Ticket #8103: loom-regression.diff

scummvm/scumm/actor.cpp

@@ -896 +896 @@
 
                 cr._outheight = _vm->virtscr->height;
 
-                // If walkbox is 0, that could mean two things:
+                // FIXME - Hack to fix two glitches in the scene where Bobbin
+                // heals Rusty: Bobbin's feet get masked when Rusty shows him
+                // what happens to The Forge, and Rusty gets masked after
+                // Bobbin heals him.
                 //
-                // Either the actor is or has been moved around with
-                // ignoreBoxes != 0. In this case, use the mask for the
-                // walkbox the actor is currently inside or, if it's not in
-                // any walkbox, don't mask at all.
+                // When an actor is moved around without regards to walkboxes,
+                // its walkbox is set to 0. Unfortunately that's a valid
+                // walkbox in older games, and its mask may be completely
+                // wrong for this purpose.
                 //
-                // This fixes two graphics glitches in Loom. Bobbin's feet
-                // are not obscured after Rusty's ghost has shown him what's
-                // happened to The Forge, and Rusty himself isn't partially
-                // obscured after Bobbin heals him.
+                // So instead use the mask of the box where the actor happens
+                // to be at the moment or, if it's not in any box, don't mask
+                // at all.
                 //
-                // Or it could mean that the actor really is in walkbox 0.
+                // Checking if ignoreBoxes != 0 isn't enough to fix all the
+                // glitches, so I have to check for walkbox 0. However, that
+                // gives too many false positives -- it breaks masking in a
+                // few other rooms, e.g. when Stoke leaves the room where he
+                // locks up "Rusty".
+                //
+                // Until someone can find the proper fix, only apply it to the
+                // one room where it's actually needed.
 
-                if (_vm->_gameId == GID_LOOM256 && walkbox == 0) {
-                        int i;
+                if (_vm->_gameId == GID_LOOM256 && _vm->_currentRoom == 34 && walkbox == 0) {
+                        int num_boxes, i;
 
                         cr._zbuf = 0;
+                        num_boxes = _vm->getNumBoxes();
+
+                        // For this particular room it won't matter in which
+                        // direction we loop. In other rooms, looping in the
+                        // other direction may pick the wrong box.
 
-                        for (i = _vm->getNumBoxes() - 1; i >= 0; i--) {
+                        for (i = 0; i < num_boxes; i++) {
                                 if (_vm->checkXYInBoxBounds(i, x, y)) {
                                         cr._zbuf = _vm->getMaskFromBox(i);
                                         break;
@@ -1141 +1155 @@
                 abr.dist = 0;
                 walkbox = 0;
         } else {
-                // FIXME: this prevents part of bug #605970 (Loom) from occuring. Not sure
-                // if there is a better way to achieve this.
+                // FIXME: this prevents part of bug #605970 (Loom) from
+                // occuring, and also fixes a walk bug with Rusty's ghost.
+                // Not sure if there is a better way to achieve this.
                 if (walkbox == 0)
                         adjustActorPos();