AGI: Change how VM timer vars are handled

Instead of directly converting play time to VM timer vars,
we only adjust VM timer vars according to play time seconds delta.
This is needed for at least Mixed Up Mother Goose. The game
sets the VM "second" variable to 0 and then uses it for syncing
the text to the songs. We even adjust second calculation, so
that the timing should always be the same and not depend on
basically luck (seconds may wrap right after setting it, because
internal cycles counter is not changed).

1 files changed, 4 insertions, 0 deletions

diff --git a/engines/agi/agi.h b/engines/agi/agi.h
index fe70c4ebc2..c5db1dfc1d 100644
--- a/engines/agi/agi.h
+++ b/engines/agi/agi.h
@@ -870,6 +870,10 @@ private:
 	uint32 _getVarSecondsHeuristicLastInstructionCounter; /**< last time VM_VAR_SECONDS were read */
 	uint16 _getVarSecondsHeuristicCounter; /**< how many times heuristic was triggered */
 
+	uint32 _playTimeInSecondsAdjust; /**< milliseconds to adjust for calculating current play time in seconds, see setVarSecondsTrigger() */
+
+	void setVarSecondsTrigger(byte newSeconds);
+
 public:
 	// Some submethods of testIfCode
 	void skipInstruction(byte op);