feat: add shadow coloring

src/shaders/colorize.wgsl

@@ -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);
+    }
 }