Implement support for STL model loading/deserialization

Cargo.toml

@@ -33,6 +33,7 @@ bmp = ["image/bmp"]
 
 obj = ["wavefront_obj"]
 gltf = ["dep:gltf"]
+stl = ["dep:stl_io"]
 
 pcd = ["pcd-rs"]
 
@@ -47,6 +48,7 @@ thiserror = "1"
 reqwest = {version = "0.11", optional = true, default-features = false }
 gltf = { version = "1", optional = true, features=["KHR_materials_ior", "KHR_materials_transmission"] }
 wavefront_obj = { version = "10", optional = true }
+stl_io = { version = "0.8.2", optional = true }
 image = { version = "0.24", optional = true, default-features = false}
 pcd-rs = { version = "0.10", optional = true, features = ["derive"] }
 data-url = {version = "0.3", optional = true }

src/io.rs

@@ -48,6 +48,9 @@ pub use saver::*;
 #[cfg(feature = "obj")]
 mod obj;
 
+#[cfg(feature = "stl")]
+mod stl;
+
 #[cfg(feature = "gltf")]
 mod gltf;
 
@@ -181,6 +184,13 @@ impl Deserialize for crate::Scene {
                 #[cfg(feature = "obj")]
                 obj::deserialize_obj(raw_assets, &path)
             }
+            "stl" => {
+                #[cfg(not(feature = "stl"))]
+                return Err(Error::FeatureMissing("stl".to_string()));
+
+                #[cfg(feature = "stl")]
+                stl::deserialize_stl(raw_assets, &path)
+            }
             "pcd" => {
                 #[cfg(not(feature = "pcd"))]
                 return Err(Error::FeatureMissing("pcd".to_string()));

src/io/stl.rs

@@ -0,0 +1,77 @@
+use std::path::PathBuf;
+
+use crate::{Node, Positions, Result, TriMesh};
+
+use crate::{io::RawAssets, Scene};
+
+use cgmath::Vector3;
+
+pub fn deserialize_stl(raw_assets: &mut RawAssets, path: &PathBuf) -> Result<Scene> {
+    let stl_bytes = raw_assets.remove(path)?;
+    let mut stl_bytes = std::io::Cursor::new(stl_bytes.to_vec());
+    let stl = stl_io::read_stl(&mut stl_bytes)?;
+
+    let positions = stl
+        .vertices
+        .iter()
+        .map(|vertex| Vector3 {
+            x: vertex[0],
+            y: vertex[1],
+            z: vertex[2],
+        })
+        .collect();
+
+    let mut indices = Vec::with_capacity(stl.faces.len() * 3);
+    let mut normals = Vec::with_capacity(stl.faces.len());
+    for face in stl.faces {
+        let face_indices = face.vertices;
+        indices.push(face_indices[0] as u32);
+        indices.push(face_indices[1] as u32);
+        indices.push(face_indices[2] as u32);
+
+        normals.push(Vector3 {
+            x: face.normal[0],
+            y: face.normal[1],
+            z: face.normal[2],
+        });
+    }
+
+    let mesh = TriMesh {
+        positions: Positions::F32(positions),
+        indices: crate::Indices::U32(indices),
+        normals: Some(normals),
+        tangents: None,
+        uvs: None,
+        colors: None,
+    };
+
+    // STL files contain only one object, so only one node
+    let node = Node {
+        geometry: Some(crate::Geometry::Triangles(mesh)),
+        ..Default::default()
+    };
+
+    Ok(Scene {
+        // stl_io does not expose the name it seems, so using path instead
+        name: path.to_str().unwrap_or("default").to_owned(),
+        children: vec![node],
+        materials: vec![],
+    })
+}
+
+#[cfg(test)]
+mod test {
+    #[test]
+    pub fn deserialize_stl_ascii() {
+        let model: crate::Model = crate::io::load_and_deserialize("test_data/cube.stl").unwrap();
+        assert_eq!(model.geometries.len(), 1);
+        assert_eq!(model.materials.len(), 0);
+    }
+
+    #[test]
+    pub fn deserialize_stl_binary() {
+        let model: crate::Model = crate::io::load_and_deserialize("test_data/suzanne.stl").unwrap();
+        assert_eq!(model.geometries.len(), 1);
+        assert_eq!(model.materials.len(), 0);
+    }
+}

src/lib.rs

@@ -226,7 +226,7 @@ pub enum Error {
     #[error("error while parsing an .pcd file")]
     Pcd(#[from] pcd_rs::anyhow::Error),
 
-    #[cfg(not(target_arch = "wasm32"))]
+    #[cfg(any(not(target_arch = "wasm32"), feature = "stl"))]
     #[error("io error")]
     IO(#[from] std::io::Error),
     #[cfg(feature = "gltf")]

test_data/cube.stl

@@ -0,0 +1,86 @@
+solid Exported from Blender-4.0.2
+facet normal 0.000000 0.000000 1.000000
+outer loop
+vertex 1.000000 1.000000 1.000000
+vertex -1.000000 1.000000 1.000000
+vertex -1.000000 -1.000000 1.000000
+endloop
+endfacet
+facet normal 0.000000 0.000000 1.000000
+outer loop
+vertex 1.000000 1.000000 1.000000
+vertex -1.000000 -1.000000 1.000000
+vertex 1.000000 -1.000000 1.000000
+endloop
+endfacet
+facet normal 0.000000 -1.000000 0.000000
+outer loop
+vertex 1.000000 -1.000000 -1.000000
+vertex 1.000000 -1.000000 1.000000
+vertex -1.000000 -1.000000 1.000000
+endloop
+endfacet
+facet normal 0.000000 -1.000000 0.000000
+outer loop
+vertex 1.000000 -1.000000 -1.000000
+vertex -1.000000 -1.000000 1.000000
+vertex -1.000000 -1.000000 -1.000000
+endloop
+endfacet
+facet normal -1.000000 0.000000 0.000000
+outer loop
+vertex -1.000000 -1.000000 -1.000000
+vertex -1.000000 -1.000000 1.000000
+vertex -1.000000 1.000000 1.000000
+endloop
+endfacet
+facet normal -1.000000 0.000000 0.000000
+outer loop
+vertex -1.000000 -1.000000 -1.000000
+vertex -1.000000 1.000000 1.000000
+vertex -1.000000 1.000000 -1.000000
+endloop
+endfacet
+facet normal 0.000000 0.000000 -1.000000
+outer loop
+vertex -1.000000 1.000000 -1.000000
+vertex 1.000000 1.000000 -1.000000
+vertex 1.000000 -1.000000 -1.000000
+endloop
+endfacet
+facet normal 0.000000 0.000000 -1.000000
+outer loop
+vertex -1.000000 1.000000 -1.000000
+vertex 1.000000 -1.000000 -1.000000
+vertex -1.000000 -1.000000 -1.000000
+endloop
+endfacet
+facet normal 1.000000 0.000000 0.000000
+outer loop
+vertex 1.000000 1.000000 -1.000000
+vertex 1.000000 1.000000 1.000000
+vertex 1.000000 -1.000000 1.000000
+endloop
+endfacet
+facet normal 1.000000 0.000000 0.000000
+outer loop
+vertex 1.000000 1.000000 -1.000000
+vertex 1.000000 -1.000000 1.000000
+vertex 1.000000 -1.000000 -1.000000
+endloop
+endfacet
+facet normal 0.000000 1.000000 0.000000
+outer loop
+vertex -1.000000 1.000000 -1.000000
+vertex -1.000000 1.000000 1.000000
+vertex 1.000000 1.000000 1.000000
+endloop
+endfacet
+facet normal 0.000000 1.000000 0.000000
+outer loop
+vertex -1.000000 1.000000 -1.000000
+vertex 1.000000 1.000000 1.000000
+vertex 1.000000 1.000000 -1.000000
+endloop
+endfacet
+endsolid Exported from Blender-4.0.2