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feat: add interpolation between fractals

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surv
2026-09-24 21:43:36 +02:00
parent 9cc5a80650
commit 51fa5ffa02
8 changed files with 624 additions and 212 deletions
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src/app.rs
+139 -9
View File
@@ -20,7 +20,7 @@ use crate::view::parse_half_height_spec;
use crate::view::parse_re_im_spec;
use crate::view::{
Big, DEFAULT_HALF_HEIGHT, ViewState, big_from_decimal_str, big_from_f64, big_to_decimal_str,
parse_view_spec, precision_for,
interpolate_view, parse_view_spec, precision_for,
};
#[cfg(not(target_arch = "wasm32"))]
use clap::Parser;
@@ -161,6 +161,35 @@ struct RequestKey {
kind: FractalKind,
power: u32,
complex_power: (f64, f64),
/// Kind-switch morph `(from_kind, weight)`, if one is running.
morph: Option<(FractalKind, f32)>,
}
/// An in-progress kind-switch animation: the iteration formula is blended per
/// step from `from` to the current kind, `(1 - w)·f_kind + w·f_from`, while the
/// camera glides from `from_view` to the new kind's default view.
struct KindMorph {
from: FractalKind,
/// Linear progress in [0, 1]; eased with smoothstep.
progress: f32,
from_view: ViewState,
to_view: ViewState,
/// Whether the morph still drives the camera. Cleared as soon as the user
/// pans/zooms, so they can take over mid-morph.
camera: bool,
}
impl KindMorph {
/// Smoothstep-eased progress.
fn eased(&self) -> f32 {
let p = self.progress.clamp(0.0, 1.0);
p * p * (3.0 - 2.0 * p)
}
/// Weight of the old kind's formula: 1 at the start, 0 at the end.
fn weight(&self) -> f32 {
1.0 - self.eased()
}
}
/// Shared state for an in-progress PNG export. The worker (a background thread
@@ -213,6 +242,12 @@ struct AnimState {
/// e-folds per second; positive zooms in, negative zooms out.
zoom_speed: f32,
/// Morph the iteration formula (and camera) when switching fractal kinds,
/// instead of cutting straight to the new kind.
kind_morph: bool,
/// Kind-switch morph duration, in seconds.
kind_morph_duration: f32,
/// Linear 2D <-> 3D transition progress in [0, 1], advanced at a constant
/// rate; `camera_state` is its smoothstep-eased value.
camera_progress: f32,
@@ -242,6 +277,8 @@ impl Default for AnimState {
lambda_angle: 0.0,
zoom: false,
zoom_speed: 0.5,
kind_morph: true,
kind_morph_duration: 1.5,
camera_progress: 0.,
camera_state: 0.,
}
@@ -309,6 +346,8 @@ pub struct FractalApp {
help_open: bool,
/// Time-based animation of colours / Julia c / Phoenix p / zoom.
anim: AnimState,
/// Kind-switch morph in progress, if any.
morph: Option<KindMorph>,
/// Smoothed frames-per-second, recomputed each ~0.5 s window. Only advances
/// while the app is actually repainting (interaction / animation / export);
@@ -327,6 +366,10 @@ pub struct FractalApp {
ref_center_re: Big,
ref_center_im: Big,
ref_half_height: f64,
/// Kind-switch morph the current `reference` was computed with. The shader
/// blends with this (not the live morph) so its delta formula always
/// matches the orbit, even while the worker lags a frame behind.
ref_morph: Option<(FractalKind, f32)>,
/// Parameters of the most recent reference request (drift baseline / dedupe).
last_request: Option<RequestKey>,
@@ -466,6 +509,7 @@ impl FractalApp {
info_open: false,
help_open: false,
anim: AnimState::default(),
morph: None,
fps: 0.0,
fps_frames: 0,
fps_window_start: 0.0,
@@ -474,6 +518,7 @@ impl FractalApp {
ref_center_re,
ref_center_im,
ref_half_height,
ref_morph: None,
last_request: None,
#[cfg(not(target_arch = "wasm32"))]
worker: crate::worker::RefWorker::spawn(),
@@ -667,6 +712,7 @@ impl FractalApp {
) {
self.mode = FractalMode::Mandelbrot;
self.view = ViewState::with_center(cre, cim, half_height);
self.morph = None;
// Presets carry a hand-tuned count; don't let the auto-scaler clobber it.
self.auto_iterations = false;
self.max_iterations = iterations.clamp(32, MAX_REF_POINTS as u32 - 1);
@@ -706,6 +752,7 @@ impl FractalApp {
/// Restore a shared state into this app.
fn apply_share(&mut self, s: &ShareState) {
self.morph = None;
self.mode = if s.julia {
FractalMode::Julia
} else {
@@ -778,6 +825,7 @@ impl FractalApp {
kind: self.kind,
power: self.power,
complex_power: self.complex_power,
morph: self.morph.as_ref().map(|m| (m.from, m.weight())),
}
}
@@ -809,11 +857,17 @@ impl FractalApp {
|| key.kind != self.kind
|| key.power != self.power
|| key.complex_power != self.complex_power
|| key.morph != self.morph.as_ref().map(|m| (m.from, m.weight()))
{
return true;
}
// Lambda in Set mode is a static fractal; don't trigger recompute on center drift.
if self.kind == FractalKind::Lambda && matches!(self.mode, FractalMode::Mandelbrot) {
// Lambda in Set mode is a static fractal; don't trigger recompute on
// center drift. (Not while morphing: the other kind's formula does
// depend on the center.)
if self.kind == FractalKind::Lambda
&& matches!(self.mode, FractalMode::Mandelbrot)
&& self.morph.is_none()
{
// But still recompute on significant zoom changes for precision
let ratio = self.view.half_height / key.half_height;
return !(0.5..=2.0).contains(&ratio);
@@ -833,8 +887,16 @@ impl FractalApp {
[dre, dim]
}
fn apply_reference(&mut self, points: Vec<[f32; 2]>, cre: Big, cim: Big, hh: f64) {
fn apply_reference(
&mut self,
points: Vec<[f32; 2]>,
cre: Big,
cim: Big,
hh: f64,
morph: Option<(FractalKind, f32)>,
) {
self.reference = Arc::new(points);
self.ref_morph = morph;
self.ref_center_re = cre;
self.ref_center_im = cim;
self.ref_half_height = hh;
@@ -865,7 +927,7 @@ impl FractalApp {
let max_iter = key.iter.min(MAX_REF_POINTS as u32 - 1);
// Lambda in Set mode has a static fractal centered at origin.
if key.kind == FractalKind::Lambda && !key.julia {
if key.kind == FractalKind::Lambda && !key.julia && key.morph.is_none() {
key.center_re = big_from_f64(0.0, precision);
key.center_im = big_from_f64(0.0, precision);
}
@@ -885,6 +947,7 @@ impl FractalApp {
phoenix_p: key.phoenix_p,
lambda_l: key.lambda_l,
complex_power: key.complex_power,
morph: key.morph,
});
self.pending = true;
}
@@ -905,6 +968,7 @@ impl FractalApp {
key.phoenix_p,
key.lambda_l,
key.complex_power,
key.morph.map(|(k, w)| (k, w as f64)),
)
} else {
compute_set_reference(
@@ -917,6 +981,7 @@ impl FractalApp {
key.phoenix_p,
key.lambda_l,
key.complex_power,
key.morph.map(|(k, w)| (k, w as f64)),
)
};
self.apply_reference(
@@ -924,6 +989,7 @@ impl FractalApp {
key.center_re.clone(),
key.center_im.clone(),
key.half_height,
key.morph,
);
}
@@ -932,7 +998,13 @@ impl FractalApp {
#[cfg(not(target_arch = "wasm32"))]
if let Some(res) = self.worker.try_take_latest() {
self.apply_reference(res.points, res.center_re, res.center_im, res.half_height);
self.apply_reference(
res.points,
res.center_re,
res.center_im,
res.half_height,
res.morph,
);
self.pending = false;
}
}
@@ -954,7 +1026,7 @@ impl FractalApp {
let max_iter = key.iter;
// Lambda in Set mode has a static fractal centered at origin.
if key.kind == FractalKind::Lambda && !key.julia {
if key.kind == FractalKind::Lambda && !key.julia && key.morph.is_none() {
key.center_re = big_from_f64(0.0, precision);
key.center_im = big_from_f64(0.0, precision);
}
@@ -974,6 +1046,7 @@ impl FractalApp {
key.phoenix_p,
key.lambda_l,
key.complex_power,
key.morph.map(|(k, w)| (k, w as f64)),
)
} else {
compute_set_reference(
@@ -986,6 +1059,7 @@ impl FractalApp {
key.phoenix_p,
key.lambda_l,
key.complex_power,
key.morph.map(|(k, w)| (k, w as f64)),
)
};
self.apply_reference(
@@ -993,6 +1067,7 @@ impl FractalApp {
key.center_re.clone(),
key.center_im.clone(),
key.half_height,
key.morph,
);
self.last_request = Some(key);
}
@@ -1052,6 +1127,7 @@ impl FractalApp {
aa_level: if self.antialias { 2 } else { 1 },
kind: self.kind as u32,
power: self.power,
morph_from: self.ref_morph.map_or(0, |(k, _)| k as u32),
dc_offset: self.dc_offset(),
phoenix_p: [self.phoenix_p.0 as f32, self.phoenix_p.1 as f32],
lambda_l: [self.lambda_l.0 as f32, self.lambda_l.1 as f32],
@@ -1059,6 +1135,7 @@ impl FractalApp {
de_coloring: (self.de_coloring || mode > 0) as u32,
rendering_mode: mode,
camera_direction: self.camera.direction(self.anim.camera_state).to_array(),
morph_w: self.ref_morph.map_or(0.0, |(_, w)| w),
camera_inv_proj: self
.camera
.orthographic(self.anim.camera_state)
@@ -1067,7 +1144,6 @@ impl FractalApp {
screen_dim: self.screen_dim,
light_count: gpu_lights(&self.lights).1,
cm_coef: complex_binomials(self.complex_power),
_pad: [0; _],
_pad3: [0; _],
}
}
@@ -1586,6 +1662,22 @@ impl FractalApp {
let p = self.anim.camera_progress;
self.anim.camera_state = p * p * (3.0 - 2.0 * p);
// Kind-switch morph: advance the per-iteration formula blend, and glide
// the camera to the new kind's default view unless the user took over.
if let Some(m) = &mut self.morph {
m.progress += dt as f32 / self.anim.kind_morph_duration.max(0.05);
if m.camera {
self.view = interpolate_view(&m.from_view, &m.to_view, m.eased() as f64);
}
if m.progress >= 1.0 {
if m.camera {
self.view = m.to_view.clone();
}
self.morph = None;
}
ui.ctx().request_repaint();
}
if !(self.anim.color || self.anim.zoom || julia_on || phoenix_on || lambda_on) {
return;
}
@@ -1701,9 +1793,23 @@ impl FractalApp {
});
}
if self.kind != prev_kind {
self.view = Self::default_view_for(self.mode, self.kind);
let to_view = Self::default_view_for(self.mode, self.kind);
// Buddhabrot has its own pipeline without the blended formula, so
// it keeps the instant switch.
self.morph =
(self.anim.kind_morph && self.mode != FractalMode::Buddhabrot).then(|| KindMorph {
from: prev_kind,
progress: 0.0,
from_view: self.view.clone(),
to_view: to_view.clone(),
camera: true,
});
if self.morph.is_none() {
self.view = to_view;
}
}
let prev_mode = self.mode;
ui.horizontal(|ui| {
ui.radio_value(&mut self.mode, FractalMode::Mandelbrot, "Set");
ui.radio_value(&mut self.mode, FractalMode::Julia, "Julia");
@@ -1714,6 +1820,9 @@ impl FractalApp {
progressively sharpens while the view stays still.",
);
});
if self.mode != prev_mode {
self.morph = None;
}
if self.mode == FractalMode::Buddhabrot {
self.buddhabrot_ui(ui);
@@ -1722,6 +1831,7 @@ impl FractalApp {
ui.add_space(4.);
if ui.button("Reset view").clicked() {
self.view = Self::default_view_for(self.mode, self.kind);
self.morph = None;
}
ui.add_space(8.0);
ui.small("Drag to pan · scroll to zoom toward the cursor");
@@ -1880,6 +1990,19 @@ impl FractalApp {
);
}
ui.checkbox(&mut self.anim.kind_morph, "Morph kind switch")
.on_hover_text(
"When picking another fractal, blend the old and new formulas \
at every iteration step and glide to the new default view.",
);
if self.anim.kind_morph {
ui.add(
egui::Slider::new(&mut self.anim.kind_morph_duration, 0.2..=10.0)
.text("morph s")
.logarithmic(true),
);
}
// Julia c only affects Julia mode; Phoenix p only the Phoenix kind.
if self.mode == FractalMode::Julia {
if ui.checkbox(&mut self.anim.julia, "Morph c").changed() && self.anim.julia {
@@ -2064,6 +2187,7 @@ impl FractalApp {
ui.add_space(4.);
if ui.button("Reset view").clicked() {
self.view = Self::default_view_for(self.mode, self.kind);
self.morph = None;
}
ui.add_space(8.0);
ui.small("Drag to pan · scroll to zoom toward the cursor");
@@ -2302,6 +2426,7 @@ impl FractalApp {
if ui.input(|i| i.key_pressed(egui::Key::R)) {
self.view = Self::default_view_for(self.mode, self.kind);
self.morph = None;
self.camera = Camera::new();
interacted = true;
}
@@ -2379,6 +2504,11 @@ impl FractalApp {
let now = ui.input(|i| i.time);
if interacted {
self.last_interact_time = now;
// The user is steering the camera: stop the kind-switch morph from
// overriding it (the formula blend itself carries on).
if let Some(m) = &mut self.morph {
m.camera = false;
}
}
let interacting = now - self.last_interact_time < INTERACT_SETTLE;
if interacting {