feat: do not watch particle by default

1 files changed, 12 insertions, 6 deletions

diff --git a/playground/src/main.rs b/playground/src/main.rs
index f585efa..5b5c157 100644
--- a/playground/src/main.rs
+++ b/playground/src/main.rs
@@ -31,7 +31,7 @@ fn main() {
             Particle::new(Point::new(5.0, 20.0), 50.0),
             Particle::new(Point::origin(), 25.0),
             Particle::new(Point::new(50.0, 0.0), 10.0),
-            Particle::new(Point::new(-100.0, -100.0), 100.0),
+            Particle::new(Point::new(-30.0, -30.0), 10.0),
         ],
         constraints: vec![],
         forces: vec![
@@ -58,7 +58,8 @@ fn main() {
     system.add_beam_constraint([5, 4]);
 
     let mut selected_particle_id = None;
-    let mut watch_particle_id = 0;
+    let mut watch_particle_id = None;
+    let mouse_particle_id = system.particles.len() - 1;
 
     let (mut rl, thread) = raylib::init()
         .size(640, 480)
@@ -85,7 +86,13 @@ fn main() {
         );
 
         let camera = Camera::new(
-            system.particles[watch_particle_id].position,
+            match watch_particle_id {
+                Some(id) => {
+                    let particle: &Particle = &system.particles[id];
+                    particle.position
+                },
+                None => Point::origin(),
+            },
             Vector::y(),
             Vector::x(),
         );
@@ -98,7 +105,6 @@ fn main() {
                 let screen_space = raylib_to_screen_space(mouse_point, &d);
                 let world_mouse = camera.screen_space_to_world(screen_space);
 
-                let mouse_particle_id = system.particles.len() - 1;
                 system.particles[mouse_particle_id].position = world_mouse;
 
                 system.forces.push(Box::new(Spring {
@@ -149,7 +155,7 @@ fn main() {
                     PointBase::<f32, 2>::new(d.get_mouse_x() as f32, d.get_mouse_y() as f32);
                 let position = PointBase::<f32, 2>::new(position.x as f32, position.y as f32);
                 if (position - mouse_point).norm() < radius {
-                    watch_particle_id = particle_id
+                    watch_particle_id = Some(particle_id)
                 }
             }
 
@@ -159,7 +165,7 @@ fn main() {
                 radius,
                 if selected_particle_id.is_some_and(|v| v == particle_id) {
                     Color::RED
-                } else if watch_particle_id == particle_id {
+                } else if watch_particle_id.is_some_and(|v| v == particle_id) {
                     Color::YELLOW
                 } else {
                     Color::BLACK