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use crate::engine::ecs::component::Component;
use crate::engine::ecs::{ComponentId, IntentValue, SignalEmitter};
/// Declares a renderable-backed stencil clip boundary.
///
/// On `init()`, emits `RegisterStencilClip` so VisualWorld records the renderable that should be
/// used as the clip source.
///
/// The renderer draws the referenced renderable into the stencil buffer
/// (color write off, stencil INCR, ref = nesting depth) before drawing the TC's
/// descendants, then restores stencil afterward with DECR. The same renderable
/// also draws normally in the color pass — it does double duty.
///
/// ## Layout use
///
/// `sync_bg_quad` attaches a layout-owned `StencilClipComponent` as a sibling of the generated
/// `__bg` helper whenever `overflow: Hidden | Scroll` is set on a style component. In that layout-
/// owned case, the computed `__bg` renderable remains the clip shape.
///
/// ## Manual use
///
/// Attach somewhere under the renderable whose mesh should define the clip region.
/// The nearest ancestor `RenderableComponent` determines the clip shape.
pub struct StencilClipComponent {
/// Stencil reference depth. `0` = auto-assign based on ancestor nesting depth.
pub stencil_ref: u8,
}
impl StencilClipComponent {
pub fn new() -> Self {
Self { stencil_ref: 0 }
}
}
impl Default for StencilClipComponent {
fn default() -> Self {
Self::new()
}
}
impl Component for StencilClipComponent {
fn name(&self) -> &'static str {
"stencil_clip"
}
fn set_id(&mut self, _component: ComponentId) {}
fn as_any(&self) -> &dyn std::any::Any {
self
}
fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
self
}
fn init(&mut self, emit: &mut dyn SignalEmitter, component: ComponentId) {
emit.push_intent_now(
component,
IntentValue::RegisterStencilClip {
component_id: component,
},
);
}
fn cleanup(&mut self, emit: &mut dyn SignalEmitter, component: ComponentId) {
emit.push_intent_now(
component,
IntentValue::UnregisterStencilClip {
component_id: component,
},
);
}
fn to_mms_ast(
&self,
_world: &crate::engine::ecs::World,
) -> crate::scripting::ast::ComponentExpression {
use crate::engine::ecs::component::ce_helpers::*;
if self.stencil_ref == 0 {
ce("StencilClip")
} else {
ce("StencilClip").with_call("stencil_ref", vec![num(self.stencil_ref as f64)])
}
}
}