screen shake - the game

assets/game_assets/blueprints/camera.json

@@ -15,5 +15,6 @@
   "Spring": {
     "spring_constant": 20.0,
     "mass": 1.0
-  }
+  },
+  "Shake": {}
 }

src/gameplay/beat_system.cpp

@@ -40,6 +40,7 @@ namespace phase_shifter::gameplay {
 		if(beat) {
 			_beat_index++;
 			LOG(plog::debug) << "beat";
+			_bus.send<Screen_shake_msg>(0.03f, 0.05f);
 
 			beats_left = size - 1 - _beat_index + _beat_offset;
 			if(beats_left <= 0 || _beat_index + 1 >= size) {

src/gameplay/camera_system.cpp

@@ -6,17 +6,28 @@ namespace phase_shifter::gameplay {
 
 	using mirrage::ecs::components::Transform_comp;
 
-	Camera_system::Camera_system(mirrage::ecs::Entity_manager& entity_manager)
-	  : _entity_manager(entity_manager)
+	Camera_system::Camera_system(mirrage::util::Message_bus& bus, mirrage::ecs::Entity_manager& entity_manager)
+	  : _mailbox(bus), _entity_manager(entity_manager)
 	{
 		_entity_manager.register_component_type<Viewtarget_comp>();
 		_entity_manager.register_component_type<Spring_comp>();
+		_entity_manager.register_component_type<Shake_comp>();
+
+		_mailbox.subscribe_to([&](Screen_shake_msg& e) {
+			for (auto& shake : _entity_manager.list<Shake_comp>()) {
+				shake.intesity = e.intensity;
+				shake.duration = e.duration;
+				shake.time_remaining = e.duration;
+			}
+		});
 	}
 
 	void Camera_system::update(mirrage::util::Time dt)
 	{
-		for(auto&& [transform, viewtarget, spring] :
-		    _entity_manager.list<Transform_comp, Viewtarget_comp, Spring_comp>()) {
+		_mailbox.update_subscriptions();
+
+		for(auto&& [transform, viewtarget, spring, shake] :
+		    _entity_manager.list<Transform_comp, Viewtarget_comp, Spring_comp, Shake_comp>()) {
 			auto target_facet = _entity_manager.get(viewtarget.target);
 
 			if(target_facet.is_some()) {
@@ -35,7 +46,13 @@ namespace phase_shifter::gameplay {
 					glm::vec3 spring_force = spring.spring_constant * (dest_pos - transform.position);
 					glm::vec3 acceleration = (spring_force + damping_force) / spring.mass;
 					spring.velocity += dt.value() * acceleration;
-					transform.position += dt.value() * spring.velocity;
+					spring.position += dt.value() * spring.velocity;
+					transform.position = spring.position;
+					if (shake.time_remaining > 0) {
+						glm::vec3 shake_direction = glm::normalize(glm::vec3{std::rand(), 0, std::rand()});
+						transform.position += shake.intesity * (shake.time_remaining / shake.duration) * shake_direction;
+						shake.time_remaining -= dt.value();
+					}
 					transform.direction(-offset);
 				}
 			}

src/gameplay/camera_system.hpp

@@ -2,18 +2,23 @@
 
 #include <mirrage/utils/units.hpp>
 #include <mirrage/ecs/entity_manager.hpp>
+#include <mirrage/utils/messagebus.hpp>
+
+#include "../messages.hpp"
 
 #include "viewtarget_comp.hpp"
 #include "spring_comp.hpp"
+#include "shake_comp.hpp"
 
 namespace phase_shifter::gameplay {
 
 	class Camera_system {
 	  public:
-		Camera_system(mirrage::ecs::Entity_manager& entity_manager);
+		Camera_system(mirrage::util::Message_bus& bus, mirrage::ecs::Entity_manager& entity_manager);
 		void update(mirrage::util::Time dt);
 
 	  private:
 		mirrage::ecs::Entity_manager& _entity_manager;
+		mirrage::util::Mailbox_collection _mailbox;
 	};
 }
\ No newline at end of file

src/gameplay/dash_system.cpp

@@ -115,6 +115,7 @@ namespace phase_shifter::gameplay {
 
 						_bus.send<Enemy_killed_msg>(k_transform.position,
 						                            glm::vec3(attack_direction.x, 0.f, attack_direction.y));
+						_bus.send<Screen_shake_msg>(0.5f, 0.3f);
 						_ecs.erase(entity);
 					}
 				}

src/gameplay/enemy_system.cpp

@@ -221,6 +221,7 @@ namespace phase_shifter::gameplay {
 				             Stadium{last_player_pos, player_pos, player_body.radius})) {
 					_entity_manager.erase(bullet_handle);
 					_bus.send<Damaged_msg>(player_handle);
+					_bus.send<Screen_shake_msg>(0.3f, 0.3f);
 				}
 			}
 		}

src/gameplay/enemy_system.hpp

@@ -12,6 +12,8 @@
 
 #include "beat_system.hpp"
 
+#include "../messages.hpp"
+
 namespace phase_shifter::gameplay {
 
 	struct Stadium {

src/gameplay/shake_comp.hpp

+#pragma once
+
+#include <mirrage/ecs/ecs.hpp>
+#include <mirrage/utils/sf2_glm.hpp>
+
+namespace phase_shifter::gameplay {
+
+	struct Shake_comp : public mirrage::ecs::Component<Shake_comp> {
+		static constexpr const char* name() { return "Shake"; }
+		using Component::Component;
+
+		float intesity = 0;
+		float duration = 0; //duration in seconds
+		float time_remaining = 0; //remaining shake time in seconds
+	};
+} // namespace phase_shifter::gameplay

src/gameplay/spring_comp.hpp

@@ -12,6 +12,7 @@ namespace phase_shifter::gameplay {
 		float spring_constant = 1.f;
 		float mass            = 1.f;
 
+		glm::vec3 position = {0.f, 0.f, 0.f};
 		glm::vec3 velocity = {0.f, 0.f, 0.f};
 	};
 

src/level/level_system.cpp

@@ -4,6 +4,7 @@
 #include "../gameplay/player_comp.hpp"
 #include "../gameplay/rigid_body_comp.hpp"
 #include "../gameplay/viewtarget_comp.hpp"
+#include "../gameplay/spring_comp.hpp"
 #include "../helper/attachment_comp.hpp"
 
 #include <mirrage/ecs/components/transform_comp.hpp>
@@ -66,6 +67,10 @@ namespace phase_shifter::level {
 				                      entity.process([=](gameplay::Viewtarget_comp& viewtarget) {
 					                      viewtarget.target = playerhandle;
 				                      });
+				                      entity.process(
+				                              [=](gameplay::Spring_comp& spring, Transform_comp& transform) {
+					                              spring.position = transform.position;
+				                              });
 			                      })
 			                      .create();
 

src/messages.hpp

@@ -29,4 +29,9 @@ namespace phase_shifter {
 		mirrage::util::Str_id id;
 	};
 
+	struct Screen_shake_msg {
+		float intensity;
+		float duration; //duration in seconds
+	};
+
 } // namespace phase_shifter

src/meta_system.cpp

@@ -43,7 +43,7 @@ namespace phase_shifter {
 	  , _combat_system(std::make_unique<gameplay::Combat_system>(engine.bus(), _entities, *_beat_system))
 	  , _attachment_system(std::make_unique<helper::Attachment_system>(_entities))
 	  , _hud_system(std::make_unique<ui::Hud_system>(engine.gui(), _entities, *_beat_system))
-	  , _camera_system(std::make_unique<gameplay::Camera_system>(_entities))
+	  , _camera_system(std::make_unique<gameplay::Camera_system>(engine.bus(), _entities))
 	  , _enemy_system(std::make_unique<gameplay::Enemy_system>(engine.bus(), _entities, *_beat_system))
 	  , _dash_system(std::make_unique<gameplay::Dash_system>(engine.bus(), _entities))
 	  , _stationary_attack_system(