Chunk load skin

src/dusk/rpg/overworld/map.c

@@ -19,23 +19,30 @@ map_t MAP;
 
 errorret_t mapInit() {
   memoryZero(&MAP, sizeof(map_t));
-
   MAP.loaded = true;
-  int32_t i = 0;
-  for(chunkunit_t z = 0; z < MAP_CHUNK_DEPTH; z++) {
-    for(chunkunit_t y = 0; y < MAP_CHUNK_HEIGHT; y++) {
-      for(chunkunit_t x = 0; x < MAP_CHUNK_WIDTH; x++) {
-        chunk_t *chunk = &MAP.chunks[i];
-        chunk->position.x = x + MAP.chunkPosition.x;
-        chunk->position.y = y + MAP.chunkPosition.y;
-        chunk->position.z = z + MAP.chunkPosition.z;
-        MAP.chunkOrder[i] = chunk;
+
+  MAP.loadPosition = (chunkpos_t){
+    -(MAP_CHUNK_SKIN),
+    -(MAP_CHUNK_SKIN),
+    -(MAP_CHUNK_SKIN)
+  };
+
+  chunkindex_t i = 0;
+  for(chunkunit_t z = 0; z < MAP_LOADED_CHUNK_DEPTH; z++) {
+    for(chunkunit_t y = 0; y < MAP_LOADED_CHUNK_HEIGHT; y++) {
+      for(chunkunit_t x = 0; x < MAP_LOADED_CHUNK_WIDTH; x++) {
+        chunk_t *chunk = &MAP.chunks[i++];
+        chunk->position = (chunkpos_t){
+          MAP.loadPosition.x + (chunkunit_t)x,
+          MAP.loadPosition.y + (chunkunit_t)y,
+          MAP.loadPosition.z + (chunkunit_t)z
+        };
         errorChain(mapChunkLoad(chunk));
-        i++;
       }
     }
   }
 
+  mapRebuildChunkOrder();
   errorOk();
 }
 
@@ -45,72 +52,77 @@ bool_t mapIsLoaded() {
 
 errorret_t mapPositionSet(const chunkpos_t newPos) {
   if(!mapIsLoaded()) errorThrow("No map loaded");
+  if(chunkPositionIsEqual(newPos, MAP.chunkPosition)) errorOk();
 
-  const chunkpos_t curPos = MAP.chunkPosition;
-  if(chunkPositionIsEqual(curPos, newPos)) {
+  // If the new render window still fits inside the current loaded area,
+  // just remap chunkOrder — no asset I/O needed.
+  const chunkpos_t lp = MAP.loadPosition;
+  if(
+    newPos.x >= lp.x &&
+    newPos.y >= lp.y &&
+    newPos.z >= lp.z &&
+    newPos.x + MAP_CHUNK_WIDTH  <= lp.x + MAP_LOADED_CHUNK_WIDTH &&
+    newPos.y + MAP_CHUNK_HEIGHT <= lp.y + MAP_LOADED_CHUNK_HEIGHT &&
+    newPos.z + MAP_CHUNK_DEPTH  <= lp.z + MAP_LOADED_CHUNK_DEPTH
+  ) {
+    MAP.chunkPosition = newPos;
+    mapRebuildChunkOrder();
     errorOk();
   }
 
-  chunkindex_t chunksRemaining[MAP_CHUNK_COUNT] = {0};
-  chunkindex_t chunksFreed[MAP_CHUNK_COUNT] = {0};
-
-  uint32_t remainingCount = 0;
-  uint32_t freedCount = 0;
-
-  for(chunkindex_t i = 0; i < MAP_CHUNK_COUNT; i++) {
-    chunk_t *chunk = &MAP.chunks[i];
-    if(
-      chunk->position.x >= newPos.x &&
-      chunk->position.x < newPos.x + MAP_CHUNK_WIDTH &&
-
-      chunk->position.y >= newPos.y &&
-      chunk->position.y < newPos.y + MAP_CHUNK_HEIGHT &&
-
-      chunk->position.z >= newPos.z &&
-      chunk->position.z < newPos.z + MAP_CHUNK_DEPTH
-    ) {
-      chunksRemaining[remainingCount++] = i;
-      continue;
-    }
-
-    chunksFreed[freedCount++] = i;
-  }
-
-  for(chunkindex_t i = 0; i < freedCount; i++) {
-    chunk_t *chunk = &MAP.chunks[chunksFreed[i]];
-    mapChunkUnload(chunk);
-  }
-
-  chunkindex_t orderIndex = 0;
-  for(chunkunit_t zOff = 0; zOff < MAP_CHUNK_DEPTH; zOff++) {
-    for(chunkunit_t yOff = 0; yOff < MAP_CHUNK_HEIGHT; yOff++) {
-      for(chunkunit_t xOff = 0; xOff < MAP_CHUNK_WIDTH; xOff++) {
-        const chunkpos_t newChunkPos = {
-          newPos.x + xOff, newPos.y + yOff, newPos.z + zOff
+  // Render window fell outside the loaded area — re-centre the load
+  // window on the new render position (skin buffer on every side).
+  const chunkpos_t newLoadPos = {
+    newPos.x - MAP_CHUNK_SKIN,
+    newPos.y - MAP_CHUNK_SKIN,
+    newPos.z - MAP_CHUNK_SKIN
   };
 
-        chunkindex_t chunkIndex = -1;
-        for(chunkindex_t i = 0; i < remainingCount; i++) {
-          chunk_t *chunk = &MAP.chunks[chunksRemaining[i]];
-          if(!chunkPositionIsEqual(chunk->position, newChunkPos)) continue;
-          chunkIndex = chunksRemaining[i];
-          break;
+  // Separate loaded chunks into "keep" and "free" buckets.
+  chunkindex_t chunksFreed[MAP_LOADED_CHUNK_COUNT];
+  uint32_t freedCount = 0;
+
+  // Use a boolean grid so the inner load loop can check O(1).
+  bool_t posLoaded[MAP_LOADED_CHUNK_WIDTH][MAP_LOADED_CHUNK_HEIGHT]
+                  [MAP_LOADED_CHUNK_DEPTH];
+  memoryZero(posLoaded, sizeof(posLoaded));
+
+  for(chunkindex_t i = 0; i < MAP_LOADED_CHUNK_COUNT; i++) {
+    chunk_t *chunk = &MAP.chunks[i];
+    chunkunit_t rx = chunk->position.x - newLoadPos.x;
+    chunkunit_t ry = chunk->position.y - newLoadPos.y;
+    chunkunit_t rz = chunk->position.z - newLoadPos.z;
+    if(
+      rx >= 0 && rx < MAP_LOADED_CHUNK_WIDTH &&
+      ry >= 0 && ry < MAP_LOADED_CHUNK_HEIGHT &&
+      rz >= 0 && rz < MAP_LOADED_CHUNK_DEPTH
+    ) {
+      posLoaded[rx][ry][rz] = true;
+    } else {
+      mapChunkUnload(chunk);
+      chunksFreed[freedCount++] = i;
+    }
   }
 
-        if(chunkIndex == -1) {
-          chunkIndex = chunksFreed[--freedCount];
-          chunk_t *chunk = &MAP.chunks[chunkIndex];
-          chunk->position = newChunkPos;
+  for(chunkunit_t z = 0; z < MAP_LOADED_CHUNK_DEPTH; z++) {
+    for(chunkunit_t y = 0; y < MAP_LOADED_CHUNK_HEIGHT; y++) {
+      for(chunkunit_t x = 0; x < MAP_LOADED_CHUNK_WIDTH; x++) {
+        if(posLoaded[x][y][z]) continue;
+        assertTrue(freedCount > 0, "No free chunk slot available.");
+        chunk_t *chunk = &MAP.chunks[chunksFreed[--freedCount]];
+        chunk->position = (chunkpos_t){
+          newLoadPos.x + (chunkunit_t)x,
+          newLoadPos.y + (chunkunit_t)y,
+          newLoadPos.z + (chunkunit_t)z
+        };
         errorChain(mapChunkLoad(chunk));
       }
-
-        MAP.chunkOrder[orderIndex++] = &MAP.chunks[chunkIndex];
-      }
     }
   }
 
+  MAP.loadPosition = newLoadPos;
   MAP.chunkPosition = newPos;
-
+  mapRebuildChunkOrder();
   errorOk();
 }
 
@@ -119,21 +131,16 @@ errorret_t mapUpdate() {
 }
 
 errorret_t mapDispose() {
-  for(chunkindex_t i = 0; i < MAP_CHUNK_COUNT; i++) {
+  for(chunkindex_t i = 0; i < MAP_LOADED_CHUNK_COUNT; i++) {
     mapChunkUnload(&MAP.chunks[i]);
   }
   errorOk();
 }
 
 void mapChunkUnload(chunk_t *chunk) {
-  uint8_t chunkIndex = (uint8_t)(chunk - MAP.chunks);
   for(uint8_t i = 0; i < CHUNK_ENTITY_COUNT_MAX; i++) {
     if(chunk->entities[i] == 0xFF) continue;
     entity_t *entity = &ENTITIES[chunk->entities[i]];
-    assertTrue(
-      entity->chunkIndex == chunkIndex,
-      "Entity chunk index does not match chunk"
-    );
     if(entity->type == ENTITY_TYPE_PLAYER) {
       entitySetChunk(entity, 0xFF);
     } else {
@@ -235,6 +242,24 @@ tile_t mapGetTile(const worldpos_t position) {
   return chunk->tiles[tileIndex];
 }
 
+void mapRebuildChunkOrder() {
+  memoryZero(MAP.chunkOrder, sizeof(MAP.chunkOrder));
+  for(chunkindex_t i = 0; i < MAP_LOADED_CHUNK_COUNT; i++) {
+    chunk_t *chunk = &MAP.chunks[i];
+    const chunkpos_t rel = {
+      chunk->position.x - MAP.chunkPosition.x,
+      chunk->position.y - MAP.chunkPosition.y,
+      chunk->position.z - MAP.chunkPosition.z
+    };
+    if(
+      rel.x < 0 || rel.x >= MAP_CHUNK_WIDTH ||
+      rel.y < 0 || rel.y >= MAP_CHUNK_HEIGHT ||
+      rel.z < 0 || rel.z >= MAP_CHUNK_DEPTH
+    ) continue;
+    MAP.chunkOrder[chunkPosToIndex(&rel)] = chunk;
+  }
+}
+
 void mapChunkLoadError(void *params, void *user) {
   assertNotNull(params, "mapChunkLoadError: params cannot be NULL");
   assertNotNull(user, "mapChunkLoadError: user cannot be NULL");

src/dusk/rpg/overworld/map.h

@@ -12,14 +12,12 @@
 #define MAP_FILE_PATH_MAX 128
 
 typedef struct map_s {
-  // char_t filePath[MAP_FILE_PATH_MAX];
-  // char_t dirPath[MAP_FILE_PATH_MAX];
-  // char_t fileName[MAP_FILE_PATH_MAX];
   bool_t loaded;
 
-  chunk_t chunks[MAP_CHUNK_COUNT];
+  chunk_t chunks[MAP_LOADED_CHUNK_COUNT];
   chunk_t *chunkOrder[MAP_CHUNK_COUNT];
   chunkpos_t chunkPosition;
+  chunkpos_t loadPosition;
 } map_t;
 
 extern map_t MAP;
@@ -106,6 +104,12 @@ void mapChunkLoadError(void *params, void *user);
  */
 void mapChunkLoaded(void *params, void *user);
 
+/**
+ * Rebuilds chunkOrder from the loaded chunks that fall within the
+ * current render window. Called whenever chunkPosition changes.
+ */
+void mapRebuildChunkOrder();
+
 /**
  * Gets the index of a chunk, within the world, at the given position.
  *

src/dusk/rpg/overworld/worldpos.h

@@ -22,6 +22,16 @@
 #define MAP_CHUNK_DEPTH 4
 #define MAP_CHUNK_COUNT (MAP_CHUNK_WIDTH * MAP_CHUNK_HEIGHT * MAP_CHUNK_DEPTH)
 
+// Extra chunks loaded on every side beyond the render window.
+// The render window can drift MAP_CHUNK_SKIN chunks in any direction
+// before a load/unload cycle is triggered.
+#define MAP_CHUNK_SKIN 1
+#define MAP_LOADED_CHUNK_WIDTH  (MAP_CHUNK_WIDTH  + MAP_CHUNK_SKIN)
+#define MAP_LOADED_CHUNK_HEIGHT (MAP_CHUNK_HEIGHT + MAP_CHUNK_SKIN)
+#define MAP_LOADED_CHUNK_DEPTH  (MAP_CHUNK_DEPTH  + MAP_CHUNK_SKIN)
+#define MAP_LOADED_CHUNK_COUNT \
+  (MAP_LOADED_CHUNK_WIDTH * MAP_LOADED_CHUNK_HEIGHT * MAP_LOADED_CHUNK_DEPTH)
+
 #define ENTITY_COUNT 32
 
 typedef int16_t worldunit_t;

src/dusk/scene/overworld/sceneoverworld.c

@@ -120,7 +120,8 @@ errorret_t sceneOverworldRender(scenedata_t *sceneData) {
 
 errorret_t sceneOverworldDrawChunks() {
   for(chunkindex_t i = 0; i < MAP_CHUNK_COUNT; i++) {
-    chunk_t *chunk = &MAP.chunks[i];
+    chunk_t *chunk = MAP.chunkOrder[i];
+    if(chunk == NULL) continue;
     if(chunk->meshCount == 0) continue;
 
     for(uint8_t m = 0; m < chunk->meshCount; m++) {