l: add facet object so that we can reder triangles, thus meshes!

l/examples/trex.rs

@@ -0,0 +1,33 @@
+use std::{path::Path, sync::Arc};
+
+use geo::{mesh::load_mesh, util::opener, Vec3};
+
+use l::*;
+
+pub fn main() -> opener::Result<()> {
+    let mesh = load_mesh(
+        Path::new(env!("CARGO_MANIFEST_DIR"))
+            .join("..")
+            .join("data")
+            .join("t-rex-skull.stl"),
+    )
+    .expect("cannot load t-rex-skull.stl");
+
+    let scene = Scene::new(
+        mesh.triangles()
+            .map(|f| Arc::new(Facet::new(f)) as Arc<dyn Object>)
+            .collect::<Vec<_>>(),
+    );
+
+    let camera = Camera::look_at(
+        Vec3::new(-30.0, -10.0, 10.0),
+        Vec3::zero(),
+        Vec3::new(0.0, 0.0, -1.0),
+    )
+    .with_perspective_projection(60.0, 1.0, 0.01, 10000.0);
+
+    let paths = render(camera, &scene, &Settings { eps: 0.001 });
+    dump_svg("trex.svg", &paths, (1024.0, 1024.0)).expect("cannot save trex.svg");
+
+    opener::open("trex.svg")
+}

l/src/object/facet.rs

@@ -0,0 +1,38 @@
+use geo::{spatial_index::Shape, triangle, Vec3};
+
+use crate::Object;
+
+#[derive(Debug)]
+pub struct Facet {
+    a: Vec3,
+    b: Vec3,
+    c: Vec3,
+}
+
+impl Facet {
+    pub fn new(triangle: [Vec3; 3]) -> Self {
+        Self {
+            a: triangle[0],
+            b: triangle[1],
+            c: triangle[2],
+        }
+    }
+}
+
+impl Shape for Facet {
+    type Intersection = f64;
+
+    fn intersection(&self, ray: &geo::ray::Ray) -> Option<Self::Intersection> {
+        triangle::ray_intersection((self.a, self.b, self.c), ray)
+    }
+
+    fn bbox(&self) -> geo::Aabb {
+        triangle::bbox(self.a, self.b, self.c)
+    }
+}
+
+impl Object for Facet {
+    fn paths(&self) -> Vec<crate::Polyline> {
+        vec![vec![self.a, self.b, self.c]]
+    }
+}

l/src/object/mod.rs

@@ -1,3 +1,5 @@
 mod cube;
+mod facet;
 
 pub use cube::Cube;
+pub use facet::Facet;