Chunk loading example

src/rpg/entity/entity.c

@@ -11,6 +11,7 @@
 #include "time/time.h"
 #include "util/math.h"
 #include "rpg/cutscene/cutscenemode.h"
+#include "rpg/world/map.h"
 
 entity_t ENTITIES[ENTITY_COUNT];
 

src/rpg/rpg.c

@@ -45,7 +45,6 @@ void rpgUpdate(void) {
   if(!TIME.fixedUpdate) return;
 
   // TODO: Do not update if the scene is not the map scene?
-
   mapUpdate();
 
   // Update overworld ents.
@@ -55,8 +54,8 @@ void rpgUpdate(void) {
     entityUpdate(ent);
   } while(++ent < &ENTITIES[ENTITY_COUNT]);
 
-  // Tick the cutscene system.
   cutsceneSystemUpdate();
+  rpgCameraUpdate();
 }
 
 void rpgDispose(void) {

src/rpg/rpgcamera.c

@@ -8,9 +8,35 @@
 #include "rpgcamera.h"
 #include "util/memory.h"
 #include "rpg/entity/entity.h"
+#include "rpg/world/map.h"
 
 rpgcamera_t RPG_CAMERA;
 
 void rpgCameraInit(void) {
   memoryZero(&RPG_CAMERA, sizeof(rpgcamera_t));
+}
+
+void rpgCameraUpdate(void) {
+  switch(RPG_CAMERA.mode) {
+    case RPG_CAMERA_MODE_FREE:
+      // Free camera mode; nothing to do.
+      break;
+
+    case RPG_CAMERA_MODE_FOLLOW_ENTITY: {
+      entity_t *entity = &ENTITIES[RPG_CAMERA.followEntity.followEntityId];
+      if(entity->type == ENTITY_TYPE_NULL) return;
+
+      // Update map position to match camera.
+      mapPositionSet(
+        (int16_t)(entity->position.x / CHUNK_WIDTH),
+        (int16_t)(entity->position.y / CHUNK_HEIGHT),
+        (int16_t)(entity->position.z / CHUNK_DEPTH)
+      );
+      break;
+    }
+
+    default:
+      // Unknown camera mode; do nothing.
+      break;
+  }
 }

src/rpg/rpgcamera.h

@@ -29,4 +29,9 @@ extern rpgcamera_t RPG_CAMERA;
 /**
  * Initializes the RPG camera.
  */
-void rpgCameraInit(void);
+void rpgCameraInit(void);
+
+/**
+ * Updates the RPG camera.
+ */
+void rpgCameraUpdate(void);

src/rpg/world/map.c

@@ -7,17 +7,119 @@
 
 #include "map.h"
 #include "util/memory.h"
+#include <stdio.h> // For printf
 
 map_t MAP;
 
+// Dummy functions for chunk loading/unloading
+void mapChunkUnload(chunk_t* chunk) {
+  // Placeholder for unloading logic
+  printf("Unloading chunk at (%d, %d, %d)\n", chunk->x, chunk->y, chunk->z);
+}
+
+void mapChunkLoad(chunk_t* chunk) {
+  // Placeholder for loading logic
+  printf("Loading chunk at (%d, %d, %d)\n", chunk->x, chunk->y, chunk->z);
+}
+
 void mapInit() {
   memoryZero(&MAP, sizeof(map_t));
 
-  for(uint32_t i = 0; i < MAP_CHUNK_COUNT; i++) {
-    MAP.chunkOrder[i] = &MAP.chunks[i];
+  uint32_t index = 0;
+  for(uint32_t z = 0; z < MAP_CHUNK_DEPTH; z++) {
+    for(uint32_t y = 0; y < MAP_CHUNK_HEIGHT; y++) {
+      for(uint32_t x = 0; x < MAP_CHUNK_WIDTH; x++) {
+        chunk_t *chunk = &MAP.chunks[index];
+        chunk->x = x;
+        chunk->y = y;
+        chunk->z = z;
+        MAP.chunkOrder[index] = chunk;
+        mapChunkLoad(chunk);
+        index++;
+      }
+    }
   }
 }
 
+void mapPositionSet(const int16_t x, const int16_t y, const int16_t z) {
+  const int16_t curX = MAP.x;
+  const int16_t curY = MAP.y;
+  const int16_t curZ = MAP.z;
+  if(curX == x && curY == y && curZ == z) return;
+
+  // Determine which chunks remain loaded
+  int32_t chunksRemaining[MAP_CHUNK_COUNT] = {0};
+  int32_t chunksFreed[MAP_CHUNK_COUNT] = {0};
+
+  uint32_t remainingCount = 0;
+  uint32_t freedCount = 0;
+
+  for(uint32_t i = 0; i < MAP_CHUNK_COUNT; i++) {
+    // Will this chunk remain loaded?
+    chunk_t *chunk = &MAP.chunks[i];
+    if(
+      chunk->x >= x && chunk->x < x + MAP_CHUNK_WIDTH &&
+      chunk->y >= y && chunk->y < y + MAP_CHUNK_HEIGHT &&
+      chunk->z >= z && chunk->z < z + MAP_CHUNK_DEPTH
+    ) {
+      // Stays loaded
+      chunksRemaining[remainingCount++] = i;
+      continue;
+    }
+
+    // Not remaining loaded
+    chunksFreed[freedCount++] = i;
+  }
+
+  // Unload the freed chunks
+  for(uint32_t i = 0; i < freedCount; i++) {
+    chunk_t *chunk = &MAP.chunks[chunksFreed[i]];
+    mapChunkUnload(chunk);
+  }
+
+  // This can probably be optimized later, for now we check each chunk and see
+  // if it needs loading or not, and update the chunk order
+  uint32_t orderIndex = 0;
+  for(uint32_t zOff = 0; zOff < MAP_CHUNK_DEPTH; zOff++) {
+    for(uint32_t yOff = 0; yOff < MAP_CHUNK_HEIGHT; yOff++) {
+      for(uint32_t xOff = 0; xOff < MAP_CHUNK_WIDTH; xOff++) {
+        const int16_t chunkX = x + xOff;
+        const int16_t chunkY = y + yOff;
+        const int16_t chunkZ = z + zOff;
+        
+        // Is this chunk already loaded (was not unloaded earlier)?
+        int32_t chunkIndex = -1;
+        for(uint32_t i = 0; i < remainingCount; i++) {
+          chunk_t *chunk = &MAP.chunks[chunksRemaining[i]];
+          if(chunk->x != chunkX) continue;
+          if(chunk->y != chunkY) continue;
+          if(chunk->z != chunkZ) continue;
+          chunkIndex = chunksRemaining[i];
+          break;
+        }
+
+        // Need to load this chunk
+        if(chunkIndex == -1) {
+          // Find a freed chunk to reuse
+          chunkIndex = chunksFreed[--freedCount];
+          chunk_t *chunk = &MAP.chunks[chunkIndex];
+          chunk->x = chunkX;
+          chunk->y = chunkY;
+          chunk->z = chunkZ;
+          mapChunkLoad(chunk);
+        }
+
+        MAP.chunkOrder[orderIndex++] = &MAP.chunks[chunkIndex];
+      }
+    }
+  }
+
+  // Update map position
+  MAP.x = x;
+  MAP.y = y;
+  MAP.z = z;
+}
+
 void mapUpdate() {
   
 }

src/rpg/world/map.h

@@ -29,4 +29,19 @@ void mapInit();
 /**
  * Updates the map.
  */
-void mapUpdate();
+void mapUpdate();
+
+/**
+ * Sets the map position and updates chunks accordingly.
+ */
+void mapPositionSet(const int16_t x, const int16_t y, const int16_t z);
+
+/**
+ * Dummy: Unloads a chunk.
+ */
+void mapChunkUnload(chunk_t* chunk);
+
+/**
+ * Dummy: Loads a chunk.
+ */
+void mapChunkLoad(chunk_t* chunk);