cranpose_liquid/

material.rs

//! The Liquid Glass material: Gaussian backdrop frost followed by wcKSRD
//! refraction applied to a composable's own bounds through
//! [`LiquidModifierExt::glass_effect`] — the analogue of SwiftUI's
//! `.glassEffect(_:in:)`.

use std::{
    cell::{Cell, RefCell},
    sync::OnceLock,
};

use cranpose_ui::{Modifier, current_density};
use cranpose_ui_graphics::{
    Color, GLASS_ACTIVITY_UNIFORM, GLASS_ADAPTIVE_FROST_UNIFORM, GLASS_ADAPTIVE_TONE_UNIFORM,
    GLASS_BLUR_RADIUS_UNIFORM, GLASS_DISPERSION_UNIFORM, GLASS_EDGE_REFRACTION_REACH_UNIFORM,
    GLASS_EDGE_RETURN_DEPTH_UNIFORM, GLASS_EDGE_SPECTRUM_UNIFORM, GLASS_EFFECT_DENSITY_UNIFORM,
    GLASS_FACE_LIGHTING_OFF_UNIFORM, GLASS_FACE_RESPONSE_UNIFORM, GLASS_FOLD_DEPTH_UNIFORM,
    GLASS_INNER_SHADOW_UNIFORM, GLASS_KEY_FILL_UNIFORM, GLASS_LAYER_CLIPPED_UNIFORM,
    GLASS_LAYERED_RETURN_UNIFORM, GLASS_LIGHT_DIRECTION_UNIFORM, GLASS_MENISCUS_ABSORPTION_UNIFORM,
    GLASS_OPTICAL_PROJECTION_UNIFORM, GLASS_OPTICAL_ZOOM_ANCHOR_UNIFORM,
    GLASS_OPTICAL_ZOOM_UNIFORM, GLASS_PHYSICAL_REFRACTION_DEPTH_ENABLED_UNIFORM,
    GLASS_PHYSICAL_REFRACTION_DEPTH_UNIFORM, GLASS_REFRACTION_CURVE_UNIFORM,
    GLASS_REFRACTION_MODE_UNIFORM, GLASS_RESTING_EDGE_SHARPNESS_UNIFORM,
    GLASS_RESTING_TINT_UNIFORM, GLASS_TOUCH_RADIUS_UNIFORM, GLASS_TRANSMISSION_REFRACTION_UNIFORM,
    GraphicsLayer, LIQUID_GLASS_WGSL, LayerShape, PlaceholderShape, Rect, RenderEffect,
    RoundedCornerShape, RuntimeShader, TileMode, liquid_glass_placeholder,
    liquid_glass_runtime_effect, specialize_liquid_glass,
};

use crate::{appearance::GlassTintAmount, theme::LiquidColors};

thread_local! {
    static GLASS_LIGHT_RETURN: Cell<(f32, f32)> = const { Cell::new((0.0, 1.0)) };
}

/// Sets the ambient glass light return direction (screen space, need not be
/// normalized — the shader normalizes). Feed device attitude here.
pub fn set_glass_light_direction(direction: (f32, f32)) {
    GLASS_LIGHT_RETURN.with(|cell| cell.set(direction));
}

/// The current ambient glass light return direction.
pub fn glass_light_direction() -> (f32, f32) {
    GLASS_LIGHT_RETURN.with(Cell::get)
}

const CAPSULE_CLIP_RADIUS: f32 = 1.0e6;

const CAPSULE_SHADER_RADIUS: f32 = -1.0;

const WCKSRD_OPTICAL_BLUR_RADIUS_PX: f32 = 2.0;

/// The shape of a glass element (also its clip and shadow shape).
#[derive(Clone, Copy, Debug, PartialEq, Default)]
pub enum LiquidShape {
    /// A pill: corner radius follows the smaller half-extent.
    #[default]
    Capsule,
    /// Rounded rectangle with the radius in dp.
    RoundedRect(f32),
    /// A circle (capsule of a square node).
    Circle,
}

impl LiquidShape {
    /// The clip shape handed to the graphics layer.
    pub fn clip_shape(&self) -> RoundedCornerShape {
        match self {
            LiquidShape::Capsule | LiquidShape::Circle => {
                RoundedCornerShape::uniform(CAPSULE_CLIP_RADIUS)
            }
            LiquidShape::RoundedRect(radius) => RoundedCornerShape::uniform(*radius),
        }
    }

    /// The layer shape (clip + shadow geometry).
    pub fn layer_shape(&self) -> LayerShape {
        LayerShape::Rounded(self.clip_shape())
    }

    fn shader_radius_px(&self, density: f32) -> f32 {
        match self {
            LiquidShape::Capsule | LiquidShape::Circle => CAPSULE_SHADER_RADIUS,
            LiquidShape::RoundedRect(radius) => radius * density,
        }
    }

    /// The corner radius in dp, the largest one making a capsule.
    fn radius_dp(&self) -> f32 {
        match self {
            LiquidShape::Capsule | LiquidShape::Circle => f32::MAX,
            LiquidShape::RoundedRect(radius) => *radius,
        }
    }
}

/// Material variant, mirroring SwiftUI's `.regular` / `.clear` glass, plus
/// the interactive lens.
#[derive(Clone, Copy, Debug, PartialEq, Eq, Default)]
pub enum GlassVariant {
    /// Frosted: strong backdrop blur, vibrancy boost, scheme-adaptive lift.
    #[default]
    Regular,
    /// Transparent: minimal blur, mild vibrancy — for media-rich backdrops.
    Clear,
    /// The interactive magnifying bubble (drag lenses, flying selection):
    /// no frost, no tone shift, a full-element dome and pronounced rainbow
    /// dispersion at the rim.
    Lens,
}

/// The projection used to transmit the captured backdrop through glass.
#[derive(Clone, Copy, Debug, PartialEq, Default)]
pub enum GlassRefraction {
    /// A radial projection toward the optical axis.
    #[default]
    Radial,
    /// A projection perpendicular to the nearest surface edge.
    Surface {
        /// Maximum inward sample displacement in dp, independent of its falloff depth.
        reach_dp: f32,
    },
    /// Successive outward and inward sample displacements with circular falloff profiles.
    /// The return amplitude is 17.5/9 times the outward amplitude. Its default depth
    /// is 7/36 of the outer profile; [`GlassDynamics::edge_return_depth_dp`] overrides it.
    EdgeLens {
        /// Outward warp amplitude in dp; refraction depth sets its falloff height.
        reach_dp: f32,
    },
    /// An outward backdrop warp followed by the material's inward surface warp.
    /// Both coordinate maps are composed before sampling, avoiding an intermediate image.
    /// Amplitudes and depths are absolute; activity controls the resting fill separately.
    LayeredSurface {
        /// Outward backdrop amplitude in dp; refraction depth sets its falloff height.
        reach_dp: f32,
        /// Inward surface amplitude in dp.
        return_reach_dp: f32,
        /// Inward surface falloff height in dp.
        return_depth_dp: f32,
    },
}

impl GlassRefraction {
    fn shader_parameters(self) -> (f32, f32) {
        match self {
            Self::Radial => (0.0, 0.0),
            Self::Surface { reach_dp } => (1.0, finite_nonnegative(reach_dp)),
            Self::EdgeLens { reach_dp } => (2.0, finite_nonnegative(reach_dp)),
            Self::LayeredSurface { reach_dp, .. } => (3.0, finite_nonnegative(reach_dp)),
        }
    }
}

fn finite_nonnegative(reach_dp: f32) -> f32 {
    if reach_dp.is_finite() {
        reach_dp.max(0.0)
    } else {
        0.0
    }
}

/// Shadow owned by a glass surface. Morphing glass evaluates the same live
/// SDF for this shadow; clipped static glass forwards the values to the layer
/// shadow primitive.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GlassShadow {
    pub color: Color,
    pub radius: f32,
    pub offset_y: f32,
    pub spread: f32,
}

impl GlassShadow {
    pub fn new(color: Color, radius: f32, offset_y: f32, spread: f32) -> Self {
        Self {
            color,
            radius: radius.max(0.0),
            offset_y,
            spread,
        }
    }

    fn uniforms(self) -> Option<[f32; 8]> {
        let values = [
            self.color.r(),
            self.color.g(),
            self.color.b(),
            self.color.a(),
            self.radius,
            self.offset_y,
            self.spread,
            1.0,
        ];
        (values.iter().all(|value| value.is_finite())
            && self.radius >= 0.0
            && (0.0..=1.0).contains(&self.color.a()))
        .then_some(values)
    }
}

/// Per-frame motion inputs for an interactive glass element, read lazily at
/// scene-build time (no recomposition per frame).
#[derive(Clone, Debug, PartialEq, Default)]
pub struct GlassDynamics {
    /// Uses a global color transfer and a white blurred contact light in place of touch glow.
    pub contact_lighting: bool,
    /// Per-frame source mapping. Layered surfaces use this to animate the backdrop
    /// and material independently of the opaque resting fill.
    pub refraction: Option<GlassRefraction>,
    /// Per-frame shadow of the persistent surface, independent of optical activity.
    pub shadow: Option<GlassShadow>,
    /// A shadow cast by the surface contour instead of its filled silhouette.
    /// The second value is the contour stroke width in dp; the shadow radius
    /// is its Gaussian standard deviation. Nonfinite or nonpositive widths disable it.
    pub ring_shadow: Option<(GlassShadow, f32)>,
    /// Independent inner return depth for an edge lens, in dp. Zero removes its depth.
    /// Nonfinite or negative values preserve the material's default depth ratio.
    pub edge_return_depth_dp: Option<f32>,
    /// Horizontal and vertical projection of the complete glass field about its primary center.
    /// Refraction, lighting and all scene shapes share the projection. Missing, nonfinite or
    /// nonpositive scales resolve to identity. This does not magnify the underlying backdrop.
    pub optical_projection: Option<(f32, f32)>,
    /// Continuous optical presence. `None` preserves the resolved material;
    /// `Some(0)` is an exact backdrop identity while retaining the same node,
    /// SDF, and pointer ride path.
    pub activity: Option<f32>,
    /// Base tint of the same persistent SDF surface at zero optical activity.
    /// Its alpha cross-fades out as the refractive material rises.
    pub resting_tint: Option<Color>,
    /// Extra specular intensity (0 = spec default; e.g. press boost).
    pub highlight_boost: f32,
    /// Per-frame saturation added to the resolved material. Interactive
    /// surfaces use this to raise chroma without changing their base tint.
    pub saturation_boost: f32,
    /// Optional per-frame multiplier for the material tint alpha. Values
    /// below one clear a resting wash; values above one densify a raised tint.
    pub tint_alpha_multiplier: Option<f32>,
    /// Blends a plain translucent tint into this material's tint, including its
    /// luminance-dependent transmission. The fraction is zero at the supplied
    /// tint and one at the material tint; refraction and lighting stay active.
    pub tint_crossfade: Option<(Color, f32)>,
    /// Shape morph: when set, the glass geometry is these node-local rects
    /// instead of the node cover — the shapeshift channel.
    pub morph: Option<GlassMorph>,
    /// Touch glow: `(x_dp, y_dp, intensity)` in node-local dp. A pressed
    /// surface concentrates saturation and a soft light in a radial
    /// gradient under the finger (never a flat recolor).
    pub touch: Option<(f32, f32, f32)>,
    /// Radius of the touch glow in dp; absent, nonpositive and nonfinite values use 58 dp.
    pub touch_radius_dp: Option<f32>,
    /// Dome press depth: how squashed the interactive dome is. At 1 the
    /// pressed dome refracts deep and vivid (wide rim band, strong
    /// chromatic split — the reference toggle's gray-hold rainbow); toward
    /// 0 the released bead relaxes shallow and its split fades with it
    /// (the reference's thin settled ring). `None` = 1.
    pub press_depth: Option<f32>,
}

impl GlassDynamics {
    fn projection(&self) -> (f32, f32) {
        self.optical_projection
            .filter(|(x, y)| x.is_finite() && y.is_finite() && *x > 0.0 && *y > 0.0)
            .unwrap_or((1.0, 1.0))
    }

    /// The universal touched-up state (user-directed law): a pressed
    /// liquid surface comes closer to the user while its OWN colors go
    /// HDR-bright and saturated, with a radial glow following the finger.
    /// Never a repaint with alternate colors — the boosts amplify whatever
    /// the surface already is. `press` is 0..1; `finger` is node-local dp
    /// (falls back to `center`, the surface's own heart).
    pub fn touched_up(
        mut self,
        press: f32,
        finger: Option<(f32, f32)>,
        center: (f32, f32),
    ) -> Self {
        let press = press.clamp(0.0, 1.0);
        if press <= 0.0 {
            return self;
        }
        self.highlight_boost += 0.85 * press;
        self.saturation_boost += 0.45 * press;
        let (fx, fy) = finger.unwrap_or(center);
        let carried = self.touch.map_or(0.0, |(_, _, i)| i);
        self.touch = Some((fx, fy, (carried + press).clamp(0.0, 1.0)));
        self
    }
}

fn foreground_is_dark(foreground: Color) -> bool {
    let foreground_luma =
        0.2126 * foreground.r() + 0.7152 * foreground.g() + 0.0722 * foreground.b();
    foreground_luma < 0.5
}

/// The tint a glass shows: `tint`, or, while it crossfades from a previous
/// tint, the two mixed by the crossfade's progress.
fn shown_tint(tint: Color, crossfade: Option<(Color, f32)>) -> Color {
    let Some((previous, progress)) = crossfade.filter(|(_, progress)| progress.is_finite()) else {
        return tint;
    };
    let progress = progress.clamp(0.0, 1.0);
    let mix = |from: f32, to: f32| from + (to - from) * progress;
    Color(
        mix(previous.0, tint.0),
        mix(previous.1, tint.1),
        mix(previous.2, tint.2),
        mix(previous.3, tint.3),
    )
}

fn boost_tint_saturation(tint: Color, boost: f32) -> Color {
    if boost.abs() <= f32::EPSILON {
        return tint;
    }
    let luma = 0.2126 * tint.r() + 0.7152 * tint.g() + 0.0722 * tint.b();
    let saturation = (1.0 + boost).max(0.0);
    Color::rgba(
        (luma + (tint.r() - luma) * saturation).clamp(0.0, 1.0),
        (luma + (tint.g() - luma) * saturation).clamp(0.0, 1.0),
        (luma + (tint.b() - luma) * saturation).clamp(0.0, 1.0),
        tint.a(),
    )
}

pub(crate) fn neutral_surface_tint(foreground: Color, light_alpha: f32, dark_alpha: f32) -> Color {
    if foreground_is_dark(foreground) {
        Color::BLACK.with_alpha(light_alpha.clamp(0.0, 1.0))
    } else {
        Color::WHITE.with_alpha(dark_alpha.clamp(0.0, 1.0))
    }
}

/// A liquid shapeshift frame: the primary shape plus any number of nearby
/// glass shapes, ALL smooth-unioned into one field — liquid glass glues to
/// whatever glass it passes near (a growing menu necks with a neighboring
/// button, the drag lens merges with the search circle). Up to
/// [`GlassMorph::MAX_SHAPES`] extra shapes; an angular wobble makes the
/// mid-flight field bubble like a droplet. All geometry is node-local dp:
/// `(center_x, center_y, width, height, corner_radius)`; radius sentinel
/// `-1` means capsule; `-2` means SUBTRACT capsule — the shape carves a
/// smooth hole in the field (the growing menu leaves its anchor button
/// crisp on top until it swallows it).
#[derive(Clone, Debug, PartialEq, Default)]
pub struct GlassMorph {
    /// The glass node's own size in dp. The shader receives all morph
    /// geometry in dp and derives px-per-dp from the renderer-injected node
    /// pixel rect divided by this — geometry then lands correctly at ANY
    /// render scale (live window density, robot captures at 1.0, fractional
    /// desktop scales). The authoring widget always knows its node size.
    pub node_size: (f32, f32),
    pub primary: (f32, f32, f32, f32, f32),
    /// Nearby glass shapes participating in the field.
    pub shapes: Vec<(f32, f32, f32, f32, f32)>,
    /// Smooth-union glue radius (dp): shapes within it neck together.
    pub glue: f32,
    /// Wobble amplitude (dp) and phase (radians).
    pub wobble_amplitude: f32,
    pub wobble_phase: f32,
    /// Viscous leading-edge bulge: while the shape travels or inflates, its
    /// side facing `bulge_direction` (radians, math convention) swells like a
    /// pulled droplet. Amplitude in dp, usually driven by morph velocity.
    pub bulge_amplitude: f32,
    pub bulge_direction: f32,
    /// Blends the primary rounded-rectangle field toward an ellipse. This is
    /// used by expanding droplets whose broad phase has continuous curvature
    /// rather than the straight sides of a capsule.
    pub ellipse_blend: f32,
    /// Smooths the primary capsule's straight-to-arc joins over this distance in dp.
    /// A positive value replaces its corner radius with the maximum capsule radius.
    /// The span is capped by half the difference between the primary side lengths.
    /// Zero or a nonfinite value preserves the primary outline.
    pub capsule_smoothing_dp: f32,
    /// Area-preserving affine strain applied to the primary shape. Extra
    /// scene shapes remain fixed so nearby glass can join the travelling
    /// droplet without being dragged through its local deformation.
    pub deformation: Option<GlassDeformation>,
    /// Offset (dp) of the optical-zoom axis from the primary SDF center. A
    /// leaning droplet's silhouette shifts toward its travel side while its
    /// curvature apex stays over the content it rides; anchoring the
    /// magnification there keeps the face filled by that content instead of
    /// pulling in whatever lies beyond it.
    pub zoom_anchor: (f32, f32),
}

/// A normalized motion axis and reciprocal scales for incompressible glass.
/// Construction derives the cross-axis scale, so callers cannot describe a
/// deformation that changes the bubble's area.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GlassDeformation {
    axis: (f32, f32),
    along: f32,
}

impl GlassDeformation {
    pub fn incompressible(axis: (f32, f32), along: f32) -> Self {
        let length = (axis.0 * axis.0 + axis.1 * axis.1).sqrt();
        let axis = if length > f32::EPSILON {
            (axis.0 / length, axis.1 / length)
        } else {
            (1.0, 0.0)
        };
        Self {
            axis,
            along: along.max(f32::EPSILON),
        }
    }

    pub fn axis(self) -> (f32, f32) {
        self.axis
    }

    pub fn along(self) -> f32 {
        self.along
    }

    pub fn across(self) -> f32 {
        1.0 / self.along
    }
}

impl GlassMorph {
    /// Shader budget for extra scene shapes.
    pub const MAX_SHAPES: usize = 8;
}

/// Reflection of opposing lights across a narrow band around the surface contour.
/// The reflected environment is brightest along the light axis and darkest between the lights.
/// Nonfinite fields or nonpositive height or spread disable this treatment.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GlassContourHighlight {
    /// Width of the reflecting band in dp.
    pub height_dp: f32,
    /// Signed distance of the band's outer edge; negative values extend outside the surface.
    pub offset_dp: f32,
    /// Reflected-light opacity, clamped to zero through one.
    pub amount: f32,
    /// Additive brightness of the reflected environment.
    pub color_bias: f32,
    /// Direction of the first light in screen-space radians; the second is opposite.
    pub angle_radians: f32,
    /// Angular extent of each light in radians.
    pub spread_radians: f32,
}

impl GlassContourHighlight {
    fn uniforms(self) -> Option<[f32; 6]> {
        let values = [
            self.height_dp,
            self.offset_dp,
            self.amount,
            self.color_bias,
            self.angle_radians,
            self.spread_radians,
        ];
        (values.iter().all(|value| value.is_finite())
            && self.height_dp > 0.0
            && self.spread_radians > 0.0)
            .then_some(values)
    }
}

/// Backdrop-dependent reflections from opposing lights, with a sharp rim and a softer inward lobe.
/// Invalid dimensions or nonfinite fields disable the reflection.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GlassSpecularHighlight {
    /// Width of the sharp reflection in dp.
    pub height_dp: f32,
    /// Direction of the first light in screen-space radians; the second is opposite.
    pub angle_radians: f32,
    /// Angular extent of each sharp reflection, in radians.
    pub spread_radians: f32,
    /// Exponent of the angular response; must be positive.
    pub curvature: f32,
    /// Opacity of the diffuse reflection, clamped to zero through one.
    pub diffuse_amount: f32,
    /// Inward extent of the diffuse reflection, in dp.
    pub diffuse_height_dp: f32,
    /// Angular extent of each diffuse reflection, in radians.
    pub diffuse_spread_radians: f32,
    /// Gain applied to the transmitted surface's chroma in the reflected color.
    pub saturation: f32,
    /// Gain applied to the transmitted surface's luminance in the reflected color.
    pub luma_gain: f32,
    /// Additive brightness of the reflected color.
    pub color_bias: f32,
}

impl GlassSpecularHighlight {
    fn uniforms(self) -> Option<[f32; 10]> {
        let values = [
            self.height_dp,
            self.angle_radians,
            self.spread_radians,
            self.curvature,
            self.diffuse_amount,
            self.diffuse_height_dp,
            self.diffuse_spread_radians,
            self.saturation,
            self.luma_gain,
            self.color_bias,
        ];
        (values.iter().all(|value| value.is_finite())
            && self.height_dp > 0.0
            && self.spread_radians > 0.0
            && self.curvature > 0.0
            && self.diffuse_height_dp > 0.0
            && self.diffuse_spread_radians > 0.0)
            .then_some(values)
    }
}

/// Opposing edge lights whose color responds to the backdrop.
/// Nonfinite fields or nonpositive height or curvature disable this treatment.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GlassKeyFill {
    /// Inward extent of the highlight, in dp.
    pub height_dp: f32,
    /// Linear reduction in brightness across the highlight's inward extent.
    pub curvature: f32,
    /// Direction of the first light in screen-space radians; the second is opposite.
    pub angle_radians: f32,
    /// Gain applied to the backdrop's chroma in the reflected color.
    pub saturation: f32,
    /// Gain applied to the backdrop's luminance in the reflected color.
    pub luma_gain: f32,
    /// Additive contribution to each reflected color channel.
    pub offset: f32,
    /// Whether the highlight width follows the surface transform or stays fixed on screen.
    pub scale_with_surface: bool,
}

impl GlassKeyFill {
    fn uniforms(self) -> Option<[f32; 7]> {
        let values = [
            self.height_dp,
            self.curvature,
            self.angle_radians,
            self.saturation,
            self.luma_gain,
            self.offset,
            f32::from(self.scale_with_surface),
        ];
        (values.iter().all(|value| value.is_finite())
            && self.height_dp > 0.0
            && self.curvature > 0.0)
            .then_some(values)
    }
}

/// Seven-tap RGB spectrum for an edge lens. Distances follow the surface transform.
/// Nonfinite values, negative extents, or opacities outside zero to one are ignored.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GlassSpectrum {
    /// Angle θ in radians. For outward normal (x, y), the sampling direction is
    /// (y cosθ + x sinθ, (x cosθ − y sinθ) × vertical_scale).
    pub angle_radians: f32,
    /// Signed spacing between adjacent taps, in dp; negative values reverse the colors.
    pub step_dp: f32,
    /// Scale of the vertical component of the sampling direction.
    pub vertical_scale: f32,
    /// Spectral opacity at the silhouette edge.
    pub opacity_near: f32,
    /// Spectral opacity at and beyond the fade depth.
    pub opacity_far: f32,
    /// Inward distance in dp over which opacity interpolates linearly.
    pub fade_depth_dp: f32,
    /// Inward distance in dp beyond which the spectrum disappears.
    pub extent_dp: f32,
}

impl GlassSpectrum {
    fn uniforms(self) -> Option<[f32; 8]> {
        let values = [
            self.angle_radians,
            self.step_dp,
            self.vertical_scale,
            self.opacity_near,
            self.opacity_far,
            self.fade_depth_dp,
            self.extent_dp,
            1.0,
        ];
        (values.iter().all(|value| value.is_finite())
            && self.vertical_scale >= 0.0
            && (0.0..=1.0).contains(&self.opacity_near)
            && (0.0..=1.0).contains(&self.opacity_far)
            && self.fade_depth_dp >= 0.0
            && self.extent_dp >= 0.0)
            .then_some(values)
    }

    fn capture_reach(self) -> f32 {
        self.step_dp.abs() * 3.0 * self.vertical_scale.max(1.0)
    }
}

/// Face attenuation before edge lighting, followed by additive illumination.
/// Edge lenses attenuate the inner refraction image before chromatic sampling.
/// Invalid or nonfinite parameters disable the response.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GlassFaceResponse {
    /// Interior color gain, from zero to one.
    pub gain: f32,
    /// Screen-space depth in dp where attenuation starts.
    pub start_dp: f32,
    /// Screen-space depth in dp where attenuation reaches its interior gain.
    /// Equal start and end apply the gain uniformly.
    pub end_dp: f32,
    /// Light added to each color channel inside the silhouette after edge lighting.
    pub illumination: f32,
}

impl GlassFaceResponse {
    fn uniforms(self) -> Option<[f32; 4]> {
        let values = [
            1.0 - self.gain,
            self.start_dp,
            self.end_dp,
            self.illumination,
        ];
        (values.iter().all(|value| value.is_finite())
            && (0.0..=1.0).contains(&self.gain)
            && self.start_dp >= 0.0
            && self.end_dp >= self.start_dp)
            .then_some(values)
    }
}

/// A fixed luminance transfer with an independent chroma gain.
/// Luminance `y` becomes `black + (white - black) * y - (1 - max_luminance) * y²`;
/// chroma is scaled by `saturation` and the combined RGB is clamped to zero–one.
#[derive(Clone, Copy, Debug, PartialEq)]
pub struct GlassFaceTone {
    /// Black input's output, from zero to one.
    pub black: f32,
    /// White endpoint before quadratic highlight compression; greater than black.
    pub white: f32,
    /// Chroma gain independent of the luminance transfer; finite and nonnegative.
    pub saturation: f32,
    /// Highlight compression endpoint, from zero to one. One disables compression.
    pub max_luminance: f32,
}

impl GlassFaceTone {
    fn uniforms(self) -> Option<[f32; 5]> {
        let values = [
            self.black,
            self.white,
            self.saturation,
            self.max_luminance,
            1.0,
        ];
        (values.iter().all(|value| value.is_finite())
            && (0.0..=1.0).contains(&self.black)
            && self.white > self.black
            && self.saturation >= 0.0
            && (0.0..=1.0).contains(&self.max_luminance))
        .then_some(values)
    }
}

/// Builder describing a glass material. Resolved against the theme at the
/// composition site, then evaluated per frame for density and dynamics.
#[derive(Clone, Debug, PartialEq)]
pub struct Glass {
    /// Optional fixed face transfer, replacing adaptive tone, saturation, contrast and lift.
    pub face_tone: Option<GlassFaceTone>,
    pub variant: GlassVariant,
    pub shape: LiquidShape,
    /// Tint over the refracted backdrop; defaults to the theme's glass tint.
    pub tint: Option<Color>,
    /// Minimum transmitted luminance for a colored tint. `None` uses alpha tinting.
    pub tint_transmission: Option<f32>,
    /// Optional sharp/blurred pane blend, separate from the color tint.
    pub tint_amount: Option<GlassTintAmount>,
    /// Diffuse pane kernel reach in dp; its Gaussian standard deviation is half this value.
    pub pane_blur_radius: f32,
    /// Backdrop blur radius in dp (defaults per variant).
    pub blur_radius: Option<f32>,
    /// Radius in dp and opacity of the blurred backdrop mixed with an edge lens’s outer warp.
    pub backdrop_blur: Option<(f32, f32)>,
    /// Saturation boost (defaults per variant).
    pub saturation: Option<f32>,
    /// wcKSRD refraction depth as a fraction of the shape inradius. Regular
    /// frosted surfaces default to zero so their backdrop stays motion-stable;
    /// interactive lenses opt into optical displacement explicitly.
    pub refraction_depth: f32,
    /// Optional physical wcKSRD refraction depth in dp. When present, this
    /// keeps the optical band equally deep across surfaces with different
    /// inradii instead of scaling it from each surface's height.
    pub refraction_depth_dp: Option<f32>,
    /// Backdrop projection model.
    pub refraction: GlassRefraction,
    /// Normalized wcKSRD ray-return exponent.
    pub refraction_curve: f32,
    /// Normalized wcKSRD spectral ray separation.
    pub dispersion: f32,
    /// Optional directional spectrum for the edge-lens projection.
    pub edge_spectrum: Option<GlassSpectrum>,
    /// Fraction of the wcKSRD displacement applied to the transmitted
    /// backdrop. Regular frosted surfaces default to zero. The mirrored
    /// meniscus follows its own optical path.
    pub transmission_refraction: f32,
    /// Energy removed from the transmitted ray at the meniscus. Reflection
    /// and spectral return follow independent paths.
    pub meniscus_absorption: f32,
    /// Depth of the rim fold band in dp: the raised lens rim replays its
    /// interior mirrored toward the edge (a pure displacement). Zero
    /// disables the fold.
    pub fold_depth: f32,
    /// Uniform face magnification of a riding lens (1.0 = no zoom).
    /// The selected refraction model controls the surrounding rim band.
    pub optical_zoom: f32,
    /// Meniscus rim reflectivity multiplier (1.0 = the reference toggle's
    /// visible rim line; near 0 = the segmented lens's invisible body).
    pub rim_reflection: f32,
    /// Optical ink recolor: the lens recolors dark transmitted ink toward
    /// this color at the given strength (the reference tab bubble's
    /// color-mask act). None = off.
    pub ink_recolor: Option<(Color, f32)>,
    /// Specular rim intensity.
    pub highlight: f32,
    /// Whether the face receives the material's diffuse directional illumination.
    pub face_lighting: bool,
    /// Replaces dome lighting with a pair of opposing edge lights.
    pub key_fill: Option<GlassKeyFill>,
    /// Contour reflection applied before the foreground's spectral dispersion.
    pub contour_highlight: Option<GlassContourHighlight>,
    /// Directional rim reflection applied above the transmitted and tinted surface.
    pub specular_highlight: Option<GlassSpecularHighlight>,
    /// Attenuation and illumination applied around the edge-light pass.
    pub face_response: Option<GlassFaceResponse>,
    /// Inset shadow on the transmitted face, covered by the chromatic foreground.
    pub inner_shadow: Option<GlassShadow>,
    /// Screen-lift override (brightening toward white; negative darkens).
    /// Defaults per variant.
    pub lift: Option<f32>,
    /// Tone-compression override around the shader's mid pivot (<1 pulls
    /// every backdrop toward mid-luminance — the reference dark menu reads
    /// bright magenta over deep purple AND dim gray over white through one
    /// law). Defaults per variant.
    pub contrast: Option<f32>,
    /// Drop shadow below the glass.
    pub shadow: bool,
    /// Per-surface shadow override.
    pub shadow_style: Option<GlassShadow>,
    /// Clip the layer to `shape`. Morphing glass disables this — coverage
    /// comes entirely from the shader's SDF.
    pub clip: bool,
    /// Foreground color whose contrast the frost must protect. `None` uses
    /// the theme label color.
    pub foreground: Option<Color>,
    /// Strength of backdrop+foreground frost adaptation.
    pub adaptive_frost: f32,
    /// Adapts the face transfer curve to the mean captured backdrop brightness.
    /// Foreground polarity selects the preferred light or dark treatment.
    pub adaptive_tone: bool,
    /// Resting edge sharpness, from a soft eight-dp fade at zero to pixel antialiasing at one.
    pub resting_edge_sharpness: f32,
}

impl Glass {
    /// A motion-stable frosted surface without optical displacement.
    pub fn regular() -> Self {
        Self {
            variant: GlassVariant::Regular,
            face_tone: None,
            shape: LiquidShape::Capsule,
            tint: None,
            tint_transmission: None,
            tint_amount: None,
            pane_blur_radius: 8.0,
            blur_radius: None,
            backdrop_blur: None,
            saturation: None,
            refraction_depth: 0.0,
            refraction_depth_dp: None,
            refraction: GlassRefraction::Radial,
            refraction_curve: 0.25,
            dispersion: 0.0,
            edge_spectrum: None,
            transmission_refraction: 0.0,
            meniscus_absorption: 1.0,
            fold_depth: 0.0,
            optical_zoom: 1.0,
            rim_reflection: 1.0,
            ink_recolor: None,
            highlight: 0.9,
            face_lighting: true,
            key_fill: None,
            contour_highlight: None,
            specular_highlight: None,
            face_response: None,
            inner_shadow: None,
            lift: None,
            contrast: None,
            shadow: true,
            shadow_style: None,
            clip: true,
            foreground: None,
            adaptive_frost: 0.65,
            adaptive_tone: false,
            resting_edge_sharpness: 0.0,
        }
    }

    pub fn clear() -> Self {
        Self {
            variant: GlassVariant::Clear,
            ..Self::regular()
        }
    }

    /// An interactive glass lens with a radial projection and spectral rim.
    /// [`Self::edge_refraction`] selects an outward rim around a uniformly magnified face.
    pub fn lens() -> Self {
        Self {
            variant: GlassVariant::Lens,
            tint: Some(Color::rgba(1.0, 1.0, 1.0, 0.07)),
            refraction_depth: 0.34,
            refraction_curve: 1.0,
            dispersion: 0.30,
            transmission_refraction: 1.0,
            highlight: 1.15,
            adaptive_frost: 0.0,
            ..Self::regular()
        }
    }

    /// Enables or disables diffuse face illumination without changing the specular rim.
    pub fn face_lighting(mut self, enabled: bool) -> Self {
        self.face_lighting = enabled;
        self
    }

    /// Sets the resting edge sharpness from zero (eight-dp fade) to one (pixel antialiasing).
    /// Out-of-range values are clamped; nonfinite values preserve the soft default.
    pub fn resting_edge_sharpness(mut self, sharpness: f32) -> Self {
        self.resting_edge_sharpness = sharpness;
        self
    }

    /// Uses opposing edge lights with a backdrop-dependent reflected color.
    /// [`Self::highlight`] controls their opacity.
    pub fn key_fill(mut self, lighting: GlassKeyFill) -> Self {
        self.key_fill = Some(lighting);
        self
    }

    /// Sets the face attenuation and illumination around the edge-light pass.
    pub fn face_response(mut self, response: GlassFaceResponse) -> Self {
        self.face_response = Some(response);
        self
    }

    /// Adds an inset shadow with a Gaussian falloff from the live surface outline.
    /// The chromatic foreground covers this shadow without refracting it.
    /// Nonfinite values, negative radii, and opacity outside zero to one disable it.
    pub fn inner_shadow(mut self, shadow: GlassShadow) -> Self {
        self.inner_shadow = shadow.uniforms().map(|_| shadow);
        self
    }

    pub fn shape(mut self, shape: LiquidShape) -> Self {
        self.shape = shape;
        self
    }

    pub fn tint(mut self, tint: Color) -> Self {
        self.tint = Some(tint);
        self
    }

    /// Colors transmitted light while retaining the backdrop's luminance structure.
    pub fn transmission_tint(mut self, tint: Color, black: f32) -> Self {
        if black.is_finite() {
            self.tint = Some(tint);
            self.tint_transmission = Some(black.clamp(0.0, 1.0));
        }
        self
    }

    pub fn blur_radius(mut self, radius_dp: f32) -> Self {
        self.blur_radius = Some(radius_dp);
        self
    }

    pub fn saturation(mut self, saturation: f32) -> Self {
        self.saturation = Some(saturation);
        self
    }

    pub fn refraction_depth(mut self, fraction: f32) -> Self {
        self.refraction_depth = fraction.clamp(0.0, 2.0);
        self.refraction_depth_dp = None;
        self
    }

    /// Uses a density-stable physical refraction depth instead of a fraction
    /// of the live shape inradius.
    pub fn refraction_depth_dp(mut self, depth_dp: f32) -> Self {
        self.refraction_depth_dp = Some(depth_dp.max(0.0));
        self
    }

    /// Selects a circular depth profile along the surface normal, preserving
    /// tangential background coordinates along straight edges. `reach_dp` sets the inward
    /// displacement independently of depth; both remain fixed under surface scaling.
    /// Negative and nonfinite reach values become zero.
    pub fn surface_refraction(mut self, reach_dp: f32) -> Self {
        self.refraction = GlassRefraction::Surface {
            reach_dp: finite_nonnegative(reach_dp),
        };
        self
    }

    /// Overrides the edge lens's spectrum; radial and surface projections use `dispersion`.
    /// Invalid profiles are ignored. The signed spacing supports continuous color reversal.
    pub fn edge_spectrum(mut self, spectrum: GlassSpectrum) -> Self {
        self.edge_spectrum = spectrum.uniforms().map(|_| spectrum);
        self
    }

    /// Selects a rim that enters inward, crests outward and returns smoothly to the face.
    /// `reach_dp` controls its maximum outward displacement; negative and nonfinite values become zero.
    /// Its inward return uses the amplitude and depth ratios in [`GlassRefraction::EdgeLens`].
    pub fn edge_refraction(mut self, reach_dp: f32) -> Self {
        self.refraction = GlassRefraction::EdgeLens {
            reach_dp: finite_nonnegative(reach_dp),
        };
        self
    }

    pub fn refraction_curve(mut self, curve: f32) -> Self {
        self.refraction_curve = curve.clamp(0.05, 1.0);
        self
    }

    pub fn dispersion(mut self, strength: f32) -> Self {
        self.dispersion = strength.clamp(0.0, 1.0);
        self
    }

    pub fn transmission_refraction(mut self, strength: f32) -> Self {
        self.transmission_refraction = strength.clamp(0.0, 1.0);
        self
    }

    pub fn meniscus_absorption(mut self, strength: f32) -> Self {
        self.meniscus_absorption = strength.clamp(0.0, 1.0);
        self
    }

    /// Sets the rim fold band depth in dp (zero disables the fold).
    pub fn fold_depth(mut self, depth_dp: f32) -> Self {
        self.fold_depth = depth_dp.max(0.0);
        self
    }

    /// Sets the uniform face magnification of a riding lens (1.0 = none).
    pub fn optical_zoom(mut self, zoom: f32) -> Self {
        self.optical_zoom = zoom.max(1.0);
        self
    }

    /// Sets the meniscus rim reflectivity (1.0 = full reference line).
    pub fn rim_reflection(mut self, reflectivity: f32) -> Self {
        self.rim_reflection = reflectivity.clamp(0.0, 2.0);
        self
    }

    /// The lens recolors dark transmitted ink toward `color` at `strength`
    /// (0..1) — the reference bubble's color-mask act as a material optic.
    pub fn ink_recolor(mut self, color: Color, strength: f32) -> Self {
        self.ink_recolor = Some((color, strength.clamp(0.0, 1.0)));
        self
    }

    pub fn highlight(mut self, highlight: f32) -> Self {
        self.highlight = highlight;
        self
    }

    /// Overrides the screen-lift (how hard the glass brightens what it
    /// shows; the bar lens uses a near-zero lift to stay transmissive).
    pub fn lift(mut self, lift: f32) -> Self {
        self.lift = Some(lift);
        self
    }

    /// Overrides the tone compression around the shader's mid pivot
    /// (values below one pull every backdrop toward mid-luminance).
    pub fn contrast(mut self, contrast: f32) -> Self {
        self.contrast = Some(contrast.max(0.05));
        self
    }

    pub fn adaptive_frost(mut self, foreground: Color, strength: f32) -> Self {
        self.foreground = Some(foreground);
        self.adaptive_frost = strength.clamp(0.0, 1.0);
        self
    }

    /// Uses the captured backdrop's mean brightness to adapt the face transfer curve.
    /// This replaces local frost adaptation, saturation, contrast, lift and
    /// the key/fill color response. Tint and edge-light geometry still apply.
    /// The foreground chooses the preferred polarity, with dark treatment over black
    /// backgrounds and light treatment over white backgrounds.
    pub fn adaptive_tone(mut self, foreground: Color) -> Self {
        self.face_tone = None;
        self.foreground = Some(foreground);
        self.adaptive_tone = true;
        self.adaptive_frost = 0.0;
        self
    }

    /// Uses a fixed face transfer without reading a mean-backdrop texture.
    /// Invalid parameters disable the fixed transfer.
    pub fn face_tone(mut self, tone: GlassFaceTone) -> Self {
        self.face_tone = tone.uniforms().map(|_| tone);
        self.adaptive_tone = false;
        self.adaptive_frost = 0.0;
        self
    }

    pub fn shadow(mut self, shadow: bool) -> Self {
        self.shadow = shadow;
        self
    }

    pub fn shadow_style(mut self, shadow: GlassShadow) -> Self {
        self.shadow_style = Some(shadow);
        self
    }

    /// Disables the layer clip: the shader's SDF coverage is the only shape
    /// (required while morphing across geometry the clip can't follow).
    pub fn no_clip(mut self) -> Self {
        self.clip = false;
        self
    }

    /// Uses a sharp/blurred backdrop blend controlled by the tint percentage.
    /// This replaces the whole-backdrop blur for this material.
    pub fn tint_amount(mut self, amount: GlassTintAmount) -> Self {
        self.tint_amount = Some(amount);
        self
    }

    /// Sets the diffuse pane's kernel reach, independently of its sharp transmitted image.
    pub fn pane_blur_radius(mut self, radius: f32) -> Self {
        if radius.is_finite() && radius >= 0.0 {
            self.pane_blur_radius = radius;
        }
        self
    }

    /// Crossfades the edge lens’s outer warp with a fixed-radius blurred backdrop.
    /// Radius uses the renderer's Gaussian convention: twice the standard deviation, in dp.
    /// Nonfinite values disable the blend; finite radius is nonnegative and opacity is clamped to 0–1.
    pub fn backdrop_blur(mut self, radius_dp: f32, opacity: f32) -> Self {
        self.backdrop_blur = (radius_dp.is_finite() && opacity.is_finite())
            .then_some((radius_dp.max(0.0), opacity.clamp(0.0, 1.0)));
        self
    }

    fn default_blur_radius(&self) -> f32 {
        match self.variant {
            GlassVariant::Regular => 8.0,
            GlassVariant::Clear => 3.0,
            GlassVariant::Lens => 0.0,
        }
    }

    fn default_saturation(&self) -> f32 {
        match self.variant {
            GlassVariant::Regular => 1.5,
            GlassVariant::Clear => 1.25,
            GlassVariant::Lens => 1.0,
        }
    }

    /// The backdrop effect this material produces for a node at `density`
    /// under `dynamics`, resolved against `colors`: the render effect the
    /// glass modifiers install, for a layer built without them.
    pub fn backdrop_effect(
        &self,
        colors: &LiquidColors,
        density: f32,
        dynamics: GlassDynamics,
    ) -> RenderEffect {
        self.resolve(colors).backdrop_effect(density, dynamics)
    }

    fn preferred_foreground(&self, colors: &LiquidColors) -> Color {
        self.foreground
            .filter(|color| {
                [color.r(), color.g(), color.b(), color.a()]
                    .iter()
                    .all(|value| value.is_finite())
            })
            .unwrap_or(colors.label)
    }

    pub(crate) fn resolve(&self, colors: &LiquidColors) -> ResolvedGlass {
        let lift = self.lift.unwrap_or(match (self.variant, colors.is_dark) {
            (GlassVariant::Regular, false) => 0.42,
            (GlassVariant::Regular, true) => -0.38,
            (GlassVariant::Clear, false) => 0.12,
            (GlassVariant::Clear, true) => -0.12,
            (GlassVariant::Lens, false) => 0.10,
            (GlassVariant::Lens, true) => -0.08,
        });
        let foreground = self.preferred_foreground(colors);
        let shadow = self.shadow_style.unwrap_or_else(|| {
            GlassShadow::new(
                Color::BLACK.with_alpha(match (self.variant, colors.is_dark) {
                    (GlassVariant::Lens, false) => 0.14,
                    (GlassVariant::Lens, true) => 0.28,
                    (_, false) => 0.16,
                    (_, true) => 0.5,
                }),
                if self.variant == GlassVariant::Lens {
                    10.0
                } else {
                    22.0
                },
                if self.variant == GlassVariant::Lens {
                    3.0
                } else {
                    8.0
                },
                if self.variant == GlassVariant::Lens {
                    -6.0
                } else {
                    -2.0
                },
            )
        });
        ResolvedGlass {
            face_tone: self.face_tone,
            shape: self.shape,
            tint: self.tint.unwrap_or(colors.glass_tint),
            tint_transmission: self.tint_transmission,
            tint_amount: self.tint_amount,
            pane_blur_radius: self.pane_blur_radius,
            backdrop_blur: self.backdrop_blur,
            blur_radius_dp: self
                .blur_radius
                .unwrap_or_else(|| self.default_blur_radius()),
            saturation: self.saturation.unwrap_or_else(|| self.default_saturation()),
            refraction_depth: self.refraction_depth,
            refraction_depth_dp: self.refraction_depth_dp,
            refraction: self.refraction,
            refraction_curve: self.refraction_curve,
            dispersion: self.dispersion,
            edge_spectrum: self.edge_spectrum,
            transmission_refraction: self.transmission_refraction,
            meniscus_absorption: self.meniscus_absorption,
            fold_depth: self.fold_depth,
            optical_zoom: self.optical_zoom,
            rim_reflection: self.rim_reflection,
            ink_recolor: self.ink_recolor,
            highlight: self.highlight,
            face_lighting: self.face_lighting,
            key_fill: self.key_fill,
            contour_highlight: self.contour_highlight,
            specular_highlight: self.specular_highlight,
            face_response: self.face_response,
            inner_shadow: self.inner_shadow,
            lift,
            contrast: self.contrast.unwrap_or(match self.variant {
                GlassVariant::Lens => 1.0,
                _ => 1.03,
            }),
            shadow: self.shadow,
            clip: self.clip,
            foreground_luma: 0.2126 * foreground.r()
                + 0.7152 * foreground.g()
                + 0.0722 * foreground.b(),
            adaptive_frost: self.adaptive_frost,
            adaptive_tone: self.adaptive_tone,
            resting_edge_sharpness: finite_nonnegative(self.resting_edge_sharpness).min(1.0),
            rim_style: if self.variant == GlassVariant::Lens {
                1.0
            } else {
                0.0
            },
            shadow_color: shadow.color,
            shadow_radius: shadow.radius,
            shadow_offset_y: shadow.offset_y,
            shadow_spread: shadow.spread,
        }
    }
}

impl Default for Glass {
    fn default() -> Self {
        Self::regular()
    }
}

#[derive(Clone, Debug, PartialEq)]
pub(crate) struct ResolvedGlass {
    specular_highlight: Option<GlassSpecularHighlight>,
    face_tone: Option<GlassFaceTone>,
    resting_edge_sharpness: f32,
    pub shape: LiquidShape,
    pub tint: Color,
    tint_transmission: Option<f32>,
    tint_amount: Option<GlassTintAmount>,
    pane_blur_radius: f32,
    backdrop_blur: Option<(f32, f32)>,
    pub blur_radius_dp: f32,
    pub saturation: f32,
    pub refraction_depth: f32,
    pub refraction_depth_dp: Option<f32>,
    pub refraction: GlassRefraction,
    pub refraction_curve: f32,
    pub dispersion: f32,
    pub edge_spectrum: Option<GlassSpectrum>,
    pub transmission_refraction: f32,
    pub meniscus_absorption: f32,
    pub fold_depth: f32,
    pub optical_zoom: f32,
    pub rim_reflection: f32,
    pub ink_recolor: Option<(Color, f32)>,
    pub highlight: f32,
    pub face_lighting: bool,
    pub key_fill: Option<GlassKeyFill>,
    /// Contour reflection applied before the foreground's spectral dispersion.
    pub contour_highlight: Option<GlassContourHighlight>,
    /// Attenuation and illumination applied around the edge-light pass.
    pub face_response: Option<GlassFaceResponse>,
    pub lift: f32,
    /// Inset shadow on the transmitted face, covered by the chromatic foreground.
    pub inner_shadow: Option<GlassShadow>,
    pub contrast: f32,
    pub shadow: bool,
    pub clip: bool,
    pub rim_style: f32,
    pub foreground_luma: f32,
    pub adaptive_frost: f32,
    pub adaptive_tone: bool,
    pub shadow_color: Color,
    pub shadow_radius: f32,
    pub shadow_offset_y: f32,
    pub shadow_spread: f32,
}

fn set_edge_return_depth(shader: &mut RuntimeShader, depth: Option<f32>) {
    if let Some(depth) = depth.filter(|depth| depth.is_finite() && *depth >= 0.0) {
        shader.set_float2(GLASS_EDGE_RETURN_DEPTH_UNIFORM, depth, 1.0);
    }
}

impl ResolvedGlass {
    /// The rounded rectangle a placeholder fills while this glass compiles:
    /// around its morph's shapes, or the whole node in its shape.
    fn placeholder_shape(&self, morph: Option<&GlassMorph>) -> PlaceholderShape {
        let Some(morph) = morph else {
            return PlaceholderShape {
                bounds: Rect {
                    x: 0.0,
                    y: 0.0,
                    width: 1.0,
                    height: 1.0,
                },
                corner_radius: self.shape.radius_dp(),
            };
        };
        let (node_width, node_height) = morph.node_size;
        let (node_width, node_height) =
            (node_width.max(f32::EPSILON), node_height.max(f32::EPSILON));
        // A radius of -2 subtracts its shape: it carves a hole in the field.
        let added = morph.shapes.iter().filter(|&&(.., radius)| radius > -1.5);
        let (left, top, right, bottom) = std::iter::once(&morph.primary).chain(added).fold(
            (f32::MAX, f32::MAX, f32::MIN, f32::MIN),
            |(left, top, right, bottom), &(center_x, center_y, width, height, _)| {
                (
                    left.min(center_x - width * 0.5),
                    top.min(center_y - height * 0.5),
                    right.max(center_x + width * 0.5),
                    bottom.max(center_y + height * 0.5),
                )
            },
        );
        // A negative radius is the shader's capsule.
        let (.., radius) = morph.primary;
        PlaceholderShape {
            bounds: Rect {
                x: left / node_width,
                y: top / node_height,
                width: (right - left) / node_width,
                height: (bottom - top) / node_height,
            },
            corner_radius: if radius < 0.0 { f32::MAX } else { radius },
        }
    }

    /// The same glass as a flat surface, for a person who asked the system
    /// for less transparency: the surface color with no blur, no refraction
    /// and no spectrum, the shape and the shadow as they were.
    pub(crate) fn without_transparency(mut self, colors: &LiquidColors) -> Self {
        self.tint = colors.surface;
        self.tint_transmission = None;
        self.tint_amount = None;
        self.backdrop_blur = None;
        self.face_tone = None;
        self.contour_highlight = None;
        self.specular_highlight = None;
        self.adaptive_tone = false;
        self.blur_radius_dp = 0.0;
        self.saturation = 1.0;
        self.refraction_depth = 0.0;
        self.refraction_depth_dp = None;
        self.dispersion = 0.0;
        self.edge_spectrum = None;
        self.transmission_refraction = 0.0;
        self.meniscus_absorption = 0.0;
        self.rim_reflection = 0.0;
        self.adaptive_frost = 0.0;
        self
    }

    fn clips_in_shader(&self) -> bool {
        self.key_fill.and_then(GlassKeyFill::uniforms).is_some()
    }
    pub(crate) fn backdrop_effect(&self, density: f32, dynamics: GlassDynamics) -> RenderEffect {
        self.runtime_effect(density, &dynamics, false)
    }

    fn blur_radii(&self, density: f32, activity: f32, content_mask: bool) -> (f32, f32) {
        if content_mask || self.tint_amount.is_some() {
            return (0.0, 0.0);
        }
        let radius = self.blur_radius_dp * density * activity;
        if radius > WCKSRD_OPTICAL_BLUR_RADIUS_PX {
            (0.0, radius)
        } else {
            (radius, 0.0)
        }
    }

    fn runtime_effect(
        &self,
        density: f32,
        dynamics: &GlassDynamics,
        content_mask: bool,
    ) -> RenderEffect {
        self.runtime_effect_with_content(density, dynamics, content_mask, false)
    }

    fn set_refraction_uniforms(
        &self,
        shader: &mut RuntimeShader,
        dynamics: &GlassDynamics,
        activity: f32,
    ) -> (f32, f32, f32) {
        let press_depth = dynamics.press_depth.unwrap_or(1.0).clamp(0.0, 1.0);
        shader.set_float(9, self.refraction_depth * activity * press_depth);
        let refraction = dynamics.refraction.unwrap_or(self.refraction);
        let (refraction_mode, refraction_reach) = refraction.shader_parameters();
        let refraction_weight = if matches!(refraction, GlassRefraction::LayeredSurface { .. }) {
            1.0
        } else {
            activity * press_depth
        };
        shader.set_float(GLASS_REFRACTION_MODE_UNIFORM, refraction_mode);
        if let GlassRefraction::LayeredSurface {
            return_reach_dp,
            return_depth_dp,
            ..
        } = refraction
        {
            shader.set_float2(
                GLASS_LAYERED_RETURN_UNIFORM,
                finite_nonnegative(return_reach_dp),
                finite_nonnegative(return_depth_dp),
            );
        }
        set_edge_return_depth(shader, dynamics.edge_return_depth_dp);
        shader.set_float(
            GLASS_EDGE_REFRACTION_REACH_UNIFORM,
            refraction_reach * refraction_weight,
        );
        shader.set_float(
            GLASS_PHYSICAL_REFRACTION_DEPTH_UNIFORM,
            self.refraction_depth_dp.unwrap_or(0.0) * refraction_weight,
        );
        shader.set_float(
            GLASS_PHYSICAL_REFRACTION_DEPTH_ENABLED_UNIFORM,
            if self.refraction_depth_dp.is_some() {
                1.0
            } else {
                0.0
            },
        );
        shader.set_float(
            GLASS_REFRACTION_CURVE_UNIFORM,
            self.refraction_curve * activity,
        );
        shader.set_float(
            GLASS_DISPERSION_UNIFORM,
            self.dispersion * activity * press_depth,
        );
        let spectrum_reach = self.set_spectrum_uniforms(shader);
        shader.set_float(
            GLASS_TRANSMISSION_REFRACTION_UNIFORM,
            self.transmission_refraction * if refraction_mode > 2.5 { 1.0 } else { activity },
        );
        shader.set_float(
            GLASS_MENISCUS_ABSORPTION_UNIFORM,
            self.meniscus_absorption * press_depth,
        );
        shader.set_float(
            GLASS_FOLD_DEPTH_UNIFORM,
            self.fold_depth.max(0.0) * press_depth,
        );
        (refraction_mode, refraction_reach, spectrum_reach)
    }

    fn set_shadow_uniforms(
        &self,
        shader: &mut RuntimeShader,
        dynamics: &GlassDynamics,
        activity: f32,
    ) -> (f32, f32) {
        let dynamic_shadow = !self.clip && self.shadow;
        let shadow = dynamics
            .shadow
            .filter(|shadow| shadow.uniforms().is_some())
            .unwrap_or_else(|| {
                GlassShadow::new(
                    self.shadow_color
                        .with_alpha(self.shadow_color.a() * 0.55 * activity),
                    self.shadow_radius,
                    self.shadow_offset_y,
                    self.shadow_spread,
                )
            });
        shader.set_float(
            102,
            if dynamic_shadow {
                shadow.color.a()
            } else {
                0.0
            },
        );
        shader.set_float(103, shadow.radius);
        shader.set_float(104, shadow.offset_y);
        shader.set_float(105, shadow.spread);
        shader.set_float4(
            cranpose_ui_graphics::GLASS_SHADOW_COLOR_UNIFORM,
            shadow.color.r(),
            shadow.color.g(),
            shadow.color.b(),
            0.0,
        );
        let ring_shadow = dynamics.ring_shadow.filter(|(ring, width)| {
            ring.color.a() > 0.0 && ring.uniforms().is_some() && width.is_finite() && *width > 0.0
        });
        if let Some((ring, width)) = ring_shadow {
            shader.set_float4(
                cranpose_ui_graphics::GLASS_RING_SHADOW_UNIFORM,
                ring.color.r(),
                ring.color.g(),
                ring.color.b(),
                ring.color.a(),
            );
            shader.set_float4(
                cranpose_ui_graphics::GLASS_RING_SHADOW_UNIFORM + 4,
                ring.radius,
                ring.offset_y,
                width,
                1.0,
            );
            shader.set_float(
                cranpose_ui_graphics::GLASS_RING_SHADOW_UNIFORM + 8,
                ring.spread,
            );
        }
        let ring_reach = ring_shadow.map_or(0.0, |(ring, width)| {
            3.0 * ring.radius + ring.offset_y.abs() + width * 0.5 + ring.spread.abs()
        });
        let contour_reach = self
            .contour_highlight
            .and_then(GlassContourHighlight::uniforms)
            .filter(|values| values[2] > 0.0 && activity > 0.0)
            .map_or(0.0, |values| (-values[1]).max(0.0));
        let visible_shadow = dynamic_shadow && shadow.color.a() > 0.0;
        let shadow_reach = if visible_shadow {
            shadow.radius + shadow.offset_y.abs() + shadow.spread.max(0.0)
        } else {
            0.0
        }
        .max(ring_reach)
        .max(contour_reach);
        // The drop shadow falls outside the node: without this reach the
        // compositor cuts it at the node's rectangle.
        shader.set_output_padding(shadow_reach);
        let offset = if visible_shadow || ring_shadow.is_some() {
            shadow
                .offset_y
                .abs()
                .max(ring_shadow.map_or(0.0, |(ring, _)| ring.offset_y.abs()))
        } else {
            0.0
        };
        (shadow_reach, offset)
    }

    fn runtime_effect_with_content(
        &self,
        density: f32,
        dynamics: &GlassDynamics,
        content_mask: bool,
        separate_content: bool,
    ) -> RenderEffect {
        let density = density.max(f32::EPSILON);
        let activity = dynamics
            .activity
            .filter(|value| value.is_finite())
            .unwrap_or(1.0)
            .clamp(0.0, 1.0);
        static SHADER: OnceLock<RuntimeShader> = OnceLock::new();
        let mut shader = SHADER
            .get_or_init(|| {
                let mut shader = RuntimeShader::new(LIQUID_GLASS_WGSL);
                shader.set_float(GLASS_ACTIVITY_UNIFORM, 1.0);
                shader.set_float2(GLASS_OPTICAL_ZOOM_ANCHOR_UNIFORM, 0.0, 0.0);
                specialize_liquid_glass(&mut shader);
                shader
            })
            .clone();
        if let Some(morph) = dynamics.morph.as_ref() {
            set_morph_uniforms(&mut shader, morph, activity);
        } else {
            shader.set_float2(0, 0.0, 0.0);
            shader.set_float(6, self.shape.shader_radius_px(density));
        }
        let projection = dynamics.projection();
        shader.set_float2(GLASS_OPTICAL_PROJECTION_UNIFORM, projection.0, projection.1);
        let (refraction_mode, refraction_reach, spectrum_reach) =
            self.set_refraction_uniforms(&mut shader, dynamics, activity);
        shader.set_float(
            GLASS_OPTICAL_ZOOM_UNIFORM,
            1.0 + (self.optical_zoom - 1.0).max(0.0) * activity,
        );
        let zoom_anchor = dynamics
            .morph
            .as_ref()
            .map_or((0.0, 0.0), |morph| morph.zoom_anchor);
        shader.set_float2(
            GLASS_OPTICAL_ZOOM_ANCHOR_UNIFORM,
            zoom_anchor.0,
            zoom_anchor.1,
        );
        shader.set_float(121, self.rim_reflection.max(0.001));
        let (ink_color, ink_strength) = self
            .ink_recolor
            .map_or((Color::TRANSPARENT, 0.0), |(color, strength)| {
                (color, strength * activity)
            });
        shader.set_float(124, ink_color.r());
        shader.set_float(125, ink_color.g());
        shader.set_float(126, ink_color.b());
        shader.set_float(127, ink_strength);
        let (light_x, light_y) = glass_light_direction();
        shader.set_float(GLASS_LIGHT_DIRECTION_UNIFORM, light_x);
        shader.set_float(GLASS_LIGHT_DIRECTION_UNIFORM + 1, light_y);
        self.set_lighting_uniforms(&mut shader, dynamics);
        shader.set_float(GLASS_EFFECT_DENSITY_UNIFORM, density);
        shader.set_float(
            11,
            (self.highlight + dynamics.highlight_boost).clamp(0.0, 2.0) * activity,
        );
        let dynamic_tint = boost_tint_saturation(self.tint, dynamics.saturation_boost);
        let dynamic_tint_alpha = (dynamic_tint.a()
            * dynamics
                .tint_alpha_multiplier
                .unwrap_or(1.0)
                .clamp(0.0, 2.0)
            * activity)
            .clamp(0.0, 1.0);
        shader.set_float4(
            14,
            dynamic_tint.r(),
            dynamic_tint.g(),
            dynamic_tint.b(),
            dynamic_tint_alpha,
        );
        if let Some((color, progress)) = dynamics.tint_crossfade.filter(|(_, p)| p.is_finite()) {
            let index = cranpose_ui_graphics::liquid_glass::GLASS_TINT_CROSSFADE_UNIFORM;
            shader.set_float(index, 1.0 + progress.clamp(0.0, 1.0));
            shader.set_float4(index + 1, color.r(), color.g(), color.b(), color.a());
        }
        let saturation = (self.saturation + dynamics.saturation_boost).max(0.0);
        shader.set_float(18, 1.0 + (saturation - 1.0) * activity);
        shader.set_float(20, self.lift * activity);
        shader.set_float(21, 0.5 * activity);
        shader.set_float2(22, 0.0, 1.0);
        shader.set_float(24, 1.0 + (self.contrast - 1.0) * activity);
        shader.set_float(28, self.rim_style * activity);
        let (wcksrd_blur_radius, gaussian_blur_radius) =
            self.blur_radii(density, activity, content_mask);
        shader.set_float(GLASS_BLUR_RADIUS_UNIFORM, wcksrd_blur_radius);
        shader.set_float(GLASS_ACTIVITY_UNIFORM, activity);
        shader.set_float(
            GLASS_RESTING_EDGE_SHARPNESS_UNIFORM,
            self.resting_edge_sharpness,
        );
        let resting_tint = dynamics.resting_tint.unwrap_or(Color::TRANSPARENT);
        shader.set_float4(
            GLASS_RESTING_TINT_UNIFORM,
            resting_tint.r(),
            resting_tint.g(),
            resting_tint.b(),
            resting_tint.a(),
        );
        shader.set_float(112, if content_mask { 1.0 } else { 0.0 });
        shader.set_float(GLASS_ADAPTIVE_FROST_UNIFORM, self.adaptive_frost * activity);
        shader.set_float(97, self.foreground_luma);
        shader.set_float(GLASS_ADAPTIVE_TONE_UNIFORM, f32::from(self.adaptive_tone));
        self.set_backdrop_uniforms(&mut shader, density, content_mask);
        shader.set_float(
            cranpose_ui_graphics::GLASS_FOREGROUND_CONTENT_UNIFORM,
            f32::from(separate_content),
        );
        let (shadow_reach, shadow_offset) = if content_mask {
            (0.0, 0.0)
        } else {
            self.set_shadow_uniforms(&mut shader, dynamics, activity)
        };
        let morph_pad = dynamics.morph.as_ref().map_or(0.0, |morph| {
            let (px, py, pw, ph, _) = morph.primary;
            let (left, top) = (px - pw * 0.5, py - ph * 0.5);
            let (right, bottom) = (px + pw * 0.5, py + ph * 0.5);
            let mut shape_reach = 0.0f32;
            for (sx, sy, sw, sh, _) in &morph.shapes {
                let reach_x = ((sx + sw * 0.5) - right)
                    .max(left - (sx - sw * 0.5))
                    .max(0.0);
                let reach_y = ((sy + sh * 0.5) - bottom)
                    .max(top - (sy - sh * 0.5))
                    .max(0.0);
                shape_reach = shape_reach.max(reach_x.max(reach_y));
            }
            let glue_pad = if morph.shapes.is_empty() {
                0.0
            } else {
                morph.glue * 2.0
            };
            morph.wobble_amplitude * 2.0 + morph.bulge_amplitude + shape_reach + glue_pad
        });
        shader.set_input_padding(if content_mask {
            0.0
        } else {
            (self.input_padding()
                + if refraction_mode > 2.5 {
                    refraction_reach + spectrum_reach
                } else if refraction_mode >= 1.5 {
                    refraction_reach * (26.5 / 9.0) + spectrum_reach
                } else {
                    refraction_reach
                }
                + morph_pad
                + wcksrd_blur_radius / density)
                * projection.0.max(projection.1).max(1.0)
        });
        if let Some(morph) = dynamics.morph.as_ref() {
            let support =
                morph_output_support(morph, activity, morph_pad, shadow_reach, shadow_offset);
            let (cx, cy, _, _, _) = morph.primary;
            let support = Rect {
                x: cx + (support.x - cx) * projection.0,
                y: cy + (support.y - cy) * projection.1,
                width: support.width * projection.0,
                height: support.height * projection.1,
            };
            let (node_w, node_h) = morph.node_size;
            let overhang = (-support.x)
                .max(-support.y)
                .max(support.x + support.width - node_w)
                .max(support.y + support.height - node_h)
                .max(0.0);
            shader.set_output_padding((morph_pad + shadow_reach + 4.0).max(overhang));
            shader.set_output_support(Some(support));
        }

        shader.set_placeholder(Some(liquid_glass_placeholder(
            shown_tint(
                Color(
                    dynamic_tint.r(),
                    dynamic_tint.g(),
                    dynamic_tint.b(),
                    dynamic_tint_alpha,
                ),
                dynamics.tint_crossfade,
            ),
            Some(self.placeholder_shape(dynamics.morph.as_ref())),
        )));
        let optical_effect = liquid_glass_runtime_effect(shader);
        if gaussian_blur_radius > f32::EPSILON {
            RenderEffect::blur_with_edge_treatment(gaussian_blur_radius, TileMode::Mirror)
                .then(optical_effect)
        } else {
            optical_effect
        }
    }

    fn set_backdrop_uniforms(&self, shader: &mut RuntimeShader, density: f32, content_mask: bool) {
        if let Some(values) = self.face_tone.and_then(GlassFaceTone::uniforms) {
            for (index, value) in values.into_iter().enumerate() {
                shader.set_float(cranpose_ui_graphics::GLASS_FACE_TONE_UNIFORM + index, value);
            }
        }
        if let Some(amount) = self.tint_amount {
            shader.set_float(
                cranpose_ui_graphics::GLASS_PANE_BLEND_UNIFORM,
                self.pane_blur_radius * density,
            );
            shader.set_float(
                cranpose_ui_graphics::GLASS_PANE_BLEND_UNIFORM + 1,
                amount.percent() / 100.0,
            );
        }
        if !content_mask && let Some((radius, opacity)) = self.backdrop_blur {
            shader.set_float2(
                cranpose_ui_graphics::GLASS_BACKDROP_BLUR_UNIFORM,
                radius * density,
                opacity,
            );
        }
    }

    fn set_spectrum_uniforms(&self, shader: &mut RuntimeShader) -> f32 {
        let spectrum = self
            .edge_spectrum
            .and_then(|spectrum| spectrum.uniforms().map(|values| (spectrum, values)));
        if let Some((spectrum, values)) = spectrum {
            for (index, value) in values.into_iter().enumerate() {
                shader.set_float(GLASS_EDGE_SPECTRUM_UNIFORM + index, value);
            }
            spectrum.capture_reach()
        } else {
            40.787 * self.dispersion
        }
    }

    fn set_lighting_uniforms(&self, shader: &mut RuntimeShader, dynamics: &GlassDynamics) {
        if let Some(values) = self
            .specular_highlight
            .and_then(GlassSpecularHighlight::uniforms)
        {
            for (index, value) in values.into_iter().enumerate() {
                shader.set_float(
                    cranpose_ui_graphics::GLASS_SPECULAR_HIGHLIGHT_UNIFORM + index,
                    value,
                );
            }
        }
        shader.set_float(
            cranpose_ui_graphics::GLASS_CONTACT_LIGHT_UNIFORM,
            f32::from(dynamics.contact_lighting),
        );
        if let Some(black) = self.tint_transmission.filter(|value| value.is_finite()) {
            shader.set_float2(
                cranpose_ui_graphics::GLASS_TINT_TRANSMISSION_UNIFORM,
                black.clamp(0.0, 1.0),
                1.0,
            );
        }
        let (touch_x, touch_y, touch_intensity) = dynamics.touch.unwrap_or((0.0, 0.0, 0.0));
        shader.set_float(118, touch_x);
        shader.set_float(119, touch_y);
        shader.set_float(120, touch_intensity.clamp(0.0, 1.0));
        shader.set_float(
            GLASS_FACE_LIGHTING_OFF_UNIFORM,
            f32::from(!self.face_lighting),
        );
        shader.set_float(
            GLASS_TOUCH_RADIUS_UNIFORM,
            dynamics
                .touch_radius_dp
                .filter(|radius| radius.is_finite() && *radius > 0.0)
                .unwrap_or(58.0),
        );
        shader.set_float(
            GLASS_LAYER_CLIPPED_UNIFORM,
            f32::from(self.clip && !self.clips_in_shader()),
        );
        if let Some(values) = self.key_fill.and_then(GlassKeyFill::uniforms) {
            for (index, value) in values.into_iter().enumerate() {
                shader.set_float(GLASS_KEY_FILL_UNIFORM + index, value);
            }
        }
        if let Some(values) = self.face_response.and_then(GlassFaceResponse::uniforms) {
            for (index, value) in values.into_iter().enumerate() {
                shader.set_float(GLASS_FACE_RESPONSE_UNIFORM + index, value);
            }
        }
        if let Some(values) = self
            .contour_highlight
            .and_then(GlassContourHighlight::uniforms)
        {
            for (index, value) in values.into_iter().enumerate() {
                shader.set_float(
                    cranpose_ui_graphics::GLASS_CONTOUR_HIGHLIGHT_UNIFORM + index,
                    value,
                );
            }
        }
        if let Some(values) = self.inner_shadow.and_then(GlassShadow::uniforms) {
            for (index, value) in values.into_iter().enumerate() {
                shader.set_float(GLASS_INNER_SHADOW_UNIFORM + index, value);
            }
        }
    }

    fn input_padding(&self) -> f32 {
        2.0
    }
}

/// Modifier extension installing the Liquid Glass material.
pub trait LiquidModifierExt {
    /// Applies the glass material to this composable's bounds: backdrop blur +
    /// lens shader, clipped to `glass.shape`, with a soft drop shadow.
    ///
    /// Must be called in composable context (the material resolves theme
    /// colors at the call site).
    fn glass_effect(self, glass: Glass) -> Modifier;

    /// [`glass_effect`](Self::glass_effect) with per-frame motion inputs; the
    /// closure is read at scene-build time, so animating tilt or highlight
    /// does not recompose.
    fn glass_effect_with(
        self,
        glass: Glass,
        dynamics: impl Fn() -> GlassDynamics + 'static,
    ) -> Modifier;
}

impl LiquidModifierExt for Modifier {
    fn glass_effect(self, glass: Glass) -> Modifier {
        self.glass_effect_with(glass, GlassDynamics::default)
    }

    fn glass_effect_with(
        self,
        glass: Glass,
        dynamics: impl Fn() -> GlassDynamics + 'static,
    ) -> Modifier {
        let colors = crate::theme::liquid_colors();
        let options = cranpose_services::local_accessibility_options().current();
        let resolved = if options.reduce_transparency {
            glass.resolve(&colors).without_transparency(&colors)
        } else {
            glass.resolve(&colors)
        };
        let shape = resolved.shape;

        let mut modifier = self;
        if resolved.shadow && resolved.clip {
            let shadow_color = resolved.shadow_color;
            let (radius, offset_y, spread) = (
                resolved.shadow_radius,
                resolved.shadow_offset_y,
                resolved.shadow_spread,
            );
            modifier = modifier.drop_shadow(shape.layer_shape(), move |scope| {
                scope.radius = radius;
                scope.spread = spread;
                scope.offset.y = offset_y;
                scope.color = shadow_color;
                scope.cutout = true;
            });
        }

        let layer = cached_glass_layer(resolved);
        modifier.graphics_layer(move || layer(current_density(), dynamics()))
    }
}

struct CachedGlassLayer<T> {
    density: u32,
    light: [u32; 2],
    dynamics: GlassDynamics,
    value: T,
}

fn cached_glass_layer(resolved: ResolvedGlass) -> impl Fn(f32, GlassDynamics) -> GraphicsLayer {
    cached_glass_layers(resolved, false, std::convert::identity)
}

pub(crate) fn cached_glass_content_layers(
    resolved: ResolvedGlass,
) -> impl Fn(f32, GlassDynamics) -> [GraphicsLayer; 2] {
    cached_glass_layers(resolved, true, |mut layer| {
        let Some(RenderEffect::Chain { first, second }) = layer.backdrop_effect.take() else {
            panic!("content layers require a sequential edge lens");
        };
        layer.backdrop_effect = Some((*second).clone());
        [
            GraphicsLayer {
                backdrop_effect: Some((*first).clone()),
                ..Default::default()
            },
            layer,
        ]
    })
}

fn cached_glass_layers<T: Clone>(
    resolved: ResolvedGlass,
    separate_content: bool,
    assemble: impl Fn(GraphicsLayer) -> T,
) -> impl Fn(f32, GlassDynamics) -> T {
    let cached = RefCell::new(None::<CachedGlassLayer<T>>);
    move |density, dynamics| {
        let direction = glass_light_direction();
        let light = [direction.0, direction.1].map(f32::to_bits);
        let mut cached = cached.borrow_mut();
        if let Some(previous) = &*cached
            && previous.density == density.to_bits()
            && previous.light == light
            && glass_dynamics_match(&previous.dynamics, &dynamics)
        {
            return previous.value.clone();
        }
        let render_effect = ((!resolved.clip && dynamics.morph.is_some())
            || (resolved.clip && resolved.clips_in_shader()))
        .then(|| resolved.runtime_effect(density, &dynamics, true));
        let layer = GraphicsLayer {
            backdrop_effect: Some(resolved.runtime_effect_with_content(
                density,
                &dynamics,
                false,
                separate_content,
            )),
            render_effect,
            shape: resolved.shape.layer_shape(),
            clip: resolved.clip && !resolved.clips_in_shader(),
            ..Default::default()
        };
        let value = assemble(layer);
        *cached = Some(CachedGlassLayer {
            density: density.to_bits(),
            light,
            dynamics,
            value: value.clone(),
        });
        value
    }
}

fn glass_dynamics_match(a: &GlassDynamics, b: &GlassDynamics) -> bool {
    let bits = |d: &GlassDynamics| {
        let GlassDynamics {
            contact_lighting,
            refraction,
            shadow,
            ring_shadow,
            edge_return_depth_dp,
            optical_projection,
            activity,
            resting_tint,
            highlight_boost,
            saturation_boost,
            tint_alpha_multiplier,
            tint_crossfade,
            morph: _,
            touch,
            touch_radius_dp,
            press_depth,
        } = d;
        (
            (
                *contact_lighting,
                ring_shadow.map(|(ring, width)| (shadow_bits(ring), width.to_bits())),
                tint_crossfade.map(|(Color(r, g, b, a), p)| [r, g, b, a, p].map(f32::to_bits)),
            ),
            refraction.map(|refraction| {
                match refraction {
                    GlassRefraction::Radial => [0.0, 0.0, 0.0, 0.0],
                    GlassRefraction::Surface { reach_dp } => [1.0, reach_dp, 0.0, 0.0],
                    GlassRefraction::EdgeLens { reach_dp } => [2.0, reach_dp, 0.0, 0.0],
                    GlassRefraction::LayeredSurface {
                        reach_dp,
                        return_reach_dp,
                        return_depth_dp,
                    } => [3.0, reach_dp, return_reach_dp, return_depth_dp],
                }
                .map(f32::to_bits)
            }),
            shadow.map(shadow_bits),
            edge_return_depth_dp.map(f32::to_bits),
            optical_projection.map(|(x, y)| [x, y].map(f32::to_bits)),
            activity.map(f32::to_bits),
            resting_tint.map(|Color(r, g, b, a)| [r, g, b, a].map(f32::to_bits)),
            [*highlight_boost, *saturation_boost].map(f32::to_bits),
            tint_alpha_multiplier.map(f32::to_bits),
            touch.map(|(x, y, strength)| [x, y, strength].map(f32::to_bits)),
            press_depth.map(f32::to_bits),
            touch_radius_dp.map(f32::to_bits),
        )
    };
    bits(a) == bits(b)
        && match (&a.morph, &b.morph) {
            (None, None) => true,
            (Some(a), Some(b)) => glass_morphs_match(a, b),
            _ => false,
        }
}

fn shadow_bits(shadow: GlassShadow) -> [u32; 7] {
    [
        shadow.color.r(),
        shadow.color.g(),
        shadow.color.b(),
        shadow.color.a(),
        shadow.radius,
        shadow.offset_y,
        shadow.spread,
    ]
    .map(f32::to_bits)
}

fn glass_morphs_match(a: &GlassMorph, b: &GlassMorph) -> bool {
    let shape_bits =
        |&(x, y, w, h, r): &(f32, f32, f32, f32, f32)| [x, y, w, h, r].map(f32::to_bits);
    let bits = |m: &GlassMorph| {
        let GlassMorph {
            node_size,
            primary,
            shapes: _,
            glue,
            wobble_amplitude,
            wobble_phase,
            bulge_amplitude,
            bulge_direction,
            ellipse_blend,
            capsule_smoothing_dp,
            deformation,
            zoom_anchor,
        } = m;
        (
            [
                node_size.0,
                node_size.1,
                *glue,
                *wobble_amplitude,
                *wobble_phase,
                *bulge_amplitude,
                *bulge_direction,
                *ellipse_blend,
                *capsule_smoothing_dp,
                zoom_anchor.0,
                zoom_anchor.1,
            ]
            .map(f32::to_bits),
            shape_bits(primary),
            deformation
                .map(|GlassDeformation { axis, along }| [axis.0, axis.1, along].map(f32::to_bits)),
        )
    };
    bits(a) == bits(b)
        && a.shapes
            .iter()
            .map(shape_bits)
            .eq(b.shapes.iter().map(shape_bits))
}

fn morph_output_support(
    morph: &GlassMorph,
    activity: f32,
    morph_pad: f32,
    shadow_reach: f32,
    shadow_offset: f32,
) -> Rect {
    let (px, py, pw, ph, _) = morph.primary;
    let (along, (ax, ay)) = morph.deformation.map_or((1.0, (1.0, 0.0)), |deformation| {
        (
            1.0 + (deformation.along() - 1.0) * activity,
            deformation.axis(),
        )
    });
    let across = 1.0 / along;
    let smallest_strain = along.min(across);
    let reach = (morph_pad + shadow_reach + 4.0) / smallest_strain;
    let rows = [
        (
            (along * ax * ax + across * ay * ay).abs(),
            ((along - across) * ax * ay).abs(),
        ),
        (
            ((along - across) * ax * ay).abs(),
            (along * ay * ay + across * ax * ax).abs(),
        ),
    ];
    let half = (pw * 0.5 + reach, ph * 0.5 + reach);
    let extent_x = rows[0].0 * half.0 + rows[0].1 * half.1;
    let extent_y = rows[1].0 * half.0 + rows[1].1 * half.1;
    let (mut left, mut top) = (px - extent_x, py - extent_y);
    let (mut right, mut bottom) = (px + extent_x, py + extent_y);
    for (sx, sy, sw, sh, _) in &morph.shapes {
        left = left.min(sx - sw * 0.5 - reach);
        top = top.min(sy - sh * 0.5 - reach);
        right = right.max(sx + sw * 0.5 + reach);
        bottom = bottom.max(sy + sh * 0.5 + reach);
    }
    Rect {
        x: left,
        y: top - shadow_offset,
        width: right - left,
        height: bottom - top + 2.0 * shadow_offset,
    }
}

fn set_morph_uniforms(shader: &mut RuntimeShader, morph: &GlassMorph, activity: f32) {
    let (node_w, node_h) = morph.node_size;
    let (cx, cy, w, h, radius) = morph.primary;
    shader.set_float2(0, node_w.max(1.0), node_h.max(1.0));
    shader.set_float2(2, cx, cy);
    shader.set_float2(4, w, h);
    shader.set_float(6, radius);
    let count = morph.shapes.len().min(GlassMorph::MAX_SHAPES);
    shader.set_float(30, count as f32);
    for (index, (sx, sy, sw, sh, sr)) in morph.shapes.iter().take(count).enumerate() {
        let base = 36 + index * 5;
        shader.set_float(base, *sx);
        shader.set_float(base + 1, *sy);
        shader.set_float(base + 2, *sw);
        shader.set_float(base + 3, *sh);
        shader.set_float(base + 4, *sr);
    }
    shader.set_float(31, morph.glue);
    shader.set_float(32, morph.wobble_amplitude * activity);
    shader.set_float(33, morph.wobble_phase);
    shader.set_float(26, morph.bulge_amplitude * activity);
    shader.set_float(27, morph.bulge_direction);
    shader.set_float(110, morph.ellipse_blend.clamp(0.0, 1.0) * activity);
    shader.set_float(
        cranpose_ui_graphics::liquid_glass::GLASS_CAPSULE_SMOOTHING_UNIFORM,
        if morph.capsule_smoothing_dp.is_finite() {
            morph.capsule_smoothing_dp.max(0.0) * activity
        } else {
            0.0
        },
    );
    if let Some(deformation) = morph.deformation {
        let axis = deformation.axis();
        let along = 1.0 + (deformation.along() - 1.0) * activity;
        shader.set_float2(106, axis.0, axis.1);
        shader.set_float(108, along);
        shader.set_float(109, 1.0 / along);
    } else {
        shader.set_float2(106, 1.0, 0.0);
        shader.set_float2(108, 1.0, 1.0);
    }
}

#[cfg(test)]
#[path = "tests/material_tests.rs"]
mod tests;

#[cfg(test)]
#[path = "tests/material_transparency_tests.rs"]
mod transparency_tests;