avm1: Stub out ActionSetProperty

Rough impl of ActionSetProperty action. Not all properties
implemented. Add DisplayObject::matrix_mut.

core/src/avm1.rs

@@ -120,6 +120,7 @@ impl Avm1 {
                 Action::RemoveSprite => self.action_remove_sprite(context)?,
                 Action::Return => self.action_return(context)?,
                 Action::SetMember => self.action_set_member(context)?,
+                Action::SetProperty => self.action_set_property(context)?,
                 Action::SetTarget(target) => self.action_set_target(context, &target)?,
                 Action::SetVariable => self.action_set_variable(context)?,
                 Action::StackSwap => self.action_stack_swap(context)?,
@@ -828,6 +829,29 @@ impl Avm1 {
         unimplemented!("Action::SetMember");
     }
 
+    fn action_set_property(&mut self, context: &mut ActionContext) -> Result<(), Error> {
+        let value = self.pop()?.as_f64()? as f32;
+        let prop_index = self.pop()?.as_u32()? as usize;
+        let clip_path = self.pop()?;
+        let path = clip_path.as_string()?;
+        if let Some(clip) =
+            Avm1::resolve_slash_path(context.active_clip, context.root, path)
+        {
+            if let Some(clip) = clip.write(context.gc_context).as_movie_clip_mut() {
+                match prop_index {
+                    0 => clip.set_x(value),
+                    1 => clip.set_y(value),
+                    2 => clip.set_x_scale(value),
+                    3 => clip.set_y_scale(value),
+                    _ => log::warn!("ActionSetProperty: Unimplemented property index {}", prop_index),
+                }
+            }
+        } else {
+            log::warn!("ActionSetProperty: Invalid path {}", path);
+        }
+        Ok(())
+    }
+
     fn action_set_variable(&mut self, context: &mut ActionContext) -> Result<(), Error> {
         // Flash 4-style variable
         let value = self.pop()?;

core/src/display_object.rs

@@ -33,6 +33,9 @@ impl<'gc> DisplayObject<'gc> for DisplayObjectBase<'gc> {
     fn matrix(&self) -> &Matrix {
         &self.transform.matrix
     }
+    fn matrix_mut(&mut self) -> &mut Matrix {
+        &mut self.transform.matrix
+    }
     fn set_matrix(&mut self, matrix: &Matrix) {
         self.transform.matrix = *matrix;
     }
@@ -76,6 +79,7 @@ pub trait DisplayObject<'gc>: 'gc + Collect {
 
     fn transform(&self) -> &Transform;
     fn matrix(&self) -> &Matrix;
+    fn matrix_mut(&mut self) -> &mut Matrix;
     fn set_matrix(&mut self, matrix: &Matrix);
     fn color_transform(&self) -> &ColorTransform;
     fn set_color_transform(&mut self, color_transform: &ColorTransform);
@@ -136,6 +140,9 @@ macro_rules! impl_display_object {
         fn matrix(&self) -> &crate::matrix::Matrix {
             self.$field.matrix()
         }
+        fn matrix_mut(&mut self) -> &mut crate::matrix::Matrix {
+            self.$field.matrix_mut()
+        }
         fn set_matrix(&mut self, matrix: &crate::matrix::Matrix) {
             self.$field.set_matrix(matrix)
         }

core/src/movie_clip.rs

@@ -118,18 +118,34 @@ impl<'gc> MovieClip<'gc> {
         self.matrix().tx
     }
 
+    pub fn set_x(&mut self, val: f32) {
+        self.matrix_mut().tx = val;
+    }
+
     pub fn y(&self) -> f32 {
         self.matrix().ty
     }
 
+    pub fn set_y(&mut self, val: f32) {
+        self.matrix_mut().ty = val;
+    }
+
     pub fn x_scale(&self) -> f32 {
         self.matrix().a * 100.0
     }
 
+    pub fn set_x_scale(&mut self, val: f32) {
+        self.matrix_mut().a = val / 100.0;
+    }
+
     pub fn y_scale(&self) -> f32 {
         self.matrix().d * 100.0
     }
 
+    pub fn set_y_scale(&mut self, val: f32) {
+        self.matrix_mut().d = val / 100.0;
+    }
+
     pub fn current_frame(&self) -> FrameNumber {
         self.current_frame
     }