surv/mandelbrot
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

feat: add lambda fractal

Browse Source
This commit is contained in:
surv
2026-09-16 20:32:48 +02:00
parent 0b90b72a00
commit afcd3c74da
6 changed files with 276 additions and 103 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/app.rs
+94 -9
View File
@@ -46,6 +46,7 @@ const KINDS: &[(FractalKind, &str)] = &[
(FractalKind::Perpendicular, "Perpendicular"),
(FractalKind::Buffalo, "Buffalo"),
(FractalKind::Phoenix, "Phoenix"),
(FractalKind::Lambda, "Lambda"),
];
/// UI label for a fractal kind.
@@ -60,7 +61,7 @@ fn kind_label(kind: FractalKind) -> &'static str {
type JuliaPreset = (&'static str, f64, f64, u32, Option<(f64, f64)>);
/// Nice-looking Julia constants offered as presets.
const JULIA_PRESETS: [&[JuliaPreset]; FractalKind::Phoenix as usize + 1] = [
const JULIA_PRESETS: [&[JuliaPreset]; FractalKind::Lambda as usize + 1] = [
&[
("dendrite", -0.8, 0.156, 400, None),
("rabbit", -0.123, 0.745, 400, None),
@@ -78,6 +79,7 @@ const JULIA_PRESETS: [&[JuliaPreset]; FractalKind::Phoenix as usize + 1] = [
("archipelago 1", -0.415, -0.267, 500, Some((-0.556, 0.253))),
("archipelago 2", -0.556, 0.253, 500, Some((-0.415, -0.267))),
],
&[],
];
type SetPreset = (
@@ -92,7 +94,7 @@ type SetPreset = (
/// Curated beautiful locations offered as one-click presets.
/// Each is `(name, center_re, center_im, half_height, iterations)`; the centers
/// are decimals parsed at full precision so deep places stay sharp.
const SET_PRESETS: [&[SetPreset]; FractalKind::Phoenix as usize + 1] = [
const SET_PRESETS: [&[SetPreset]; FractalKind::Lambda as usize + 1] = [
&[
(
"Seahorse Valley",
@@ -142,6 +144,7 @@ const SET_PRESETS: [&[SetPreset]; FractalKind::Phoenix as usize + 1] = [
1000,
Some((-0.9, -0.49)),
)],
&[],
];
/// Parameters a reference orbit was (or will be) computed for. Used to decide
@@ -153,6 +156,7 @@ struct RequestKey {
julia: bool,
julia_c: (f64, f64),
phoenix_p: (f64, f64),
lambda_l: (f64, f64),
iter: u32,
kind: FractalKind,
power: u32,
@@ -196,6 +200,13 @@ struct AnimState {
phoenix_base: (f64, f64),
phoenix_angle: f64,
/// Drift the Lambda distortion `λ` around a circle.
lambda: bool,
lambda_speed: f32,
lambda_radius: f64,
lambda_base: (f64, f64),
lambda_angle: f64,
/// Continuously zoom toward the current center.
zoom: bool,
/// e-folds per second; positive zooms in, negative zooms out.
@@ -217,6 +228,11 @@ impl Default for AnimState {
phoenix_radius: 0.08,
phoenix_base: (0.0, 0.0),
phoenix_angle: 0.0,
lambda: false,
lambda_speed: 0.05,
lambda_radius: 0.08,
lambda_base: (0.0, 0.0),
lambda_angle: 0.0,
zoom: false,
zoom_speed: 0.5,
}
@@ -234,6 +250,8 @@ pub struct FractalApp {
julia_c: (f64, f64),
/// Distortion constant `p` for the Phoenix kind (`z^2 + c + p·z_{n-1}`).
phoenix_p: (f64, f64),
/// Distortion constant `l` for the Lambda kind (`l·z(1 - z_{n-1})`).
lambda_l: (f64, f64),
max_iterations: u32,
/// When set, `max_iterations` tracks the zoom depth automatically (so deep
/// zooms stay sharp without hand-tuning); the manual slider takes over when
@@ -356,6 +374,7 @@ impl FractalApp {
power: 3,
julia_c: (-0.8, 0.156),
phoenix_p: (-0.5, 0.0),
lambda_l: (-0.5, 0.0),
max_iterations: 512,
auto_iterations: true,
color_scale: 0.15,
@@ -517,6 +536,7 @@ impl FractalApp {
iterations: self.max_iterations,
julia_c: self.julia_c,
phoenix_p: self.phoenix_p,
lambda_l: self.lambda_l,
color_scale: self.color_scale,
color_offset: self.color_offset,
palette: self.palette,
@@ -534,6 +554,7 @@ impl FractalApp {
self.power = s.power.clamp(2, 8);
self.julia_c = s.julia_c;
self.phoenix_p = s.phoenix_p;
self.lambda_l = s.lambda_l;
self.color_scale = s.color_scale;
self.color_offset = s.color_offset;
self.palette = (s.palette as usize).min(PALETTE_NAMES.len() - 1) as u32;
@@ -582,6 +603,7 @@ impl FractalApp {
FractalKind::Perpendicular => (-0.5, 0.0, 1.5),
FractalKind::Buffalo => (-0.5, -0.5, 1.5),
FractalKind::Phoenix => (0.0, 0.0, 1.6),
FractalKind::Lambda => (0.0, 0.0, 1.6),
};
ViewState::with_center(big_from_f64(cr, 53), big_from_f64(ci, 53), hh)
}
@@ -594,6 +616,7 @@ impl FractalApp {
julia: matches!(self.mode, FractalMode::Julia),
julia_c: self.julia_c,
phoenix_p: self.phoenix_p,
lambda_l: self.lambda_l,
iter: self.max_iterations,
kind: self.kind,
power: self.power,
@@ -609,7 +632,8 @@ impl FractalApp {
/// Whether the reference should be (re)computed: parameters changed, or the
/// view drifted / zoomed far enough that the current reference no longer
/// serves it well.
/// serves it well. Lambda in Set mode has a static fractal (doesn't depend
/// on center), so we skip center drift checks but allow zoom precision updates.
fn should_request(&self) -> bool {
let Some(key) = &self.last_request else {
return true;
@@ -617,12 +641,19 @@ impl FractalApp {
if key.julia != matches!(self.mode, FractalMode::Julia)
|| key.julia_c != self.julia_c
|| key.phoenix_p != self.phoenix_p
|| key.lambda_l != self.lambda_l
|| key.iter != self.max_iterations
|| key.kind != self.kind
|| key.power != self.power
{
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) {
// 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);
}
let ratio = self.view.half_height / key.half_height;
self.drift_from(key) > 0.5 * self.view.half_height || !(0.5..=2.0).contains(&ratio)
}
@@ -650,10 +681,16 @@ impl FractalApp {
/// thread and pick up completed results. Web: compute inline.
fn ensure_reference(&mut self) {
if self.should_request() {
let key = self.current_key();
let mut key = self.current_key();
let precision = self.view.precision_bits();
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 {
key.center_re = big_from_f64(0.0, precision);
key.center_im = big_from_f64(0.0, precision);
}
#[cfg(not(target_arch = "wasm32"))]
{
self.worker.request(crate::worker::RefRequest {
@@ -667,6 +704,7 @@ impl FractalApp {
kind: key.kind,
power: key.power,
phoenix_p: key.phoenix_p,
lambda_l: key.lambda_l,
});
self.pending = true;
}
@@ -685,6 +723,7 @@ impl FractalApp {
key.kind,
key.power,
key.phoenix_p,
key.lambda_l,
)
} else {
compute_set_reference(
@@ -695,6 +734,7 @@ impl FractalApp {
key.kind,
key.power,
key.phoenix_p,
key.lambda_l,
)
};
self.apply_reference(
@@ -727,12 +767,13 @@ impl FractalApp {
is_julia: matches!(self.mode, FractalMode::Julia) as u32,
palette_id: self.palette,
aa_level: if self.antialias { 2 } else { 1 },
kind: self.kind.shader_id(),
kind: self.kind as u32,
power: self.power,
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],
de_coloring: self.de_coloring as u32,
_pad: [0, 0, 0],
_pad: [0],
}
}
@@ -1046,10 +1087,11 @@ impl FractalApp {
/// repaint while active. Animations render at full resolution/AA (they do not
/// trigger the interaction low-res pass).
fn tick_animations(&mut self, ui: &egui::Ui) {
// Julia c only matters in Julia mode; Phoenix p only for the Phoenix kind.
// Julia c only matters in Julia mode; Phoenix p only for the Phoenix kind; Lambda λ only for Lambda kind.
let julia_on = self.anim.julia && self.mode == FractalMode::Julia;
let phoenix_on = self.anim.phoenix && self.kind == FractalKind::Phoenix;
if !(self.anim.color || self.anim.zoom || julia_on || phoenix_on) {
let lambda_on = self.anim.lambda && self.kind == FractalKind::Lambda;
if !(self.anim.color || self.anim.zoom || julia_on || phoenix_on || lambda_on) {
return;
}
@@ -1076,6 +1118,15 @@ impl FractalApp {
self.anim.phoenix_base.1 + self.anim.phoenix_radius * s,
);
}
let lambda_on = self.anim.lambda && self.kind == FractalKind::Lambda;
if lambda_on {
self.anim.lambda_angle += std::f64::consts::TAU * self.anim.lambda_speed as f64 * dt;
let (s, c) = self.anim.lambda_angle.sin_cos();
self.lambda_l = (
self.anim.lambda_base.0 + self.anim.lambda_radius * c,
self.anim.lambda_base.1 + self.anim.lambda_radius * s,
);
}
if self.anim.zoom && self.anim.zoom_speed != 0.0 {
let min_hh = DEFAULT_HALF_HEIGHT * 1.0e-26; // practical f32-perturbation depth
let max_hh = DEFAULT_HALF_HEIGHT * 4.0;
@@ -1124,6 +1175,22 @@ impl FractalApp {
ui.label("i");
});
}
if self.kind == FractalKind::Lambda {
ui.horizontal(|ui| {
ui.label("λ =");
ui.add(
egui::DragValue::new(&mut self.lambda_l.0)
.speed(0.001)
.range(-2.0..=2.0),
);
ui.add(
egui::DragValue::new(&mut self.lambda_l.1)
.speed(0.001)
.range(-2.0..=2.0),
);
ui.label("i");
});
}
if self.kind != prev_kind {
self.view = Self::default_view_for(self.mode, self.kind);
}
@@ -1133,7 +1200,7 @@ impl FractalApp {
ui.radio_value(&mut self.mode, FractalMode::Julia, "Julia");
});
if self.mode == FractalMode::Julia {
if self.mode == FractalMode::Julia && self.kind != FractalKind::Lambda {
ui.horizontal(|ui| {
ui.label("c =");
ui.add(
@@ -1271,6 +1338,24 @@ impl FractalApp {
);
}
}
if self.kind == FractalKind::Lambda {
if ui.checkbox(&mut self.anim.lambda, "Morph λ").changed() && self.anim.lambda {
self.anim.lambda_base = self.lambda_l;
self.anim.lambda_angle = 0.0;
}
if self.anim.lambda {
ui.add(
egui::Slider::new(&mut self.anim.lambda_speed, 0.005..=0.5)
.text("λ rev/s")
.logarithmic(true),
);
ui.add(
egui::Slider::new(&mut self.anim.lambda_radius, 0.005..=0.5)
.text("λ radius")
.logarithmic(true),
);
}
}
});
ui.separator();