1 files changed, 75 insertions, 0 deletions
diff --git a/engines/scumm/script_v4.cpp b/engines/scumm/script_v4.cpp
index 630c09642e..5691f6707c 100644
--- a/engines/scumm/script_v4.cpp
+++ b/engines/scumm/script_v4.cpp
@@ -42,6 +42,9 @@ void ScummEngine_v4::setupOpcodes() {
 
 	OPCODE(0x50, o4_pickupObject);
 	OPCODE(0xd0, o4_pickupObject);
+
+	OPCODE(0x5c, o4_oldRoomEffect);
+	OPCODE(0xdc, o4_oldRoomEffect);
 }
 
 void ScummEngine_v4::o4_pickupObject() {
@@ -67,4 +70,76 @@ void ScummEngine_v4::o4_pickupObject() {
 	runInventoryScript(1);
 }
 
+void ScummEngine_v4::o4_oldRoomEffect() {
+	int a;
+
+	_opcode = fetchScriptByte();
+	if ((_opcode & 0x1F) == 3) {
+		a = getVarOrDirectWord(PARAM_1);
+
+#if 1
+		if (_game.platform == Common::kPlatformFMTowns && _game.version == 3) {
+			// FIXME / TODO: OK the first thing to note is: at least in Zak256,
+			// maybe also in other games, this opcode does a bit more. I added
+			// some stubs here, but somebody with a full IDA or more knowledge
+			// about this will have to fill in the gaps. At least now we know
+			// that something is missing here :-)
+
+			if (a == 4) {
+				//printf("o5_oldRoomEffect ODDBALL: _opcode = 0x%x, a = 0x%x\n", _opcode, a);
+				// No idea what byte_2FCCF is, but it's a globale boolean flag.
+				// I only add it here as a temporary hack to make the pseudo code compile.
+				// Maybe it is just there as a reentry protection guard, given
+				// how it is used? It might also correspond to _screenEffectFlag.
+				int byte_2FCCF = 0;
+
+				// For now, we force a redraw of the screen background. This
+				// way the Zak end credits seem to work mostly correct.
+				VirtScreen *vs = &_virtscr[kMainVirtScreen];
+				restoreBackground(Common::Rect(0, vs->topline, vs->w, vs->topline + vs->h));
+				vs->setDirtyRange(0, vs->h);
+				updateDirtyScreen(kMainVirtScreen);
+
+				if (byte_2FCCF) {
+					// Here now "sub_1C44" is called, which sets byte_2FCCF to 0 then
+					// calls yet another sub (which also reads byte_2FCCF):
+
+					byte_2FCCF = 0;
+					//call sub_0BB3
+
+
+					// Now sub_085C is called. This is quite simply: it sets
+					// 0xF000 bytes. starting at 0x40000 to 0. No idea what that
+					// buffer is, maybe a screen buffer, though. Note that
+					// 0xF000 = 320*192.
+					// Maybe this is also the charset mask being cleaned?
+
+					// call sub_085C
+
+
+					// And then sub_1C54 is called, which is almost identical to
+					// the above sub_1C44, only it sets byte_2FCCF to 1:
+
+					byte_2FCCF = 1;
+					// call sub_0BB3
+
+				} else {
+					// Here only sub_085C is called (see comment above)
+
+					// call sub_085C
+				}
+			return;
+			}
+#endif
+
+		}
+		if (a) {
+			_switchRoomEffect = (byte)(a & 0xFF);
+			_switchRoomEffect2 = (byte)(a >> 8);
+		} else {
+			fadeIn(_newEffect);
+		}
+	}
+}
+
 } // End of namespace Scumm