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SCI: Fix ICEMAN destroyer timer, bug #11017
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@sluicebox @bluegr
sluicebox authored and bluegr committed Jul 12, 2019
1 parent 3094dd6 commit 4dc9752
Showing 1 changed file with 127 additions and 0 deletions.
127 changes: 127 additions & 0 deletions engines/sci/engine/script_patches.cpp
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Expand Up @@ -105,6 +105,7 @@ static const char *const selectorNameTable[] = {
"handsOff", // system selector
"handsOn", // system selector
"localize", // Freddy Pharkas
"roomFlags", // Iceman
"put", // Police Quest 1 VGA
"changeState", // Quest For Glory 1 VGA, QFG4
"hide", // Quest For Glory 1 VGA, QFG4
Expand Down Expand Up @@ -215,6 +216,7 @@ enum ScriptPatcherSelectors {
SELECTOR_handsOff,
SELECTOR_handsOn,
SELECTOR_localize,
SELECTOR_roomFlags,
SELECTOR_put,
SELECTOR_changeState,
SELECTOR_hide,
Expand Down Expand Up @@ -2694,6 +2696,128 @@ static const SciScriptPatcherEntry gk2Signatures[] = {

#endif

// When spotting the destroyer, timing problems prevent completing the bridge
// scene at fast game speeds.
//
// In the control room, room 25, ego and the captain go to the bridge, room 28,
// where they spot ships in an effectively automatic scene. When this completes
// they return to the control room, the captain falls, and the player regains
// control of ego and has to walk to the control panel. This entire sequence
// has to be completed within 400 game cycles or the destroyer kills the sub,
// but the bridge timing is in wall time and has at least 25 seconds of delays,
// which at faster speeds is longer than 400 cycles. The bridge also animates
// during messages, causing the timer to run while reading, so even at slower
// speeds the game can illogically end before the ships are revealed.
//
// There are several problems here but the real bug is that the timer starts
// before the player has control. We fix this by disabling the timer during the
// bridge and resetting it to 120 game cycles when the player regains control.
// This preserves the original timer duration in the control room, where the
// real timed action is, and is compatible with existing saved games. When the
// timer expires, subMarineScript:changeState(9) no longer ends the game if
// subMarine:roomFlags flag 2 isn't set, which captainfallsScript sets at the
// same time that it now calls subMarineScript:changeState(8).
//
// Applies to: All versions
// Responsible methods: subMarineScript:changeState, captainfallsScript:changeState
// Fixes bug #11017
static const uint16 icemanDestroyerTimer1Signature[] = {
0x30, SIG_UINT16(0x0022), // bnt 0022 [ state 8 ]
SIG_ADDTOOFFSET(+0x1f),
SIG_MAGICDWORD,
0x32, SIG_UINT16(0x0074), // jmp 0074 [ end of method ]
0x3c, // dup
0x35, 0x08, // ldi 08
0x1a, // eq?
0x30, SIG_UINT16(0x0008), // bnt 0008 [ state 9 ]
0x34, SIG_UINT16(0x0190), // ldi 0190
0x65, 0x10, // aTop cycles [ cycles = 400 ]
0x32, SIG_UINT16(0x0065), // jmp 0065 [ end of method ]
0x3c, // dup
0x35, 0x09, // ldi 09
0x1a, // eq?
0x30, SIG_UINT16(0x0023), // bnt 0023 [ state 15 ]
0x8f, 0x00, // lsp 00
0x35, 0x02, // ldi 02
0x22, // lt? [ didn't reach control panel? ]
0x30, SIG_UINT16(0x0014), // bnt 0014 [ skip death if reached control panel ]
SIG_END
};

static const uint16 icemanDestroyerTimer1Patch[] = {
0x30, PATCH_UINT16(0x001f), // bnt 001f [ state 8 ]
PATCH_ADDTOOFFSET(+0x1f),
0x3c, // dup
0x35, 0x08, // ldi 08
0x1a, // eq?
0x31, 0x04, // bnt 04 [ state 9 ]
0x35, 0x78, // ldi 78
0x65, 0x10, // aTop cycles [ cycles = 120 ]
0x3c, // dup
0x35, 0x09, // ldi 09
0x1a, // eq?
0x31, 0x2c, // bnt 2c [ state 15 ]
0x38, PATCH_SELECTOR16(roomFlags), // pushi roomFlags
0x76, // push0
0x63, 0x08, // pToa client
0x4a, 0x04, // send 04 [ subMarine roomFlags? ]
0x7a, // push2 [ flag 2 set when captain falls ]
0x12, // and [ has captain fallen? ]
0x31, 0x19, // bnt 19 [ skip death if captain hasn't fallen ]
0x8f, 0x00, // lsp 00
0x22, // lt? [ didn't reach control panel? ]
0x31, 0x14, // bnt 14 [ skip death if reached control panel ]
PATCH_END
};

static const uint16 icemanDestroyerTimer2Signature[] = {
// print four messages
0x7a, // push2
0x38, SIG_UINT16(0x0187), // pushi 0187
SIG_MAGICDWORD,
0x7a, // push2
0x47, 0xff, 0x00, 0x04, // calle proc255_0 [ print 391 2 ]
SIG_ADDTOOFFSET(+20), // [ print 391 3, print 391 4 ]
0x7a, // push2
0x38, SIG_UINT16(0x0187), // pushi 0187
0x39, 0x05, // pushi 05
0x47, 0xff, 0x00, 0x04, // calle proc255_0 [ print 391 5 ]
SIG_END,
};

static const uint16 icemanDestroyerTimer2Patch[] = {
// print four messages using a loop
0x35, 0x02, // ldi 02
0xa7, 0x01, // sap 01
0x8f, 0x01, // lsp 01
0x35, 0x05, // ldi 05
0x24, // le? [ loop while 2 <= param1 <= 5 ]
0x31, 0x0e, // bnt 0e [ exit loop ]
0x7a, // push2
0x38, PATCH_UINT16(0x0187), // pushi 0187
0x8f, 0x01, // lsp 01
0x47, 0xff, 0x00, 0x04, // calle proc255_0 [ print 391 param1 ]
0xcf, 0x01, // +sp 01 [ increment and push param1 ]
0x33, 0xed, // jmp ed [ continue loop ]
// reset subMarineScript timer
0x39, PATCH_SELECTOR8(script), // pushi script
0x76, // push0
0x51, 0x5c, // class subMarine
0x4a, 0x04, // send 04 [ subMarine script? ]
0x39, PATCH_SELECTOR8(changeState), // pushi changeState
0x78, // push1
0x39, 0x08, // pushi 08
0x4a, 0x06, // send 06 [ subMarineScript changeState: 8 ]
PATCH_END
};

// script, description, signature patch
static const SciScriptPatcherEntry icemanSignatures[] = {
{ true, 314, "destroyer timer (1/2)", 1, icemanDestroyerTimer1Signature, icemanDestroyerTimer1Patch },
{ true, 391, "destroyer timer (2/2)", 1, icemanDestroyerTimer2Signature, icemanDestroyerTimer2Patch },
SCI_SIGNATUREENTRY_TERMINATOR
};

// ===========================================================================
// At least during the harpy scene, export 29 of script 0 is called and has an
// issue where temp[3] won't get inititialized, but is later used to set
Expand Down Expand Up @@ -14987,6 +15111,9 @@ void ScriptPatcher::processScript(uint16 scriptNr, SciSpan<byte> scriptData) {
signatureTable = gk2Signatures;
break;
#endif
case GID_ICEMAN:
signatureTable = icemanSignatures;
break;
case GID_KQ5:
signatureTable = kq5Signatures;
break;
Expand Down

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