Propagate the RNG to the action context. This lets random work.

core/src/avm1.rs

@@ -21,6 +21,7 @@ pub struct ActionContext<'a, 'gc, 'gc_context> {
     pub root: DisplayNode<'gc>,
     pub start_clip: DisplayNode<'gc>,
     pub active_clip: DisplayNode<'gc>,
+    pub rng: &'a mut SmallRng,
     pub audio: &'a mut dyn crate::backend::audio::AudioBackend,
     pub navigator: &'a mut dyn crate::backend::navigator::NavigatorBackend
 }
@@ -28,7 +29,6 @@ pub struct ActionContext<'a, 'gc, 'gc_context> {
 pub struct Avm1<'gc> {
     swf_version: u8,
     stack: Vec<Value<'gc>>,
-    rng: SmallRng,
     constant_pool: Vec<String>,
     locals: HashMap<String, Value<'gc>>,
     globals: GcCell<'gc, Object<'gc>>,
@@ -50,7 +50,6 @@ impl<'gc> Avm1<'gc> {
         Self {
             swf_version,
             stack: vec![],
-            rng: SmallRng::from_seed([0u8; 16]), // TODO(Herschel): Get a proper seed on all platforms.
             constant_pool: vec![],
             locals: HashMap::new(),
             globals: GcCell::allocate(gc_context, create_globals(gc_context)),
@@ -912,9 +911,9 @@ impl<'gc> Avm1<'gc> {
         Ok(())
     }
 
-    fn action_random_number(&mut self, _context: &mut ActionContext) -> Result<(), Error> {
+    fn action_random_number(&mut self, context: &mut ActionContext) -> Result<(), Error> {
         let max = self.pop()?.as_f64()? as u32;
-        let val = self.rng.gen_range(0, max);
+        let val = context.rng.gen_range(0, max);
         self.push(Value::Number(val.into()));
         Ok(())
     }

core/src/avm1/globals.rs

@@ -1,5 +1,6 @@
 use crate::avm1::{Object, Value, ActionContext};
 use gc_arena::{MutationContext, GcCell};
+use rand::Rng;
 
 mod math;
 
@@ -27,11 +28,14 @@ pub fn getURL<'a, 'gc>(
 }
 
 pub fn random<'gc>(
-    _action_context: &mut ActionContext<'_, 'gc, '_>,
+    action_context: &mut ActionContext<'_, 'gc, '_>,
     _this: GcCell<'gc, Object<'gc>>,
     args: &[Value<'gc>],
 ) -> Value<'gc> {
-    Value::Number(4.0) //chosen by fair dice roll. guaranteed to be random.
+    match args.get(0) {
+        Some(Value::Number(max)) => Value::Number(action_context.rng.gen_range(0.0f64, max).floor()),
+        _ => Value::Undefined //TODO: Shouldn't this be an error condition?
+    }
 }
 
 pub fn create_globals<'gc>(gc_context: MutationContext<'gc, '_>) -> Object<'gc> {

core/src/avm1/globals/math.rs

@@ -1,6 +1,7 @@
 use crate::avm1::{ActionContext, Object, Value};
 use gc_arena::{GcCell, MutationContext};
 use std::f64::NAN;
+use rand::Rng;
 
 macro_rules! wrap_std {
     ( $object: ident, $gc_context: ident, $($name:expr => $std:path),* ) => {{
@@ -36,11 +37,11 @@ fn atan2<'gc>(
 }
 
 pub fn random<'gc>(
-    _action_context: &mut ActionContext<'_, 'gc, '_>,
+    action_context: &mut ActionContext<'_, 'gc, '_>,
     _this: GcCell<'gc, Object<'gc>>,
     _args: &[Value<'gc>],
 ) -> Value<'gc> {
-    Value::Number(0.4) //chosen by fair dice roll. guaranteed to be random.
+    Value::Number(action_context.rng.gen_range(0.0f64, 1.0f64))
 }
 
 pub fn create<'gc>(gc_context: MutationContext<'gc, '_>) -> GcCell<'gc, Object<'gc>> {
@@ -87,6 +88,7 @@ mod tests {
     use crate::display_object::DisplayObject;
     use crate::movie_clip::MovieClip;
     use gc_arena::rootless_arena;
+    use rand::{rngs::SmallRng, SeedableRng};
 
     macro_rules! test_std {
     ( $test: ident, $name: expr, $($args: expr => $out: expr),* ) => {
@@ -119,6 +121,7 @@ mod tests {
                 root,
                 start_clip: root,
                 active_clip: root,
+                rng: &mut SmallRng::from_seed([0u8; 16]),
                 audio: &mut NullAudioBackend::new(),
                 navigator: &mut NullNavigatorBackend::new()
             };

core/src/player.rs

@@ -5,6 +5,7 @@ use crate::library::Library;
 use crate::movie_clip::MovieClip;
 use crate::prelude::*;
 use crate::transform::TransformStack;
+use rand::{rngs::SmallRng, SeedableRng};
 use gc_arena::{make_arena, ArenaParameters, Collect, GcCell, MutationContext};
 use log::info;
 use std::sync::Arc;
@@ -33,6 +34,8 @@ pub struct Player<Audio: AudioBackend, Renderer: RenderBackend, Navigator: Navig
     view_matrix: Matrix,
     inverse_view_matrix: Matrix,
 
+    rng: SmallRng,
+
     gc_arena: GcArena,
     background_color: Color,
 
@@ -88,6 +91,8 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
             view_matrix: Default::default(),
             inverse_view_matrix: Default::default(),
 
+            rng: SmallRng::from_seed([0u8; 16]), // TODO(Herschel): Get a proper seed on all platforms.
+
             gc_arena: GcArena::new(ArenaParameters::default(), |gc_context| GcRoot {
                 library: GcCell::allocate(gc_context, Library::new()),
                 root: GcCell::allocate(
@@ -205,7 +210,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
             }
         }
 
-        let (global_time, swf_data, swf_version, background_color, renderer, audio, navigator, is_mouse_down) = (
+        let (global_time, swf_data, swf_version, background_color, renderer, audio, navigator, rng, is_mouse_down) = (
             self.global_time,
             &mut self.swf_data,
             self.swf_version,
@@ -213,6 +218,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
             &mut self.renderer,
             &mut self.audio,
             &mut self.navigator,
+            &mut self.rng,
             &mut self.is_mouse_down,
         );
 
@@ -224,6 +230,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
                 library: gc_root.library.write(gc_context),
                 background_color,
                 avm: gc_root.avm.write(gc_context),
+                rng,
                 renderer,
                 audio,
                 navigator,
@@ -269,14 +276,15 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
             return false;
         }
 
-        let (global_time, swf_data, swf_version, background_color, renderer, audio, navigator) = (
+        let (global_time, swf_data, swf_version, background_color, renderer, audio, navigator, rng) = (
             self.global_time,
             &mut self.swf_data,
             self.swf_version,
             &mut self.background_color,
             &mut self.renderer,
             &mut self.audio,
-            &mut self.navigator
+            &mut self.navigator,
+            &mut self.rng
         );
 
         let mouse_pos = &self.mouse_pos;
@@ -295,6 +303,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
                     library: gc_root.library.write(gc_context),
                     background_color,
                     avm: gc_root.avm.write(gc_context),
+                    rng,
                     renderer,
                     audio,
                     navigator,
@@ -330,7 +339,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
     }
 
     fn preload(&mut self) {
-        let (global_time, swf_data, swf_version, background_color, renderer, audio, navigator) = (
+        let (global_time, swf_data, swf_version, background_color, renderer, audio, navigator, rng) = (
             self.global_time,
             &mut self.swf_data,
             self.swf_version,
@@ -338,6 +347,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
             &mut self.renderer,
             &mut self.audio,
             &mut self.navigator,
+            &mut self.rng
         );
 
         self.gc_arena.mutate(|gc_context, gc_root| {
@@ -348,6 +358,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
                 library: gc_root.library.write(gc_context),
                 background_color,
                 avm: gc_root.avm.write(gc_context),
+                rng,
                 renderer,
                 audio,
                 navigator,
@@ -376,14 +387,15 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
     }
 
     pub fn run_frame(&mut self) {
-        let (global_time, swf_data, swf_version, background_color, renderer, audio, navigator) = (
+        let (global_time, swf_data, swf_version, background_color, renderer, audio, navigator, rng) = (
             self.global_time,
             &mut self.swf_data,
             self.swf_version,
             &mut self.background_color,
             &mut self.renderer,
             &mut self.audio,
-            &mut self.navigator
+            &mut self.navigator,
+            &mut self.rng
         );
 
         self.gc_arena.mutate(|gc_context, gc_root| {
@@ -394,6 +406,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
                 library: gc_root.library.write(gc_context),
                 background_color,
                 avm: gc_root.avm.write(gc_context),
+                rng,
                 renderer,
                 audio,
                 navigator,
@@ -478,6 +491,7 @@ impl<Audio: AudioBackend, Renderer: RenderBackend, Navigator: NavigatorBackend>
                     root,
                     start_clip: root,
                     active_clip: root,
+                    rng: update_context.rng,
                     audio: update_context.audio,
                     navigator: update_context.navigator,
                 };
@@ -548,6 +562,7 @@ pub struct UpdateContext<'a, 'gc, 'gc_context> {
     pub renderer: &'a mut dyn RenderBackend,
     pub audio: &'a mut dyn AudioBackend,
     pub navigator: &'a mut dyn NavigatorBackend,
+    pub rng: &'a mut SmallRng,
     pub actions: Vec<(DisplayNode<'gc>, crate::tag_utils::SwfSlice)>,
     pub active_clip: DisplayNode<'gc>,
 }