Arena works better now and I can give a list of sprites to work as fixtures in a scene.

assets/bosses.json

@@ -14,11 +14,15 @@
         "boss":  {
           "start_pos": "boss5",
           "scale": 0.6,
-          "mid_cell": true
-        }
+          "mid_cell": true,
+          "sprite": "rat_king_boss"
+        },
+        "fixtures": [
+          {"name": "torch_crappy", "scale": 0.8, "cell": "torch1"},
+          {"name": "torch_crappy", "scale": 0.8, "cell": "torch2"}
+        ]
       },
       {"_type": "Combat", "hp": 20, "max_hp": 20, "damage": 20, "dead": false},
-      {"_type": "Sprite", "name": "rat_king_boss", "width": 720, "height": 720, "scale": 0.8, "stationary": true},
       {"_type": "Sound", "attack": "Marmot_Scream_1", "death": "Creature_Death_1"}
     ]
   }

assets/enemies.json

@@ -23,7 +23,7 @@
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "ai_script": "Enemy::actions", "ai_start_name": "Enemy::initial_state", "ai_goal_name": "Enemy::final_state"},
       {"_type": "Personality", "hearing_distance": 5, "tough": false},
-      {"_type": "Sprite", "name": "gold_savior", "width": 256, "height": 256, "width": 256, "height": 256, "scale": 1.0},
+      {"_type": "Sprite", "name": "gold_savior", "scale": 1.0},
       {"_type": "Sound", "attack": "Sword_Hit_2", "death": "Humanoid_Death_1"}
     ]
   },
@@ -38,7 +38,7 @@
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "ai_script": "Enemy::actions", "ai_start_name": "Enemy::initial_state", "ai_goal_name": "Enemy::final_state"},
       {"_type": "Personality", "hearing_distance": 5, "tough": true},
-      {"_type": "Sprite", "name": "armored_knight", "width": 256, "height": 256, "width": 256, "height": 256, "scale": 1.0},
+      {"_type": "Sprite", "name": "armored_knight", "scale": 1.0},
       {"_type": "Sound", "attack": "Sword_Hit_2", "death": "Humanoid_Death_1"}
     ]
   },
@@ -53,7 +53,7 @@
       {"_type": "Motion", "dx": 0, "dy": 0, "random": true},
       {"_type": "EnemyConfig", "ai_script": "Enemy::actions", "ai_start_name": "Enemy::initial_state", "ai_goal_name": "Enemy::final_state"},
       {"_type": "Personality", "hearing_distance": 5, "tough": true},
-      {"_type": "Sprite", "name": "axe_ranger", "width": 256, "height": 256, "scale": 1.0},
+      {"_type": "Sprite", "name": "axe_ranger", "scale": 1.0},
       {"_type": "Sound", "attack": "Sword_Hit_2", "death": "Ranger_1"}
     ]
   },
@@ -68,7 +68,7 @@
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "ai_script": "Enemy::actions", "ai_start_name": "Enemy::initial_state", "ai_goal_name": "Enemy::final_state"},
       {"_type": "Personality", "hearing_distance": 5, "tough": false},
-      {"_type": "Sprite", "name": "rat_with_sword", "width": 256, "height": 256, "scale": 1.0},
+      {"_type": "Sprite", "name": "rat_with_sword", "scale": 1.0},
       {"_type": "Sound", "attack": "Small_Rat", "death": "Creature_Death_1"}
     ]
   },
@@ -83,7 +83,7 @@
       {"_type": "Motion", "dx": 0, "dy": 0, "random": false},
       {"_type": "EnemyConfig", "ai_script": "Enemy::actions", "ai_start_name": "Enemy::initial_state", "ai_goal_name": "Enemy::final_state"},
       {"_type": "Personality", "hearing_distance": 5, "tough": true},
-      {"_type": "Sprite", "name": "hairy_spider", "width": 256, "height": 256, "scale": 1.0},
+      {"_type": "Sprite", "name": "hairy_spider", "scale": 1.0},
       {"_type": "Sound", "attack": "Spider_1", "death": "Spider_2"}
     ]
   }

boss/ui.cpp

@@ -15,8 +15,8 @@ namespace boss {
     $scene(world->get<components::BossFight>($boss_id)),
     $combat_ui(true)
   {
-    auto& sprite = $world->get<components::Sprite>($boss_id);
-    $boss_sprite = textures::get_sprite(sprite.name);
+    std::string sprite_name = $scene.boss["sprite"];
+    $boss_sprite = textures::get_sprite(sprite_name);
 
     // floor is std::optional
     if($scene.floor) {
@@ -25,14 +25,21 @@ namespace boss {
 
     $player_sprite = textures::get_sprite($scene.player["sprite"]);
 
-    dbc::check(animation::has(sprite.name), "add boss animation to animations.json");
-    $boss_anim = animation::load(sprite.name);
+    dbc::check(animation::has(sprite_name), "add boss animation to animations.json");
+    $boss_anim = animation::load(sprite_name);
 
-    $torch_left = textures::get_sprite("torch_crappy");
-    $torch_left_anim = animation::load("torch_crappy");
-    $torch_right.texture = $torch_left.texture;
-    $torch_right.sprite = std::make_shared<sf::Sprite>(*$torch_right.texture);
-    $torch_right_anim = animation::load("torch_crappy");
+    for(auto& fixture : $scene.fixtures) {
+      std::string name = fixture["name"];
+      auto st = textures::get_sprite(name);
+      // clone the sprite so it can be positioned
+      st.sprite = std::make_shared<sf::Sprite>(*st.texture);
+
+      auto anim = animation::load(name);
+      float scale = fixture["scale"];
+      std::string cell = fixture["cell"];
+
+      $fixtures.emplace_back(st, anim, cell, scale);
+    }
   }
 
   void UI::init() {
@@ -57,8 +64,9 @@ namespace boss {
       position_sprite($floor_sprite, $scene.floor_pos, 1.0, false);
     }
 
-    position_sprite($torch_left, "torch1", 1.0, false);
-    position_sprite($torch_right, "torch2", 1.0, false);
+    for(auto& fixture : $fixtures) {
+      position_sprite(fixture.st, fixture.cell, fixture.scale, false);
+    }
 
     $arena.init();
 
@@ -103,10 +111,9 @@ namespace boss {
     window.draw(*$boss_sprite.sprite);
     window.draw(*$player_sprite.sprite);
 
-    window.draw(*$torch_left.sprite);
-    window.draw(*$torch_right.sprite);
-
-    // $arena.debug_layout(window);
+    for(auto& fixture : $fixtures) {
+      window.draw(*fixture.st.sprite);
+    }
   }
 
   bool UI::mouse(float x, float y, Modifiers mods) {

boss/ui.hpp

@@ -7,6 +7,13 @@
 #include "gui/combat_ui.hpp"
 #include "components.hpp"
 
+struct AnimatedFixture {
+  textures::SpriteTexture st;
+  components::Animation anim;
+  std::string cell;
+  float scale;
+};
+
 namespace boss {
   using std::shared_ptr;
   using namespace DinkyECS;
@@ -25,10 +32,7 @@ namespace boss {
     components::Animation $boss_anim;
     sf::Vector2f $boss_pos;
 
-    SpriteTexture $torch_left;
-    SpriteTexture $torch_right;
-    components::Animation $torch_left_anim;
-    components::Animation $torch_right_anim;
+    std::vector<AnimatedFixture> $fixtures;
 
     UI(shared_ptr<World> world, Entity boss_id);
 

components.cpp

@@ -1,4 +1,5 @@
 #include "components.hpp"
+
 #include "point.hpp"
 #include "easings.hpp"
 

components.hpp

@@ -76,12 +76,18 @@ namespace components {
     int hp = 10;
   };
 
+  struct Sprite {
+    string name;
+    float scale;
+  };
+
   struct BossFight {
     std::string background;
     std::optional<std::string> floor;
     std::string floor_pos;
     json player;
     json boss;
+    json fixtures;
   };
 
   struct Combat {
@@ -105,12 +111,6 @@ namespace components {
     std::vector<std::string> events;
   };
 
-  struct Sprite {
-    string name;
-    int width;
-    int height;
-  };
-
   struct Sound {
     std::string attack;
     std::string death;
@@ -149,8 +149,8 @@ namespace components {
   using ComponentMap = std::unordered_map<std::string, ReflFuncSignature>;
 
   ENROLL_COMPONENT(Tile, display, foreground, background);
-  ENROLL_COMPONENT(BossFight, background, floor, floor_pos, player, boss);
-  ENROLL_COMPONENT(Sprite, name, width, height);
+  ENROLL_COMPONENT(BossFight, background, floor, floor_pos, player, boss, fixtures);
+  ENROLL_COMPONENT(Sprite, name, scale);
   ENROLL_COMPONENT(Curative, hp);
   ENROLL_COMPONENT(LightSource, strength, radius);
   ENROLL_COMPONENT(Position, location.x, location.y);

systems.cpp

@@ -669,7 +669,7 @@ void System::spawn_attack(World& world, int attack_id, DinkyECS::Entity enemy) {
   auto effect = ritual.element == FIRE ? "burning_animation" : "lightning_animation";
 
   auto effect_id = world.entity();
-  world.set<Sprite>(effect_id, {effect, 256, 256});
+  world.set<Sprite>(effect_id, {effect, 1.0f});
   world.set<Temporary>(effect_id, {true});
 
   auto shader = shaders::get(ritual.element == FIRE ? "flame" : "lightning");

tests/animation2.cpp

@@ -0,0 +1,117 @@
+#include <catch2/catch_test_macros.hpp>
+#include <fmt/core.h>
+#include <string>
+#include <coroutine>
+#include <chrono>
+#include "rand.hpp"
+#include <thread>
+#include <vector>
+#include "components.hpp"
+#include <iostream>
+#include "stats.hpp"
+#include "simplefsm.hpp"
+#include "textures.hpp"
+#include "animation.hpp"
+
+using namespace std::chrono_literals;
+using components::Animation;
+using TheClock = std::chrono::steady_clock;
+using TimeDelta = TheClock::duration;
+using TimePoint = std::chrono::time_point<TheClock>;
+const TimeDelta MIN_TICK = 200ms;
+
+struct AnimationState {
+  Animation anim;
+  TimeDelta wait = 1s;
+  sf::Vector2f scale{1.0, 1.0};
+  sf::Vector2f pos{0.0, 0.0};
+  sf::IntRect rect{{0, 0}, {300, 300}};
+
+  void step() {
+    anim.step(scale, pos, rect);
+  }
+
+  void apply(textures::SpriteTexture& st) {
+    animation::apply(anim, *st.sprite, pos);
+  }
+};
+
+struct AnimationQueue {
+  std::vector<AnimationState> active;
+  TimePoint last_tick;
+  TimeDelta wait_for = MIN_TICK;
+  size_t in_queue = 0;
+  size_t chunk = 1000;
+
+  TimeDelta delta() {
+    return TheClock::now() - last_tick;
+  }
+
+  void tick() {
+    last_tick = TheClock::now();
+  }
+
+  size_t add(Animation& anim, int initial_wait) {
+    active.emplace_back(anim, TheClock::duration(initial_wait));
+    return active.size() - 1;
+  }
+
+  AnimationState& get(size_t id) {
+    return active.at(id);
+  }
+
+  void render() {
+    wait_for = MIN_TICK;
+    auto dt = delta();
+
+    for(size_t i = 0; i < chunk; i++) {
+      in_queue++;
+      auto& a = active[in_queue % active.size()];
+
+      if(!a.anim.playing) continue;
+
+      if(a.wait < wait_for) {
+        wait_for = a.wait;
+      }
+
+      if(a.wait < dt) {
+        // fmt::println("play animation: {} total                  ", active.size());
+        a.step();
+      }
+    }
+  }
+};
+
+TEST_CASE("simple coroutine animation test", "[coro]") {
+  AnimationQueue queue;
+  Animation anim;
+  anim.play();
+
+  for(int i = 0; i < 100; i++) {
+    int time = Random::uniform(16, 32);
+    size_t id = queue.add(anim, time);
+    auto& what = queue.get(id);
+
+    REQUIRE(what.wait == TheClock::duration(time));
+  }
+
+  dbc::check(queue.active.size() > 0, "zero size queue after adding is impossible.");
+  queue.tick();
+  Stats stats;
+
+  for(int i = 0; i < 10000; i++) {
+    auto start = stats.time_start();
+    auto delta = queue.delta();
+
+    queue.render();
+
+    if(delta > queue.wait_for) {
+      queue.add(anim, Random::uniform(100, 5000));
+      queue.tick();
+    }
+
+    stats.sample_time(start);
+  }
+
+  fmt::print("stdev: {}, mean: {}\r", stats.stddev(), stats.mean());
+}