importer/stl: finish ascii stl loader

src/importer/stl.rs

@@ -1,18 +1,113 @@
-use std::io::{Read, Seek, BufReader};
+use std::io::{Read, Seek, BufReader, BufRead};
 
 use crate::{importer::ObjMesh, importer::Object, importer::Material, aabb::AABB, mesh::Vertex};
 
 const STL_HEADER_SIZE: u64 = 80;
-// might not be enough since it's not guaranteed. we'll see
-const ASCII_STL_MAGIC: [u8; 11] = [0x73, 0x6F, 0x6C, 0x69, 0x64, 0x20, 0x61, 0x73, 0x63, 0x69, 0x69]; // "solid ascii"
+const STL_TRIANGLE_SIZE: usize = 50;
 
 #[repr(packed(2))]
+#[derive(Debug)]
 struct STLTriangle {
     normal: glm::Vec3,
     verts: [glm::Vec3; 3],
     attribute_byte_count: u16
 }
 
+struct FacetIterator<R: Read> {
+    reader: BufReader<R>,
+}
+
+impl<R: Read> FacetIterator<R> {
+    fn new(reader: R) -> Self {
+        FacetIterator {
+            reader: BufReader::new(reader),
+        }
+    }
+}
+
+impl<R: Read> Iterator for FacetIterator<R> {
+    type Item = STLTriangle;
+
+    fn next(&mut self) -> Option<STLTriangle> {
+        let mut line = String::with_capacity(0x50);
+        let mut normal = glm::vec3(0.0, 0.0, 0.0);
+        let mut vertices = Vec::with_capacity(3);
+
+        loop {
+            match self.reader.read_line(&mut line) {
+                Ok(0) => return None, // Reached EOF
+                Ok(_) => {
+                    if line.contains("normal") {
+                        let mut norm_iter = line.split_whitespace().skip(2).map(|s| s.parse::<f32>().unwrap());
+                        normal.x = norm_iter.next().unwrap();
+                        normal.y = norm_iter.next().unwrap();
+                        normal.z = norm_iter.next().unwrap();
+                    } else if line.contains("vertex") {
+                        let mut vertex_iter = line.split_whitespace().skip(1).map(|s| s.parse::<f32>().unwrap());
+                        vertices.push(glm::vec3(vertex_iter.next().unwrap(), vertex_iter.next().unwrap(), vertex_iter.next().unwrap()));
+                    } else if line.contains("endfacet") {
+                        break;
+                    }
+                }
+                // TODO: might need to panic and log here in the future
+                Err(_) => return None, // Error reading
+            }
+            line.clear();
+        }
+
+        let mut verts_iter = vertices.iter();
+
+        Some(STLTriangle{
+            normal,
+            verts: [*verts_iter.next().unwrap(), *verts_iter.next().unwrap(), *verts_iter.next().unwrap()],
+            attribute_byte_count: 0
+        })
+    }
+}
+
+fn parse_ascii_stl(file: std::fs::File) -> Result<Object, Box<dyn std::error::Error>> {
+    let mut reader = BufReader::new(file);
+    let mut vertices = Vec::new();
+    let mut indices = Vec::new();
+    let mut min_aabb = glm::vec3(f32::MAX, f32::MAX, f32::MAX);
+    let mut max_aabb = glm::vec3(f32::MIN, f32::MIN, f32::MIN);
+
+    reader.read_line(&mut String::new())?; // Skip the first line (solid name)
+    let facet_iter = FacetIterator::new(reader);
+
+    let tex_coords = glm::vec2(0.0, 0.0);
+
+    for (i, triangle) in facet_iter.enumerate() {
+        for vert in triangle.verts {
+            vertices.push(Vertex{
+                position: glm::vec3(vert.x, vert.y, vert.z),
+                normal: glm::vec3(triangle.normal.x, triangle.normal.y, triangle.normal.z),
+                tex_coords,
+            });
+
+            min_aabb = glm::min(min_aabb, vert);
+            max_aabb = glm::max(max_aabb, vert);
+        }
+
+        indices.push(i as u32 * 3);
+        indices.push(i as u32 * 3 + 1);
+        indices.push(i as u32 * 3 + 2);
+    }
+
+    let aabb = AABB::new(min_aabb, max_aabb);
+
+    Ok(Object{
+        name: "default_object".to_string(),
+        meshes: vec![ObjMesh{
+            name: "default_mesh".to_string(),
+            vertices,
+            indices,
+            material: Some(Material::default())
+        }],
+        aabb,
+    })
+} 
+
 #[derive(Debug)]
 struct TrianglesIter<R: Read> {
     reader: R,
@@ -25,7 +120,7 @@ impl<R: Read> TrianglesIter<R> {
     fn new(reader: R, triangles_to_read: usize) -> Self {
         TrianglesIter {
             reader,
-            buf: vec![0u8; 50],
+            buf: vec![0u8; STL_TRIANGLE_SIZE],
             triangles_to_read,
             triangles_read: 0,
         }
@@ -62,10 +157,6 @@ impl<R: Read> Iterator for TrianglesIter<R> {
     }
 }
 
-fn parse_ascii_stl(file: std::fs::File) -> Result<Object, Box<dyn std::error::Error>> {
-    // TODO:
-} 
-
 fn parse_binary_stl(mut file: std::fs::File) -> Result<Object, Box<dyn std::error::Error>> {
     // skip header for now
     file.seek(std::io::SeekFrom::Start(STL_HEADER_SIZE))?;
@@ -92,29 +183,8 @@ fn parse_binary_stl(mut file: std::fs::File) -> Result<Object, Box<dyn std::erro
                 tex_coords,
             });
 
-            if vert.x < min_aabb.x {
-                min_aabb.x = vert.x;
-            }
-
-            if vert.y < min_aabb.y {
-                min_aabb.y = vert.y;
-            }
-
-            if vert.z < min_aabb.z {
-                min_aabb.z = vert.z;
-            }
-
-            if vert.x > max_aabb.x {
-                max_aabb.x = vert.x;
-            }
-
-            if vert.y > max_aabb.y {
-                max_aabb.y = vert.y;
-            }
-
-            if vert.z > max_aabb.z {
-                max_aabb.z = vert.z;
-            }
+            min_aabb = glm::min(min_aabb, vert);
+            max_aabb = glm::max(max_aabb, vert);
         }
 
         indices.push(i as u32*3);
@@ -136,21 +206,30 @@ fn parse_binary_stl(mut file: std::fs::File) -> Result<Object, Box<dyn std::erro
     })
 } 
 
+fn is_ascii(buf: &[u8]) -> bool {
+    for b in buf {
+        if *b > 127 {
+            return false;
+        }
+    }
+
+    true
+}
+
 pub fn load_stl(mut file: std::fs::File) -> Result<Object, Box<dyn std::error::Error>> {
-    let mut buf: [u8; 11] = [0; 11];
+    let mut buf: [u8; 512] = [0; 512];
     let _ = file.read_exact(&mut buf);
     _ = file.seek(std::io::SeekFrom::Start(0));
-    let is_ascii = buf == ASCII_STL_MAGIC;
+    let is_ascii = is_ascii(&buf);
 
+    let now = std::time::Instant::now();
     let obj = if is_ascii {
         parse_ascii_stl(file)?
     } else {
         parse_binary_stl(file)?
     };
-    let now = std::time::Instant::now();
-    let obj = parse_binary_stl(file)?;
     let elapsed = now.elapsed();
-    println!("STL file loaded in {} ms", elapsed.as_millis());
+    println!("STL file loaded in {} µs", elapsed.as_micros());
 
     Ok(obj)
 }