debug_ui: Improve mask/maskee fields

core/src/debug_ui/display_object.rs

@@ -11,7 +11,7 @@ use crate::debug_ui::movie::open_movie_button;
 use crate::debug_ui::Message;
 use crate::display_object::{
     AutoSizeMode, Avm2Button, Bitmap, ButtonState, DisplayObject, EditText, InteractiveObject,
-    LayoutDebugBoxesFlag, MovieClip, Stage, TDisplayObject, TDisplayObjectContainer,
+    LayoutDebugBoxesFlag, MovieClip, RenderMask, Stage, TDisplayObject, TDisplayObjectContainer,
     TInteractiveObject,
 };
 use crate::focus_tracker::Highlight;
@@ -1337,29 +1337,43 @@ impl DisplayObjectWindow {
                 }
                 ui.end_row();
 
-                if let Some(other) = object.masker() {
-                    ui.label("Masker");
-                    open_display_object_button(
-                        ui,
-                        context,
-                        messages,
-                        other,
-                        &mut self.hovered_debug_rect,
-                    );
-                    ui.end_row();
+                ui.label("Mask");
+                match object.get_render_mask() {
+                    RenderMask::None => {
+                        ui.weak("None");
+                    }
+                    RenderMask::Stencil(mask) | RenderMask::Alpha(mask) => {
+                        ui.horizontal(|ui| {
+                            open_display_object_button(
+                                ui,
+                                context,
+                                messages,
+                                mask,
+                                &mut self.hovered_debug_rect,
+                            );
+                            match object.get_render_mask() {
+                                RenderMask::None => unreachable!(),
+                                RenderMask::Stencil(_) => ui.weak("(stencil)"),
+                                RenderMask::Alpha(_) => ui.weak("(alpha)"),
+                            };
+                        });
+                    }
                 }
+                ui.end_row();
 
+                ui.label("Maskee");
                 if let Some(other) = object.maskee() {
-                    ui.label("Maskee");
                     open_display_object_button(
                         ui,
                         context,
                         messages,
                         other,
                         &mut self.hovered_debug_rect,
                     );
-                    ui.end_row();
+                } else {
+                    ui.weak("None");
                 }
+                ui.end_row();
 
                 ui.label("Cache as Bitmap");
                 ui.horizontal(|ui| {

core/src/display_object.rs

@@ -229,6 +229,27 @@ impl Default for RenderOptions {
     }
 }
 
+#[derive(Clone, Collect, Debug)]
+#[collect(no_drop)]
+pub enum RenderMask<'gc> {
+    /// There's no mask.
+    None,
+
+    /// Stencil masks are the classic, default masks used in Flash Player.
+    ///
+    /// The masker behaves like a stencil, and masks everything outside its
+    /// rendered pixels irrespectively of the pixels themselves.
+    /// The maskee acts like being masked with the masker's hit test image.
+    Stencil(DisplayObject<'gc>),
+
+    /// Alpha masks are the more advanced (and more intuitive) masks used when
+    /// CAB is enabled.
+    ///
+    /// The maskee is being masked based on the value of the masker's alpha
+    /// channel.
+    Alpha(DisplayObject<'gc>),
+}
+
 #[derive(Clone, Collect)]
 #[collect(no_drop)]
 // Ensure this always has the same alignment as its subclasses (needed for `Gc` casts).
@@ -1132,26 +1153,15 @@ pub fn apply_standard_mask_and_scroll<'gc, F>(
         });
     }
 
-    enum Mask<'gc> {
-        None,
-        Stencil(DisplayObject<'gc>),
-        Alpha(DisplayObject<'gc>),
-    }
-
-    let mask = match this.masker() {
-        None => Mask::None,
-        Some(mask) if this.is_bitmap_cached() && mask.is_bitmap_cached() => Mask::Alpha(mask),
-        Some(mask) => Mask::Stencil(mask),
-    };
-
+    let mask = this.get_render_mask();
     let mut mask_transform = ruffle_render::transform::Transform::default();
-    if let Mask::Stencil(m) | Mask::Alpha(m) = mask {
+    if let RenderMask::Stencil(m) | RenderMask::Alpha(m) = mask {
         if options.apply_transform {
             mask_transform.matrix = this.global_to_local_matrix().unwrap_or_default();
         }
         mask_transform.matrix *= m.local_to_global_matrix();
     }
-    if let Mask::Stencil(m) = mask {
+    if let RenderMask::Stencil(m) = mask {
         context.commands.push_mask();
         context.transform_stack.push(&mask_transform);
         m.render_self(context);
@@ -1177,7 +1187,7 @@ pub fn apply_standard_mask_and_scroll<'gc, F>(
         context.commands.activate_mask();
     }
 
-    if let Mask::Alpha(m) = mask {
+    if let RenderMask::Alpha(m) = mask {
         let original_commands = std::mem::take(&mut context.commands);
 
         draw(context);
@@ -1210,7 +1220,7 @@ pub fn apply_standard_mask_and_scroll<'gc, F>(
         context.commands.pop_mask();
     }
 
-    if let Mask::Stencil(m) = mask {
+    if let RenderMask::Stencil(m) = mask {
         context.commands.deactivate_mask();
         context.transform_stack.push(&mask_transform);
         m.render_self(context);
@@ -1908,6 +1918,17 @@ pub trait TDisplayObject<'gc>:
         DisplayObjectBase::set_maskee(Gc::write(mc, self.base()), node);
     }
 
+    #[no_dynamic]
+    fn get_render_mask(self) -> RenderMask<'gc> {
+        match self.masker() {
+            None => RenderMask::None,
+            Some(mask) if self.is_bitmap_cached() && mask.is_bitmap_cached() => {
+                RenderMask::Alpha(mask)
+            }
+            Some(mask) => RenderMask::Stencil(mask),
+        }
+    }
+
     /// High level method for setting the mask. Sets both masker and maskee.
     ///
     /// Equivalent to setting the mask from AVM.