From fcd09c1d1db748d7d94be9c95e430faa0346b839 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?T=C3=81NCZOS=20Vilmos=20Zsombor?=
 <vilmos.zsombor@tanczos.dev>
Date: Sat, 31 May 2025 23:35:57 +0200
Subject: [PATCH] get some more variables from storage

---
 assets/shaders/mandelbulb.wgsl | 12 +++++---
 src/main.rs                    |  7 +----
 src/mandelbulb.rs              | 56 +++++++++++++++++++++++++++++-----
 3 files changed, 58 insertions(+), 17 deletions(-)

diff --git a/assets/shaders/mandelbulb.wgsl b/assets/shaders/mandelbulb.wgsl
index bc9de50..b4c84d3 100644
--- a/assets/shaders/mandelbulb.wgsl
+++ b/assets/shaders/mandelbulb.wgsl
@@ -10,6 +10,10 @@ struct VoluMaterial {
     model_inverse: mat4x4<f32>,
     power: f32,
     iterations: i32,
+    max_distance: f32,
+    max_steps: i32,
+    ray_epsilon: f32,
+    normal_epsilon: f32,
 }
 
 @group(2) @binding(100)
@@ -47,7 +51,7 @@ fn mandelbulb_sdf(p: vec3<f32>) -> f32 {
 }
 
 fn mandelbulb_normal(p: vec3<f32>) -> vec3<f32> {
-    let e = 0.001;
+    let e = volu_material.normal_epsilon;
     let dx = mandelbulb_sdf(p + vec3<f32>(e, 0.0, 0.0)) - mandelbulb_sdf(p - vec3<f32>(e, 0.0, 0.0));
     let dy = mandelbulb_sdf(p + vec3<f32>(0.0, e, 0.0)) - mandelbulb_sdf(p - vec3<f32>(0.0, e, 0.0));
     let dz = mandelbulb_sdf(p + vec3<f32>(0.0, 0.0, e)) - mandelbulb_sdf(p - vec3<f32>(0.0, 0.0, e));
@@ -56,9 +60,9 @@ fn mandelbulb_normal(p: vec3<f32>) -> vec3<f32> {
 
 fn raymarch(ray_origin: vec3<f32>, ray_direction: vec3<f32>) -> f32 {
     var t = 0.0;
-    let max_distance = 100.0;
-    let max_steps = 128;
-    let epsilon = 0.001;
+    let max_distance = volu_material.max_distance;
+    let max_steps = volu_material.max_steps;
+    let epsilon = volu_material.ray_epsilon;
 
     for (var i = 0; i < max_steps; i++) {
         let current_pos = ray_origin + t * ray_direction;
diff --git a/src/main.rs b/src/main.rs
index 588d557..2041992 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -27,12 +27,7 @@ fn setup(
 ) {
     let transform = Transform::from_xyz(0.0, 0.0, 0.0);
 
-    let storage = buffers.add(ShaderStorageBuffer::from(MandelbulbStorage {
-        mesh_translation: transform.translation,
-        model_inverse: transform.compute_matrix().inverse(),
-        power: 8.0,
-        iterations: 32,
-    }));
+    let storage = buffers.add(ShaderStorageBuffer::from(MandelbulbStorage::default()));
 
     commands.spawn((
         Mesh3d(meshes.add(Cuboid::new(2.0, 2.0, 2.0))),
diff --git a/src/mandelbulb.rs b/src/mandelbulb.rs
index 82dab75..ca30cfc 100644
--- a/src/mandelbulb.rs
+++ b/src/mandelbulb.rs
@@ -13,13 +13,38 @@ const SHADER_ASSET_PATH: &str = "shaders/mandelbulb.wgsl";
 
 pub fn plugin(app: &mut App) {
     app.add_plugins(MaterialPlugin::<MandelbulbMaterial>::default())
+        .init_resource::<MandelbulbSettings>()
         .add_systems(Update, update_volu_material);
 }
 
+#[derive(Resource)]
+struct MandelbulbSettings {
+    power: f32,
+    iterations: i32,
+    max_distance: f32,
+    max_steps: i32,
+    ray_epsilon: f32,
+    normal_epsilon: f32,
+}
+
+impl Default for MandelbulbSettings {
+    fn default() -> Self {
+        Self {
+            power: 8.,
+            iterations: 256,
+            max_distance: 100.,
+            max_steps: 128,
+            ray_epsilon: 0.001,
+            normal_epsilon: 0.001,
+        }
+    }
+}
+
 fn update_volu_material(
     q: Query<(&Transform, &MeshMaterial3d<MandelbulbMaterial>)>,
     mut volu_materials: ResMut<Assets<MandelbulbMaterial>>,
     mut buffers: ResMut<Assets<ShaderStorageBuffer>>,
+    settings: Res<MandelbulbSettings>,
 ) {
     for (transform, material) in q.iter() {
         let volu_material = volu_materials.get_mut(material.0.id()).unwrap();
@@ -28,11 +53,24 @@ fn update_volu_material(
             .get_mut(volu_material.extension.storage.id())
             .unwrap();
 
+        let MandelbulbSettings {
+            power,
+            iterations,
+            max_distance,
+            max_steps,
+            ray_epsilon,
+            normal_epsilon,
+        } = *settings;
+
         let volu_storage = MandelbulbStorage {
             mesh_translation: transform.translation,
             model_inverse: transform.compute_matrix(),
-            power: 8.0,
-            iterations: 32,
+            power,
+            iterations,
+            max_distance,
+            max_steps,
+            ray_epsilon,
+            normal_epsilon,
         };
 
         buffer.set_data(volu_storage);
@@ -42,7 +80,7 @@ fn update_volu_material(
 #[derive(Asset, AsBindGroup, Reflect, Debug, Clone)]
 pub struct MandelbulbExtension {
     #[storage(100, read_only)]
-    pub storage: Handle<ShaderStorageBuffer>,
+    storage: Handle<ShaderStorageBuffer>,
 }
 
 impl MaterialExtension for MandelbulbExtension {
@@ -65,8 +103,12 @@ impl MandelbulbExtension {
 
 #[derive(ShaderType, Clone, Default, Debug)]
 pub struct MandelbulbStorage {
-    pub mesh_translation: Vec3,
-    pub model_inverse: Mat4,
-    pub power: f32,
-    pub iterations: i32,
+    mesh_translation: Vec3,
+    model_inverse: Mat4,
+    power: f32,
+    iterations: i32,
+    max_distance: f32,
+    max_steps: i32,
+    ray_epsilon: f32,
+    normal_epsilon: f32,
 }