viewport_lib/interaction/widgets/
sphere.rs

1//! Sphere widget: draggable center handle and radius handle.
2
3use crate::interaction::clip_plane::ray_plane_intersection;
4use crate::renderer::{ClipObject, ClipShape, GlyphItem, GlyphType, PolylineItem};
5use parry3d::math::{Pose, Vector};
6use parry3d::query::{Ray, RayCast};
7
8use super::{WidgetContext, WidgetResult, ctx_ray, handle_world_radius};
9
10#[derive(Clone, Copy, PartialEq, Eq, Debug)]
11enum SphereHandle {
12    Center,
13    Radius,
14}
15
16/// An interactive sphere widget with a draggable center and radius handle.
17///
18/// Use `clip_object()` to get the visual fill/outline (push into
19/// `fd.effects.clip_objects` with `clip_geometry: false`), and `handle_glyphs()`
20/// for the draggable handle spheres (push into `fd.scene.glyphs`).
21///
22/// # Usage
23///
24/// ```rust,ignore
25/// let mut sphere = SphereWidget::new(glam::Vec3::ZERO, 2.0);
26///
27/// // Each frame:
28/// sphere.update(&ctx);
29/// fd.effects.clip_objects.push(sphere.clip_object());
30/// fd.scene.glyphs.push(sphere.handle_glyphs(HANDLE_ID, &ctx));
31/// ```
32pub struct SphereWidget {
33    /// World-space center of the sphere.
34    pub center: glam::Vec3,
35    /// Radius in world units.
36    pub radius: f32,
37    /// RGBA fill color (alpha controls transparency of the fill).
38    pub color: [f32; 4],
39
40    hovered_handle: Option<SphereHandle>,
41    active_handle: Option<SphereHandle>,
42    drag_plane_normal: glam::Vec3,
43    drag_plane_d: f32,
44    drag_anchor_world: glam::Vec3,
45    drag_anchor_radius: f32,
46}
47
48impl SphereWidget {
49    /// Create a new sphere widget.
50    pub fn new(center: glam::Vec3, radius: f32) -> Self {
51        Self {
52            center,
53            radius: radius.max(0.01),
54            color: [0.3, 0.6, 1.0, 0.25],
55            hovered_handle: None,
56            active_handle: None,
57            drag_plane_normal: glam::Vec3::Z,
58            drag_plane_d: 0.0,
59            drag_anchor_world: glam::Vec3::ZERO,
60            drag_anchor_radius: 0.0,
61        }
62    }
63
64    /// True while a drag session is in progress.
65    pub fn is_active(&self) -> bool {
66        self.active_handle.is_some()
67    }
68
69    /// Process input for this frame. Returns `Updated` if state changed.
70    pub fn update(&mut self, ctx: &WidgetContext) -> WidgetResult {
71        let (ro, rd) = ctx_ray(ctx);
72        let mut updated = false;
73
74        if self.active_handle.is_none() {
75            self.hovered_handle = self.hit_test(ro, rd, ctx);
76        }
77
78        if ctx.drag_started {
79            if let Some(handle) = self.hovered_handle {
80                let anchor = match handle {
81                    SphereHandle::Center => self.center,
82                    SphereHandle::Radius => self.radius_handle_pos(),
83                };
84                let fwd = glam::Vec3::from(ctx.camera.forward);
85                let n = -fwd;
86                self.drag_plane_normal = n;
87                self.drag_plane_d = -n.dot(anchor);
88                self.drag_anchor_world = anchor;
89                self.drag_anchor_radius = self.radius;
90                self.active_handle = Some(handle);
91            }
92        }
93
94        if let Some(handle) = self.active_handle {
95            if ctx.released || (!ctx.dragging && !ctx.drag_started) {
96                self.active_handle = None;
97                self.hovered_handle = None;
98            } else if let Some(hit) =
99                ray_plane_intersection(ro, rd, self.drag_plane_normal, self.drag_plane_d)
100            {
101                match handle {
102                    SphereHandle::Center => {
103                        let delta = hit - self.drag_anchor_world;
104                        let new_center = self.center + delta;
105                        if (new_center - self.center).length_squared() > 1e-10 {
106                            self.center = new_center;
107                            self.drag_anchor_world = hit;
108                            updated = true;
109                        }
110                    }
111                    SphereHandle::Radius => {
112                        let new_r = (hit - self.center).length().max(0.01);
113                        if (new_r - self.radius).abs() > 1e-5 {
114                            self.radius = new_r;
115                            updated = true;
116                        }
117                    }
118                }
119            }
120        }
121
122        if updated { WidgetResult::Updated } else { WidgetResult::None }
123    }
124
125    /// Build a `ClipObject` for the sphere visual (fill + outline).
126    ///
127    /// Push into `fd.effects.clip_objects`. `clip_geometry` is set to `false` so
128    /// the sphere only renders as a visual indicator and does not clip geometry.
129    pub fn clip_object(&self) -> ClipObject {
130        let edge = [self.color[0], self.color[1], self.color[2], 1.0];
131        ClipObject {
132            shape: ClipShape::Sphere {
133                center: self.center.to_array(),
134                radius: self.radius,
135            },
136            color: Some(self.color),
137            edge_color: Some(edge),
138            clip_geometry: false,
139            enabled: true,
140            hovered: self.hovered_handle.is_some(),
141            active: self.active_handle.is_some(),
142            ..ClipObject::default()
143        }
144    }
145
146    /// Build a `PolylineItem` of three great circle rings (XY, XZ, YZ planes).
147    ///
148    /// Push into `fd.scene.polylines` for a scene-pass outline consistent with
149    /// how `BoxWidget::wireframe_item` is used. `id` is the pick ID (0 = not pickable).
150    pub fn wireframe_item(&self, id: u64) -> PolylineItem {
151        const STEPS: usize = 64;
152        let mut positions: Vec<[f32; 3]> = Vec::with_capacity(STEPS * 3 + 3);
153        let mut strip_lengths: Vec<u32> = Vec::with_capacity(3);
154        let c = self.center;
155        let r = self.radius;
156
157        for ring in 0..3_usize {
158            for i in 0..=STEPS {
159                let a = i as f32 * std::f32::consts::TAU / STEPS as f32;
160                let (s, co) = a.sin_cos();
161                let p = match ring {
162                    0 => glam::Vec3::new(co * r, s * r, 0.0),
163                    1 => glam::Vec3::new(co * r, 0.0, s * r),
164                    _ => glam::Vec3::new(0.0, co * r, s * r),
165                };
166                positions.push((c + p).to_array());
167            }
168            strip_lengths.push((STEPS + 1) as u32);
169        }
170
171        let line_color = [self.color[0], self.color[1], self.color[2], 1.0];
172        PolylineItem {
173            positions,
174            strip_lengths,
175            default_color: line_color,
176            line_width: 1.5,
177            id,
178            ..PolylineItem::default()
179        }
180    }
181
182    /// Build a `GlyphItem` with sphere handles: one at the center, one at the
183    /// radius edge (along +X from center).
184    ///
185    /// `id_base` is the pick ID for the center handle; `id_base + 1` for the radius handle.
186    pub fn handle_glyphs(&self, id_base: u64, ctx: &WidgetContext) -> GlyphItem {
187        let rp = self.radius_handle_pos();
188        let r_center = handle_world_radius(self.center, &ctx.camera, ctx.viewport_size.y, 10.0);
189        let r_rh = handle_world_radius(rp, &ctx.camera, ctx.viewport_size.y, 8.0);
190
191        let sc = if self.hovered_handle == Some(SphereHandle::Center)
192            || self.active_handle == Some(SphereHandle::Center)
193        {
194            1.0_f32
195        } else {
196            0.2
197        };
198        let sr = if self.hovered_handle == Some(SphereHandle::Radius)
199            || self.active_handle == Some(SphereHandle::Radius)
200        {
201            1.0_f32
202        } else {
203            0.2
204        };
205
206        GlyphItem {
207            positions: vec![self.center.to_array(), rp.to_array()],
208            vectors: vec![[r_center, 0.0, 0.0], [r_rh, 0.0, 0.0]],
209            scale: 1.0,
210            scale_by_magnitude: true,
211            scalars: vec![sc, sr],
212            scalar_range: Some((0.0, 1.0)),
213            glyph_type: GlyphType::Sphere,
214            id: id_base,
215            ..GlyphItem::default()
216        }
217    }
218
219    // -----------------------------------------------------------------------
220    // Internal
221    // -----------------------------------------------------------------------
222
223    fn radius_handle_pos(&self) -> glam::Vec3 {
224        self.center + glam::Vec3::X * self.radius
225    }
226
227    fn hit_test(
228        &self,
229        ray_origin: glam::Vec3,
230        ray_dir: glam::Vec3,
231        ctx: &WidgetContext,
232    ) -> Option<SphereHandle> {
233        let ray = Ray::new(
234            Vector::new(ray_origin.x, ray_origin.y, ray_origin.z),
235            Vector::new(ray_dir.x, ray_dir.y, ray_dir.z),
236        );
237
238        let rp = self.radius_handle_pos();
239        let rh_r = handle_world_radius(rp, &ctx.camera, ctx.viewport_size.y, 12.0);
240        let ch_r = handle_world_radius(self.center, &ctx.camera, ctx.viewport_size.y, 12.0);
241
242        let rh_ball = parry3d::shape::Ball::new(rh_r);
243        let ch_ball = parry3d::shape::Ball::new(ch_r);
244
245        let rh_pose = Pose::from_parts(
246            [rp.x, rp.y, rp.z].into(),
247            glam::Quat::IDENTITY,
248        );
249        let ch_pose = Pose::from_parts(
250            [self.center.x, self.center.y, self.center.z].into(),
251            glam::Quat::IDENTITY,
252        );
253
254        let t_rh = rh_ball
255            .cast_ray(&rh_pose, &ray, f32::MAX, true)
256            .map(|i| i);
257        let t_ch = ch_ball
258            .cast_ray(&ch_pose, &ray, f32::MAX, true)
259            .map(|i| i);
260
261        match (t_ch, t_rh) {
262            (Some(tc), Some(tr)) => {
263                Some(if tc <= tr { SphereHandle::Center } else { SphereHandle::Radius })
264            }
265            (Some(_), None) => Some(SphereHandle::Center),
266            (None, Some(_)) => Some(SphereHandle::Radius),
267            (None, None) => None,
268        }
269    }
270}
viewport_lib/interaction/widgets/sphere.rs

viewport_lib/interaction/widgets/
sphere.rs
