core: Add a "preload everything we know about" method

core/src/loader.rs

@@ -351,6 +351,24 @@ impl<'gc> LoadManager<'gc> {
         let loader = self.get_loader_mut(handle).unwrap();
         loader.sound_loader_avm2(player, request)
     }
+
+    /// Process tags on all loaders in the Parsing phase.
+    pub fn preload_tick(context: &mut UpdateContext<'_, 'gc, '_>, limit: &mut ExecutionLimit) {
+        let handles: Vec<_> = context.load_manager.0.iter().map(|(h, _)| h).collect();
+
+        for handle in handles {
+            let status = match context.load_manager.get_loader(handle) {
+                Some(Loader::Movie { loader_status, .. }) => Some(loader_status),
+                _ => None,
+            };
+
+            if matches!(status, Some(LoaderStatus::Parsing)) {
+                if let Err(e) = Loader::preload_tick(handle, context, limit) {
+                    log::error!("Error encountered while preloading movie: {}", e);
+                }
+            }
+        }
+    }
 }
 
 impl<'gc> Default for LoadManager<'gc> {
@@ -493,7 +511,6 @@ impl<'gc> Loader<'gc> {
                 target_clip,
                 event_handler,
                 movie,
-                loader_status,
                 ..
             }) => {
                 if movie.is_none() {
@@ -501,8 +518,6 @@ impl<'gc> Loader<'gc> {
                     return Ok(());
                 }
 
-                *loader_status = LoaderStatus::Parsing;
-
                 (*target_clip, *event_handler, movie.clone().unwrap())
             }
             None => return Err(Error::Cancelled),
@@ -692,7 +707,12 @@ impl<'gc> Loader<'gc> {
                                 )?);
 
                                 match uc.load_manager.get_loader_mut(handle) {
-                                    Some(Loader::Movie { movie: old, .. }) => {
+                                    Some(Loader::Movie {
+                                        movie: old,
+                                        loader_status,
+                                        ..
+                                    }) => {
+                                        *loader_status = LoaderStatus::Parsing;
                                         *old = Some(movie.clone())
                                     }
                                     _ => unreachable!(),

core/src/player.rs

@@ -401,7 +401,12 @@ impl Player {
             stage.build_matrices(&mut activation.context);
         });
 
-        self.preload();
+        self.preload(&mut ExecutionLimit::none());
+
+        if self.swf.is_action_script_3() && self.warn_on_unsupported_content {
+            self.ui.display_unsupported_message();
+        }
+
         self.audio.set_frame_rate(self.frame_rate);
     }
 
@@ -1323,25 +1328,20 @@ impl Player {
         needs_render
     }
 
-    /// Preload the first movie in the player.
+    /// Preload all pending movies in the player, including the root movie.
     ///
-    /// This should only be called once. Further movie loads should preload the
+    /// This should be called periodically with a reasonable execution limit.
-    /// specific `MovieClip` referenced.
+    /// By default, the Player will do so after every `run_frame` using a limit
-    fn preload(&mut self) {
+    /// derived from the current frame rate and execution time. Clients that
+    /// want synchronous or 'lockstep' preloading may call this function with
+    /// an unlimited execution limit.
+    fn preload(&mut self, limit: &mut ExecutionLimit) {
         self.mutate_with_update_context(|context| {
             let root = context.stage.root_clip();
-            let preload_done = root
+            root.as_movie_clip().unwrap().preload(context, limit);
-                .as_movie_clip()
-                .unwrap()
-                .preload(context, &mut ExecutionLimit::none());
 
-            if !preload_done {
+            LoadManager::preload_tick(context, limit);
-                log::warn!("Preloading of root clip did not complete in a single call.");
-            }
         });
-        if self.swf.is_action_script_3() && self.warn_on_unsupported_content {
-            self.ui.display_unsupported_message();
-        }
     }
 
     pub fn run_frame(&mut self) {