Entity loading and unloading implemented somewhat

src/dusk/entity/entity.c

@@ -7,6 +7,7 @@
 
 #include "entity.h"
 #include "assert/assert.h"
+#include "util/memory.h"
 
 entity_t ENTITIES[ENTITY_COUNT_MAX] = {0};
 
@@ -24,6 +25,8 @@ void entityInit(entity_t *entity, const entitytype_t type) {
     ENTITY_CALLBACKS[type].init,
     "Entity type has no init callback"
   );
+  
+  memoryZero(entity, sizeof(entity_t));
 
   entity->type = type;
   ENTITY_CALLBACKS[type].init(entity);

src/dusk/world/chunk.c

@@ -172,14 +172,20 @@ void chunkMapSetPosition(const uint16_t x, const uint16_t y) {
 void chunkLoad(chunk_t *chunk, const uint16_t x, const uint16_t y) {
   assertNotNull(chunk, "Chunk pointer is null");
 
+  // Zero out the chunk data.
+  memoryZero(chunk, sizeof(chunk_t));
+
+  // Set the chunk coordinates.
   chunk->x = x;
   chunk->y = y;
 
+  // Only load data if the chunk is within bounds.
   if(x >= WORLD_WIDTH || y >= WORLD_HEIGHT) {
     memorySet(chunk->tiles, 0, sizeof(chunk->tiles));
     return;
   }
   
+  // Is chunk data defined?
   const chunkdata_t *chunkData = WORLD_CHUNKS[y * WORLD_WIDTH + x];
   if(chunkData == NULL) {
     memorySet(chunk->tiles, 0, sizeof(chunk->tiles));
@@ -201,15 +207,19 @@ void chunkLoad(chunk_t *chunk, const uint16_t x, const uint16_t y) {
   while(data < chunkData->entities + CHUNK_ENTITY_COUNT_MAX) {
     if(data->type == ENTITY_TYPE_NULL) break;
 
+    // Store that this chunk owns this entity ID.
+    chunk->entityIDs[chunk->entityCount++] = data->id;
+
     // Check entity isn't loaded (still).
     entity = ENTITIES;
     do {
-      if(entity->id == data->id) break;
+      if(entity->type != ENTITY_TYPE_NULL && entity->id == data->id) break;
       entity++;
     } while(entity < ENTITIES + ENTITY_COUNT_MAX);
 
     if(entity != ENTITIES + ENTITY_COUNT_MAX) {
       // Entity is already loaded, skip it.
+      printf("Entity ID %u already loaded, skipping...\n", data->id);
       data++;
       continue;
     }
@@ -240,5 +250,54 @@ void chunkLoad(chunk_t *chunk, const uint16_t x, const uint16_t y) {
 }
 
 void chunkUnload(chunk_t *chunk) {
+  uint8_t i;
+  entity_t *entity;
+  uint32_t id;
   assertNotNull(chunk, "Chunk pointer is null");
+
+  // Iterate over each entity this chunk owns.
+  i = 0;
+  while(i < chunk->entityCount) {
+    id = chunk->entityIDs[i++];
+
+    // Now, do we need to unload this entity?
+    bool_t shouldUnload = false;
+
+    // Now, find the entity loaded with this ID. It should be impossible for 
+    // this entity to be unloaded (but may change in future).
+    entity = ENTITIES;
+    do {
+      if(entity->type != ENTITY_TYPE_NULL && entity->id == id) break;
+      entity++;
+    } while(entity < ENTITIES + ENTITY_COUNT_MAX);
+
+    // If the entity is still within our chunk bounds, it's getting unloaded
+    if(
+      entity->x >= chunk->x * CHUNK_WIDTH * TILE_WIDTH &&
+      entity->x < (chunk->x + 1) * CHUNK_WIDTH * TILE_WIDTH &&
+      entity->y >= chunk->y * CHUNK_HEIGHT * TILE_HEIGHT &&
+      entity->y < (chunk->y + 1) * CHUNK_HEIGHT * TILE_HEIGHT
+    ) {
+      shouldUnload = true;
+    } else {
+      assertUnreachable(
+        "Entity has left its chunk bounds, we should not be unloading it but "
+        "I have yet to implement that properly. It will need to self-manage "
+        "its own unloading somehow, and also not be in a null chunk "
+        "when it does so."
+      );
+    }
+
+    // This entity is still in use, leave it loaded.
+    if(!shouldUnload) continue;
+
+    assertTrue(
+      entity < ENTITIES + ENTITY_COUNT_MAX,
+      "Entity ID not found for unloading"
+    );
+
+    // NULL the entity type, effectively unloading it.
+    printf("Unloading entity ID %u\n", entity->id);
+    entity->type = ENTITY_TYPE_NULL;
+  }
 }

src/dusk/world/chunk.h

@@ -20,8 +20,8 @@
 typedef struct {
   uint16_t x, y;
   tile_t tiles[CHUNK_TILE_COUNT];
-  // int32_t entityIDs[CHUNK_ENTITY_COUNT_MAX];
-  // uint8_t entityCount;
+  uint32_t entityIDs[CHUNK_ENTITY_COUNT_MAX];
+  uint8_t entityCount;
 } chunk_t;
 
 typedef struct {

src/dusk/world/overworld.c

@@ -41,6 +41,15 @@ void overworldUpdate() {
     entityUpdate(entity++);
   } while(entity->type != ENTITY_TYPE_NULL);
 
+  // Testing, follow player
+  entity = &ENTITIES[0]; // Player entity
+  assertTrue(
+    entity->type == ENTITY_TYPE_PLAYER,
+    "First entity must be player"
+  );
+  OVERWORLD_CAMERA_X = (uint32_t)floorf(entity->x);
+  OVERWORLD_CAMERA_Y = (uint32_t)floorf(entity->y);
+
   uint16_t x, y;
   if(OVERWORLD_CAMERA_X < RENDER_WIDTH / 2) {
     x = 0;

src/duskraylib/display/draw/drawoverworld.c

@@ -26,13 +26,13 @@ void drawOverworldDraw(void) {
   if(OVERWORLD_CAMERA_X < RENDER_WIDTH / 2) {
     DRAW_OVERWORLD_CAMERA.target.x = 0;
   } else {
-    DRAW_OVERWORLD_CAMERA.target.x = (OVERWORLD_CAMERA_X - RENDER_WIDTH) / 2;
+    DRAW_OVERWORLD_CAMERA.target.x = OVERWORLD_CAMERA_X - (RENDER_WIDTH / 2);
   }
 
   if(OVERWORLD_CAMERA_Y < RENDER_HEIGHT / 2) {
     DRAW_OVERWORLD_CAMERA.target.y = 0;
   } else {
-    DRAW_OVERWORLD_CAMERA.target.y = (OVERWORLD_CAMERA_Y - RENDER_HEIGHT) / 2;
+    DRAW_OVERWORLD_CAMERA.target.y = OVERWORLD_CAMERA_Y - (RENDER_HEIGHT / 2);
   }
   
   BeginMode2D(DRAW_OVERWORLD_CAMERA);