avm2: Implement DisplayObject z getter/setter

They replace flash.display.DisplayObject z getter/setter stubs.
The z value (z translation) is now taken into account in wgpu rendering.

Author: cookie-s

core/src/avm2/globals/flash/display/display_object.rs

@@ -413,20 +413,30 @@ pub fn set_y<'gc>(
 }
 
 pub fn get_z<'gc>(
-    activation: &mut Activation<'_, 'gc>,
-    _this: Value<'gc>,
+    _activation: &mut Activation<'_, 'gc>,
+    this: Value<'gc>,
     _args: &[Value<'gc>],
 ) -> Result<Value<'gc>, Error<'gc>> {
-    avm2_stub_getter!(activation, "flash.display.DisplayObject", "z");
-    Ok(0.into())
+    let this = this.as_object().unwrap();
+
+    if let Some(dobj) = this.as_display_object() {
+        return Ok(dobj.z().into());
+    }
+    Ok(Value::Undefined)
 }
 
 pub fn set_z<'gc>(
     activation: &mut Activation<'_, 'gc>,
-    _this: Value<'gc>,
-    _args: &[Value<'gc>],
+    this: Value<'gc>,
+    args: &[Value<'gc>],
 ) -> Result<Value<'gc>, Error<'gc>> {
-    avm2_stub_setter!(activation, "flash.display.DisplayObject", "z");
+    let this = this.as_object().unwrap();
+
+    if let Some(dobj) = this.as_display_object() {
+        let z = args.get_f64(activation, 0)?;
+        dobj.set_z(activation.gc(), z);
+        dobj.base_mut(activation.gc()).set_has_matrix3d_stub(true);
+    }
     Ok(Value::Undefined)
 }
 

core/src/avm2/globals/flash/geom/transform.rs

@@ -339,7 +339,8 @@ pub fn get_matrix_3d<'gc>(
     let display_object = get_display_object(this);
     if display_object.base().has_matrix3d_stub() {
         let matrix = *get_display_object(this).base().matrix();
-        let matrix3d = Matrix3D::from(matrix);
+        let mut matrix3d = Matrix3D::from(matrix);
+        matrix3d.set_tz(display_object.z());
         matrix3d_to_object(matrix3d, activation)
     } else {
         Ok(Value::Null)
@@ -359,19 +360,19 @@ pub fn set_matrix_3d<'gc>(
 
     let display_object = get_display_object(this);
 
-    let (matrix, has_matrix3d) = {
+    let (matrix, has_matrix3d, tz) = {
         match args.try_get_object(activation, 0) {
             Some(obj) => {
                 let matrix3d = object_to_matrix3d(obj, activation)?;
                 let matrix = Matrix::from(matrix3d);
                 let tz = matrix3d.tz();
-                display_object.base_mut(activation.gc()).set_tz(tz);
-                (matrix, true)
+                (matrix, true, tz)
             }
-            None => (Matrix::IDENTITY, false),
+            None => (Matrix::IDENTITY, false, 0.0),
         }
     };
 
+    display_object.base_mut(activation.gc()).set_matrix_tz(tz);
     display_object.set_matrix(activation.gc(), matrix);
     if let Some(parent) = display_object.parent() {
         // Self-transform changes are automatically handled,

core/src/display_object.rs

@@ -336,7 +336,11 @@ impl<'gc> DisplayObjectBase<'gc> {
         &mut self.transform.matrix
     }
 
-    pub fn set_tz(&mut self, tz: f64) {
+    pub fn matrix_tz(&mut self) -> f64 {
+        self.transform.tz
+    }
+
+    pub fn set_matrix_tz(&mut self, tz: f64) {
         self.transform.tz = tz;
     }
 
@@ -379,6 +383,17 @@ impl<'gc> DisplayObjectBase<'gc> {
         changed
     }
 
+    fn z(&self) -> f64 {
+        self.transform.tz
+    }
+
+    fn set_z(&mut self, tz: f64) -> bool {
+        let changed = self.matrix_tz() != tz;
+        self.set_transformed_by_script(true);
+        self.set_matrix_tz(tz);
+        changed
+    }
+
     /// Caches the scale and rotation factors for this display object, if necessary.
     /// Calculating these requires heavy trig ops, so we only do it when `_xscale`, `_yscale` or
     /// `_rotation` is accessed.
@@ -1380,6 +1395,25 @@ pub trait TDisplayObject<'gc>:
         }
     }
 
+    /// The `z` position in local space.
+    /// Returned by the `z` ActionScript properties.
+    fn z(&self) -> f64 {
+        self.base().z()
+    }
+
+    /// Sets the `z` position of this display object in local space.
+    /// Set by the `z` ActionScript properties.
+    /// This invalidates any ancestors cacheAsBitmap automatically.
+    fn set_z(&self, gc_context: &Mutation<'gc>, z: f64) {
+        if self.base_mut(gc_context).set_z(z) {
+            if let Some(parent) = self.parent() {
+                // Self-transform changes are automatically handled,
+                // we only want to inform ancestors to avoid unnecessary invalidations for tx/ty
+                parent.invalidate_cached_bitmap(gc_context);
+            }
+        }
+    }
+
     /// The rotation in degrees this display object in local space.
     /// Returned by the `_rotation`/`rotation` ActionScript properties.
     fn rotation(&self, gc_context: &Mutation<'gc>) -> Degrees {