ArcBetweenPoints Example⁋

This example demonstrates ArcBetweenPoints.

https://github.com/user-attachments/assets/9595ce1d-2390-4d4d-958f-9299755460b7

arc_between_points.mp4

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use env_logger::Env;
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use itertools::Itertools;
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use ranim::animation::fading::FadingAnimSchedule;
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use ranim::color::HueDirection;
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use ranim::glam::{DMat2, dvec2};
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use ranim::items::group::Group;
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use ranim::items::vitem::ArcBetweenPoints;
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use ranim::prelude::*;
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use ranim::timeline::TimeMark;
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#[scene]
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struct ArcBetweenPointsScene;
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impl TimelineConstructor for ArcBetweenPointsScene {
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    fn construct<'t: 'r, 'r>(
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        self,
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        timeline: &'t RanimTimeline,
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        _camera: &'r mut Rabject<'t, CameraFrame>,
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    ) {
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        let center = dvec2(0.0, 0.0);
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        let start_color = color!("#FF8080FF");
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        let end_color = color!("#58C4DDFF");
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        let ntan = 16;
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        let nrad = 5;
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        let arcs = (0..nrad)
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            .map(|i| {
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                let radius = 6.0 * (i + 1) as f64 / nrad as f64;
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                let width = 6.0 * ((nrad - i) as f64 / nrad as f64).powi(2);
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                let angle = std::f64::consts::PI * 7.0 / 4.0 * (i + 1) as f64 / nrad as f64;
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                (radius, width, angle)
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            })
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            .cartesian_product(0..ntan)
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            .map(|((rad, width, angle), j)| {
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                let color = start_color.lerp(
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                    end_color,
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                    j as f32 / (ntan - 1) as f32,
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                    HueDirection::Increasing,
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                );
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                let vec = DMat2::from_angle(std::f64::consts::PI * 2.0 / ntan as f64 * j as f64)
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                    * dvec2(rad, 0.0);
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                let mut arc = ArcBetweenPoints {
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                    start: center.extend(0.0),
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                    end: (center + vec).extend(0.0),
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                    angle,
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                }
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                .build();
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                arc.set_color(color)
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                    .set_fill_opacity(0.0)
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                    .set_stroke_width(width as f32);
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                arc
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            })
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            .collect::<Group<_>>();
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        let mut arcs = timeline.insert(arcs);
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        let arcs_fade_in = arcs.lagged_anim(0.2, |item| item.fade_in());
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        timeline.play(arcs_fade_in.with_total_duration(3.0)).sync();
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        timeline.insert_time_mark(
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            timeline.duration_secs(),
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            TimeMark::Capture("preview.png".to_string()),
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        );
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    }
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}
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fn main() {
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    #[cfg(debug_assertions)]
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    env_logger::Builder::from_env(Env::default().default_filter_or("arc_between_points=trace"))
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        .init();
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    #[cfg(not(debug_assertions))]
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    env_logger::Builder::from_env(Env::default().default_filter_or("arc_between_points=info"))
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        .init();
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    render_scene(ArcBetweenPointsScene, &AppOptions::default());
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}
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