use mutable vectors, to collect into several at once

src/lib.rs

@@ -6,6 +6,7 @@ use glam::{Mat4, UVec2, Vec3, vec3};
 
 use crate::{
 	camera::OrbitalCamera,
+	ray::Ray,
 	render::lines::{LookParams, Mesh, Pipeline, Vertex},
 	trace::{Scene, Source, Sphere},
 };
@@ -189,36 +190,45 @@ impl Core {
 		};
 
 		let mut prng = rand_pcg::Pcg64::new(42, 0);
-		let rays: Vec<Vertex> = (0..10000)
-			.flat_map(|_| {
-				let ray = source.make_ray(&mut prng);
-				if let Some(ray) = scene.trace_ray(ray) {
-					[
-						Vertex {
-							pos: ray.base - 0.02 * ray.dir,
-							color: vec3(1., 1., 1.),
-						},
-						Vertex {
-							pos: ray.base,
-							color: vec3(0., 1., 0.),
-						},
-					]
-				} else {
-					[
-						Vertex {
-							pos: ray.base,
-							color: vec3(1., 1., 1.),
-						},
-						Vertex {
-							pos: ray.base + 0.1 * ray.dir,
-							color: vec3(1., 0., 0.),
-						},
-					]
-				}
-			})
-			.collect();
+		let source_rays: Vec<Ray> = (0..1024).map(|_| source.make_ray(&mut prng)).collect();
+		let mut source_ray_display: Vec<Vertex> = Vec::with_capacity(source_rays.len());
+		let mut hits: Vec<Ray> = Vec::with_capacity(source_rays.len());
+		for ray in source_rays {
+			if let Some(hit) = scene.trace_ray(ray) {
+				hits.push(hit);
+				source_ray_display.extend([
+					Vertex {
+						pos: ray.base,
+						color: vec3(1., 1., 1.),
+					},
+					Vertex {
+						pos: ray.base + 0.1 * ray.dir,
+						color: vec3(0., 1., 0.),
+					},
+					Vertex {
+						pos: hit.base - 0.02 * hit.dir,
+						color: vec3(0., 0., 1.),
+					},
+					Vertex {
+						pos: hit.base,
+						color: vec3(1., 1., 1.),
+					},
+				]);
+			} else {
+				source_ray_display.extend([
+					Vertex {
+						pos: ray.base,
+						color: vec3(1., 1., 1.),
+					},
+					Vertex {
+						pos: ray.base + 0.1 * ray.dir,
+						color: vec3(1., 0., 0.),
+					},
+				]);
+			}
+		}
 		self.pipeline
-			.render(&mut pass, [&Mesh::new(&self.device, &rays)]);
+			.render(&mut pass, [&Mesh::new(&self.device, &source_ray_display)]);
 
 		drop(pass);
 		self.queue.submit(std::iter::once(encoder.finish()));