examples

commit 9f2c69b4af7d95cc5592864416d1bb4c143a2054
parent 317ff4eee92b6038d53305429b2cce648ad633e1
Author: Henry Wilson <henry@henryandlizzy.uk>
Date:   Tue,  5 Apr 2022 23:49:45 +0100

gl-asteroids: Delete bullets which exit the arena

Diffstat:
M
src/gl-asteroids.cpp
 | 
58
++++++++++++++++++++++++++++++++++++++++++++--------------

1 file changed, 44 insertions(+), 14 deletions(-)
diff --git a/src/gl-asteroids.cpp b/src/gl-asteroids.cpp
@@ -48,7 +48,7 @@ coord const rockv4[] = {{0, 0}, {1, 0}, {.6,.4}, {0, .5}, {-.3,.6}, {-1, 0}, {-.
 
 color const rockc[] = {{.5,.5,.5}, {.2,.2,.2}};
 
-coord const bulletv[] = {{0, 4}, {1, 1}, {-1, 1}, {1, -4}, {-1, -4}};
+coord const bulletv[] = {{0, 1}, {.25, .25}, {-.25, .25}, {.25, -1}, {-.25, -1}};
 color const bulletc[] = {{.0,.8,.0}, {.0,.4,.0}, {.0,.4,.0}, {.0,.0,.0}};
 
 coord starsv[64];
@@ -125,17 +125,31 @@ struct physics
 	void move(float dt)
 	{
 		pos += vel * dt;
-		if (pos.x > 1 && vel.x > 0)
-			pos.x -= 2;
-		else if (pos.x < -1 && vel.x < 0)
-			pos.x += 2;
-
-		if (pos.y > 1 && vel.y > 0)
-			pos.y -= 2;
-		else if (pos.y < -1 && vel.y < 0)
-			pos.y += 2;
 		rot += ang_mom * dt;
 	}
+	static void wrap_pos(float& pos, float vel)
+	{
+		if (pos > 1 && vel > 0)
+			pos -= 2;
+		else if (pos < -1 && vel < 0)
+			pos += 2;
+	}
+	void wrap_pos(void)
+	{
+		wrap_pos(pos.x, vel.x);
+		wrap_pos(pos.y, vel.y);
+	}
+	static bool left_axis(float pos, float vel, float scale)
+	{
+		if (vel < 0)
+			pos = -pos;
+
+		return pos > 1 + scale;
+	}
+	bool left_arena() const
+	{
+		return left_axis(pos.x, vel.x, scale) or left_axis(pos.y, vel.y, scale);
+	}
 };
 
 bool is_colliding(physics const& a, physics const& b)
@@ -205,6 +219,7 @@ struct particle
 			p.e.p.move(dt);
 		}
 		std::erase_if(particles, [](auto& p) { return p.ttl <= 0; });
+		std::erase_if(particles, [](auto const& p) { return p.e.p.left_arena(); });
 	}
 	static void draw_all()
 	{
@@ -271,6 +286,7 @@ visual const& random_rock_visual(void)
 int main(int argc, char* argv[])
 {
 	unsigned score = 0;
+	unsigned ammo = 10;
 
 	std::random_device rd;
 	std::default_random_engine gen(rd());
@@ -288,7 +304,7 @@ int main(int argc, char* argv[])
 
 	float last_t = glfwGetTime();
 
-	float rock_time = 1, bullet_time = 0;
+	float rock_time = 1, bullet_time = 0, ammo_refill_time = .3;
 
 	for (auto& c : starsv)
 		c.x = dis_p(gen), c.y = dis_p(gen);
@@ -326,15 +342,22 @@ int main(int argc, char* argv[])
 			rocks.emplace_back(random_rock_visual(), physics{p, v, 0, dis_a(gen), scale});
 		}
 
-		if (is_pressed(GLFW_KEY_SPACE) && bullet_time < t)
+		if (ammo < 20 && ammo_refill_time < t)
+		{
+			++ammo;
+			ammo_refill_time += .4;
+		}
+
+		if (is_pressed(GLFW_KEY_SPACE) && bullet_time < t && ammo)
 		{
-			bullet_time = t + .3f;
+			--ammo;
+			bullet_time = t + .15f;
 
 			bullets.emplace_back(bullet, s);
 			auto& b = bullets.back().p;
 
 			b.ang_mom = 0;
-			b.scale /= 5;
+			b.scale /= 1.25;
 			b.vel += {(float)sin(b.rot), (float)cos(b.rot)};
 		}
 
@@ -359,10 +382,15 @@ int main(int argc, char* argv[])
 		// resolve motion
 
 		for (auto& r : rocks)
+		{
 			r.p.move(dt);
+			r.p.wrap_pos();
+		}
 		for (auto& b : bullets)
 			b.p.move(dt);
+
 		s.move(dt);
+		s.wrap_pos();
 		particle::move_all(dt);
 
 		// handle collisions
@@ -418,6 +446,8 @@ int main(int argc, char* argv[])
 			break;
 		}
 
+		std::erase_if(bullets, [](auto const& e) { return e.p.left_arena(); });
+
 		draw_scene(t);
 	}