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    /// RGBA color for the drag handles. When set (non-zero alpha), overrides the default LUT coloring.
40    pub handle_color: [f32; 4],
41
42    hovered_handle: Option<SphereHandle>,
43    active_handle: Option<SphereHandle>,
44    drag_plane_normal: glam::Vec3,
45    drag_plane_d: f32,
46    drag_anchor_world: glam::Vec3,
47    drag_anchor_radius: f32,
48}
49
50impl SphereWidget {
51    /// Create a new sphere widget.
52    pub fn new(center: glam::Vec3, radius: f32) -> Self {
53        Self {
54            center,
55            radius: radius.max(0.01),
56            color: [0.3, 0.6, 1.0, 0.25],
57            handle_color: [0.0; 4],
58            hovered_handle: None,
59            active_handle: None,
60            drag_plane_normal: glam::Vec3::Z,
61            drag_plane_d: 0.0,
62            drag_anchor_world: glam::Vec3::ZERO,
63            drag_anchor_radius: 0.0,
64        }
65    }
66
67    /// True while a drag session is in progress.
68    pub fn is_active(&self) -> bool {
69        self.active_handle.is_some()
70    }
71
72    /// Process input for this frame. Returns `Updated` if state changed.
73    pub fn update(&mut self, ctx: &WidgetContext) -> WidgetResult {
74        let (ro, rd) = ctx_ray(ctx);
75        let mut updated = false;
76
77        if self.active_handle.is_none() {
78            let hit = self.hit_test(ro, rd, ctx);
79            // On the drag_started frame the cursor can be right at the edge and the
80            // hit test may miss by a hair. Keep the previous hover so the drag still
81            // registers if the handle was highlighted on the frame before the click.
82            if hit.is_some() || !ctx.drag_started {
83                self.hovered_handle = hit;
84            }
85        }
86
87        if ctx.drag_started {
88            if let Some(handle) = self.hovered_handle {
89                let anchor = match handle {
90                    SphereHandle::Center => self.center,
91                    SphereHandle::Radius => self.radius_handle_pos(),
92                };
93                let fwd = glam::Vec3::from(ctx.camera.forward);
94                let n = -fwd;
95                self.drag_plane_normal = n;
96                self.drag_plane_d = -n.dot(anchor);
97                self.drag_anchor_world = anchor;
98                self.drag_anchor_radius = self.radius;
99                self.active_handle = Some(handle);
100            }
101        }
102
103        if let Some(handle) = self.active_handle {
104            if ctx.released || (!ctx.dragging && !ctx.drag_started) {
105                self.active_handle = None;
106                self.hovered_handle = None;
107            } else if let Some(hit) =
108                ray_plane_intersection(ro, rd, self.drag_plane_normal, self.drag_plane_d)
109            {
110                match handle {
111                    SphereHandle::Center => {
112                        let delta = hit - self.drag_anchor_world;
113                        let new_center = self.center + delta;
114                        if (new_center - self.center).length_squared() > 1e-10 {
115                            self.center = new_center;
116                            self.drag_anchor_world = hit;
117                            updated = true;
118                        }
119                    }
120                    SphereHandle::Radius => {
121                        let new_r = (hit - self.center).length().max(0.01);
122                        if (new_r - self.radius).abs() > 1e-5 {
123                            self.radius = new_r;
124                            updated = true;
125                        }
126                    }
127                }
128            }
129        }
130
131        if updated { WidgetResult::Updated } else { WidgetResult::None }
132    }
133
134    /// Build a `ClipObject` for the sphere visual (fill + outline).
135    ///
136    /// Push into `fd.effects.clip_objects`. `clip_geometry` is set to `false` so
137    /// the sphere only renders as a visual indicator and does not clip geometry.
138    pub fn clip_object(&self) -> ClipObject {
139        let edge = [self.color[0], self.color[1], self.color[2], 1.0];
140        ClipObject {
141            shape: ClipShape::Sphere {
142                center: self.center.to_array(),
143                radius: self.radius,
144            },
145            color: Some(self.color),
146            edge_color: Some(edge),
147            clip_geometry: false,
148            enabled: true,
149            hovered: self.hovered_handle.is_some(),
150            active: self.active_handle.is_some(),
151            ..ClipObject::default()
152        }
153    }
154
155    /// Build a `PolylineItem` of three great circle rings (XY, XZ, YZ planes).
156    ///
157    /// Push into `fd.scene.polylines` for a scene-pass outline consistent with
158    /// how `BoxWidget::wireframe_item` is used. `id` is the pick ID (0 = not pickable).
159    pub fn wireframe_item(&self, id: u64) -> PolylineItem {
160        const STEPS: usize = 64;
161        let mut positions: Vec<[f32; 3]> = Vec::with_capacity(STEPS * 3 + 3);
162        let mut strip_lengths: Vec<u32> = Vec::with_capacity(3);
163        let c = self.center;
164        let r = self.radius;
165
166        for ring in 0..3_usize {
167            for i in 0..=STEPS {
168                let a = i as f32 * std::f32::consts::TAU / STEPS as f32;
169                let (s, co) = a.sin_cos();
170                let p = match ring {
171                    0 => glam::Vec3::new(co * r, s * r, 0.0),
172                    1 => glam::Vec3::new(co * r, 0.0, s * r),
173                    _ => glam::Vec3::new(0.0, co * r, s * r),
174                };
175                positions.push((c + p).to_array());
176            }
177            strip_lengths.push((STEPS + 1) as u32);
178        }
179
180        let line_color = [self.color[0], self.color[1], self.color[2], 1.0];
181        PolylineItem {
182            positions,
183            strip_lengths,
184            default_color: line_color,
185            line_width: 1.5,
186            id,
187            ..PolylineItem::default()
188        }
189    }
190
191    /// Build a `GlyphItem` with sphere handles: one at the center, one at the
192    /// radius edge (along +X from center).
193    ///
194    /// `id_base` is the pick ID for the center handle; `id_base + 1` for the radius handle.
195    pub fn handle_glyphs(&self, id_base: u64, ctx: &WidgetContext) -> GlyphItem {
196        let rp = self.radius_handle_pos();
197        let r_center = handle_world_radius(self.center, &ctx.camera, ctx.viewport_size.y, 10.0);
198        let r_rh = handle_world_radius(rp, &ctx.camera, ctx.viewport_size.y, 8.0);
199
200        let sc = if self.hovered_handle == Some(SphereHandle::Center)
201            || self.active_handle == Some(SphereHandle::Center)
202        {
203            1.0_f32
204        } else {
205            0.2
206        };
207        let sr = if self.hovered_handle == Some(SphereHandle::Radius)
208            || self.active_handle == Some(SphereHandle::Radius)
209        {
210            1.0_f32
211        } else {
212            0.2
213        };
214
215        GlyphItem {
216            positions: vec![self.center.to_array(), rp.to_array()],
217            vectors: vec![[r_center, 0.0, 0.0], [r_rh, 0.0, 0.0]],
218            scale: 1.0,
219            scale_by_magnitude: true,
220            scalars: vec![sc, sr],
221            scalar_range: Some((0.0, 1.0)),
222            glyph_type: GlyphType::Sphere,
223            id: id_base,
224            default_color: self.handle_color,
225            use_default_color: self.handle_color[3] > 0.0,
226            ..GlyphItem::default()
227        }
228    }
229
230    // -----------------------------------------------------------------------
231    // Internal
232    // -----------------------------------------------------------------------
233
234    fn radius_handle_pos(&self) -> glam::Vec3 {
235        self.center + glam::Vec3::X * self.radius
236    }
237
238    fn hit_test(
239        &self,
240        ray_origin: glam::Vec3,
241        ray_dir: glam::Vec3,
242        ctx: &WidgetContext,
243    ) -> Option<SphereHandle> {
244        let ray = Ray::new(
245            Vector::new(ray_origin.x, ray_origin.y, ray_origin.z),
246            Vector::new(ray_dir.x, ray_dir.y, ray_dir.z),
247        );
248
249        let rp = self.radius_handle_pos();
250        let rh_r = handle_world_radius(rp, &ctx.camera, ctx.viewport_size.y, 8.0);
251        let ch_r = handle_world_radius(self.center, &ctx.camera, ctx.viewport_size.y, 10.0);
252
253        let rh_ball = parry3d::shape::Ball::new(rh_r);
254        let ch_ball = parry3d::shape::Ball::new(ch_r);
255
256        let rh_pose = Pose::from_parts(
257            [rp.x, rp.y, rp.z].into(),
258            glam::Quat::IDENTITY,
259        );
260        let ch_pose = Pose::from_parts(
261            [self.center.x, self.center.y, self.center.z].into(),
262            glam::Quat::IDENTITY,
263        );
264
265        let t_rh = rh_ball
266            .cast_ray(&rh_pose, &ray, f32::MAX, true)
267            .map(|i| i);
268        let t_ch = ch_ball
269            .cast_ray(&ch_pose, &ray, f32::MAX, true)
270            .map(|i| i);
271
272        match (t_ch, t_rh) {
273            (Some(tc), Some(tr)) => {
274                Some(if tc <= tr { SphereHandle::Center } else { SphereHandle::Radius })
275            }
276            (Some(_), None) => Some(SphereHandle::Center),
277            (None, Some(_)) => Some(SphereHandle::Radius),
278            (None, None) => None,
279        }
280    }
281}
viewport_lib/interaction/widgets/sphere.rs

viewport_lib/interaction/widgets/
sphere.rs
