SCI32: Enable optional explicit memory management of hunk entries

Bitmaps in ScrollWindow and Robot code are managed by the kernel
and not by game scripts, although they must be able to be
referenced through a reg_t. To prevent incorrect GC of bitmaps
that are in use but not referenced by any game script, explicit
memory management of hunk entries can be enabled.

1 files changed, 18 insertions, 11 deletions

diff --git a/engines/sci/engine/gc.cpp b/engines/sci/engine/gc.cpp
index b229490570..e0467e9461 100644
--- a/engines/sci/engine/gc.cpp
+++ b/engines/sci/engine/gc.cpp
@@ -143,23 +143,30 @@ AddrSet *findAllActiveReferences(EngineState *s) {
 	const Common::Array<SegmentObj *> &heap = s->_segMan->getSegments();
 	uint heapSize = heap.size();
 
-	// Init: Explicitly loaded scripts
 	for (uint i = 1; i < heapSize; i++) {
-		if (heap[i] && heap[i]->getType() == SEG_TYPE_SCRIPT) {
-			Script *script = (Script *)heap[i];
+		if (heap[i]) {
+			// Init: Explicitly loaded scripts
+			if (heap[i]->getType() == SEG_TYPE_SCRIPT) {
+				Script *script = (Script *)heap[i];
 
-			if (script->getLockers()) { // Explicitly loaded?
-				wm.pushArray(script->listObjectReferences());
+				if (script->getLockers()) { // Explicitly loaded?
+					wm.pushArray(script->listObjectReferences());
+				}
+			}
+
+			// Init: Explicitly opted-out hunks
+			else if (heap[i]->getType() == SEG_TYPE_HUNK) {
+				HunkTable *ht = static_cast<HunkTable *>(heap[i]);
+
+				for (uint j = 0; j < ht->_table.size(); j++) {
+					if (!ht->_table[j].data.gc) {
+						wm.push(make_reg(i, j));
+					}
+				}
 			}
 		}
 	}
 
-#ifdef ENABLE_SCI32
-	// Init: ScrollWindows
-	if (g_sci->_gfxControls32)
-		wm.pushArray(g_sci->_gfxControls32->listObjectReferences());
-#endif
-
 	debugC(kDebugLevelGC, "[GC] -- Finished explicitly loaded scripts, done with root set");
 
 	processWorkList(s->_segMan, wm, heap);