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SCI32: Fix QFG4 cave tentacle
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Fixes wriggling and retraction when hero travels over the pit, bug #10615
Supersedes commit 259f262
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@Vhati
Vhati committed Dec 27, 2018
1 parent 4b2dc67 commit 0f99b7d
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Showing 2 changed files with 199 additions and 1 deletion.
198 changes: 198 additions & 0 deletions engines/sci/engine/script_patches.cpp
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Expand Up @@ -158,9 +158,11 @@ static const char *const selectorNameTable[] = {
"plane", // RAMA
"state", // RAMA
"getSubscriberObj", // RAMA
"cue", // QFG4
"loop", // QFG4
"moveSpeed", // QFG4
"setLooper", // QFG4
"setSpeed", // QFG4
"value", // QFG4
#endif
NULL
Expand Down Expand Up @@ -244,9 +246,11 @@ enum ScriptPatcherSelectors {
SELECTOR_plane,
SELECTOR_state,
SELECTOR_getSubscriberObj,
SELECTOR_cue,
SELECTOR_loop,
SELECTOR_moveSpeed,
SELECTOR_setLooper,
SELECTOR_setSpeed,
SELECTOR_value
#endif
};
Expand Down Expand Up @@ -9262,6 +9266,196 @@ static const uint16 qfg4Tarot5PriorityPatch[] = {
PATCH_END
};

// When crossing the cave's tightrope in room 710, a tentacle emerges, and then
// its animation freezes - in ScummVM, not the original interpreter. This
// happens because of an extraneous argument passed to setCycle().
//
// (tentacle setCycle: RandCycle tentacle)
//
// RandCycle can accept an optional arg, but it expects a number, not an
// object. ScummVM doesn't catch the faulty arithmetic and behaves abnormally.
// We remove the bad arg.
//
// Applies to at least: English CD, English floppy, German floppy
// Responsible method: sTentacleDeath::changeState(3) in script 710
// Fixes bug: #10615
static const uint16 qfg4TentacleWriggleSignature[] = {
SIG_MAGICDWORD,
0x38, SIG_SELECTOR16(setCycle), // pushi setCycle
0x7a, // push2
0x51, SIG_ADDTOOFFSET(+1), // class RandCycle
0x36, // push
0x72, SIG_ADDTOOFFSET(+2), // loffsa tentacle
0x36, // push
0x72, SIG_ADDTOOFFSET(+2), // loffsa tentacle
0x4a, SIG_UINT16(0x0008), // send 08
SIG_END
};

static const uint16 qfg4TentacleWrigglePatch[] = {
PATCH_ADDTOOFFSET(+3),
0x78, // push1 (1 setCycle arg)
PATCH_ADDTOOFFSET(+3), // ...
0x35, 0x00, // ldi 0 (erase 2 bytes)
0x35, 0x00, // ldi 0 (erase 2 bytes)
PATCH_ADDTOOFFSET(+3), // ...
0x4a, PATCH_UINT16(0x0006), // send 06
PATCH_END
};

// When crossing the cave's tightrope in room 710, a tentacle emerges. The
// tentacle is supposed to reach a state where it waits indefinitely for an
// external cue() to retract. If the speed slider is too high, a fighter
// reaches the other side and sends a cue() before the tentacle is ready to
// receive it. The tentacle never retracts.
//
// The fighter script (crossByHand) drains stamina in state 2 as hero moves
// across. A slower speed would cost extra stamina. We add a delay after that
// part is over, in state 3, just as hero is about to dismount. When state 4
// cues, the tentacle script (sTentacleDeath) will be ready (state 3).
//
// To create that delay we set the "cycles" property for a countdown and remove
// all other advancement mechanisms. State 3 had a cue from say() and a
// self-cue(). The former's "self" arg becomes null. The latter is erased.
//
// Crossing from the left (crossByHandLeft) doesn't require fixing.
//
// Applies to at least: English CD, English floppy, German floppy
// Responsible method: crossByHand::changeState(3) in script 710
// Fixes bug: #10615
static const uint16 qfg4PitRopeFighterSignature[] = {
0x65, SIG_ADDTOOFFSET(+1), // aTop state
SIG_ADDTOOFFSET(+269), // ...
0x31, 0x1e, // bnt 30d (set a flag and say() on 1st crossing, else cue)
SIG_ADDTOOFFSET(+8), // ...
0x38, SIG_SELECTOR16(say), // pushi say ("You just barely made it")
0x38, SIG_UINT16(0x0005), // pushi 5d
0x39, 0x0a, // pushi 10d
0x39, 0x06, // pushi 6d
0x39, 0x20, // pushi 32d
0x76, // push0
0x7c, // pushSelf
SIG_ADDTOOFFSET(+5), // ...
0x32, SIG_ADDTOOFFSET(+2), // jmp ?? [end the switch]
SIG_MAGICDWORD,
0x38, SIG_SELECTOR16(cue), // pushi cue
0x76, // push0
0x54, SIG_UINT16(0x0004), // self 04
0x32, SIG_ADDTOOFFSET(+2), // jmp ?? [end the switch]
SIG_END
};

static const uint16 qfg4PitRopeFighterPatch[] = {
PATCH_ADDTOOFFSET(+271), // ... (2 + 269)
0x31, 0x1b, // bnt 26d (skip the say w/o ending the switch)
PATCH_ADDTOOFFSET(+21), // ... (8 + 13)
0x76, // push0 (null caller, so say won't cue crossByHand)
PATCH_ADDTOOFFSET(+5), // ...
// (no jmp, self-cue becomes cycles)
0x35, 0x20, // ldi 32d
0x65, PATCH_GETORIGINALBYTE(1)+6, // aTop cycles (property offset = @state + 6d)
0x33, 0x04, // jmp 4d [skip waste bytes, end the switch]
PATCH_END
};

// As above, mages at high speed can get across the pit in room 710 before
// tentacle is ready to receive a cue().
//
// As luck would have it, hero's speed is cached and restored. Twice actually.
//
// Overview of the mage script (sLevitateOverPit)
// State 1-3: Cache hero's slider-based speed.
// Set a temporary speed as hero unfurls the cloth.
// Restore the original value.
// Call handsOn(). Wait for an external cue().
// State 4: Call handsOff().
// If cued by the Levitate spell (script 21), go to 5-7.
// A plain cue() from anywhere else, leads to state 8.
// State 5-7: Move across the pit. Skip to state 9.
// State 8: An abort message.
// State 9-10: Cache hero's speed again.
// Set a temporary speed as hero folds up the cloth.
// Restore the original value, and normalize hero. Call handsOn().
//
// Patch 1: We overwrite some derelict code in state 5, caching the
// slider-based speed again, in case the player adjusted it before casting
// Levitate, then setting a fixed speed of our own for the crossing.
//
// Patch 2: Patch 1 already cached and clobbered the speed. We remove the
// original attempt to cache again in state 9.
//
// The result is caching/restoration at the beginning, aborting or caching and
// crossing with our fixed value, and a restoration at the end (whichever value
// was last cached). The added travel time has no side effect for mages.
//
// Mages have no other script to levitate across from left to right. At some
// point in development, the meaning of "register" changed. The derelict
// state 5 code thought 0/1 meant move right/left. Whereas state 4 decides 0/1
// means abort/cross, only ever moving left. The rightward MoveTo never runs.
//
// Applies to at least: English CD, English floppy, German floppy
// Responsible method: sLevitateOverPit::changeState(5) in script 710
// Fixes bug: #10615
static const uint16 qfg4PitRopeMageSignature1[] = {
0x30, SIG_UINT16(0x0017), // bnt 23d [if register == 0 (never), move right]
SIG_ADDTOOFFSET(+20), // ... (move left)
0x32, SIG_ADDTOOFFSET(+2), // jmp ?? [end the switch]

0x38, SIG_SELECTOR16(setMotion), // pushi setMotion (move right)
0x38, SIG_UINT16(0x0004), // pushi 4d
0x51, SIG_ADDTOOFFSET(1), // class MoveTo
0x36, // push
SIG_MAGICDWORD,
0x38, SIG_UINT16(0x00da), // pushi 218d
0x39, 0x30, // pushi 48d
0x7c, // pushSelf
0x81, 0x00, // lag global[0] (hero)
0x4a, SIG_UINT16(0x000c), // send 12d
0x32, SIG_ADDTOOFFSET(+2), // jmp ?? [end the switch]
SIG_END
};

static const uint16 qfg4PitRopeMagePatch1[] = {
0x34, PATCH_UINT16(0x0000), // ldi 0 (erase the branch)
PATCH_ADDTOOFFSET(+20), // ...

0x38, SIG_SELECTOR16(cycleSpeed), // pushi cycleSpeed
0x76, // push0
0x81, 0x00, // lag global[0] (hero)
0x4a, SIG_UINT16(0x0004), // send 4d
0xa3, 0x02, // sal local[2] (cache again)
//
0x38, SIG_SELECTOR16(setSpeed), // pushi setSpeed
0x78, // push1
0x39, 0x08, // pushi 8d (set our fixed speed)
0x81, 0x00, // lag global[0] (hero)
0x4a, SIG_UINT16(0x0006), // send 6d
0x5c, // selfID (erase 1 byte to keep disasm aligned)
PATCH_END
};

// Responsible method: sLevitateOverPit::changeState(9) in script 710
static const uint16 qfg4PitRopeMageSignature2[] = {
SIG_MAGICDWORD,
0x35, 0x09, // ldi 9d (case 9 label)
0x38, SIG_SELECTOR16(cycleSpeed), // pushi cycleSpeed
SIG_ADDTOOFFSET(+6), // ...
0xa3, 0x02, // sal local[2] (original re-cache)
SIG_ADDTOOFFSET(+48), // ...
0x38, SIG_SELECTOR16(cycleSpeed), // pushi cycleSpeed
0x78, // push1
0x8b, 0x02, // lsl local[2] (restore cached speed)
SIG_END
};

static const uint16 qfg4PitRopeMagePatch2[] = {
PATCH_ADDTOOFFSET(+11), // (don't cache our fixed speed)
0x35, 0x00, // ldi 0 (erase 2 bytes)
PATCH_ADDTOOFFSET(+48), // ...
0x38, PATCH_SELECTOR16(setSpeed), // pushi setSpeed (keep cycleSpeed & moveSpeed sync'd)
PATCH_END
};

// script, description, signature patch
static const SciScriptPatcherEntry qfg4Signatures[] = {
{ true, 0, "prevent autosave from deleting save games", 1, qg4AutosaveSignature, qg4AutosavePatch },
Expand Down Expand Up @@ -9301,6 +9495,10 @@ static const SciScriptPatcherEntry qfg4Signatures[] = {
{ false, 663, "CD: fix crest bookshelf", 1, qfg4CrestBookshelfCDSignature, qfg4CrestBookshelfCDPatch },
{ false, 663, "Floppy: fix crest bookshelf", 1, qfg4CrestBookshelfFloppySignature, qfg4CrestBookshelfFloppyPatch },
{ true, 663, "CD/Floppy: fix crest bookshelf motion", 1, qfg4CrestBookshelfMotionSignature, qfg4CrestBookshelfMotionPatch },
{ true, 710, "fix tentacle wriggle cycler", 1, qfg4TentacleWriggleSignature, qfg4TentacleWrigglePatch },
{ true, 710, "fix tentacle retraction for fighter", 1, qfg4PitRopeFighterSignature, qfg4PitRopeFighterPatch },
{ true, 710, "fix tentacle retraction for mage (1/2)", 1, qfg4PitRopeMageSignature1, qfg4PitRopeMagePatch1 },
{ true, 710, "fix tentacle retraction for mage (2/2)", 1, qfg4PitRopeMageSignature2, qfg4PitRopeMagePatch2 },
{ true, 800, "fix setScaler calls", 1, qfg4SetScalerSignature, qfg4SetScalerPatch },
{ true, 800, "fix grapnel removing hero's scaler", 1, qfg4RopeScalerSignature, qfg4RopeScalerPatch },
{ true, 803, "fix sliding down slope", 1, qfg4SlidingDownSlopeSignature, qfg4SlidingDownSlopePatch },
Expand Down
2 changes: 1 addition & 1 deletion engines/sci/engine/workarounds.cpp
View file
Expand Up @@ -87,7 +87,7 @@ const SciWorkaroundEntry arithmeticWorkarounds[] = {
{ GID_QFG1VGA, 301, 928, 0, "Blink", "init", NULL, 0, 0, { WORKAROUND_FAKE, 0 } }, // op_div: when entering the inn, gets called with 1 parameter, but 2nd parameter is used for div which happens to be an object
{ GID_QFG2, 200, 200, 0, "astro", "messages", NULL, 0, 0, { WORKAROUND_FAKE, 0 } }, // op_lsi: when getting asked for your name by the astrologer - bug #5152
{ GID_QFG3, 780, 999, 0, "", "export 6", NULL, 0, 0, { WORKAROUND_FAKE, 0 } }, // op_add: trying to talk to yourself at the top of the giant tree - bug #6692
{ GID_QFG4, 710,64941, 0, "RandCycle", "doit", NULL, 0, 0, { WORKAROUND_FAKE, 1 } }, // op_gt: when the tentacle appears in the third room of the caves
// { GID_QFG4, 710,64941, 0, "RandCycle", "doit", NULL, 0, 0, { WORKAROUND_FAKE, 1 } }, // op_gt: when the tentacle appears in the third room of the caves
{ GID_TORIN, 51400,64928, 0, "Blink", "init", NULL, 0, 0, { WORKAROUND_FAKE, 1 } }, // op_div: when Lycentia knocks Torin out after he removes her collar
SCI_WORKAROUNDENTRY_TERMINATOR
};
Expand Down

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