New Example - Simple Physics Simulation (Confetti)

examples/confetti.rs

@@ -0,0 +1,221 @@
+use macroquad::prelude::*;
+extern crate micromath;
+use micromath::F32Ext;
+
+fn clip(pos: f32, bound: f32, velocity: f32) -> f32 {
+    if pos > bound {
+        let delta = (pos - bound).abs();
+        let mut new_velocity = velocity;
+        if velocity > 0.0 {
+            new_velocity = -velocity
+        }
+        if (new_velocity.abs() + BALL_RADIUS) < delta {
+            return -delta / get_fps() as f32 * 60.0;
+        }
+        return new_velocity * FLOOR_LOSS;
+    }
+    velocity
+}
+
+fn clip_minus(pos: f32, bound: f32, velocity: f32) -> f32 {
+    return -clip(bound, pos, -velocity);
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct Ball {
+    id: usize,
+    x: f32,
+    y: f32,
+    x_vel: f32,
+    y_vel: f32,
+    color: Color,
+}
+
+// Customizable
+const FLOOR_LOSS: f32 = 0.9;
+const DRAG: f32 = 0.998;
+const GRAVITY: f32 = 1.0;
+const MAX_VEL: f32 = 40.0;
+
+const BALL_RADIUS: f32 = 5.0;
+
+// Please, don't change
+static mut BALL_ID: usize = 0;
+const BALL_RADIUS_SQR: f32 = BALL_RADIUS * BALL_RADIUS;
+
+impl Ball {
+    fn new(x: f32, y: f32, seed: usize) -> Ball {
+        let id;
+        unsafe {
+            id = BALL_ID;
+            BALL_ID += 1;
+        }
+
+        let seed = seed % (usize::MAX / 64);
+        let random = (32_1239 * seed * seed * seed * 17 + id) % 1000;
+        let x_vel = random % 9;
+        let x_vel = (x_vel as f32 - 4.0) / 1.5;
+
+        return Ball {
+            id,
+            x,
+            y,
+            x_vel,
+            y_vel: 0.0,
+            color: Color::from_rgba(
+                (random as usize * 47 % 255) as u8,
+                (random as usize * 29 % 255) as u8,
+                (random as usize * 101 % 255) as u8,
+                255,
+            ),
+        };
+    }
+
+    fn tick(&mut self) {
+        self.x_vel *= DRAG;
+        self.y_vel *= DRAG;
+
+        self.x += self.x_vel;
+        self.y += self.y_vel;
+
+        self.x = self.x.clamp(-3000.0, 3000.0);
+        self.x = if self.x.is_normal() { self.x } else { 0.0 };
+        self.y = self.y.clamp(-3000.0, 3000.0);
+        self.y = if self.y.is_normal() { self.y } else { 0.0 };
+        self.y_vel = self.y_vel.clamp(-MAX_VEL, MAX_VEL);
+        self.y_vel = if self.y_vel.is_normal() {
+            self.y_vel
+        } else {
+            0.0
+        };
+        self.x_vel = self.x_vel.clamp(-MAX_VEL, MAX_VEL);
+        self.x_vel = if self.x_vel.is_normal() {
+            self.x_vel
+        } else {
+            0.0
+        };
+
+        self.y_vel = clip(self.y, screen_height(), self.y_vel + GRAVITY);
+        self.x_vel = clip(self.x, screen_width(), self.x_vel);
+        self.x_vel = clip_minus(self.x, 0.0, self.x_vel);
+        self.y_vel = clip_minus(self.y, -screen_height(), self.y_vel);
+    }
+
+    fn draw(&self) {
+        draw_circle(self.x, self.y - BALL_RADIUS, BALL_RADIUS, self.color);
+    }
+
+    fn collide(&mut self, balls: &[Ball]) {
+        unsafe {
+            let skip = (BALL_ID / 1000).max(8);
+
+            for other in balls {
+                if other.id == self.id || other.id % 10 < skip {
+                    continue;
+                }
+
+                let dx = self.x - other.x;
+                let dy = self.y - other.y;
+                let distance_sqr = dx * dx + dy * dy;
+
+                if distance_sqr > BALL_RADIUS_SQR {
+                    continue;
+                }
+
+                let distance = distance_sqr.sqrt();
+                if distance == 0.0 {
+                    continue;
+                }
+                let nx = dx / distance;
+                let ny = dy / distance;
+
+                let relative_velocity_x = self.x_vel - other.x_vel;
+                let relative_velocity_y = self.y_vel - other.y_vel;
+                let relative_velocity_normal = relative_velocity_x * nx + relative_velocity_y * ny;
+
+                if relative_velocity_normal > 0.0 {
+                    continue;
+                }
+
+                let impulse = (2.0 * relative_velocity_normal) / 2.0 * FLOOR_LOSS;
+
+                self.x_vel -= (impulse * nx).clamp(-MAX_VEL, MAX_VEL);
+                self.y_vel -= (impulse * ny).clamp(-MAX_VEL, MAX_VEL);
+            }
+        }
+    }
+}
+
+#[macroquad::main("AM - Confetti")]
+async fn main() {
+    let mut balls: Vec<Ball> = Vec::new();
+    let mut frame_count: usize = 0;
+    loop {
+        // Loop start
+        frame_count += 1;
+        clear_background(Color {
+            r: 0.95,
+            g: 0.9,
+            b: 0.9,
+            a: 1.0,
+        });
+
+        // Handle Inputs
+        if is_mouse_button_down(MouseButton::Left) {
+            let (mouse_x, mouse_y) = mouse_position();
+            balls.push(Ball::new(mouse_x, mouse_y, frame_count));
+            balls.push(Ball::new(mouse_x, mouse_y, frame_count));
+        }
+        if is_mouse_button_pressed(MouseButton::Right) {
+            let (mouse_x, mouse_y) = mouse_position();
+            balls.push(Ball::new(mouse_x, mouse_y, frame_count))
+        }
+        if is_key_pressed(KeyCode::Space) {
+            unsafe {
+                BALL_ID = 0;
+                balls.clear();
+            }
+        }
+
+        // Handle Tick
+        let balls_prev = balls.to_vec();
+        for ball in &mut balls {
+            ball.collide(&balls_prev);
+            ball.tick();
+            ball.draw();
+        }
+
+        unsafe {
+            if BALL_ID == 0 {
+                draw_text(
+                    "Click anywhere to begin!",
+                    screen_width() / 2.0 - 240.0,
+                    screen_height() / 2.0,
+                    48.0,
+                    RED,
+                );
+            } else {
+                draw_text(
+                    &format!(
+                        "Balls: {}\nFPS: {} {}",
+                        BALL_ID,
+                        get_fps(),
+                        if BALL_ID > 1000 {
+                            "(Press Space to Reset)"
+                        } else {
+                            ""
+                        }
+                    ),
+                    15.0,
+                    25.0,
+                    32.0,
+                    BLACK,
+                );
+            }
+        }
+
+        next_frame().await
+    }
+}
+// Andrew McCall <3
+// https://github.com/Andrew-McCall/MacroquadConfetti