Use a more lenient asteroid spawning strategy

Two large asteroids are created to start.
New asteroids are only created when the total asteroid area is below 12.
Large asteroids have 4 area, medium asteroids have 2, and small
asteroids have 1.
Asteroid true sizes are based on multiples of a base number.

src/asteroids.rs

@@ -1,6 +1,6 @@
 use crate::{HEIGHT, WIDTH};
 use macroquad::{prelude::*, rand::gen_range};
-#[derive(Clone)]
+#[derive(Clone, PartialEq, Eq)]
 pub enum AsteroidSize {
     Large,
     Medium,
@@ -19,12 +19,14 @@ pub struct Asteroid {
     pub alive: bool,
 }
 
+const BASE_SIZE: f32 = 20.;
+
 impl Asteroid {
     pub fn new(size: AsteroidSize) -> Self {
         let (sides, radius) = match size {
-            AsteroidSize::Large => (gen_range(6, 10), gen_range(50., 65.)),
+            AsteroidSize::Large => (gen_range(6, 10), BASE_SIZE * 4.),
-            AsteroidSize::Medium => (gen_range(5, 6), gen_range(35., 50.)),
+            AsteroidSize::Medium => (gen_range(5, 6), BASE_SIZE * 2.),
-            AsteroidSize::Small => (gen_range(3, 5), 25.),
+            AsteroidSize::Small => (gen_range(3, 5), BASE_SIZE),
         };
         let mut r = vec2(
             if gen_range(0., 1.) > 0.5 { -1. } else { 1. },

src/world.rs

@@ -29,9 +29,6 @@ impl World {
             asteroids: vec![
                 Asteroid::new_to(vec2(0., 0.), 1.5, AsteroidSize::Large),
                 Asteroid::new(AsteroidSize::Large),
-                Asteroid::new(AsteroidSize::Large),
-                Asteroid::new(AsteroidSize::Large),
-                Asteroid::new(AsteroidSize::Large),
             ],
             ..Default::default()
         }
@@ -115,7 +112,26 @@ impl World {
         // }) < self.max_asteroids
         //     || self.player.lifespan % 200 == 0
         // {
-        if self.player.lifespan % 200 == 0 {
+        let num_small: usize = self
+            .asteroids
+            .iter()
+            .filter(|a| a.size == AsteroidSize::Small)
+            .map(|_| 1)
+            .sum();
+        let num_medium: usize = self
+            .asteroids
+            .iter()
+            .filter(|a| a.size == AsteroidSize::Medium)
+            .map(|_| 1)
+            .sum();
+        let num_large: usize = self
+            .asteroids
+            .iter()
+            .filter(|a| a.size == AsteroidSize::Large)
+            .map(|_| 1)
+            .sum();
+        let area = num_small + num_medium * 2 + num_large * 4;
+        if self.player.lifespan % 200 == 0 && area < 12 {
             self.asteroids
                 .push(Asteroid::new_to(self.player.pos, 1.5, AsteroidSize::Large));
         }