From b72ae89980010451c39e4d40b42004ea693cab27 Mon Sep 17 00:00:00 2001
From: Alex Clink <alexclink@gmail.com>
Date: Wed, 17 Nov 2021 23:30:32 -0500
Subject: [PATCH] Add ship collision

---
 src/asteroids.cr | 45 ++++++++++++++++++++++++++++++++++++++-------
 src/ship.cr      | 19 +++++++++++++++++--
 2 files changed, 55 insertions(+), 9 deletions(-)

diff --git a/src/asteroids.cr b/src/asteroids.cr
index d5bd06a..3e7f78f 100644
--- a/src/asteroids.cr
+++ b/src/asteroids.cr
@@ -31,6 +31,7 @@ class Asteroids < Game
   @explosions = [] of Explosion
   @controller : Controller(LibSDL::Keycode)
   @asteroid_count = 3
+  @restart_timer = 0.0
 
   def initialize(*args)
     super
@@ -39,7 +40,7 @@ class Asteroids < Game
       ship.position = Vector2.new(x: width / 2.0, y: height / 2.0)
     end
 
-    generate_asteroids
+    setup_round
 
     @controller = Controller(LibSDL::Keycode).new({
       LibSDL::Keycode::UP    => "Thrust",
@@ -50,9 +51,15 @@ class Asteroids < Game
   end
 
   def generate_asteroids
+    center_size = Vector2.new(20.0, 20.0)
+    center_pos = Vector2.new((width.to_f / 2.0) - (center_size.x / 2.0), (height.to_f / 2.0) - (center_size.y / 2.0))
+
     @asteroid_count.times do
       @asteroids << Asteroid.build do |a|
-        a.position = Vector2.new(x: rand(0.0..width.to_f), y: rand(0.0..height.to_f))
+        loop do
+          a.position = Vector2.new(x: rand(0.0..width.to_f), y: rand(0.0..height.to_f))
+          break if (a.position.x < center_pos.x || a.position.x > center_pos.x + center_size.x) && (a.position.y < center_pos.y || a.position.y > center_pos.y + center_size.y)
+        end
         v_max = 30.0
         a.velocity = Vector2.new(x: rand(-v_max..v_max), y: rand(-v_max..v_max))
         a.rotation_speed = rand(-5.0..5.0)
@@ -64,6 +71,17 @@ class Asteroids < Game
     end
   end
 
+  def setup_round
+    @restart_timer = 0.0
+    @asteroids = [] of Asteroid
+    generate_asteroids
+    @bullets = [] of Bullet
+    @ship.blew_up = false
+    @ship.position = Vector2.new(x: width / 2.0, y: height / 2.0)
+    @ship.velocity = Vector2.new(0.0, 0.0)
+    @ship.rotation_speed = 0.0
+  end
+
   def wrap(position : Vector2)
     position.x = 0.0 if position.x > @width
     position.x = @width.to_f64 if position.x < 0.0
@@ -75,14 +93,14 @@ class Asteroids < Game
   end
 
   def update(dt : Float64)
-    if @asteroids.size == 0
+    if @asteroids.size == 0 && !@ship.blew_up
       @asteroid_count += 1
-      generate_asteroids
-      @ship.position = Vector2.new(x: width / 2.0, y: height / 2.0)
-      @ship.velocity = Vector2.new(0.0, 0.0)
-      @ship.rotation_speed = 0.0
+      setup_round
     end
 
+    @restart_timer += dt if @ship.blew_up
+    setup_round if @restart_timer > 3.0
+
     @ship.rotate_right(dt) if @controller.action?("Rotate Right")
     @ship.rotate_left(dt) if @controller.action?("Rotate Left")
     @ship.thrust(dt) if @controller.action?("Thrust")
@@ -159,6 +177,19 @@ class Asteroids < Game
     end
 
     @explosions.reject! { |e| e.emitting == false && e.particles.none? }
+    @asteroids.each do |a|
+      if @ship.collides_with?(a)
+        @ship.blew_up = true
+        @explosions << Explosion.build do |e|
+          e.size = 10.0
+          e.position = @ship.position
+          e.velocity = @ship.velocity
+          e.emit_freq = 0.01
+          e.strength = 30
+          e.max_age = 1.0
+        end
+      end
+    end
   end
 
   def draw
diff --git a/src/ship.cr b/src/ship.cr
index 48bdc4e..6b5a0c5 100644
--- a/src/ship.cr
+++ b/src/ship.cr
@@ -8,6 +8,8 @@ class Ship < Sprite
   @emitter : Emitter
   @l_emitter : Emitter
   @r_emitter : Emitter
+  @projected_points : Array(Vector2)? = nil
+  property blew_up : Bool = false
 
   def initialize
     super
@@ -76,7 +78,20 @@ class Ship < Sprite
     @velocity.y += Math.sin(@rotation) * dt * @t_engine
   end
 
+  def projected_points
+    @projected_points ||= project_points(@frame)
+  end
+
+  def collides_with?(asteroid : Asteroid)
+    return false if @blew_up
+    projected_points.any? do |point|
+      asteroid.position.distance(point) < asteroid.radius
+    end
+  end
+
   def update(dt : Float64)
+    return if @blew_up
+    @projected_points = nil
     update_position(dt)
 
     @fire_cooldown -= dt unless can_fire?
@@ -98,6 +113,7 @@ class Ship < Sprite
   end
 
   def draw(renderer)
+    return if @blew_up
     @emitter.draw(renderer)
     @emitter.emitting = false
     @l_emitter.draw(renderer)
@@ -105,8 +121,7 @@ class Ship < Sprite
     @r_emitter.draw(renderer)
     @r_emitter.emitting = false
 
-    frame = project_points(@frame)
     renderer.draw_color = SDL::Color[255, 255, 255, 255]
-    draw_frame(renderer, frame)
+    draw_frame(renderer, projected_points)
   end
 end