mesh display: allow switching perspective/orthographic in runtime

src/bin/mesh/main.rs

@@ -1,12 +1,14 @@
 use glam::*;
 use refraction::mesh_loader::load_mesh;
 use refraction::mesh_tracer::{trace_to_mesh, Mesh};
+use show_image::event::{ElementState, VirtualKeyCode, WindowEvent};
 use show_image::{exit, ImageInfo, ImageView, WindowOptions};
 use std::env;
 use std::error::Error;
 use std::f32::consts::PI;
 use std::fs::File;
 use std::io::BufReader;
+use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
 
 const W: i32 = 320;
 const H: i32 = 240;
@@ -109,6 +111,10 @@ fn test_projs() {
 	check(ortho, 9., 1., 8.);
 }
 
+// add_event_handler wants 'static + Send. Let it be so.
+static PROJ_INDEX: AtomicUsize = AtomicUsize::new(0);
+static PROJS: [fn(dist: f32, off: Vec2) -> (Vec3, Vec3); 2] = [persp, ortho];
+
 #[show_image::main]
 fn main() -> Result<(), Box<dyn Error>> {
 	let args: Vec<String> = env::args().collect();
@@ -121,10 +127,20 @@ fn main() -> Result<(), Box<dyn Error>> {
 		let mut f = BufReader::new(f);
 		load_mesh(&mut f)?
 	};
-	let proj = persp;
 	let window = show_image::create_window("Raytracing", WindowOptions::default())?;
+	window.add_event_handler(|_wnd, ev, _ctl| {
+		if let WindowEvent::KeyboardInput(ev) = ev {
+			if ev.input.state != ElementState::Pressed {
+				return;
+			}
+			if let Some(VirtualKeyCode::Tab) = ev.input.key_code {
+				PROJ_INDEX.store((PROJ_INDEX.load(Relaxed) + 1) % PROJS.len(), Relaxed);
+			}
+		}
+	})?;
 	loop {
 		for phi in 0..360 {
+			let proj = PROJS[PROJ_INDEX.load(Relaxed)];
 			let m_view = ypr_to_mat(vec3(
 				(135.0 + phi as f32) * PI / 180.0,
 				-30.0 * PI / 180.0,