examples

commit 3917a91f68f8dceb8155bf59c92df22f8152d23e
parent 9636e425c8ecf42cd00f574ced88656a5d528ac2
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Thu, 28 Apr 2022 22:58:00 +0100

gl-asteroids: Tidy up a bit using inheritance

Diffstat:
M
src/gl-asteroids.cpp
 | 
42
++++++++++++++++++++++++++++--------------

1 file changed, 28 insertions(+), 14 deletions(-)
diff --git a/src/gl-asteroids.cpp b/src/gl-asteroids.cpp
@@ -265,9 +265,13 @@ struct entity
 	}
 };
 
-struct particle
+static bool left_arena(entity const& e)
+{
+	return e.phys.left_arena();
+}
+
+struct particle : entity
 {
-	entity ent;
 	float ttl;
 
 	static particle& make_particle(entity e, float ttl)
@@ -279,15 +283,15 @@ struct particle
 		for (auto& p : particles)
 		{
 			p.ttl -= dt;
-			p.ent.phys.move(dt);
+			p.phys.move(dt);
 		}
 		std::erase_if(particles, [](auto& p) { return p.ttl <= 0; });
-		std::erase_if(particles, [](auto const& p) { return p.ent.phys.left_arena(); });
+		std::erase_if(particles, left_arena);
 	}
 	static void draw_all()
 	{
 		for (auto& p : particles)
-			p.ent.draw();
+			p.draw();
 	}
 private:
 	static std::vector<particle> particles;
@@ -302,10 +306,19 @@ bool is_pressed(int key)
 	return glfwGetKey(w, key) != GLFW_RELEASE;
 }
 
+struct powerup : entity
+{
+	std::function<void(void)> cb;
+
+	powerup(entity e, std::function<void(void)> c)
+	:	entity(e)
+	,	cb(c)
+	{}
+};
+
 std::vector<entity> rocks;
 std::vector<entity> bullets;
-std::optional<entity> powerups;
-std::function<void(void)> powerup_cb;
+std::optional<powerup> powerups;
 
 physics ship_phys{{}, {}, 0.f, 0.f, .06f};
 bool up = false;
@@ -450,21 +463,22 @@ int main(int argc, char* argv[])
 			}
 
 			visual const* vis;
+			std::function<void(void)> cb;
 
 			static int type;
 			switch (type++ % 2)
 			{
 			case 0:
 				vis = &powerup_bulletspeed;
-				powerup_cb = [&firerate](){ firerate += .5f; };
+				cb = [&firerate](){ firerate += .5f; };
 				break;
 			case 1:
 				vis = &powerup_firerate;
-				powerup_cb = [&bullet_speed](){ bullet_speed += .2f; };
+				cb = [&bullet_speed](){ bullet_speed += .2f; };
 				break;
 			}
 
-			powerups.emplace(*vis, physics{p, v, 0, 0, scale});
+			powerups.emplace(entity{*vis, physics{p, v, 0, 0, scale}}, cb);
 		}
 
 		if (ammo < 20 && ammo_refill_time < t)
@@ -597,7 +611,7 @@ int main(int argc, char* argv[])
 			if (is_colliding(ship_phys, powerups->phys))
 			{
 				play_sample(blip);
-				powerup_cb();
+				powerups->cb();
 				powerups.reset();
 				score += 10;
 			}
@@ -615,10 +629,10 @@ int main(int argc, char* argv[])
 			break;
 		}
 
-		score -= std::erase_if(bullets, [](auto const& e) { return e.phys.left_arena(); });
-		score -= std::erase_if(rocks, [](auto const& e) { return e.phys.left_arena(); });
+		score -= std::erase_if(bullets, left_arena);
+		score -= std::erase_if(rocks, left_arena);
 
-		if (powerups && powerups->phys.left_arena())
+		if (powerups && left_arena(*powerups))
 		{
 			powerups.reset();
 			--score;