From 3ec7505214e2cb1cafafe5d215519f8706820893 Mon Sep 17 00:00:00 2001
From: Klemen Plestenjak <plestenjak.klemen@gmail.com>
Date: Fri, 29 Dec 2023 20:03:01 +0100
Subject: [PATCH] Generalize easing system (works for all components now)

---
 game/components.h          | 14 +++-----------
 game/systems/s_animation.c | 28 +++++++---------------------
 game/systems/s_event.c     |  3 ++-
 game/systems/systems.h     | 12 +++++-------
 4 files changed, 17 insertions(+), 40 deletions(-)

diff --git a/game/components.h b/game/components.h
index 2811c10..8ea175f 100644
--- a/game/components.h
+++ b/game/components.h
@@ -111,20 +111,13 @@ typedef struct Animation {
 } Animation;
 extern ECS_COMPONENT_DECLARE(Animation);
 
-typedef enum EasingType {
-    EASE_ROTATION,
-    EASE_POS_X,
-    EASE_POS_Y,
-    EASE_SIZE_X,
-    EASE_SIZE_Y,
-} EasingType;
-
 typedef struct Easing {
-    EasingType type;
+    ecs_entity_t compID;
+    size_t       memberOffset;
+
     BzEaseType easingFunc;
 
     // start + target * (easeStart + (easeTarget * x) + easeOffset) + offset
-
     f32 target;
     f32 start;
     f32 offset;
@@ -135,7 +128,6 @@ typedef struct Easing {
     f32 x;
     f32 elapsed;
     f32 duration;
-
     //struct Easing *next;
 } Easing;
 extern ECS_COMPONENT_DECLARE(Easing);
diff --git a/game/systems/s_animation.c b/game/systems/s_animation.c
index 669acb0..68f2588 100644
--- a/game/systems/s_animation.c
+++ b/game/systems/s_animation.c
@@ -51,15 +51,14 @@ void updateAnimation(ecs_iter_t *it) {
 }
 
 void updateEasingSystem(ecs_iter_t *it) {
-    Easing   *easing   = ecs_field(it, Easing, 1);
-    Position *position = ecs_field(it, Position, 2);
-    Size     *size     = ecs_field(it, Size, 3);
-    Rotation *rotation = ecs_field(it, Rotation, 4);
+    Easing *easing = ecs_field(it, Easing, 1);
 
     f32 dt = GetFrameTime();
 
     for (i32 i = 0; i < it->count; i++) {
         ecs_entity_t entity = it->entities[i];
+        if (!ecs_has_id(ECS, entity, easing[i].compID))
+            continue;
         if (easing[i].elapsed > easing[i].duration) {
             ecs_remove(ECS, entity, Easing);
             continue;
@@ -76,22 +75,9 @@ void updateEasingSystem(ecs_iter_t *it) {
         // Outer
         x = e->start + e->target * x + e->offset;
 
-        switch (easing->type) {
-            case EASE_ROTATION:
-                rotation[i] = x;
-                break;
-            case EASE_POS_X:
-                position[i].x = x;
-                break;
-            case EASE_POS_Y:
-                position[i].y = x;
-                break;
-            case EASE_SIZE_X:
-                size[i].x = x;
-                break;
-            case EASE_SIZE_Y:
-                size[i].y = x;
-                break;
-        }
+        u8 *compData = ecs_get_mut_id(ECS, entity, easing[i].compID);
+        compData += easing[i].memberOffset;
+
+        *(f32 *) compData = x;
     }
 }
diff --git a/game/systems/s_event.c b/game/systems/s_event.c
index 4a0600a..6d5f0b5 100644
--- a/game/systems/s_event.c
+++ b/game/systems/s_event.c
@@ -7,7 +7,8 @@ i32 harvestEvent(ecs_entity_t entity, HarvestEvent event) {
     BZ_ASSERT(ecs_has(ECS, entity, Resource));
 
     ecs_set(ECS, entity, Easing, {
-        .type = EASE_ROTATION,
+        .compID = ecs_id(Rotation),
+        .memberOffset = 0,
         .easingFunc = BZ_EASE_OUT_ELASTIC,
         .duration = 0.4f,
 
diff --git a/game/systems/systems.h b/game/systems/systems.h
index d04b0ec..fbdd0ac 100644
--- a/game/systems/systems.h
+++ b/game/systems/systems.h
@@ -36,13 +36,6 @@ void updateUnitAISystem(ecs_iter_t *it);
  */
 void updateUnitActionsSystem(ecs_iter_t *it);
 
-/*
- * 1: Easing
- * 2: Position
- * 3: Size
- * 4: Rotation
- */
-void updateEasingSystem(ecs_iter_t *it);
 
 /**********************************
  * Animation Systems
@@ -61,6 +54,11 @@ void updateAnimationState(ecs_iter_t *it);
  */
 void updateAnimation(ecs_iter_t *it);
 
+/*
+ * 1: Easing
+ */
+void updateEasingSystem(ecs_iter_t *it);
+
 /**********************************
  * Entity Systems
  **********************************/