fix(planets): bind orbit radius to disk_outer so planets sit outside the disk
Planets were landing on/in the accretion disk. Root cause: orbit radius was r = radius_factor · kerr_isco(χ), keyed off the disk's INNER edge. The disk extends from ISCO out to disk_outer (default 25), so for every spin the planets' radii fell inside the disk's radial span: χ=0: planets r ∈ [4.5, 17.25], disk [3, 25] — all inside χ=1: planets r ∈ [0.75, 2.88], disk [0.5, 25] — all inside, near hole Re-keyed to the disk OUTER edge: r = radius_factor · disk_outer. With the factor now meaning "multiple of disk_outer" (default 1.3, slider 1.1..=2.0, per-planet jitter ±0.25 floored at 1.05), planets stay at r ≈ 32.5 — reliably outside the disk regardless of spin, while still close enough for lensing to curve their images. Changes: - orbit_position: new disk_outer param, r = radius_factor · disk_outer - orbit_system: passes params.disk_outer - spawn_planet_system: jitter range tightened to ±0.25 around the factor, floor 1.05 (was ±0.75 around an ISCO-keyed k, floor 1.0) - params default planet_radius_factor 2.5 → 1.3 (new semantics) - UI: slider 1.5..=5.0 → 1.1..=2.0, label "Radius (× disk outer)", readout shows orbit r and disk_outer instead of ISCO - tests updated for the new signature and r = factor · disk_outer invariant
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@ -212,11 +212,12 @@ impl Default for BlackHoleParams {
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// at 2× by default — enough to soften the rings — with High (4×)
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// available in the UI for a fully smooth Gargantua look.
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aa_quality: if cfg!(target_arch = "wasm32") { AaQuality::Off } else { AaQuality::Low },
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// Planets: 6 颗, k=2.5 (r ∈ [1.25, 7.5], 横跨强场区),
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// 种子 42, time_scale 50× (Ω_LT 在 r=8 转一圈 ~25 min, 放大才可见).
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// Planets: 6 颗. 半径基准是 disk_outer (默认 25), factor 1.3 →
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// r ≈ 32.5, 稳定在盘外 (盘范围 [isco, 25]). 早期用 ISCO 作基准会让
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// 行星落进盘的径向范围. 种子 42, time_scale 50× (进动慢, 需放大).
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planets_enabled: true,
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planet_count_target: 6,
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planet_radius_factor: 2.5,
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planet_radius_factor: 1.3,
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planet_seed: 42,
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planet_time_scale: 50.0,
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}
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@ -33,17 +33,21 @@ pub struct OrbitParams {
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#[derive(Resource, Default)]
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pub struct PlanetSystemDirty(pub bool);
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/// 由轨道根数 + 当前 (模拟)时间 + 自旋, 计算行星世界空间位置.
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/// 由轨道根数 + 当前 (模拟)时间 + 自旋 + 盘外半径, 计算行星世界空间位置.
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/// 纯函数: 无 Bevy 依赖, 可独立测试.
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///
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/// 物理:
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/// - r = k · kerr_isco(χ)
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/// - r = radius_factor · disk_outer (绑定盘外缘, 保证行星在盘外)
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/// - Ω_φ = kerr_orbital_frequency(r, χ) (轨道角速度)
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/// - Ω_LT = kerr_nodal_precession(r, χ) (轨道面绕 Y 轴的进动率)
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/// 轨道面基 (u, v) 由 inclination + longitude_of_node 构造, 然后绕 Y 轴
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/// 整体旋转 Ω_LT·t (Lense-Thirring 进动).
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pub fn orbit_position(orbit: &OrbitParams, t: f32, chi: f32) -> Vec3 {
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let r = orbit.radius_factor * crate::physics::kerr_isco(chi);
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///
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/// 注: 半径基准是 disk_outer 而非 kerr_isco(χ). 早期版本用 ISCO 作基准,
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/// 但盘从 ISCO 向外延伸到 disk_outer (默认 25), 用 ISCO 会让行星落在
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/// 盘的径向范围内 (与盘重叠/被盘淹没). disk_outer 保证行星永远在盘外.
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pub fn orbit_position(orbit: &OrbitParams, t: f32, chi: f32, disk_outer: f32) -> Vec3 {
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let r = orbit.radius_factor * disk_outer;
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let omega_phi = crate::physics::kerr_orbital_frequency(r, chi);
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let omega_lt = crate::physics::kerr_nodal_precession(r, chi);
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@ -86,7 +90,7 @@ pub fn orbit_system(
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// time_scale 放大模拟时间, 让慢进动在合理时间内可见 (Ω_LT 在 r=8 转一圈 ~25 min)
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let t = time.elapsed_secs() * params.planet_time_scale;
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for (orbit, mut planet) in &mut query {
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planet.center = orbit_position(orbit, t, params.spin);
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planet.center = orbit_position(orbit, t, params.spin, params.disk_outer);
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}
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}
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@ -172,10 +176,11 @@ pub fn spawn_planet_system(
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let inclination = rng.gen_range(0.0..PI);
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let longitude = rng.gen_range(0.0..TAU);
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let phase = rng.gen_range(0.0..TAU);
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// 半径因子以 UI 的 planet_radius_factor 为中心 ±0.75 散布, 既让滑条
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// 真正控制轨道尺度, 又保留 per-planet 半径多样性 (避免全同半径).
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// 滑条范围 1.5..=5.0, 散布后实际 k ∈ [0.75, 5.75], 钳到 ISCO 外.
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let radius_factor = (params.planet_radius_factor + rng.gen_range(-0.75..0.75)).max(1.0);
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// 半径因子 = planet_radius_factor ± 0.25 (per-planet 散布).
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// orbit_position 用 r = radius_factor · disk_outer, 所以这个因子是
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// "盘外缘的倍数": 1.0 = 紧贴盘外, 1.5 = 盘外 50%. 默认滑条 1.3 让行星
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// 稳定在盘外, 散布保留 per-planet 半径多样性. 钳到 1.05 以上保证始终盘外.
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let radius_factor = (params.planet_radius_factor + rng.gen_range(-0.25..0.25)).max(1.05);
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// 颜色: 暖色行星 (橙/红/黄系), 避开蓝色 (易与背景星混淆)
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let hue = rng.gen_range(0.02..0.13);
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let color = hsv_to_rgb(hue, rng.gen_range(0.5..0.9), rng.gen_range(0.7..1.0));
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@ -219,17 +224,18 @@ mod tests {
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#[test]
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fn orbit_position_radius_is_preserved() {
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// 不管时间/相位, 行星到原点距离应恒等于 r = k·isco(χ)
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// 不管时间/相位, 行星到原点距离应恒等于 r = radius_factor · disk_outer
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let orbit = OrbitParams {
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radius_factor: 2.5,
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radius_factor: 1.3,
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inclination: 0.7,
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longitude_of_node: 1.3,
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phase: 0.5,
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};
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let chi = 0.8;
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let expected_r = 2.5 * crate::physics::kerr_isco(chi);
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let disk_outer = 25.0;
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let expected_r = 1.3 * disk_outer;
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for t in [0.0_f32, 1.0, 5.5, 100.0] {
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let pos = orbit_position(&orbit, t, chi);
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let pos = orbit_position(&orbit, t, chi, disk_outer);
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let dist = pos.length();
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assert!(
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(dist - expected_r).abs() < 1e-4,
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@ -243,13 +249,13 @@ mod tests {
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fn orbit_position_zero_spin_keeps_equatorial_plane() {
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// χ=0: 无进动, 倾角 0 (赤道面) 的行星应严格在 y=0 平面
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let orbit = OrbitParams {
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radius_factor: 3.0,
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radius_factor: 1.3,
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inclination: 0.0,
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longitude_of_node: 0.0,
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phase: 0.0,
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};
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for t in [0.0_f32, 1.0, 10.0] {
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let pos = orbit_position(&orbit, t, 0.0);
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let pos = orbit_position(&orbit, t, 0.0, 25.0);
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assert!(pos.y.abs() < 1e-5, "χ=0 equatorial orbit should stay in y=0 plane at t={}", t);
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}
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}
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@ -258,13 +264,13 @@ mod tests {
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fn orbit_position_advances_with_time() {
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// 不同时间应给不同位置 (除非极端巧合)
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let orbit = OrbitParams {
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radius_factor: 3.0,
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radius_factor: 1.3,
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inclination: 0.5,
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longitude_of_node: 0.0,
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phase: 0.0,
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};
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let p0 = orbit_position(&orbit, 0.0, 0.5);
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let p1 = orbit_position(&orbit, 1.0, 0.5);
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let p0 = orbit_position(&orbit, 0.0, 0.5, 25.0);
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let p1 = orbit_position(&orbit, 1.0, 0.5, 25.0);
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assert!((p0 - p1).length() > 0.01, "planet should move over time");
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}
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}
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@ -69,9 +69,8 @@ pub fn ui_system(
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);
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ui.checkbox(&mut params.planets_enabled, "Enable");
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ui.add(egui::Slider::new(&mut params.planet_count_target, 0..=8).text("Count"));
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ui.add(egui::Slider::new(&mut params.planet_radius_factor, 1.5..=5.0).text("Radius factor k"));
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let isco = crate::physics::kerr_isco(params.spin);
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ui.label(format!("ISCO: {:.3} → r = {:.3}", isco, params.planet_radius_factor * isco));
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ui.add(egui::Slider::new(&mut params.planet_radius_factor, 1.1..=2.0).text("Radius (× disk outer)"));
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ui.label(format!("Orbit r = {:.2} (disk outer: {:.1})", params.planet_radius_factor * params.disk_outer, params.disk_outer));
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ui.add(egui::Slider::new(&mut params.planet_seed, 0..=1000).text("Seed"));
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ui.add(egui::Slider::new(&mut params.planet_time_scale, 1.0..=200.0).text("Time scale"));
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let curr = (
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