avm1: Correct depth calculation for AVM1 clips pending removal and add tests

core/src/avm1.rs

@@ -12,7 +12,7 @@ mod callable_value;
 mod debug;
 mod error;
 mod fscommand;
-mod globals;
+pub(crate) mod globals;
 mod object;
 mod property;
 mod property_map;

core/src/avm1/globals.rs

@@ -1168,7 +1168,7 @@ pub fn create_globals<'gc>(
 /// The depth of objects placed on the timeline in the Flash IDE start from 0 in the SWF,
 /// but are negative when queried from MovieClip.getDepth().
 /// Add this to convert from AS -> SWF depth.
-const AVM_DEPTH_BIAS: i32 = 16384;
+pub const AVM_DEPTH_BIAS: i32 = 16384;
 
 /// The maximum depth that the AVM will allow you to swap or attach clips to.
 /// What is the derivation of this number...?

core/src/display_object/container.rs

@@ -915,7 +915,8 @@ impl<'gc> ChildContainer<'gc> {
         }
 
         let cur_depth = child.depth();
-        child.set_depth(context.gc_context, -cur_depth);
+        // Note that the depth returned by AS will be offset by the `AVM_DEPTH_BIAS`, so this is really `-(cur_depth+1+AVM_DEPTH_BIAS)`
+        child.set_depth(context.gc_context, -cur_depth - 1);
 
         if let Some(mc) = child.as_movie_clip() {
             // Clip events should still fire

tests/tests/swfs/avm1/unload/output.txt

@@ -1,4 +1,9 @@
 Frame 1:
+clip.depth = -16383
+clip2.depth = -16381
+clip3.depth = 0
+clip4.depth = 1
+clip5.depth = -16379
 clip = _level0.clip
 clip._x = 125.5
 clip2 = _level0.clip2
@@ -15,6 +20,10 @@ clip2 = undefined
 clip3 = undefined
 clip4 = undefined
 clip5 = _level0.clip5
+clip.depth = -16386
+clip2.depth = undefined
+Fixme(5492)
+clip5.depth = -16390
 End frame 2
 unload clipEvent
 unload clipEvent 2
@@ -25,12 +34,19 @@ clip2 = undefined
 clip3 = undefined
 clip4 = undefined
 clip5 = undefined
+clip.depth = -16386
+clip2.depth = undefined
+Fixme(5492)
+clip5.depth = undefined
 End frame 3
 Frame 4
 clip = undefined
 clip._x = undefined
 clip2 = undefined
-clip3 = undefined
+Fixme(5492)
-clip4 = undefined
 clip5 = undefined
+clip.depth = undefined
+clip2.depth = undefined
+Fixme(5492)
+clip5.depth = undefined
 End frame 4