Crumbs from eaten food

src/items.cpp

@@ -1,6 +1,15 @@
 #include "play.h"
 
+constexpr float CRUMB_LIFE = 1.5f;
+constexpr float CRUMB_SHRINK = 0.3f;
+constexpr float CRUMB_SIZE_MAX = 0.35f;
+constexpr float CRUMB_SIZE_MIN = 0.15f;
+constexpr float CRUMB_SPEED_X = 4;
+constexpr float CRUMB_SPEED_Y_MAX = 7;
+constexpr float CRUMB_SPEED_Y_MIN = 2;
+constexpr float CRUMB_SPIN = 15;
 constexpr float HOLD_SPIN = 0.1f;
+constexpr int CRUMB_COUNT = 6;
 constexpr float ROTATION_GROUND_DAMPING = 0.85f;
 constexpr float ROTATION_MAX = 90;
 constexpr float ROTATION_RETURN_SPEED = 120;
@@ -14,6 +23,77 @@ void Items::add(Play& play, int id, Vec2 position, Vec2 velocity, float rotation
     discovered[id] = true;
 }
 
+// Bursts slices of an item's graphic from where it is, to fall and bounce like items until they shrink away.
+void Items::crumbs_spawn(ItemEntity& source)
+{
+    for (int i = 0; i < CRUMB_COUNT; i++)
+    {
+        ItemEntity& crumb = crumbs.emplace_back(source);
+        float fraction = random_get(CRUMB_SIZE_MIN, CRUMB_SIZE_MAX);
+        for (LayerChange& layer : crumb.actor.layers)
+        {
+            if (!layer.isRegion)
+                continue;
+            Vec2 size = layer.size * fraction;
+            layer.crop = {layer.crop.x + random_get(0, layer.size.x - size.x),
+                          layer.crop.y + random_get(0, layer.size.y - size.y)};
+            layer.size = size;
+            layer.pivot = size / 2;
+        }
+        crumb.velocity = {random_get(-CRUMB_SPEED_X, CRUMB_SPEED_X), -random_get(CRUMB_SPEED_Y_MIN, CRUMB_SPEED_Y_MAX)};
+        crumb.angularVelocity = random_get(-CRUMB_SPIN, CRUMB_SPIN);
+        crumb.life = (int)(CRUMB_LIFE * TICK_RATE);
+    }
+}
+
+// Moves an item or crumb a tick under gravity, bouncing off the bounds and settling on the ground. True if it bounced.
+static bool motion_update(Play& play, ItemEntity& entity)
+{
+    Area& area = play.character->area;
+    Rect bounds = play.bounds;
+    Vec2& position = entity.actor.position;
+    Vec2& velocity = entity.velocity;
+    float& rotation = *entity.actor.rotation;
+    float gravity = play.character->catalog.items[entity.id].gravity;
+    gravity = gravity != 0 ? gravity : area.gravity;
+    float right = bounds.x + bounds.w;
+    float bottom = bounds.y + bounds.h;
+    bool isBounced = false;
+    position = position + velocity;
+    rotation += entity.angularVelocity;
+    if (position.x <= bounds.x || position.x >= right)
+    {
+        position.x = position.x <= bounds.x ? bounds.x + 1 : right - 1;
+        velocity.x = -velocity.x * area.friction;
+        entity.angularVelocity = -entity.angularVelocity * area.friction;
+        rotation = -rotation;
+        isBounced = true;
+    }
+    if (position.y <= bounds.y || position.y >= bottom)
+    {
+        if (position.y >= bottom && velocity.y <= gravity)
+        {
+            position.y = bottom;
+            velocity = {velocity.x * area.friction, 0};
+            rotation = std::remainder(rotation, 360.0f);
+            float step = ROTATION_RETURN_SPEED * TICK;
+            rotation = std::abs(rotation) <= step ? 0 : rotation - std::copysign(step, rotation);
+            entity.angularVelocity *= ROTATION_GROUND_DAMPING;
+        }
+        else
+        {
+            velocity.y = -velocity.y;
+            entity.angularVelocity *= area.friction;
+            isBounced = true;
+        }
+        velocity.y *= area.friction;
+    }
+    velocity.x *= area.airResistance;
+    velocity.y += gravity;
+    position = {std::clamp(position.x, bounds.x, right), std::clamp(position.y, bounds.y, bottom)};
+    return isBounced;
+}
+
 // Forgets which item is being eaten, and lets go of the held one unless asked to keep it.
 void Items::drop(Hold hold)
 {
@@ -175,6 +255,7 @@ void Items::update(Play& play, Pointer pointer)
                         stats.digestionRate = std::clamp(stats.digestionRate + item.digestionBonus,
                                                          traits.digestionRateMin, traits.digestionRateMax);
                         stats.totalConsumed++;
+                        crumbs_spawn(entity);
                         removed = held;
                         drop();
                         feeding.animation = body.actor.animation;
@@ -224,20 +305,11 @@ void Items::update(Play& play, Pointer pointer)
 
     int moved = -1;
     bool isTargetLocked = pointer.target >= 0 && pointer.target < (int)list.size();
-    float right = bounds.x + bounds.w;
-    float bottom = bounds.y + bounds.h;
     for (int i = 0; i < (int)list.size(); i++)
     {
         ItemEntity& entity = list[i];
         Vec2& position = entity.actor.position;
-        Vec2& velocity = entity.velocity;
-        float& rotation = *entity.actor.rotation;
-        float gravity = character.catalog.items[entity.id].gravity;
-        gravity = gravity != 0 ? gravity : area.gravity;
         entity.actor.update(audio);
-        position = position + velocity;
-        rotation += entity.angularVelocity;
-
         if (is_point_in_rect(entity.actor.bounds_get(), pointer.position) && !pointer.isCaptured &&
             (!isTargetLocked || i == pointer.target))
         {
@@ -269,39 +341,28 @@ void Items::update(Play& play, Pointer pointer)
             }
         }
 
-        if (i != held)
+        if (i == held)
         {
-            if (position.x <= bounds.x || position.x >= right)
-            {
-                position.x = position.x <= bounds.x ? bounds.x + 1 : right - 1;
-                velocity.x = -velocity.x * area.friction;
-                entity.angularVelocity = -entity.angularVelocity * area.friction;
-                rotation = -rotation;
+            *entity.actor.rotation += entity.angularVelocity;
+            position = {std::clamp(position.x, bounds.x, bounds.x + bounds.w),
+                        std::clamp(position.y, bounds.y, bounds.y + bounds.h)};
+        }
+        else if (motion_update(play, entity))
             audio.play(character.sounds[SOUND_BOUNCE]);
     }
-            if (position.y <= bounds.y || position.y >= bottom)
+
+    for (int i = 0; i < (int)crumbs.size(); i++)
     {
-                if (position.y >= bottom && velocity.y <= gravity)
+        ItemEntity& crumb = crumbs[i];
+        if (--crumb.life <= 0)
         {
-                    position.y = bottom;
-                    velocity = {velocity.x * area.friction, 0};
-                    rotation = std::remainder(rotation, 360.0f);
-                    float step = ROTATION_RETURN_SPEED * TICK;
-                    rotation = std::abs(rotation) <= step ? 0 : rotation - std::copysign(step, rotation);
-                    entity.angularVelocity *= ROTATION_GROUND_DAMPING;
+            crumbs.erase(crumbs.begin() + i--);
+            continue;
         }
-                else
-                {
-                    velocity.y = -velocity.y;
-                    entity.angularVelocity *= area.friction;
-                    audio.play(character.sounds[SOUND_BOUNCE]);
-                }
-                velocity.y *= area.friction;
-            }
-            velocity.x *= area.airResistance;
-            velocity.y += gravity;
-        }
-        position = {std::clamp(position.x, bounds.x, right), std::clamp(position.y, bounds.y, bottom)};
+        motion_update(play, crumb);
+        float shrink = std::min(1.0f, crumb.life / (CRUMB_LIFE * CRUMB_SHRINK * TICK_RATE));
+        for (LayerChange& layer : crumb.actor.layers)
+            layer.scale = Vec2{shrink - 1, shrink - 1} * PERCENT;
     }
 
     if (moved >= 0 && moved < (int)list.size() - 1)

src/play.cpp

@@ -273,8 +273,12 @@ void Play::render(Renderer& renderer, Vec2 screenSize)
     area.render(renderer, view);
     body.actor.render(renderer, view);
     if (!text.isScene)
+    {
         for (ItemEntity& entity : items.list)
             entity.actor.render(renderer, view);
+        for (ItemEntity& crumb : items.crumbs)
+            crumb.actor.render(renderer, view);
+    }
     if (autofeed.isActive)
         autoCursor.render(renderer, view);
     for (Actor& particle : particles)

src/play.h

@@ -50,12 +50,14 @@ struct Pointer
     bool isRightClicked = false;
 };
 
+// An item in the world, or a crumb of one (which has a life, in ticks).
 struct ItemEntity
 {
     Actor actor;
     Vec2 velocity;
     float angularVelocity = 0;
     int id = 0;
+    int life = 0;
 };
 
 struct Toast
@@ -116,6 +118,7 @@ struct Feeding
 class Items
 {
 public:
+    std::vector<ItemEntity> crumbs;
     std::vector<ItemEntity> list;
     std::vector<int> spawnQueue;
     std::vector<bool> discovered;
@@ -130,6 +133,7 @@ public:
     void update(Play& play, Pointer pointer);
     void add(Play& play, int id, Vec2 position, Vec2 velocity = {}, float rotation = 0);
     void drop(Hold hold = HOLD_RELEASE);
+    void crumbs_spawn(ItemEntity& source);
     void spawn_queue_add(Play& play, int id);
     void spawn_queue_add(Play& play);
     int spawn_delay_get(Play& play);