Remove mesh fixup (#79)

Mesh fixup doesn't actually guarantee manifold models [1], so the extra
complexity isn't worth it.

[1] https://www.mattkeeter.com/blog/2023-04-23-adversarial

CHANGELOG.md

@@ -2,6 +2,10 @@
 - Removed `threads` parameter from various `Settings` objects when targeting
   `wasm32`, so that it's harder to accidentally spawn threads (which would
   panic).
+- Removed `min_depth` / `max_depth` distinction in meshing; this doesn't
+  actually guarantee manifold models
+  (see [this scale-invariant adversarial model](https://www.mattkeeter.com/blog/2023-04-23-adversarial/)),
+  so the extra complexity isn't worth it.
 
 # 0.2.4
 The highlight of this release is a refactoring of how shapes are handled in Rhai

demo/src/main.rs

@@ -90,14 +90,10 @@ struct ImageSettings {
 
 #[derive(Parser)]
 struct MeshSettings {
-    /// Minimum octree depth
+    /// Octree depth
     #[clap(short, long)]
     depth: u8,
 
-    /// Maximum octree depth
-    #[clap(long)]
-    max_depth: Option<u8>,
-
     /// Name of a `.stl` file to write
     #[clap(short, long)]
     out: Option<PathBuf>,
@@ -251,8 +247,7 @@ fn run_mesh<S: fidget::eval::Shape>(
     for _ in 0..settings.n {
         let settings = fidget::mesh::Settings {
             threads: settings.threads,
-            min_depth: settings.depth,
-            max_depth: settings.max_depth.unwrap_or(settings.depth),
+            depth: settings.depth,
             ..Default::default()
         };
         let octree = fidget::mesh::Octree::build(&shape, settings);

fidget/benches/mesh.rs

@@ -15,8 +15,7 @@ pub fn colonnade_octree_thread_sweep(c: &mut Criterion) {
         c.benchmark_group("speed vs threads (colonnade, octree) (depth 6)");
     for threads in [1, 4, 8] {
         let cfg = &fidget::mesh::Settings {
-            min_depth: 6,
-            max_depth: 6,
+            depth: 6,
             threads: threads.try_into().unwrap(),
             ..Default::default()
         };
@@ -40,8 +39,7 @@ pub fn colonnade_mesh(c: &mut Criterion) {
     let (ctx, root) = fidget::Context::from_text(COLONNADE.as_bytes()).unwrap();
     let shape_vm = &fidget::vm::VmShape::new(&ctx, root).unwrap();
     let cfg = fidget::mesh::Settings {
-        min_depth: 8,
-        max_depth: 8,
+        depth: 8,
         ..Default::default()
     };
     let octree = &fidget::mesh::Octree::build(shape_vm, cfg);

fidget/src/mesh/mod.rs

@@ -27,8 +27,7 @@
 //! let tree = fidget::rhai::eval("sphere(0, 0, 0, 0.6)")?;
 //! let shape = VmShape::from_tree(&tree);
 //! let settings = Settings {
-//!     min_depth: 4,
-//!     max_depth: 4,
+//!     depth: 4,
 //!     ..Default::default()
 //! };
 //! let o = Octree::build(&shape, settings);
@@ -46,7 +45,6 @@ use crate::shape::Bounds;
 mod builder;
 mod cell;
 mod dc;
-mod fixup;
 mod frame;
 mod gen;
 mod octree;
@@ -83,17 +81,8 @@ impl Mesh {
 /// Settings when building an octree and mesh
 #[derive(Copy, Clone, Debug)]
 pub struct Settings {
-    /// Minimum depth to recurse in the octree
-    pub min_depth: u8,
-
-    /// Maximum depth to recurse in the octree
-    ///
-    /// If this is `> min_depth`, then after the octree is initially built
-    /// (recursing to `min_depth`), cells with escaped vertices are subdivided
-    /// recursively up to a limit of `max_depth`.
-    ///
-    /// This is **much slower**.
-    pub max_depth: u8,
+    /// Depth to recurse in the octree
+    pub depth: u8,
 
     /// Bounds for meshing
     pub bounds: Bounds<3>,
@@ -109,8 +98,7 @@ pub struct Settings {
 impl Default for Settings {
     fn default() -> Self {
         Self {
-            min_depth: 3,
-            max_depth: 3,
+            depth: 3,
             bounds: Default::default(),
 
             #[cfg(not(target_arch = "wasm32"))]