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feat: add shadow coloring

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surv
2026-09-18 11:01:29 +02:00
parent 7c347a5abf
commit 2cd06c4219
6 changed files with 129 additions and 35 deletions
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Cargo.toml
+2 -1
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@@ -26,7 +26,8 @@ web-sys = { version = "0.3.105", features = ["Window", "Location", "Url", "UrlSe
# Release: optimize hard (fractal math is hot).
[profile.release]
opt-level = 3
codegen-units = 1
# codegen-units = 1
debug = true
# Dev: keep our own crate debuggable, but optimize dependencies (dashu, wgpu,
# egui) so the explorer is actually interactive during development.
src/app.rs
+42 -17
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@@ -29,6 +29,8 @@ const INTERACT_DOWNSCALE: u32 = 2;
const INTERACT_SETTLE: f64 = 0.12;
/// Palette names; index maps to `palette_id` in the shader.
const PALETTE_NAMES: &[&str] = &["Amber", "Rainbow", "Ember", "Lime", "Grayscale"];
/// Shadow palette names; index maps to `palette_id` in the shader.
const SHADOW_PALETTE_NAMES: &[&str] = &["Grayscale", "Red & Blue"];
/// Buddhabrot tonemap style names; index maps to `BuddhabrotUniforms::palette`.
const BUDDHA_PALETTE_NAMES: &[&str] = &["Nebula", "Yellow", "Grayscale"];
@@ -121,7 +123,7 @@ const SET_PRESETS: [&[SetPreset]; FractalKind::Lambda as usize + 1] = [
"-0.7436438870371587",
"0.1318259042053",
8.0e-8,
10000,
2000,
None,
),
],
@@ -262,11 +264,14 @@ pub struct FractalApp {
color_scale: f32,
color_offset: f32,
palette: u32,
shadow_palette: u32,
/// Supersample each pixel 2×2 for smoother edges (costs ~4× fragment work).
antialias: bool,
/// Distance-estimation shading: darkens toward the set boundary using the
/// orbit derivative, giving crisp filaments at deep zoom instead of speckle.
de_coloring: bool,
// Use shadow coloring
shadow: bool,
/// Render as a Buddhabrot (Monte-Carlo orbit-density histogram) instead of
/// the ordinary escape-time set. Plain f32 view — no deep zoom, no
@@ -401,8 +406,10 @@ impl FractalApp {
color_scale: 0.15,
color_offset: 0.0,
palette: 0,
shadow_palette: 0,
antialias: false,
de_coloring: false,
shadow: false,
buddhabrot: false,
buddha_r_cap: 50,
buddha_g_cap: 500,
@@ -576,6 +583,7 @@ impl FractalApp {
color_scale: self.color_scale,
color_offset: self.color_offset,
palette: self.palette,
shadow_palette: self.shadow_palette,
}
}
@@ -594,6 +602,8 @@ impl FractalApp {
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;
self.shadow_palette =
(s.shadow_palette as usize).min(SHADOW_PALETTE_NAMES.len() - 1) as u32;
// The link carries an explicit iteration count; honor it rather than
// letting the auto-scaler immediately overwrite it.
self.auto_iterations = false;
@@ -802,14 +812,16 @@ impl FractalApp {
bailout_sq: BAILOUT_SQ,
is_julia: matches!(self.mode, FractalMode::Julia) as u32,
palette_id: self.palette,
shadow_palette_id: self.shadow_palette,
aa_level: if self.antialias { 2 } else { 1 },
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],
de_coloring: (self.de_coloring | self.shadow) as u32,
shadow: self.shadow as u32,
_pad: [0; _],
}
}
@@ -833,11 +845,11 @@ impl FractalApp {
r_cap: self.buddha_r_cap,
g_cap: self.buddha_g_cap,
b_cap: self.buddha_b_cap,
seed: 0, // set by the callback's own dispatch counter
seed: 0, // set by the callback's own dispatch counter
samples_this_dispatch: 0, // set by the callback
exposure: self.buddha_exposure,
width: 0, // set by the callback from size_px
height: 0, // set by the callback from size_px
width: 0, // set by the callback from size_px
height: 0, // set by the callback from size_px
total_samples: 0.0, // tracked by the renderer across frames
palette: self.buddha_palette,
_pad: [0; 3],
@@ -1354,22 +1366,35 @@ impl FractalApp {
.logarithmic(true),
);
ui.add(egui::Slider::new(&mut self.color_offset, 0.0..=1.0).text("color offset"));
egui::ComboBox::from_label("palette")
.selected_text(PALETTE_NAMES[self.palette as usize])
.show_ui(ui, |ui| {
for (i, name) in PALETTE_NAMES.iter().enumerate() {
ui.selectable_value(&mut self.palette, i as u32, *name);
}
});
ui.checkbox(&mut self.shadow, "Shadow");
if !self.shadow {
egui::ComboBox::from_label("palette")
.selected_text(PALETTE_NAMES[self.palette as usize])
.show_ui(ui, |ui| {
for (i, name) in PALETTE_NAMES.iter().enumerate() {
ui.selectable_value(&mut self.palette, i as u32, *name);
}
});
} else {
egui::ComboBox::from_label("palette")
.selected_text(SHADOW_PALETTE_NAMES[self.shadow_palette as usize])
.show_ui(ui, |ui| {
for (i, name) in SHADOW_PALETTE_NAMES.iter().enumerate() {
ui.selectable_value(&mut self.shadow_palette, i as u32, *name);
}
});
}
ui.checkbox(&mut self.antialias, "Antialiasing (2×2)")
.on_hover_text("Supersample each pixel for smoother edges (~4× slower).");
ui.checkbox(&mut self.de_coloring, "Distance shading")
.on_hover_text(
"Shade by distance to the set boundary (from the orbit derivative) \
if !self.shadow {
ui.checkbox(&mut self.de_coloring, "Distance shading")
.on_hover_text(
"Shade by distance to the set boundary (from the orbit derivative) \
for crisp filaments at deep zoom. Exact for the holomorphic kinds \
(Mandelbrot/Multibrot/Phoenix), approximate for the abs-based kinds \
(Burning Ship/Tricorn/Celtic/Perpendicular/Buffalo).",
);
);
}
ui.collapsing("Animation", |ui| {
ui.checkbox(&mut self.anim.color, "Cycle colours")
src/fractal/renderer.rs
+6 -2
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@@ -46,6 +46,8 @@ fn color_differs(a: &Uniforms, b: &Uniforms) -> bool {
a.color_offset != b.color_offset
|| a.color_scale != b.color_scale
|| a.palette_id != b.palette_id
|| a.shadow_palette_id != b.shadow_palette_id
|| a.shadow != b.shadow
}
/// GPU-side view + coloring parameters. Layout must match `Uniforms` in the
@@ -64,12 +66,14 @@ pub struct Uniforms {
/// 0 = Mandelbrot, 1 = Julia.
pub is_julia: u32,
pub palette_id: u32,
pub shadow_palette_id: u32,
/// Supersampling factor per axis: 1 = off, 2 = 2×2 (4 samples).
pub aa_level: u32,
/// Iteration formula (`FractalKind::shader_id`).
pub kind: u32,
/// Exponent for the Multibrot kind.
pub power: u32,
pub _pad: [u32; 1],
/// Complex offset of the view center from the reference center, so a stale
/// or reused reference (computed at a slightly different center) still maps
/// correctly. Added to every pixel's per-pixel offset.
@@ -83,8 +87,8 @@ pub struct Uniforms {
pub lambda_l: [f32; 2],
/// 0 = escape-time coloring, 1 = distance-estimation shading.
pub de_coloring: u32,
/// Padding to a 16-byte multiple (uniform buffer requirement).
pub _pad: [u32; 1],
// 0 = classic colors, 1 = shadows
pub shadow: u32,
}
/// Offscreen textures for the two-pass render, recreated whenever the widget's
src/fractal/share.rs
+5
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@@ -29,6 +29,8 @@ pub struct ShareState {
pub color_offset: f32,
/// Palette index (`palette_id` in the shader).
pub palette: u32,
/// Shadow palette index (`shadow_palette_id` in the shader).
pub shadow_palette: u32,
}
impl ShareState {
@@ -110,6 +112,7 @@ impl ShareState {
color_scale: map.get("cs").and_then(|s| s.parse().ok()).unwrap_or(0.02),
color_offset: map.get("co").and_then(|s| s.parse().ok()).unwrap_or(0.0),
palette: map.get("pal").and_then(|s| s.parse().ok()).unwrap_or(0),
shadow_palette: map.get("spal").and_then(|s| s.parse().ok()).unwrap_or(0),
})
}
}
@@ -134,6 +137,7 @@ mod tests {
color_scale: 0.02,
color_offset: 0.25,
palette: 3,
shadow_palette: 1,
};
let d = ShareState::decode(&s.encode()).unwrap();
assert_eq!(d.julia, s.julia);
@@ -146,6 +150,7 @@ mod tests {
assert_eq!(d.julia_c, s.julia_c);
assert_eq!(d.phoenix_p, s.phoenix_p);
assert_eq!(d.palette, s.palette);
assert_eq!(d.shadow_palette, s.shadow_palette);
}
#[test]
src/shaders/colorize.wgsl
+66 -14
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@@ -20,12 +20,15 @@ struct Uniforms {
bailout_sq: f32,
is_julia: u32,
palette_id: u32,
shadow_palette_id: u32,
aa_level: u32,
kind: u32,
power: u32,
dc_offset: vec2<f32>,
phoenix_p: vec2<f32>,
lambda_l: vec2<f32>,
de_coloring: u32,
shadow: u32,
};
@group(0) @binding(0) var<uniform> u: Uniforms;
@@ -34,18 +37,18 @@ struct Uniforms {
// Smooth cyclic palettes (Inigo Quilez cosine palettes). Must match the palette
// in mandelbrot.wgsl.
fn palette(id: u32, t: f32) -> vec3<f32> {
if (id == 4u) {
if id == 4u {
return vec3<f32>(t, t, t); // grayscale
}
let a = vec3<f32>(0.5, 0.5, 0.5);
let b = vec3<f32>(0.5, 0.5, 0.5);
var c = vec3<f32>(1.0, 1.0, 1.0);
var d = vec3<f32>(0.00, 0.10, 0.20); // 0: amber / blue
if (id == 1u) {
if id == 1u {
d = vec3<f32>(0.00, 0.33, 0.67); // rainbow
} else if (id == 2u) {
} else if id == 2u {
d = vec3<f32>(0.30, 0.20, 0.20); // warm ember
} else if (id == 3u) {
} else if id == 3u {
c = vec3<f32>(1.0, 1.0, 0.5);
d = vec3<f32>(0.80, 0.90, 0.30); // lime / magenta
}
@@ -62,17 +65,66 @@ fn vs_main(@builtin(vertex_index) idx: u32) -> @builtin(position) vec4<f32> {
return vec4<f32>(verts[idx], 0.0, 1.0);
}
fn load(x: i32, y: i32) -> vec3<f32> {
let dist = textureLoad(data_tex, vec2<i32>(x, y), 0).g;
return vec3<f32>(f32(x), f32(y), dist);
}
fn compute_light(normal: vec3<f32>, light: vec3<f32>) -> vec3<f32> {
return vec3<f32>((dot(normal, normalize(light)) + 0.2) / 1.2);
}
fn uncharted2tonemap(x: vec3<f32>) -> vec3<f32> {
// Paramètres de la courbe de Hable
let A = 0.15; // Shoulder strength
let B = 0.50; // Linear strength
let C = 0.10; // Linear angle
let D = 0.20; // Toe strength
let E = 0.02; // Toe numerator / shoarder angle/etc.
let F = 0.30; // Toe denominator
return ((x * (A * x + C * B) + D * E) / (x * (A * x + B) + D * F)) - E / F;
}fn filmic(color: vec3<f32>) -> vec3<f32> {
let exposure_bias = 2.0;
let curr = uncharted2tonemap(color * exposure_bias);
// Valeur blanche maximale de référence
let white_scale = vec3(1.0) / uncharted2tonemap(vec3(4.2));
return curr * white_scale;
}
@fragment
fn fs_main(@builtin(position) pos: vec4<f32>) -> @location(0) vec4<f32> {
let d = textureLoad(data_tex, vec2<i32>(i32(pos.x), i32(pos.y)), 0);
let ci = d.r;
let de = d.g;
let interior_frac = d.b;
if u.shadow != 0u {
if textureLoad(data_tex, vec2<i32>(i32(pos.x), i32(pos.y)), 0).b != 0. {
return vec4<f32>(0., 0.11, 0.54, 1.0);
} else {
let d = array<vec3<f32>, 3>(load(i32(pos.x), i32(pos.y)), load(i32(pos.x + 1), i32(pos.y)), load(i32(pos.x), i32(pos.y + 1)));
let t = fract(ci * u.color_scale + u.color_offset);
var col = palette(u.palette_id, t) * de;
// Anti-alias the set boundary: fade toward black by the fraction of the
// pixel's sub-samples that landed in the interior.
col = col * (1.0 - interior_frac);
return vec4<f32>(col, 1.0);
let normal = normalize(cross(d[1] - d[0], d[2] - d[0]));
var color: vec3<f32>;
if u.shadow_palette_id == 0u {
color = compute_light(normal,vec3<f32>(.5, .5, .5));
} else {
color = compute_light(normal, vec3<f32>(0., .5, .5)) * vec3<f32>(1., 0.5, 0.5) + compute_light(normal, vec3<f32>(0.5, 0., .5)) * vec3<f32>(0.5, 1., 1.);
color = filmic(color);
}
return vec4<f32>(color, 1.0);
}
} else {
let d = textureLoad(data_tex, vec2<i32>(i32(pos.x), i32(pos.y)), 0);
let ci = d.r;
let de = d.g;
let interior_frac = d.b;
let t = fract(ci * u.color_scale + u.color_offset);
var col = palette(u.palette_id, t) * de;
// Anti-alias the set boundary: fade toward black by the fraction of the
// pixel's sub-samples that landed in the interior.
col = col * (1.0 - interior_frac);
return vec4<f32>(col, 1.0);
}
}
src/shaders/mandelbrot.wgsl
+8 -1
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@@ -21,6 +21,7 @@ struct Uniforms {
bailout_sq: f32,
is_julia: u32,
palette_id: u32,
shadow_palette_id: u32,
aa_level: u32,
// Iteration formula (see the KIND_* constants below).
kind: u32,
@@ -35,6 +36,8 @@ struct Uniforms {
lambda_l: vec2<f32>,
// 0 = escape-time coloring, 1 = distance-estimation shading.
de_coloring: u32,
// 0 = classic colors, 1 = shadows
shadow: u32,
};
const KIND_MANDELBROT: u32 = 0u;
@@ -326,7 +329,11 @@ fn iterate_sample(offset: vec2<f32>, px: f32) -> Sample {
let zmag = sqrt(max(z2, 1.0));
let dzmag = sqrt(max(dot(dz, dz), 1e-20));
let d = zmag * log(zmag) / dzmag;
de = clamp(d / max(px, 1e-30), 0.0, 1.0);
var max_de = 1.;
if u.shadow != 0u {
max_de = 1000.;
}
de = clamp(d / max(px, 1e-30), 0.0, max_de);
}
return Sample(ci, de, true);
}