Animations now can have a stationary option which tries to keep them 'in place' while growing, effectively removing the forward motion.

assets/bosses.json

@@ -3,8 +3,8 @@
     "components": [
       {"_type": "BossFight", "background": "boss_fight_background", "weapon_sound": "Sword_Hit_2"},
       {"_type": "Combat", "hp": 20, "max_hp": 20, "damage": 20, "dead": false},
-      {"_type": "Animation", "easing": 3, "ease_rate": 0.2,  "scale": 0.2, "simple": false, "frames": 2, "speed": 0.02, "scale": 0.2},
-      {"_type": "Sprite", "name": "rat_king_boss", "width": 720, "height": 720, "scale": 0.8},
+      {"_type": "Animation", "easing": 3, "ease_rate": 0.2, "simple": false, "frames": 2, "speed": 0.02, "scale": 0.2},
+      {"_type": "Sprite", "name": "rat_king_boss", "width": 720, "height": 720, "scale": 0.8, "stationary": false},
       {"_type": "Sound", "attack": "Marmot_Scream_1", "death": "Creature_Death_1"}
     ]
   },
@@ -15,7 +15,15 @@
         "weapon_sound": "Sword_Hit_2"
       },
       {"_type": "Combat", "hp": 20, "max_hp": 20, "damage": 20, "dead": false},
-      {"_type": "Animation", "easing": 0, "ease_rate": 0.1,  "scale": 0.2, "simple": true, "frames": 2, "speed": 0.02, "scale": 0.2},
+      {"_type": "Animation",
+        "easing": 1,
+        "ease_rate": 0.1,
+        "simple": false,
+        "frames": 2,
+        "speed": 0.02,
+        "scale": 0.1,
+        "stationary": true
+      },
       {"_type": "Sprite",
         "name": "devils_fingers_sprite",
         "width": 720,

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", "easing": 1, "ease_rate": 0.2,  "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, "stationary": false},
       {"_type": "Sprite", "name": "armored_knight", "width": 256, "height": 256, "width": 256, "height": 256, "scale": 1.0},
       {"_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", "width": 256, "height": 256, "scale": 1.0},
-      {"_type": "Animation", "easing": 3, "ease_rate": 0.5,  "scale": 0.1, "simple": false, "frames": 2, "speed": 0.6},
+      {"_type": "Animation", "easing": 3, "ease_rate": 0.5,  "scale": 0.1, "simple": false, "frames": 2, "speed": 0.6, "stationary": false},
       {"_type": "Sound", "attack": "Sword_Hit_2", "death": "Ranger_1"}
     ]
   },
@@ -48,7 +48,7 @@
       {"_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", "easing": 3, "ease_rate": 0.5,  "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, "stationary": false},
       {"_type": "Sprite", "name": "rat_with_sword", "width": 256, "height": 256, "scale": 1.0},
       {"_type": "Sound", "attack": "Small_Rat", "death": "Creature_Death_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", "easing": 2, "ease_rate": 0.5,  "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, "stationary": false},
       {"_type": "Sprite", "name": "hairy_spider", "width": 256, "height": 256, "scale": 1.0},
       {"_type": "Sound", "attack": "Spider_1", "death": "Spider_2"}
     ]

boss_fight_ui.cpp

@@ -42,8 +42,10 @@ namespace gui {
     auto bounds = $boss_image.sprite->getLocalBounds();
     auto bg_bounds = $boss_background.sprite->getLocalBounds();
     float x_diff = bg_bounds.size.x / 2;
+
+    $boss_pos = {float(BOSS_VIEW_X) + x_diff, bounds.size.y / 2};
     $boss_image.sprite->setOrigin({bounds.size.x / 2, bounds.size.y / 2});
-    $boss_image.sprite->setPosition({float(BOSS_VIEW_X) + x_diff, bounds.size.y / 2});
+    $boss_image.sprite->setPosition($boss_pos);
   }
 
   void BossFightUI::configure_background() {
@@ -88,9 +90,13 @@ namespace gui {
   void BossFightUI::bounce_boss(sf::RenderWindow& window) {
     sf::IntRect frame_rect{{0,0},{$sprite_config.width,$sprite_config.height}};
     sf::Vector2f scale{$sprite_config.scale, $sprite_config.scale};
-    $animation.step(scale, frame_rect);
+    sf::Vector2f pos{$boss_pos.x, $boss_pos.y};
+
+    $animation.step(scale, pos, frame_rect);
     $boss_image.sprite->setScale(scale);
 
+    if($animation.stationary) $boss_image.sprite->setPosition(pos);
+
     if(!sound::playing($sounds.attack) && $animation.current == 1) {
       sound::play($sounds.attack);
     }

boss_fight_ui.hpp

@@ -19,6 +19,7 @@ namespace gui {
     public:
       sf::Clock $clock;
       bool $boss_hit = false;
+      sf::Vector2f $boss_pos;
       components::Combat $combat;
       components::Sprite $sprite_config;
       components::Sound $sounds;

components.cpp

@@ -54,12 +54,16 @@ namespace components {
     }
   }
 
-  void Animation::step(sf::Vector2f& scale_out, sf::IntRect& rect_out) {
+  void Animation::step(sf::Vector2f& scale_out, sf::Vector2f& pos_out, sf::IntRect& rect_out) {
     if(playing && current < frames) {
       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(stationary) {
+        pos_out.y = pos_out.y - (pos_out.y * scale_out.y - pos_out.y);
+      }
+
       if(!simple) {
         rect_out.position.x += current * texture_width;
       }

components.hpp

@@ -112,16 +112,17 @@ namespace components {
     bool simple = true;
     int frames = 10;
     float speed = 0.3f;
+    ease::Style easing = ease::IN_OUT_BACK;
+    float ease_rate = 0.5f;
+    bool stationary = false;
     int current = 0;
     bool playing = false;
     float subframe = 0;
-    ease::Style easing = ease::IN_OUT_BACK;
-    float ease_rate = 0.5f;
     int texture_width = TEXTURE_WIDTH;
 
     void play();
     float twitching();
-    void step(sf::Vector2f& scale_out, sf::IntRect& rect_out);
+    void step(sf::Vector2f& scale_out, sf::Vector2f& pos_out, sf::IntRect& rect_out);
   };
 
   template <typename T> struct NameOf;
@@ -138,7 +139,8 @@ 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, easing, ease_rate);
+  ENROLL_COMPONENT(Animation, scale, simple, frames,
+      speed, easing, ease_rate, stationary);
   ENROLL_COMPONENT(Sound, attack, death);
 
   using ReflFuncSignature = std::function<void(DinkyECS::World& world, DinkyECS::Entity ent, nlohmann::json &j)>;

raycaster.cpp

@@ -158,7 +158,7 @@ void Raycaster::sprite_casting(sf::RenderTarget &target) {
 
       if($level.world->has<components::Animation>(rec.second)) {
         auto& animation = $level.world->get<components::Animation>(rec.second);
-        if(animation.playing) animation.step(scale, in_texture);
+        if(animation.playing) animation.step(scale, position, in_texture);
       }
 
       sf_sprite->setOrigin(origin);