[Scummvm-git-logs] scummvm master -> 9a02b5327548153cba5d53caef5161a910707f8d

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Summary:
9a02b53275 SCUMM: MM NES - Workaround to fix intro logo scroll hang with 256px viewport


Commit: 9a02b5327548153cba5d53caef5161a910707f8d
    https://github.com/scummvm/scummvm/commit/9a02b5327548153cba5d53caef5161a910707f8d
Author: Robert Megone (robert.megone at gmail.com)
Date: 2026-02-14T01:22:05+01:00

Commit Message:
SCUMM: MM NES - Workaround to fix intro logo scroll hang with 256px viewport

Changed paths:
    engines/scumm/resource.cpp


diff --git a/engines/scumm/resource.cpp b/engines/scumm/resource.cpp
index b1f543fec90..d13e4641e03 100644
--- a/engines/scumm/resource.cpp
+++ b/engines/scumm/resource.cpp
@@ -1720,6 +1720,51 @@ void ScummEngine::applyWorkaroundIfNeeded(ResType type, int idx) {
 
 	int size = getResourceSize(type, idx);
 	
+	// WORKAROUND: Maniac Mansion (NES) logo scroll gets stuck because ScummVM uses a 256px wide view.
+	// The original expects a 224px wide screen, so the camera never reaches the script's wait threshold.
+	// Patch script 120 at runtime by locating the camera-wait loop and changing its compare.
+
+	if (_game.id == GID_MANIAC &&
+		_game.platform == Common::kPlatformNES) {
+
+		if (type == rtScript && idx == 120) {
+			byte *scriptRes = getResourceAddress(type, idx);
+			const uint32 scriptResSize = (size > 0) ? (uint32)size : 0;
+
+			if (scriptRes && scriptResSize >= 8) {
+				byte *code = scriptRes + 8;
+				const uint32 codeSize = scriptResSize - 8;
+
+				const byte logoCamWaitPrefix[] = {
+					0x32, 0x0A,
+					0x12, 0x46,
+					0x80,
+					0x38, 0x02
+				};
+
+				const uint32 prefixSize = (uint32)sizeof(logoCamWaitPrefix);
+
+				if (codeSize >= prefixSize + 5) {
+					for (uint32 i = 0; i + prefixSize + 5 <= codeSize; ++i) {
+						if (memcmp(code + i, logoCamWaitPrefix, prefixSize) == 0) {
+							const uint32 immOff = i + 7;
+							const uint32 tailOff = i + 8;
+
+							if (code[tailOff + 0] == 0x00 &&
+								code[tailOff + 1] == 0xF9 &&
+								code[tailOff + 2] == 0xFF &&
+								code[tailOff + 3] == 0x62) {
+
+								code[immOff] = 0x2C;
+								break;
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+	
 	// WORKAROUND: The MI2 DOS NI demo relies on a prerecorded save file ("demo.rec") to start correctly.
 	// Without it, the demo can select an invalid path and attempt to load missing rooms.
 	// We patch script 77 to force the intended startup behavior so the demo begins in a valid scene.