSignature, qfg4ConditionalVoidPatch }, + { true, 830, "fix conditional void calls", 2, qfg4ConditionalVoidSignature, qfg4ConditionalVoidPatch }, + { true, 835, "fix conditional void calls", 3, qfg4ConditionalVoidSignature, qfg4ConditionalVoidPatch }, + { true, 840, "fix conditional void calls", 2, qfg4ConditionalVoidSignature, qfg4ConditionalVoidPatch }, + { true, 855, "fix conditional void calls", 1, qfg4ConditionalVoidSignature, qfg4ConditionalVoidPatch }, + { true, 870, "fix conditional void calls", 5, qfg4ConditionalVoidSignature, qfg4ConditionalVoidPatch }, { true, 64990, "increase number of save games (1/2)", 1, sci2NumSavesSignature1, sci2NumSavesPatch1 }, { true, 64990, "increase number of save games (2/2)", 1, sci2NumSavesSignature2, sci2NumSavesPatch2 }, { true, 64990, "disable change directory button", 1, sci2ChangeDirSignature, sci2ChangeDirPatch }, |