From 0b34262db68836a661d0d9cbebe5b68c28dacba0 Mon Sep 17 00:00:00 2001
From: Rodolfo Barcelli Jo <rodolfo.barcelli@gmail.com>
Date: Wed, 21 Jan 2026 19:06:41 +0800
Subject: [PATCH] Add: Implemented ECS initialization and reset functions

---
 becs3.h | 60 +++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 43 insertions(+), 17 deletions(-)

diff --git a/becs3.h b/becs3.h
index adcbce8..05a01b0 100644
--- a/becs3.h
+++ b/becs3.h
@@ -48,7 +48,7 @@ bool BECS_ComponentHas(BECS_ECS *ecs, BECS_Entity entity, BECS_ComponentID compo
 #define BECS_MAX_COMPONENTS 64
 #endif /* BECS_MAX_COMPONENTS */
 
-#define BECS_NULL_ENTITY
+#define BECS_NULL_ENTITY BECS_MAX_COMPONENTS + 1
 #define BECS_INVALID_COMPONENT_ID UINT32_MAX
 
 typedef uint64_t BECS_Signature;
@@ -73,10 +73,10 @@ struct BECS_ECS {
 
     /* Entity Management */
     uint32_t entityCount;
-    BECS_Signature entitySignatures[BECS_MAX_COMPONENTS];
-    bool aliveEntites[BECS_MAX_COMPONENTS];
+    BECS_Signature entitySignatures[BECS_MAX_ENTITIES];
+    bool aliveEntites[BECS_MAX_ENTITIES];
 
-    BECS_Entity freeEntities[BECS_MAX_COMPONENTS];
+    BECS_Entity freeEntities[BECS_MAX_ENTITIES];
     uint32_t freeEntityCount;
 
     /* Component Management */
@@ -85,29 +85,29 @@ struct BECS_ECS {
 };
 
 /* Signature Helpers */
-static inline BECS_Signature BECS_SignatureSet(BECS_Signature sig, BECS_ComponentID componentId)
+static BECS_Signature BECS_SignatureSet(BECS_Signature sig, BECS_ComponentID componentId)
 {
     return sig | (1ULL << componentId);
 }
 
-static inline bool ecs_signature_has(BECS_Signature sig, BECS_ComponentID component_id)
+static bool ecs_signature_has(BECS_Signature sig, BECS_ComponentID component_id)
 {
     return (sig & (1ULL << component_id)) != 0;
 }
 
-static inline bool ecs_signature_matches(BECS_Signature entitySig, BECS_Signature querySig)
+static bool ecs_signature_matches(BECS_Signature entitySig, BECS_Signature querySig)
 {
     return (entitySig & querySig) == querySig;
 }
 
 /* Memory Arena */
 
-BECS_Arena BECS_CreateArena(void *memory, size_t size)
+BECS_Arena BECS_CreateArena(void *memory, size_t capacity)
 {
     uintptr_t baseOffset = 64 - ((uintptr_t)memory % 64);
     BECS_Arena arena = {
         baseOffset,
-        size,
+        capacity,
         memory
     };
     return arena;
@@ -140,7 +140,8 @@ static void BECS_ComponentPoolInit
     pool->denseArray = BECS_AllocateMemory(arena, componentSize * capacity);
     pool->denseEntityMapping = (BECS_Entity *)BECS_AllocateMemory(arena, sizeof(BECS_Entity) * capacity);
 
-    for (uint32_t i = 0; i < BECS_MAX_ENTITIES; i++)
+    uint32_t i;
+    for (i = 0; i < BECS_MAX_ENTITIES; i++)
     {
         pool->sparseArray[i] = UINT32_MAX;
     }
@@ -198,19 +199,44 @@ static bool BECS_ComponentPoolHas(BECS_ComponentPool *pool, BECS_Entity entity)
 
 /* World API Functions */
 
-/* TODO: Implement Initialization Functions
-
-BECS_ECS BECS_InitECS(BECS_Arena *arena)
+BECS_ECS BECS_InitECS(void *memory, size_t size)
 {
-    NOTE: Make use of memset here
+    BECS_ECS ecs;
+    ecs.arena = BECS_CreateArena(memory, size);
+    ecs.entityCount = 0;
+    memset(ecs.entitySignatures, 0, sizeof(BECS_Signature) * BECS_MAX_ENTITIES);
+    memset(ecs.aliveEntites, 0, sizeof(bool) * BECS_MAX_ENTITIES);
+    memset(ecs.freeEntities, BECS_NULL_ENTITY, sizeof(BECS_Entity) * BECS_MAX_ENTITIES);
+    ecs.freeEntityCount = 0;
+
+    ecs.componentTypeCount = 0;
+    uint32_t i;
+    for (i = 0; i < BECS_MAX_COMPONENTS; i++)
+    {
+        ecs.componentPools[i].denseArray = NULL;
+        ecs.componentPools[i].denseEntityMapping = NULL;
+    }
+
+    return ecs;
 }
 
 void BECS_ResetECS(BECS_ECS *ecs)
 {
-    NOTE: Make use of memset here
-}
+    ecs->arena = BECS_CreateArena(ecs->arena.memory, ecs->arena.capacity);
+    ecs->entityCount = 0;
+    memset(ecs->entitySignatures, 0, sizeof(BECS_Signature) * BECS_MAX_ENTITIES);
+    memset(ecs->aliveEntites, 0, sizeof(bool) * BECS_MAX_ENTITIES);
+    memset(ecs->freeEntities, BECS_NULL_ENTITY, sizeof(BECS_Entity) * BECS_MAX_ENTITIES);
+    ecs->freeEntityCount = 0;
 
-*/
+    ecs->componentTypeCount = 0;
+    uint32_t i;
+    for (i = 0; i < BECS_MAX_COMPONENTS; i++)
+    {
+        ecs->componentPools[i].denseArray = NULL;
+        ecs->componentPools[i].denseEntityMapping = NULL;
+    }
+}
 
 /* Entity API Functions */