better window bounding boxes

I also switch to using generalized Rect instead of an app for places where i was using the window boundary

src/main.rs

@@ -1,6 +1,5 @@
 mod drawable;
 mod engine;
-mod particle;
 
 use drawable::DrawShape;
 use engine::{PhysicsEngine, PhysicsState};
@@ -8,33 +7,49 @@ use engine::{PhysicsEngine, PhysicsState};
 use nalgebra::vector;
 use nannou::prelude::*;
 use rapier2d::{
-    dynamics::{RigidBodyBuilder, RigidBodySet},
+    dynamics::{RigidBodyBuilder, RigidBodyHandle, RigidBodySet},
     geometry::{ColliderBuilder, ColliderSet},
 };
 
 const WINDOW_WIDTH: u32 = 512;
 const WINDOW_HEIGHT: u32 = WINDOW_WIDTH;
 const PARTICLE_COUNT: u32 = 200;
-const PARTICLE_SIZE: f32 = 10.0;
+const PARTICLE_SIZE: f32 = 5.;
 
 struct Model {
     // Store the window ID so we can refer to this specific window later if needed.
-    _window: WindowId,
+    window: WindowId,
     // particles: Vec<Particle>,
     engine: PhysicsEngine,
 }
 
-fn fill_particles(_app: &App, colliders: &mut ColliderSet, bodies: &mut RigidBodySet) {
-    let boundary = _app.window_rect();
-    for _ in 0..PARTICLE_COUNT {
+fn random_vec_in_rect(boundary: &Rect) -> nalgebra::Vector2<f32> {
     let x = random_range(-100., 100.);
     let y = random_range(-150., boundary.top());
 
+    vector![x, y]
+}
+
+fn fill_particles(boundary: &Rect, colliders: &mut ColliderSet, bodies: &mut RigidBodySet) {
+    // Keeping track of already placed balls to avoid overlap
+    // Need to look into a way to do this with rapier directly
+    let mut positions: Vec<nalgebra::Vector2<f32>> = Vec::new();
+
+    for _ in 0..PARTICLE_COUNT {
+        let mut xy = random_vec_in_rect(boundary);
+        while !positions
+            .iter()
+            .all(|pos| pos.metric_distance(&xy) > PARTICLE_SIZE * 2.)
+        {
+            xy = random_vec_in_rect(boundary)
+        }
+        positions.push(xy);
+
         /* Create the bouncing ball. */
-        let rigid_body = RigidBodyBuilder::dynamic()
-            .translation(vector![x, y])
+        let rigid_body = RigidBodyBuilder::dynamic().translation(xy).build();
+        let collider = ColliderBuilder::ball(PARTICLE_SIZE)
+            .restitution(0.1)
             .build();
-        let collider = ColliderBuilder::ball(5.).restitution(0.1).build();
         let ball_body_handle = bodies.insert(rigid_body);
         colliders.insert_with_parent(collider, ball_body_handle, bodies);
     }
@@ -46,7 +61,7 @@ fn model(app: &App) -> Model {
     // per app
 
     // Create a new window! Store the ID so we can refer to it later.
-    let _window = app
+    let window = app
         .new_window()
         .size(WINDOW_WIDTH, WINDOW_HEIGHT)
         .title("nannou")
@@ -57,43 +72,79 @@ fn model(app: &App) -> Model {
 
     let mut engine = PhysicsEngine {
         state: PhysicsState {
-            gravity: vector![0.0, -9.81 * 10.0],
+            gravity: vector![0., -9.81 * 10.],
             ..Default::default()
         },
         ..Default::default()
     };
 
+    let boundary = app.window(window).unwrap().rect();
+
     /* Create the ground. */
-    let collider = ColliderBuilder::cuboid(100.0, 10.0)
-        .translation(vector![0.0, -200.0])
+    let collider = ColliderBuilder::cuboid(boundary.w(), 4.)
+        .translation(vector![0., boundary.bottom()])
         .build();
     engine.state.colliders.insert(collider);
 
-    // let mut particles = Vec::new();
+    /* Create the walls. */
+    let collider = ColliderBuilder::cuboid(4., boundary.h())
+        .translation(vector![boundary.left(), 0.])
+        .build();
+    engine.state.colliders.insert(collider);
+    let collider = ColliderBuilder::cuboid(4., boundary.h())
+        .translation(vector![boundary.right(), 0.])
+        .build();
+    engine.state.colliders.insert(collider);
 
-    // fill_particles(app, &mut particles);
-    fill_particles(app, &mut engine.state.colliders, &mut engine.state.bodies);
+    /* Create the ceiling. */
+    let collider = ColliderBuilder::cuboid(boundary.w(), 4.)
+        .translation(vector![0., boundary.top()])
+        .build();
+    engine.state.colliders.insert(collider);
 
-    Model {
-        _window,
-        // particles,
-        engine,
-    }
+    fill_particles(
+        &boundary,
+        &mut engine.state.colliders,
+        &mut engine.state.bodies,
+    );
+
+    Model { window, engine }
 }
 
 // Handle events related to the window and update the model if necessary
-fn event(app: &App, _model: &mut Model, event: WindowEvent) {
+fn event(app: &App, model: &mut Model, event: WindowEvent) {
     if let KeyReleased(Key::Escape) = event {
         app.quit()
     }
 
-    // if let Resized(_) = event {
-    //     model.particles.clear();
-    //
-    //     fill_particles(app, &mut model.particles);
-    // }
+    if let Resized(_) = event {
+        // Rust borrowing rules means I need to first gather a list of handles,
+        // then delete them all
+        let handles: Vec<RigidBodyHandle> = model
+            .engine
+            .state
+            .bodies
+            .iter()
+            .map(|(handle, _)| handle)
+            .collect();
 
-    // println!("{:?}", event);
+        for handle in handles {
+            model.engine.state.bodies.remove(
+                handle,
+                &mut model.engine.state.islands,
+                &mut model.engine.state.colliders,
+                &mut model.engine.state.joints,
+                &mut model.engine.state.multibody_joints,
+                true,
+            );
+        }
+
+        fill_particles(
+            &app.window(model.window).unwrap().rect(),
+            &mut model.engine.state.colliders,
+            &mut model.engine.state.bodies,
+        );
+    }
 }
 
 // Update the state of your application here. By default, this gets called right before `view`.

src/particle.rs

@@ -1,43 +0,0 @@
-use crate::drawable::Drawable;
-use crate::PARTICLE_SIZE;
-
-use nannou::prelude::*;
-
-#[derive(Debug)]
-pub struct Particle {
-    pub pos: Vec2,
-    pub start_pos: Vec2,
-    pub radius: f32,
-    pub time_offset: f32,
-}
-
-impl Particle {
-    pub fn new(pos: Vec2) -> Self {
-        Self {
-            pos,
-            start_pos: pos,
-            ..Default::default()
-        }
-    }
-}
-
-impl Default for Particle {
-    fn default() -> Self {
-        Self {
-            pos: Default::default(),
-            radius: PARTICLE_SIZE,
-            start_pos: Default::default(),
-            time_offset: random_range(-PI, PI),
-        }
-    }
-}
-
-impl Drawable for Particle {
-    fn draw(&self, draw: &Draw) {
-        draw.ellipse()
-            .color(RED)
-            .stroke_weight(1.0)
-            .radius(self.radius)
-            .xy(self.pos);
-    }
-}