Draw the tube better

Cargo.lock

@@ -1721,6 +1721,15 @@ dependencies = [
  "either",
 ]
 
+[[package]]
+name = "itertools"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "413ee7dfc52ee1a4949ceeb7dbc8a33f2d6c088194d9f922fb8318faf1f01186"
+dependencies = [
+ "either",
+]
+
 [[package]]
 name = "itertools-num"
 version = "0.1.3"
@@ -3101,6 +3110,7 @@ dependencies = [
  "flo_draw",
  "glam 0.27.0",
  "glium",
+ "itertools 0.13.0",
  "itertools-num",
  "rand",
  "rand_pcg",

Cargo.toml

@@ -23,6 +23,7 @@ flo_canvas = "0.3.1"
 itertools-num = "0.1.3"
 glium = "0.35.0"
 winit = "0.30.5"
+itertools = "0.13.0"
 
 [dev-dependencies]
 approx = "0.5.1"

src/bin/wireframe/scene.rs

@@ -1,4 +1,5 @@
 use glam::*;
+use itertools::{chain, iproduct};
 
 use refraction::ifaces::{DebugTraceable, Traceable};
 use refraction::tube::metric::Tube;
@@ -30,6 +31,18 @@ fn draw_rect(center: Vec3, u: Vec3, v: Vec3) -> Line {
 	])
 }
 
+fn draw_ellipse(center: Vec3, u: Vec3, v: Vec3) -> Line {
+	let segments = 47;
+	let step = 2. * std::f32::consts::PI / segments as f32;
+	Line::Loop(
+		(0..segments)
+			.map(|k| k as f32 * step)
+			.map(Vec2::from_angle)
+			.map(|d| center + d.x * u + d.y * v)
+			.collect(),
+	)
+}
+
 pub fn build() -> Vec<FancyLine> {
 	let tube = Tube {
 		inner_radius: 30.0,
@@ -113,17 +126,18 @@ trait Renderable {
 
 impl Renderable for Tube {
 	fn render(&self) -> Vec<Line> {
-		vec![
-			draw_rect(
-				vec3(0., 0., 0.),
-				vec3(self.outer_radius, 0., 0.),
-				vec3(0., self.external_halflength, 0.),
-			),
-			draw_rect(
-				vec3(0., 0., 0.),
-				vec3(self.inner_radius, 0., 0.),
-				vec3(0., self.external_halflength, 0.),
-			),
-		]
+		let lines = 17;
+		let step = 2. * std::f32::consts::PI / lines as f32;
+		let r = 0.5 * (self.outer_radius + self.inner_radius);
+		let w = 0.5 * (self.outer_radius - self.inner_radius);
+		let l = vec3(0., self.external_halflength, 0.);
+		let along = (0..lines)
+			.map(|k| k as f32 * step)
+			.map(Vec2::from_angle)
+			.map(|d| vec3(d.x, 0., d.y))
+			.map(|d| draw_rect(r * d, w * d, l));
+		let caps = iproduct!([self.inner_radius, self.outer_radius], [-l, l])
+			.map(|(r, l)| draw_ellipse(l, vec3(r, 0., 0.), vec3(0., 0., r)));
+		chain!(along, caps).collect()
 	}
 }