commit b97c6055a1944a494307fdaecab584eed8e7733c
Author: Alex Selimov <alex@alexselimov.com>
Date:   Mon Feb 10 22:48:23 2025 -0500

    Initial commit with STL parser

diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..4a319a5
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,7 @@
+[package]
+name = "roctree"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+anyhow = "*"
diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..fa3c805
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,2 @@
+pub mod stl;
+pub mod utilities;
diff --git a/src/stl/mod.rs b/src/stl/mod.rs
new file mode 100644
index 0000000..67c567f
--- /dev/null
+++ b/src/stl/mod.rs
@@ -0,0 +1 @@
+pub mod parser;
diff --git a/src/stl/parser.rs b/src/stl/parser.rs
new file mode 100644
index 0000000..09bc43f
--- /dev/null
+++ b/src/stl/parser.rs
@@ -0,0 +1,295 @@
+use anyhow::Result;
+use anyhow::{anyhow, Context};
+use std::collections::HashMap;
+use std::fs::File;
+use std::io::{BufRead, BufReader, Read};
+use std::path::Path;
+
+/// Representation of an STL mesh
+/// Vertices are stored in vec with repeat vertices removed. Each vertex is represented as an
+/// [f32; 3]. Triangles are represented as a [usize; 3] where each entry is an index in the
+/// vertices Vec
+pub struct StlSolid {
+    vertices: Vec<[f32; 3]>,
+    triangles: Vec<[usize; 3]>,
+    normals: Vec<[f32; 3]>,
+}
+
+pub fn parse_ascii_stl(file_path: &impl AsRef<Path>) -> Result<StlSolid> {
+    let file = File::open(file_path.as_ref())
+        .with_context(|| format!("Failed to open file \'{:?}\'!", file_path.as_ref()))?;
+
+    let mut lines = BufReader::new(file).lines();
+
+    // the first line starts with solid <name>
+    match lines.next() {
+        Some(Ok(line)) => {
+            if !line.starts_with("solid ") {
+                return Err(anyhow!("STL file does not start with \'solid\'!"));
+            }
+        }
+        Some(Err(err)) => {
+            return Err(anyhow!("Failed to read the first line!\nError: {}", err));
+        }
+        None => return Err(anyhow!("Failed to read from the file!")),
+    }
+
+    let mut lines = lines
+        .map_while(Result::ok)
+        .filter(|line| !line.trim().is_empty());
+
+    // facet normal -0.01905 -0.770147 0.637582
+    //     outer loop
+    //     vertex 3.29426 -0.2921 0.067036
+    //     vertex 3.35026 -0.216682 0.159808
+    //     vertex 3.11981 -0.142593 0.242416
+    //     endloop
+    // endfacet
+    let mut unique_vertices: HashMap<String, usize> = HashMap::new();
+    let mut normals: Vec<[f32; 3]> = Vec::new();
+    let mut triangles: Vec<[usize; 3]> = Vec::new();
+
+    // Main reading loop
+    while let Some(line) = lines.next() {
+        let line = line.trim();
+
+        // Read the facet normal
+        if line.starts_with("facet normal ") {
+            let pts = line
+                .split_whitespace()
+                .skip(2)
+                .map(|num| num.parse())
+                .collect::<Result<Vec<f32>, _>>()
+                .map_err(|err| anyhow!("Failed to parse normal coordinates! Err: {err:?}"))?;
+
+            normals.push([
+                *pts.first()
+                    .ok_or(anyhow!("facet normal should have 3 positions"))?,
+                *pts.get(1)
+                    .ok_or(anyhow!("facet normal should have 3 positions"))?,
+                *pts.get(2)
+                    .ok_or(anyhow!("facet normal should have 3 positions"))?,
+            ]);
+
+            // outer loop
+            lines.next();
+            let mut indices = [0; 3];
+            for index in indices.iter_mut() {
+                if let Some(line) = lines.next() {
+                    if !unique_vertices.contains_key(&line) {
+                        unique_vertices.insert(line.clone(), unique_vertices.len());
+                    }
+                    *index = unique_vertices[&line];
+                }
+            }
+            triangles.push(indices);
+
+            // endloop
+            lines.next();
+            // endfacet
+            lines.next();
+        }
+    }
+
+    // Now convert the unique vertices to a vec
+    let mut vertices = vec![[0.0; 3]; unique_vertices.len()];
+    for (k, v) in unique_vertices.iter() {
+        let pts = k
+            .split_whitespace()
+            .skip(1)
+            .map(|num| num.parse())
+            .collect::<Result<Vec<f32>, _>>()
+            .map_err(|err| anyhow!("Failed to parse vertex coordinates! Err: {err:?}"))?;
+        vertices[*v] = [
+            *pts.first()
+                .ok_or(anyhow!("vertex should have 3 positions"))?,
+            *pts.get(1)
+                .ok_or(anyhow!("vertex should have 3 positions"))?,
+            *pts.get(2)
+                .ok_or(anyhow!("vertex should have 3 positions"))?,
+        ];
+    }
+
+    Ok(StlSolid {
+        vertices,
+        triangles,
+        normals,
+    })
+}
+
+/// Parse a binary stl file
+/// The specification for a binary stl file can be found at:
+/// https://www.loc.gov/preservation/digital/formats/fdd/fdd000505.shtml
+pub fn parse_binary_stl(file_path: &impl AsRef<Path>) -> Result<StlSolid> {
+    let mut file = File::open(file_path.as_ref())
+        .with_context(|| format!("Failed to open file \'{:?}\'!", file_path.as_ref()))?;
+
+    let mut header = [0u8; 80];
+    file.read_exact(&mut header)
+        .with_context(|| "Failed to read header from binary STL")?;
+
+    let mut num_triangles_bytes = [0u8; 4];
+    file.read_exact(&mut num_triangles_bytes)
+        .with_context(|| "Failed to read number of triangles from binary STL")?;
+    let num_triangles = u32::from_le_bytes(num_triangles_bytes);
+
+    let mut unique_vertices: HashMap<String, usize> = HashMap::new();
+    let mut normals: Vec<[f32; 3]> = Vec::new();
+    let mut vertices: Vec<[f32; 3]> = Vec::new();
+    let mut triangles: Vec<[usize; 3]> = Vec::new();
+
+    // Main reading loop
+    for _i in 0..num_triangles {
+        let mut buffer = [0u8; 50];
+        file.read_exact(&mut buffer)
+            .with_context(|| "Failed to read triangle from binary stl")?;
+
+        normals.push([
+            f32::from_le_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]),
+            f32::from_le_bytes([buffer[4], buffer[5], buffer[6], buffer[7]]),
+            f32::from_le_bytes([buffer[8], buffer[9], buffer[10], buffer[11]]),
+        ]);
+
+        let mut indices = [0; 3];
+        for (i, index) in indices.iter_mut().enumerate() {
+            let offset = 12 + i * 12;
+            let mut vertex = [0.0; 3];
+            vertex[0] = f32::from_le_bytes([
+                buffer[offset],
+                buffer[offset + 1],
+                buffer[offset + 2],
+                buffer[offset + 3],
+            ]);
+            vertex[1] = f32::from_le_bytes([
+                buffer[offset + 4],
+                buffer[offset + 5],
+                buffer[offset + 6],
+                buffer[offset + 7],
+            ]);
+            vertex[2] = f32::from_le_bytes([
+                buffer[offset + 8],
+                buffer[offset + 9],
+                buffer[offset + 10],
+                buffer[offset + 11],
+            ]);
+            let key = format!("{vertex:?}").to_string();
+            if !unique_vertices.contains_key(&key) {
+                vertices.push(vertex);
+                unique_vertices.insert(key.clone(), unique_vertices.len());
+            }
+            //Safe to unwrap because we validate the key is present
+            *index = *(unique_vertices.get(&key).unwrap());
+        }
+        triangles.push(indices);
+    }
+
+    Ok(StlSolid {
+        vertices,
+        triangles,
+        normals,
+    })
+}
+
+#[cfg(test)]
+pub mod test {
+    use super::*;
+    use crate::assert_vec_tol;
+
+    struct VerticesNormalsTriangles(Vec<[f32; 3]>, Vec<[f32; 3]>, Vec<[usize; 3]>);
+
+    fn get_real_cube() -> VerticesNormalsTriangles {
+        let unique_vertices = vec![
+            [13.0, -22.0, 20.0],
+            [13.0, -22.0, 0.0],
+            [13.0, -2.0, 0.0],
+            [13.0, -2.0, 20.0],
+            [-7.0, -2.0, 20.0],
+            [-7.0, -2.0, 0.0],
+            [-7.0, -22.0, 0.0],
+            [-7.0, -22.0, 20.0],
+        ];
+        let normals = vec![
+            [1.0, -0.0, 0.0],
+            [1.0, -0.0, 0.0],
+            [-1.0, -0.0, -0.0],
+            [-1.0, -0.0, 0.0],
+            [0.0, 0.0, 1.0],
+            [-0.0, 0.0, 1.0],
+            [0.0, 0.0, -1.0],
+            [0.0, 0.0, -1.0],
+            [0.0, 1.0, 0.0],
+            [0.0, 1.0, -0.0],
+            [0.0, -1.0, 0.0],
+            [0.0, -1.0, 0.0],
+        ];
+        let triangles = vec![
+            [0, 1, 2],
+            [0, 2, 3],
+            [4, 5, 6],
+            [4, 6, 7],
+            [3, 4, 7],
+            [3, 7, 0],
+            [1, 6, 5],
+            [1, 5, 2],
+            [3, 2, 5],
+            [3, 5, 4],
+            [7, 6, 1],
+            [7, 1, 0],
+        ];
+
+        VerticesNormalsTriangles(unique_vertices, normals, triangles)
+    }
+    #[test]
+    pub fn test_parse_ascii_stl() {
+        let stl_solid = parse_ascii_stl(&"test_files/ascii_cube.stl").unwrap();
+
+        let VerticesNormalsTriangles(unique_vertices, normals, triangles) = get_real_cube();
+        // First check vertices
+        if stl_solid.vertices.len() != unique_vertices.len() {
+            panic!("Parsed incorrect number of vertices")
+        }
+        for (read, real) in stl_solid.vertices.iter().zip(unique_vertices.iter()) {
+            assert_vec_tol!(read, real, 1e-7);
+        }
+
+        // Now check the normals
+
+        for (read, real) in stl_solid.normals.iter().zip(normals.iter()) {
+            assert_vec_tol!(read, real, 1e-7);
+        }
+
+        // Now check the triangle indices
+
+        for (read, real) in stl_solid.triangles.iter().zip(triangles.iter()) {
+            for (idx1, idx2) in read.iter().zip(real.iter()) {
+                assert_eq!(idx1, idx2);
+            }
+        }
+    }
+
+    #[test]
+    pub fn test_parse_binary_stl() {
+        let stl_solid = parse_binary_stl(&"test_files/binary_cube.stl").unwrap();
+
+        let VerticesNormalsTriangles(unique_vertices, normals, triangles) = get_real_cube();
+        // First check vertices
+        if stl_solid.vertices.len() != unique_vertices.len() {
+            panic!("Parsed incorrect number of vertices")
+        }
+        for (read, real) in stl_solid.vertices.iter().zip(unique_vertices.iter()) {
+            assert_vec_tol!(read, real, 1e-7);
+        }
+
+        // Now check the normals
+        for (read, real) in stl_solid.normals.iter().zip(normals.iter()) {
+            assert_vec_tol!(read, real, 1e-7);
+        }
+
+        // Now check the triangle indices
+        for (read, real) in stl_solid.triangles.iter().zip(triangles.iter()) {
+            for (idx1, idx2) in read.iter().zip(real.iter()) {
+                assert_eq!(idx1, idx2);
+            }
+        }
+    }
+}
diff --git a/src/utilities/mod.rs b/src/utilities/mod.rs
new file mode 100644
index 0000000..6755121
--- /dev/null
+++ b/src/utilities/mod.rs
@@ -0,0 +1,2 @@
+#[cfg(test)]
+pub mod test_macros;
diff --git a/src/utilities/test_macros.rs b/src/utilities/test_macros.rs
new file mode 100644
index 0000000..aa5c0af
--- /dev/null
+++ b/src/utilities/test_macros.rs
@@ -0,0 +1,21 @@
+#[macro_export]
+macro_rules! assert_vec_tol {
+    ($a:expr, $b:expr, $tolerance:expr) => {{
+        let a = $a;
+        let b = $b;
+        let tolerance = $tolerance;
+
+        if a.len() != b.len() {
+            panic!("Vectors have different lengths: {} != {}", a.len(), b.len());
+        }
+
+        for (i, (&val_a, &val_b)) in a.iter().zip(b.iter()).enumerate() {
+            if (val_a - val_b).abs() >= tolerance {
+                panic!(
+                    "Values at index {} differ by more than the tolerance: {} != {} (tolerance = {})",
+                    i, val_a, val_b, tolerance
+                );
+            }
+        }
+    }};
+}
diff --git a/test_files/ascii_cube.stl b/test_files/ascii_cube.stl
new file mode 100644
index 0000000..5841d56
--- /dev/null
+++ b/test_files/ascii_cube.stl
@@ -0,0 +1,86 @@
+solid STL generated by MeshLab
+  facet normal  1.000000e+00  0.000000e+00  0.000000e+00
+    outer loop
+      vertex   1.300000e+01 -2.200000e+01  2.000000e+01
+      vertex   1.300000e+01 -2.200000e+01  0.000000e+00
+      vertex   1.300000e+01 -2.000000e+00  0.000000e+00
+    endloop
+  endfacet
+  facet normal  1.000000e+00 -0.000000e+00  0.000000e+00
+    outer loop
+      vertex   1.300000e+01 -2.200000e+01  2.000000e+01
+      vertex   1.300000e+01 -2.000000e+00  0.000000e+00
+      vertex   1.300000e+01 -2.000000e+00  2.000000e+01
+    endloop
+  endfacet
+  facet normal -1.000000e+00  0.000000e+00 -0.000000e+00
+    outer loop
+      vertex  -7.000000e+00 -2.000000e+00  2.000000e+01
+      vertex  -7.000000e+00 -2.000000e+00  0.000000e+00
+      vertex  -7.000000e+00 -2.200000e+01  0.000000e+00
+    endloop
+  endfacet
+  facet normal -1.000000e+00 -0.000000e+00  0.000000e+00
+    outer loop
+      vertex  -7.000000e+00 -2.000000e+00  2.000000e+01
+      vertex  -7.000000e+00 -2.200000e+01  0.000000e+00
+      vertex  -7.000000e+00 -2.200000e+01  2.000000e+01
+    endloop
+  endfacet
+  facet normal  0.000000e+00  0.000000e+00  1.000000e+00
+    outer loop
+      vertex   1.300000e+01 -2.000000e+00  2.000000e+01
+      vertex  -7.000000e+00 -2.000000e+00  2.000000e+01
+      vertex  -7.000000e+00 -2.200000e+01  2.000000e+01
+    endloop
+  endfacet
+  facet normal  0.000000e+00  0.000000e+00  1.000000e+00
+    outer loop
+      vertex   1.300000e+01 -2.000000e+00  2.000000e+01
+      vertex  -7.000000e+00 -2.200000e+01  2.000000e+01
+      vertex   1.300000e+01 -2.200000e+01  2.000000e+01
+    endloop
+  endfacet
+  facet normal  0.000000e+00  0.000000e+00 -1.000000e+00
+    outer loop
+      vertex   1.300000e+01 -2.200000e+01  0.000000e+00
+      vertex  -7.000000e+00 -2.200000e+01  0.000000e+00
+      vertex  -7.000000e+00 -2.000000e+00  0.000000e+00
+    endloop
+  endfacet
+  facet normal  0.000000e+00  0.000000e+00 -1.000000e+00
+    outer loop
+      vertex   1.300000e+01 -2.200000e+01  0.000000e+00
+      vertex  -7.000000e+00 -2.000000e+00  0.000000e+00
+      vertex   1.300000e+01 -2.000000e+00  0.000000e+00
+    endloop
+  endfacet
+  facet normal  0.000000e+00  1.000000e+00  0.000000e+00
+    outer loop
+      vertex   1.300000e+01 -2.000000e+00  2.000000e+01
+      vertex   1.300000e+01 -2.000000e+00  0.000000e+00
+      vertex  -7.000000e+00 -2.000000e+00  0.000000e+00
+    endloop
+  endfacet
+  facet normal  0.000000e+00  1.000000e+00  0.000000e+00
+    outer loop
+      vertex   1.300000e+01 -2.000000e+00  2.000000e+01
+      vertex  -7.000000e+00 -2.000000e+00  0.000000e+00
+      vertex  -7.000000e+00 -2.000000e+00  2.000000e+01
+    endloop
+  endfacet
+  facet normal  0.000000e+00 -1.000000e+00  0.000000e+00
+    outer loop
+      vertex  -7.000000e+00 -2.200000e+01  2.000000e+01
+      vertex  -7.000000e+00 -2.200000e+01  0.000000e+00
+      vertex   1.300000e+01 -2.200000e+01  0.000000e+00
+    endloop
+  endfacet
+  facet normal  0.000000e+00 -1.000000e+00  0.000000e+00
+    outer loop
+      vertex  -7.000000e+00 -2.200000e+01  2.000000e+01
+      vertex   1.300000e+01 -2.200000e+01  0.000000e+00
+      vertex   1.300000e+01 -2.200000e+01  2.000000e+01
+    endloop
+  endfacet
+endsolid vcg
diff --git a/test_files/binary_cube.stl b/test_files/binary_cube.stl
new file mode 100644
index 0000000..c3712fc
Binary files /dev/null and b/test_files/binary_cube.stl differ