Animations now have an easing/ease_rate setting that will do a dynamic scaling effect on them during the animation sequence.

assets/config.json

@@ -53,7 +53,7 @@
   "player": {
   },
   "worldgen": {
-    "enemy_probability": 50,
+    "enemy_probability": 80,
     "empty_room_probability": 10,
     "device_probability": 10
   }

assets/enemies.json

@@ -20,7 +20,7 @@
       {"_type": "Combat", "hp": 20, "max_hp": 20, "damage": 1, "dead": false},
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "hearing_distance": 5},
-      {"_type": "Animation", "scale": 0.1, "simple": true, "frames": 10, "speed": 0.3},
+      {"_type": "Animation", "easing": 1, "ease_rate": 0.2,  "scale": 0.1, "simple": true, "frames": 10, "speed": 0.3},
       {"_type": "Sprite", "name": "armored_knight"},
       {"_type": "Sound", "attack": "Sword_Hit_2", "death": "Humanoid_Death_1"}
     ]
@@ -35,7 +35,7 @@
       {"_type": "Motion", "dx": 0, "dy": 0, "random": true},
       {"_type": "EnemyConfig", "hearing_distance": 5},
       {"_type": "Sprite", "name": "axe_ranger"},
-      {"_type": "Animation", "scale": 0.1, "simple": false, "frames": 10, "speed": 0.6},
+      {"_type": "Animation", "easing": 3, "ease_rate": 0.5,  "scale": 0.1, "simple": false, "frames": 10, "speed": 0.6},
       {"_type": "Sound", "attack": "Sword_Hit_2", "death": "Ranger_1"}
     ]
   },
@@ -49,7 +49,7 @@
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "hearing_distance": 5},
       {"_type": "Sprite", "name": "evil_eye"},
-      {"_type": "Animation", "scale": 0.1, "simple": false, "frames": 10, "speed": 0.3},
+      {"_type": "Animation", "easing": 3, "ease_rate": 0.1,  "scale": 0.1, "simple": false, "frames": 10, "speed": 0.3},
       {"_type": "Sound", "attack": "Evil_Eye_Sound_2", "death": "Evil_Eye_Sound_1"}
     ]
   },
@@ -62,7 +62,7 @@
       {"_type": "Combat", "hp": 20, "max_hp": 20, "damage": 20, "dead": false},
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "hearing_distance": 10},
-      {"_type": "Animation", "scale": 0.1, "simple": true, "frames": 10, "speed": 1.0},
+      {"_type": "Animation", "easing": 3, "ease_rate": 0.5,  "scale": 0.1, "simple": true, "frames": 10, "speed": 1.0},
       {"_type": "Sprite", "name": "rat_with_sword"},
       {"_type": "Sound", "attack": "Small_Rat", "death": "Creature_Death_1"}
     ]
@@ -76,7 +76,7 @@
       {"_type": "Combat", "hp": 50, "max_hp": 50, "damage": 50, "dead": false},
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "hearing_distance": 3},
-      {"_type": "Animation", "scale": 0.1, "simple": true, "frames": 10, "speed": 1.0},
+      {"_type": "Animation", "easing": 2, "ease_rate": 0.2,  "scale": 0.1, "simple": true, "frames": 10, "speed": 1.0},
       {"_type": "Sprite", "name": "rat_king"},
       {"_type": "Sound", "attack": "Medium_Rat", "death": "Creature_Death_1"}
     ]
@@ -90,7 +90,7 @@
       {"_type": "Combat", "hp": 20, "max_hp": 20, "damage": 20, "dead": false},
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "hearing_distance": 10},
-      {"_type": "Animation", "scale": 0.1, "simple": true, "frames": 10, "speed": 1.0},
+      {"_type": "Animation", "easing": 2, "ease_rate": 0.5,  "scale": 0.1, "simple": true, "frames": 10, "speed": 1.0},
       {"_type": "Sprite", "name": "hairy_spider"},
       {"_type": "Sound", "attack": "Spider_1", "death": "Spider_2"}
     ]

components.cpp

@@ -1,5 +1,6 @@
 #include "components.hpp"
 #include "point.hpp"
+#include "easings.hpp"
 
 namespace components {
   ENROLL_COMPONENT(Position, location.x, location.y);
@@ -7,7 +8,7 @@ namespace components {
   ENROLL_COMPONENT(Motion, dx, dy, random);
   ENROLL_COMPONENT(Combat, hp, max_hp, damage, dead);
   ENROLL_COMPONENT(Device, config, events);
-  ENROLL_COMPONENT(Animation, scale, simple, frames, speed);
+  ENROLL_COMPONENT(Animation, scale, simple, frames, speed, easing, ease_rate);
   ENROLL_COMPONENT(Sound, attack, death);
 
   void configure_entity(const ComponentMap& component_map, DinkyECS::World& world, DinkyECS::Entity ent, json& data) {
@@ -41,11 +42,28 @@ namespace components {
     }
   }
 
+  float Animation::twitching() {
+    switch(easing) {
+      case ease::SINE:
+        return ease::sine(float(frames) / subframe * ease_rate);
+      case ease::OUT_CIRC:
+        return ease::sine(ease::out_circ(float(frames) / subframe * ease_rate));
+      case ease::OUT_BOUNCE:
+        return ease::sine(ease::out_bounce(float(frames) / subframe * ease_rate));
+      case ease::IN_OUT_BACK:
+        return ease::sine(ease::in_out_back(float(frames) / subframe * ease_rate));
+      default:
+        dbc::sentinel(
+            fmt::format("Invalid easing {} given to animation",
+              int(easing)));
+    }
+  }
+
   void Animation::step(sf::Vector2f& scale_out, sf::IntRect& rect_out) {
     if(playing && current < frames) {
-      scale_out.x += scale;
-      scale_out.y += scale;
-
+      float tick = twitching();
+      scale_out.x = std::lerp(scale_out.x, scale_out.x + scale, tick);
+      scale_out.y = std::lerp(scale_out.y, scale_out.y + scale, tick);
       if(!simple) {
         rect_out.position.x += current * TEXTURE_WIDTH;
       }

components.hpp

@@ -9,6 +9,7 @@
 #include <functional>
 #include <nlohmann/json.hpp>
 #include <nlohmann/json_fwd.hpp>
+#include "easings.hpp"
 
 #define ENROLL_COMPONENT(COMPONENT, ...)                         \
     NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE(COMPONENT, __VA_ARGS__);  \
@@ -105,8 +106,11 @@ namespace components {
     int current = 0;
     bool playing = false;
     float subframe = 0;
+    ease::Style easing = ease::IN_OUT_BACK;
+    float ease_rate = 0.5f;
 
     void play();
+    float twitching();
     void step(sf::Vector2f& scale_out, sf::IntRect& rect_out);
   };
 

dbc.hpp

@@ -20,7 +20,7 @@ namespace dbc {
   class PostCondError : public Error {};
 
   void log(const string &message);
-  void sentinel(const string &message);
+  [[noreturn]] void sentinel(const string &message);
   void pre(const string &message, bool test);
   void pre(const string &message, std::function<bool()> tester);
   void post(const string &message, bool test);

easings.hpp

@@ -3,6 +3,10 @@
 
 namespace ease {
 
+  enum Style {
+    SINE, OUT_CIRC, OUT_BOUNCE, IN_OUT_BACK, NONE
+  };
+
   inline double sine(double x) {
     return (std::sin(x) + 1.0) / 2.0;
   }

main.cpp

@@ -6,7 +6,7 @@
 int main(int argc, char* argv[]) {
   textures::init();
   sound::init();
-  sound::mute(false);
+  sound::mute(true);
   gui::FSM main;
   main.event(gui::Event::STARTED);
   Autowalker walker(main);

raycaster.cpp

@@ -151,8 +151,9 @@ void Raycaster::sprite_casting(sf::RenderTarget &target) {
       int d = y * texture_height - $height * half_height + sprite_height * half_height;
       int tex_y = ((d * texture_height) / sprite_height) / texture_height;
 
+      sf::Vector2f origin{texture_width / 2, texture_height / 2};
       sf::Vector2f scale{sprite_scale_w, sprite_scale_h};
-      sf::Vector2f position{x, y};
+      sf::Vector2f position{x + origin.x * scale.x, y + origin.y * scale.y};
       sf::IntRect in_texture{ {tex_x, tex_y}, {tex_render_width, texture_height}};
 
       if($level.world->has<components::Animation>(rec.second)) {
@@ -160,6 +161,7 @@ void Raycaster::sprite_casting(sf::RenderTarget &target) {
         if(animation.playing) animation.step(scale, in_texture);
       }
 
+      sf_sprite->setOrigin(origin);
       sf_sprite->setScale(scale);
       sf_sprite->setTextureRect(in_texture);
       sf_sprite->setPosition(position);