MADS: Properly implement cursor hotspot handling

1 files changed, 31 insertions, 2 deletions

diff --git a/engines/mads/events.cpp b/engines/mads/events.cpp
index 5d6a16ff1f..870a902866 100644
--- a/engines/mads/events.cpp
+++ b/engines/mads/events.cpp
@@ -90,9 +90,38 @@ void EventsManager::waitCursor() {
 void EventsManager::changeCursor() {
 	if (_cursorSprites) {
 		MSprite *cursor = _cursorSprites->getFrame(_cursorId - 1);
-		CursorMan.replaceCursor(cursor->getData(), cursor->w, cursor->h, 0, 0,
-			cursor->getTransparencyIndex());
+		assert(cursor->w == cursor->h);
+		byte transIndex = cursor->getTransparencyIndex();
+
+		// Check for hotspot indication pixels along the right-hand and bottom
+		// row. Put together, these give the cursor's hotspot x,y
+		int hotspotX = 0, hotspotY = 0;
+		byte *cursorData = cursor->getData();
+		for (int idx = 0; idx < cursor->w; ++idx) {
+			if (cursorData[(cursor->h - 1) * cursor->w + idx] != transIndex)
+				hotspotX = idx;
+
+			if (cursorData[(cursor->h + 1) * cursor->w - 1] != transIndex)
+				hotspotY = idx;
+		}
+
+		// Reduce the cursor data to remove the last column from each row, since
+		// the cursor routines don't have a pitch option
+		byte *destCursor = new byte[(cursor->w - 1) * (cursor->h - 1)];
+		byte *srcP = cursorData;
+		byte *destP = destCursor;
+
+		for (int idx = 0; idx < (cursor->h - 1); ++idx) {
+			Common::copy(srcP, srcP + cursor->w - 1, destP);
+			srcP += cursor->w;
+			destP += cursor->w - 1;
+		}
+
+		// Set the raw cursor data to use
+		CursorMan.replaceCursor(destCursor, cursor->w - 1, cursor->h - 1, 
+			hotspotX, hotspotY, transIndex);
 		showCursor();
+		delete[] destCursor;
 	}
 }