add chunk caching

7 files changed, 255 insertions, 385 deletions

diff --git a/src/chunkedtiledmap.c b/src/chunkedtiledmap.c
deleted file mode 100644
index a3019af..0000000
--- a/src/chunkedtiledmap.c
+++ /dev/null
@@ -1,263 +0,0 @@
-#include <raylib.h>
-#include <stdlib.h>
-#include <stdio.h>
-#include <unistd.h>
-
-#include "chunkedtiledmap.h"
-
-const int endian = 1;
-#define is_bigendian() ( (*(char*)&endian) == 0 )
-
-
-void textureFromPixels(Texture2D *texOut, Color *pixels, int width, int height) {
-    Image checkedIm = {
-        .data = pixels,
-        .width = width,
-        .height = height,
-        .format = PIXELFORMAT_UNCOMPRESSED_R8G8B8A8,
-        .mipmaps = 1
-    };
-
-    *texOut = LoadTextureFromImage(checkedIm);
-}
-
-
-//! read a big endian bytes from file
-int readb(char * out, size_t noBytes, FILE * file) {
-    if (!fread(out, (size_t)1, (size_t) noBytes, file))
-        return 1;
-
-    if (is_bigendian()) 
-        return 0;
-
-    int tmp;
-    // reverse byte order
-    for(int i = 0; i < noBytes/2; i++) {
-        tmp = out[i];
-        out[i] = out[noBytes-i-1];
-        out[noBytes-i-1] = tmp;
-    }
-
-    return 0;
-}
-
-int writeb(char * in, size_t noBytes, FILE * file) {
-    if (!is_bigendian()) {
-        int tmp;
-        // reverse byte order
-        for(int i = 0; i < noBytes/2; i++) {
-            tmp = in[i];
-            in[i] = in[noBytes-i-1];
-            in[noBytes-i-1] = tmp;
-        }
-        
-    }
-
-    return fwrite(in, (size_t)1, (size_t) noBytes, file);
-}
-
-void buildChunkTree(ChunkedTiledMap *tiledMap) {
-    // initialise chunk tree
-    tiledMap->chunkTree = NULL;
-
-    size_t chunkSizeBytes = tiledMap->chunkWidth * tiledMap->chunkHeight;
-    // calculate how much space there is until the end of the file
-    // TODO save the number of chunks total to avoid having to jump around to find referenceso
-    // or just keep reading chunks until eof or other descriptor
-    long chunksStart = ftell(tiledMap->file);
-    fseek(tiledMap->file, 0, SEEK_END);
-    long totalChunksSize = ftell(tiledMap->file) - chunksStart;
-
-    fseek(tiledMap->file, chunksStart, SEEK_SET);
-
-    for (int n = 0; n < totalChunksSize; n += chunkSizeBytes + 8) {
-        int x, y;
-        readb((char *)&x, 4, tiledMap->file);
-        readb((char *)&y, 4, tiledMap->file);
-        long pointer = ftell(tiledMap->file);
-
-        kdtree_insert(&tiledMap->chunkTree, x, y, (char *) pointer);
-        fseek(tiledMap->file, chunkSizeBytes, SEEK_CUR);
-    }
-}
-
-ChunkedTiledMap openTiledMap(char * filename) {
-    ChunkedTiledMap tiledMap;
-
-    if (!(tiledMap.file = fopen(filename, "r+b"))) {
-        fprintf(stderr, "Failed to load %s\n", filename);
-    }
-
-    FILE * file = tiledMap.file;
-    
-    // skip header 
-    fseek(file, 10, SEEK_CUR);
-    // 4 bytes for int width
-    readb((char *)&tiledMap.chunkWidth, 4, file);
-    // 4 bytes for int height
-    readb((char *)&tiledMap.chunkHeight, 4, file);
-
-    // read the pixel size of each tile
-    readb((char *)&tiledMap.tileSize, 4, file);
-
-    // read the atlas size
-    readb((char *)&tiledMap.atlasSize[0], 4, file);
-    readb((char *)&tiledMap.atlasSize[1], 4, file);
-
-    // read the atlas itself
-    size_t atlasSizeBytes = tiledMap.atlasSize[0]*tiledMap.tileSize*tiledMap.atlasSize[1]*tiledMap.tileSize*4;
-    tiledMap.atlasData = malloc(atlasSizeBytes);
-    fread(tiledMap.atlasData, atlasSizeBytes, (size_t) 1, file);
-    
-    tiledMap.tileCount = tiledMap.atlasSize[0]*tiledMap.atlasSize[1] + 1;
-
-    buildChunkTree(&tiledMap);
-    return tiledMap;
-}
-
-//! write a chunk to the file
-char* writeChunk(ChunkedTiledMap *tiledMap, int x, int y, char * chunk) {
-    size_t chunkSizeBytes = tiledMap->chunkWidth * tiledMap->chunkHeight;
-
-
-    long pos = (long) kdtree_search(tiledMap->chunkTree, x, y);
-
-    fseek(tiledMap->file, pos, SEEK_SET);
-    fwrite(chunk, 1, chunkSizeBytes, tiledMap->file);
-    return chunk;
-}
-
-char* loadChunk(ChunkedTiledMap tiledMap, int x, int y) {
-    // TODO add caching for this
-    size_t chunkSizeBytes = tiledMap.chunkWidth * tiledMap.chunkHeight;
-    char * chunk = malloc(chunkSizeBytes);
-
-    long pos = (long) kdtree_search(tiledMap.chunkTree, x, y);
-    // if this chunk is not indexed, return NULL
-    if (pos == 0)
-        return NULL;
-
-    fseek(tiledMap.file, pos, SEEK_SET);
-    fread(chunk, 1, chunkSizeBytes, tiledMap.file);
-    return chunk;
-}
-
-char * appendChunk(ChunkedTiledMap *tiledMap, int x, int y, char * chunk) {
-    // TODO does this actually need tiledMap as a pointer
-    size_t chunkSizeBytes = tiledMap->chunkWidth * tiledMap->chunkHeight;
-
-    fseek(tiledMap->file, 0, SEEK_END);
-
-    // calculate position before writing
-    long pos = ftell(tiledMap->file) + 8; 
-    kdtree_insert(&tiledMap->chunkTree, x, y, (char *)pos);
-
-    int chunkx, chunky;
-    writeb((char *) &x, 4, tiledMap->file);
-    writeb((char *) &y, 4, tiledMap->file);
-    fwrite(chunk, 1, chunkSizeBytes, tiledMap->file);
-
-    return chunk;
-}
-
-char * appendEmptyChunk(ChunkedTiledMap * tiledMap, int x, int y) {
-    char * chunk = calloc(tiledMap->chunkWidth*tiledMap->chunkHeight, 1);
-    return appendChunk(tiledMap, x, y, chunk);
-}
-
-char getChunkedTile(ChunkedTiledMap tiledMap, int x, int y) {
-    // TODO put this calculation in function
-    int inChunkX = x % tiledMap.chunkWidth;
-    int inChunkY = y % tiledMap.chunkHeight;
-    int chunkX = (x - inChunkX) / tiledMap.chunkWidth;
-    int chunkY = (y - inChunkY) / tiledMap.chunkHeight;
-
-    char * chunk = loadChunk(tiledMap, chunkX, chunkY);
-    if (chunk == NULL)
-        return 0;
-
-    char v = chunk[inChunkY * tiledMap.chunkWidth + inChunkX];
-    return v;
-}
-
-char setChunkedTile(ChunkedTiledMap * tiledMap, int x, int y, char value) {
-    int inChunkX = x % tiledMap->chunkWidth;
-    int inChunkY = y % tiledMap->chunkHeight;
-    int chunkX = (x - inChunkX) / tiledMap->chunkWidth;
-    int chunkY = (y - inChunkY) / tiledMap->chunkHeight;
-
-    char * chunk = loadChunk(*tiledMap, chunkX, chunkY);
-    if (chunk == NULL)
-        chunk = appendEmptyChunk(tiledMap, chunkX, chunkY);
-
-    chunk[inChunkY * tiledMap->chunkWidth + inChunkX] = value;
-
-    writeChunk(tiledMap, chunkX, chunkY, chunk);
-
-    return value;
-}
-
-
-void writeTiledMapHeader(ChunkedTiledMap tiledMap) {
-    FILE * file = tiledMap.file;
-    size_t atlasSizeBytes = tiledMap.atlasSize[0]*tiledMap.tileSize*tiledMap.atlasSize[1]*tiledMap.tileSize*4;
-
-    // write header information from the start of the file
-    fseek(file, 0, SEEK_SET);
-    fwrite("TILEFILEv3", 10, 1, file);
-
-    writeb((char *) &tiledMap.chunkWidth, 4, file);
-    writeb((char *) &tiledMap.chunkHeight, 4, file);
-
-    writeb((char *) &tiledMap.tileSize, 4, file);
-    writeb((char *) &tiledMap.atlasSize[0], 4, file);
-    writeb((char *) &tiledMap.atlasSize[1], 4, file);
-
-    fwrite(tiledMap.atlasData, 1, atlasSizeBytes, file);
-    // since chunks are already directly written here, do not write anything else
-    // TODO when caching, commit everything left in cache here
-}
-
-ChunkedTiledMap openNewTiledMap(char * filename, Image atlas, int tileSize, int chunkWidth, int chunkHeight, int width, int height) {
-    ChunkedTiledMap tiledMap;
-    tiledMap.chunkWidth = chunkWidth;
-    tiledMap.chunkHeight = chunkHeight;
-
-    tiledMap.tileSize = tileSize;
-
-    tiledMap.atlasSize[0] = atlas.width / tileSize;
-    tiledMap.atlasSize[1] = atlas.height / tileSize;
-
-    tiledMap.atlasData = LoadImageColors(atlas);
-    tiledMap.tileCount = tiledMap.atlasSize[0]*tiledMap.atlasSize[1] + 1;
-
-    tiledMap.chunkTree = NULL;
-
-    if (!(tiledMap.file = fopen(filename, "wb"))) {
-        fprintf(stderr, "Failed to load %s\n", filename);
-    }
-
-    writeTiledMapHeader(tiledMap);
-    for (int x = 0; x < width; x++) {
-        for (int y = 0; y < height; y++) {
-            char * chunk = calloc(chunkWidth*chunkHeight, 1);
-            appendChunk(&tiledMap, x, y,  chunk);
-        }
-    }
-    
-    // reopen the file in read+write mode
-    fclose(tiledMap.file);
-
-    if (!(tiledMap.file = fopen(filename, "r+b"))) {
-        fprintf(stderr, "Failed to load %s\n", filename);
-    }
-
-    return tiledMap;
-}
-
-void closeTiledMap(ChunkedTiledMap tiledMap) {
-    kdtree_free(&tiledMap.chunkTree);
-    UnloadImageColors(tiledMap.atlasData);
-    fclose(tiledMap.file);
-}
-
diff --git a/src/chunkedtiledmap.h b/src/chunkedtiledmap.h
deleted file mode 100644
index 8bc2aaa..0000000
--- a/src/chunkedtiledmap.h
+++ /dev/null
@@ -1,24 +0,0 @@
-#include <raylib.h>
-#include "kdtree.h"
-
-typedef struct ChunkedTiledMap {
-    FILE * file;
-    int chunkWidth;
-    int chunkHeight;
-    int tileSize;
-    int atlasSize[2];
-    int tileCount;
-    Color * atlasData;
-    kdtree_t * chunkTree;
-} ChunkedTiledMap;
-
-void textureFromPixels(Texture2D *texOut, Color *pixels, int width, int height);
-ChunkedTiledMap openTiledMap(char * filename);
-char * loadChunk(ChunkedTiledMap tiledMap, int x, int y);
-char getChunkedTile(ChunkedTiledMap tiledMap, int x, int y);
-char setChunkedTile(ChunkedTiledMap * tiledMap, int x, int y, char value);
-char * appendChunk(ChunkedTiledMap * tiledMap, int x, int y, char * chunk);
-void writeTiledMapHeader(ChunkedTiledMap tiledMap);
-ChunkedTiledMap openNewTiledMap(char * filename, Image atlas, int tileSize, int chunkWidth, int chunkHeight, int width, int height);
-void closeTiledMap(ChunkedTiledMap tiledMap);
-
diff --git a/src/editor.c b/src/editor.c
index 46afe37..2c9de3a 100644
--- a/src/editor.c
+++ b/src/editor.c
@@ -23,7 +23,7 @@ void drawOverlay(Tiled tiled) {
 
 void modifyTile(Tiled *tiled, int tile) {
     setChunkedTile(&tiled->tiledMap, selectedTile[0], selectedTile[1], tile);
-    redrawTiledMap(*tiled);
+    redrawTile(*tiled, selectedTile[0], selectedTile[1]);
 }
 
 void setDrawMode(Tiled *tiled, int tile) {
@@ -34,10 +34,10 @@ void setDrawMode(Tiled *tiled, int tile) {
 
 void handleInputs(Tiled *tiled) {
     if (IsMouseButtonPressed(MOUSE_BUTTON_LEFT))
-        setDrawMode(tiled, getChunkedTile(tiled->tiledMap, selectedTile[0], selectedTile[1]) + 1);
+        setDrawMode(tiled, getChunkedTile(&tiled->tiledMap, selectedTile[0], selectedTile[1]) + 1);
 
     if (IsMouseButtonPressed(MOUSE_BUTTON_RIGHT))
-        setDrawMode(tiled, getChunkedTile(tiled->tiledMap, selectedTile[0], selectedTile[1]) - 1);
+        setDrawMode(tiled, getChunkedTile(&tiled->tiledMap, selectedTile[0], selectedTile[1]) - 1);
 
     if (IsMouseButtonPressed(MOUSE_BUTTON_MIDDLE))
         setDrawMode(tiled, 0);
@@ -69,11 +69,11 @@ void update(Tiled *tiled) {
     handleInputs(tiled);
 }
 
-ChunkedTiledMap launchEditor(ChunkedTiledMap tiledMap) {
+void launchEditor(TiledMap * tiledMap) {
     SetConfigFlags(FLAG_WINDOW_RESIZABLE);
     InitWindow(SCREEN_W, SCREEN_H, "tiled");
 
-    Tiled tiled = initTiled(tiledMap);
+    Tiled tiled = initTiled(*tiledMap);
 
     while (!WindowShouldClose()) {
         update(&tiled);
@@ -92,7 +92,6 @@ ChunkedTiledMap launchEditor(ChunkedTiledMap tiledMap) {
     unloadTiled(&tiled);
 
     CloseWindow();
-    return tiledMap;
 }
 
 void printUsage(char *progname) {
@@ -104,8 +103,8 @@ int main(int argc, char *argv[]) {
     char * tiledFilePath;
     const char * atlasFilePath = NULL;
     int tileSize = 16;
-    int mapSize = 2;
-    int chunkSize = 2;
+    int mapSize = 1;
+    int chunkSize = 16;
 
     int flags, opt;
     while ((opt = getopt(argc, argv, "c:s:a:h")) != -1) {
@@ -126,7 +125,7 @@ int main(int argc, char *argv[]) {
 
     tiledFilePath = argv[optind];
 
-    ChunkedTiledMap tiledMap;
+    TiledMap tiledMap;
     if (access(tiledFilePath, F_OK)) {
         if (atlasFilePath == NULL) {
             fprintf(stderr, "Atlas file must be specified!\n");
@@ -139,6 +138,6 @@ int main(int argc, char *argv[]) {
         tiledMap = openTiledMap(tiledFilePath);
     }
 
-    launchEditor(tiledMap);
-    closeTiledMap(tiledMap);
+    launchEditor(&tiledMap);
+    closeTiledMap(&tiledMap);
 }
diff --git a/src/tiled.c b/src/tiled.c
index f490d6a..0628523 100644
--- a/src/tiled.c
+++ b/src/tiled.c
@@ -48,15 +48,25 @@ Vector2 translateTiledScreenPosition(Tiled tiled, Vector2 tiledPos) {
     };
 }
 
+void redrawTile(Tiled tiled, int x, int y) {
+    BeginTextureMode(tiled.tilemapTexture);
+    unsigned char v = getChunkedTile(&tiled.tiledMap, x, y);
+    Color c = (Color){ 
+        v, 0, 0, 255 
+    };
+    DrawPixel(x, tiled.mapSize[1] - y - 1, c);
+    EndTextureMode();
+}
+
 void redrawTiledMap(Tiled tiled) {
     BeginTextureMode(tiled.tilemapTexture);
     for (int y = 0; y < tiled.mapSize[1]; y++) {
         for (int x = 0; x < tiled.mapSize[0]; x++) {
-            unsigned char v = getChunkedTile(tiled.tiledMap, x, tiled.mapSize[1] - y - 1);
+            unsigned char v = getChunkedTile(&tiled.tiledMap, x, y);
             Color c = (Color){ 
                 v, 0, 0, 255 
             };
-            DrawPixel(x, y, c);
+            DrawPixel(x, tiled.mapSize[1] - y - 1, c);
         }
     }
     EndTextureMode();
@@ -64,7 +74,7 @@ void redrawTiledMap(Tiled tiled) {
 }
 
 
-Tiled initTiled(ChunkedTiledMap tiledMap) {
+Tiled initTiled(TiledMap tiledMap) {
     Tiled tiled;
     tiled.tiledMap = tiledMap;
 
diff --git a/src/tiled.h b/src/tiled.h
index 11518e7..c3d0950 100644
--- a/src/tiled.h
+++ b/src/tiled.h
@@ -1,12 +1,12 @@
 #include <raylib.h>
 
-#include "chunkedtiledmap.h"
+#include "tiledmap.h"
 
 #define SCREEN_W 1280
 #define SCREEN_H 720
 
 typedef struct Tiled {
-    ChunkedTiledMap tiledMap;
+    TiledMap tiledMap;
     float zoom;
     Vector2 offset;
 
@@ -27,14 +27,14 @@ typedef struct Tiled {
 
     int atlasTextureLoc;
     int tilemapTextureLoc;
-
 } Tiled;
 
 void updateTiledCamera(Tiled *tiled);
 Vector2 translateTiledPosition(Tiled tiled, Vector2 screenPos);
 Vector2 translateTiledScreenPosition(Tiled tiled, Vector2 tiledPos);
-Tiled initTiled(ChunkedTiledMap tiledMap);
+Tiled initTiled(TiledMap tiledMap);
 void drawTiled(Tiled *tiled);
 void unloadTiled(Tiled *tiled);
 void redrawTiledMap(Tiled tiled);
+void redrawTile(Tiled tiled, int x, int y);
 
diff --git a/src/tiledmap.c b/src/tiledmap.c
index e274a6e..1c6964b 100644
--- a/src/tiledmap.c
+++ b/src/tiledmap.c
@@ -1,12 +1,12 @@
 #include <raylib.h>
 #include <stdlib.h>
 #include <stdio.h>
-#include <string.h>
+#include <unistd.h>
 
 #include "tiledmap.h"
 
-const int i = 1;
-#define is_bigendian() ( (*(char*)&i) == 0 )
+const int endian = 1;
+#define is_bigendian() ( (*(char*)&endian) == 0 )
 
 void textureFromPixels(Texture2D *texOut, Color *pixels, int width, int height) {
     Image checkedIm = {
@@ -20,16 +20,26 @@ void textureFromPixels(Texture2D *texOut, Color *pixels, int width, int height)
     *texOut = LoadTextureFromImage(checkedIm);
 }
 
-//! read rgba image from file
-void readrgba(Texture2D *loc, int width, int height, FILE *file) {
-    Color *pixels = malloc(width*height*4);
-    fread(pixels, (size_t) width*height*4, (size_t) 1, file);
-    textureFromPixels(loc, pixels, width, height);
-}
 
+//! read a big endian bytes from file
+int readb(char * out, size_t noBytes, FILE * file) {
+    if (!fread(out, (size_t)1, (size_t) noBytes, file))
+        return 1;
 
+    if (is_bigendian()) 
+        return 0;
+
+    int tmp;
+    // reverse byte order
+    for(int i = 0; i < noBytes/2; i++) {
+        tmp = out[i];
+        out[i] = out[noBytes-i-1];
+        out[noBytes-i-1] = tmp;
+    }
+
+    return 0;
+}
 
-//! write a big endian bytes from file
 int writeb(char * in, size_t noBytes, FILE * file) {
     if (!is_bigendian()) {
         int tmp;
@@ -45,53 +55,50 @@ int writeb(char * in, size_t noBytes, FILE * file) {
     return fwrite(in, (size_t)1, (size_t) noBytes, file);
 }
 
-//! read a big endian bytes from file
-int readb(char * out, size_t noBytes, FILE * file) {
-    if (!fread(out, (size_t)1, (size_t) noBytes, file))
-        return 1;
+void buildChunkTree(TiledMap *tiledMap) {
+    // initialise chunk tree
+    tiledMap->chunkTree = NULL;
 
-    if (is_bigendian()) 
-        return 0;
+    size_t chunkSizeBytes = tiledMap->chunkWidth * tiledMap->chunkHeight;
+    // calculate how much space there is until the end of the file
+    // TODO save the number of chunks total to avoid having to jump around to find referenceso
+    // or just keep reading chunks until eof or other descriptor
+    long chunksStart = ftell(tiledMap->file);
+    fseek(tiledMap->file, 0, SEEK_END);
+    long totalChunksSize = ftell(tiledMap->file) - chunksStart;
 
-    int tmp;
-    // reverse byte order
-    for(int i = 0; i < noBytes/2; i++) {
-        tmp = out[i];
-        out[i] = out[noBytes-i-1];
-        out[noBytes-i-1] = tmp;
-    }
+    fseek(tiledMap->file, chunksStart, SEEK_SET);
 
-    return 0;
-}
+    for (int n = 0; n < totalChunksSize; n += chunkSizeBytes + 8) {
+        int x, y;
+        readb((char *)&x, 4, tiledMap->file);
+        readb((char *)&y, 4, tiledMap->file);
+        long pointer = ftell(tiledMap->file);
 
-char getTiledMapTile(TiledMap tiledMap, int pos[2]) {
-    return tiledMap.tilelayout[pos[1]*tiledMap.width + pos[0]];
-}
+        CachedChunk * cached = malloc(sizeof(CachedChunk));
+        cached->filePos = pointer;
+        cached->chunk = NULL;
 
-void setTiledMapTile(TiledMap tiledMap, int pos[2], char tile) {
-    tiledMap.tilelayout[pos[1]*tiledMap.width + pos[0]] = tile;
+        kdtree_insert(&tiledMap->chunkTree, x, y, (char *) cached);
+        fseek(tiledMap->file, chunkSizeBytes, SEEK_CUR);
+    }
 }
 
-//! load tilemap data from file
-TiledMap loadTiledMap(char * filename) {
+TiledMap openTiledMap(char * filename) {
     TiledMap tiledMap;
-    FILE * file;
 
-    if (!(file = fopen(filename, "rb"))) {
+    if (!(tiledMap.file = fopen(filename, "r+b"))) {
         fprintf(stderr, "Failed to load %s\n", filename);
-        return tiledMap;
     }
 
+    FILE * file = tiledMap.file;
+    
     // skip header 
     fseek(file, 10, SEEK_CUR);
     // 4 bytes for int width
-    readb((char *)&tiledMap.width, 4, file);
+    readb((char *)&tiledMap.chunkWidth, 4, file);
     // 4 bytes for int height
-    readb((char *)&tiledMap.height, 4, file);
-
-    size_t layoutSize = tiledMap.width*tiledMap.height;
-    tiledMap.tilelayout = malloc(layoutSize);
-    fread(tiledMap.tilelayout, layoutSize, 1, file);
+    readb((char *)&tiledMap.chunkHeight, 4, file);
 
     // read the pixel size of each tile
     readb((char *)&tiledMap.tileSize, 4, file);
@@ -104,52 +111,183 @@ TiledMap loadTiledMap(char * filename) {
     size_t atlasSizeBytes = tiledMap.atlasSize[0]*tiledMap.tileSize*tiledMap.atlasSize[1]*tiledMap.tileSize*4;
     tiledMap.atlasData = malloc(atlasSizeBytes);
     fread(tiledMap.atlasData, atlasSizeBytes, (size_t) 1, file);
-
+    
     tiledMap.tileCount = tiledMap.atlasSize[0]*tiledMap.atlasSize[1] + 1;
 
-    fclose(file);
+    buildChunkTree(&tiledMap);
     return tiledMap;
 }
 
-TiledMap openNewTiledMap(Image atlas, int tileSize, int width, int height) {
-    TiledMap tiledMap;
-    tiledMap.width = width;
-    tiledMap.height = height;
-    tiledMap.tilelayout = malloc(width * height);
+//! save chunk to file
+void commitChunk(TiledMap * tiledMap, CachedChunk * cached) {
+    size_t chunkSizeBytes = tiledMap->chunkWidth * tiledMap->chunkHeight;
 
-    tiledMap.tileSize = tileSize;
+    fseek(tiledMap->file, cached->filePos, SEEK_SET);
+    fwrite(cached->chunk, 1, chunkSizeBytes, tiledMap->file);
+}
 
-    tiledMap.atlasSize[0] = atlas.width / tileSize;
-    tiledMap.atlasSize[1] = atlas.height / tileSize;
+void unloadChunk(TiledMap * tiledMap, CachedChunk * cached) {
+    // commit a chunk before unloading
+    commitChunk(tiledMap, cached);
 
-    tiledMap.atlasData = LoadImageColors(atlas);
-
-    return tiledMap;
+    // free memory
+    free(cached->chunk);
+    cached->chunk = NULL;
 }
 
-void saveTiledMap(char * filename, TiledMap tiledMap) {
-    FILE * file;
+//! load a chunk into the cache and return it 
+CachedChunk * loadChunk(TiledMap * tiledMap, int x, int y) {
+    // TODO add caching for this
+    size_t chunkSizeBytes = tiledMap->chunkWidth * tiledMap->chunkHeight;
 
-    if (!(file = fopen(filename, "wb"))) {
-        fprintf(stderr, "Failed to load %s\n", filename);
-        return;
+
+    CachedChunk *cached = (CachedChunk * ) kdtree_search(tiledMap->chunkTree, x, y);
+    // if this chunk is not indexed, return NULL
+    if (cached == NULL)
+        return NULL;
+
+    // if this chunk is not loaded into memory, load it
+    if (cached->chunk == NULL) {
+        cached->chunk = malloc(chunkSizeBytes);
+        fseek(tiledMap->file, cached->filePos, SEEK_SET);
+        fread(cached->chunk, 1, chunkSizeBytes, tiledMap->file);
     }
-    size_t layoutSize = tiledMap.width*tiledMap.height;
+
+    return cached;
+}
+
+CachedChunk * createChunk(TiledMap *tiledMap, int x, int y, Chunk chunk) {
+    size_t chunkSizeBytes = tiledMap->chunkWidth * tiledMap->chunkHeight;
+
+    fseek(tiledMap->file, 0, SEEK_END);
+
+    // calculate position before writing
+    long pos = ftell(tiledMap->file) + 8; 
+    CachedChunk *cached = malloc(sizeof(CachedChunk));
+    cached->filePos = pos;
+    cached->chunk = chunk;
+
+    kdtree_insert(&tiledMap->chunkTree, x, y, (char *) cached);
+
+    int chunkx, chunky;
+    writeb((char *) &x, 4, tiledMap->file);
+    writeb((char *) &y, 4, tiledMap->file);
+    fwrite(chunk, 1, chunkSizeBytes, tiledMap->file);
+
+    return cached;
+}
+
+CachedChunk * createEmptyChunk(TiledMap * tiledMap, int x, int y) {
+    Chunk chunk = calloc(tiledMap->chunkWidth*tiledMap->chunkHeight, 1);
+    return createChunk(tiledMap, x, y, chunk);
+}
+
+char getChunkedTile(TiledMap *tiledMap, int x, int y) {
+    // TODO put this calculation in function
+    int inChunkX = x % tiledMap->chunkWidth;
+    int inChunkY = y % tiledMap->chunkHeight;
+    int chunkX = (x - inChunkX) / tiledMap->chunkWidth;
+    int chunkY = (y - inChunkY) / tiledMap->chunkHeight;
+
+    CachedChunk * cached = loadChunk(tiledMap, chunkX, chunkY);
+    if (cached == NULL)
+        return 0;
+
+    if (cached->chunk == NULL)
+        return 0;
+
+    char v = cached->chunk[inChunkY * tiledMap->chunkWidth + inChunkX];
+    return v;
+}
+
+char setChunkedTile(TiledMap * tiledMap, int x, int y, char value) {
+    int inChunkX = x % tiledMap->chunkWidth;
+    int inChunkY = y % tiledMap->chunkHeight;
+    int chunkX = (x - inChunkX) / tiledMap->chunkWidth;
+    int chunkY = (y - inChunkY) / tiledMap->chunkHeight;
+
+    CachedChunk * cached = loadChunk(tiledMap, chunkX, chunkY);
+    if (cached == NULL)
+        cached = createEmptyChunk(tiledMap, chunkX, chunkY);
+
+    cached->chunk[inChunkY * tiledMap->chunkWidth + inChunkX] = value;
+
+    // TODO do this when unloading
+    //commitChunk(tiledMap, cached);
+    return value;
+}
+
+
+void writeTiledMapHeader(TiledMap tiledMap) {
+    FILE * file = tiledMap.file;
     size_t atlasSizeBytes = tiledMap.atlasSize[0]*tiledMap.tileSize*tiledMap.atlasSize[1]*tiledMap.tileSize*4;
 
-    fwrite("TILEFILEv2", 10, 1, file);
+    // write header information from the start of the file
+    fseek(file, 0, SEEK_SET);
+    fwrite("TILEFILEv3", 10, 1, file);
 
-    writeb((char *) &tiledMap.width, 4, file);
-    writeb((char *) &tiledMap.height, 4, file);
-    
-    fwrite(tiledMap.tilelayout, 1, layoutSize, file);
+    writeb((char *) &tiledMap.chunkWidth, 4, file);
+    writeb((char *) &tiledMap.chunkHeight, 4, file);
 
     writeb((char *) &tiledMap.tileSize, 4, file);
     writeb((char *) &tiledMap.atlasSize[0], 4, file);
     writeb((char *) &tiledMap.atlasSize[1], 4, file);
 
     fwrite(tiledMap.atlasData, 1, atlasSizeBytes, file);
+    // since chunks are already directly written here, do not write anything else
+    // TODO when caching, commit everything left in cache here
+}
 
-    fclose(file);
-    fprintf(stderr, "Written tiledfiled to %s\n", filename);
+TiledMap openNewTiledMap(char * filename, Image atlas, int tileSize, int chunkWidth, int chunkHeight, int width, int height) {
+    TiledMap tiledMap;
+    tiledMap.chunkWidth = chunkWidth;
+    tiledMap.chunkHeight = chunkHeight;
+
+    tiledMap.tileSize = tileSize;
+
+    tiledMap.atlasSize[0] = atlas.width / tileSize;
+    tiledMap.atlasSize[1] = atlas.height / tileSize;
+
+    tiledMap.atlasData = LoadImageColors(atlas);
+    tiledMap.tileCount = tiledMap.atlasSize[0]*tiledMap.atlasSize[1] + 1;
+
+    tiledMap.chunkTree = NULL;
+
+    if (!(tiledMap.file = fopen(filename, "wb"))) {
+        fprintf(stderr, "Failed to load %s\n", filename);
+    }
+
+    writeTiledMapHeader(tiledMap);
+    for (int x = 0; x < width; x++) {
+        for (int y = 0; y < height; y++) {
+            char * chunk = calloc(chunkWidth*chunkHeight, 1);
+            createChunk(&tiledMap, x, y,  chunk);
+        }
+    }
+    
+    // reopen the file in read+write mode
+    fclose(tiledMap.file);
+
+    if (!(tiledMap.file = fopen(filename, "r+b"))) {
+        fprintf(stderr, "Failed to load %s\n", filename);
+    }
+
+    return tiledMap;
 }
+
+void unloadChunks(TiledMap *tiledMap, kdtree_t * root) {
+    if (root == NULL)
+        return;
+
+    unloadChunks(tiledMap, root->left);
+    unloadChunks(tiledMap, root->right);
+    unloadChunk(tiledMap, (CachedChunk *)root->value);
+}
+
+void closeTiledMap(TiledMap *tiledMap) {
+    unloadChunks(tiledMap, tiledMap->chunkTree);
+    kdtree_free(&tiledMap->chunkTree);
+    UnloadImageColors(tiledMap->atlasData);
+    fclose(tiledMap->file);
+}
+
diff --git a/src/tiledmap.h b/src/tiledmap.h
index fb9c789..2c4cf94 100644
--- a/src/tiledmap.h
+++ b/src/tiledmap.h
@@ -1,23 +1,33 @@
 #include <raylib.h>
+#include "kdtree.h"
 
-typedef struct TiledMap {
-    int width;
-    int height;
-    char * tilelayout;
+#define CHUNK_CACHE_SIZE 32
+
+typedef char * Chunk;
+
+typedef struct CachedChunk {
+    long filePos;
+    Chunk chunk;
+} CachedChunk;
+
+typedef struct ChunkedTiledMap {
+    FILE * file;
+    int chunkWidth;
+    int chunkHeight;
     int tileSize;
     int atlasSize[2];
     int tileCount;
     Color * atlasData;
+    kdtree_t * chunkTree;
 } TiledMap;
 
 void textureFromPixels(Texture2D *texOut, Color *pixels, int width, int height);
+TiledMap openTiledMap(char * filename);
+CachedChunk * loadChunk(TiledMap *tiledMap, int x, int y);
+char getChunkedTile(TiledMap *tiledMap, int x, int y);
+char setChunkedTile(TiledMap * tiledMap, int x, int y, char value);
+CachedChunk * createChunk(TiledMap * tiledMap, int x, int y, Chunk chunk);
+void writeTiledMapHeader(TiledMap tiledMap);
+TiledMap openNewTiledMap(char * filename, Image atlas, int tileSize, int chunkWidth, int chunkHeight, int width, int height);
+void closeTiledMap(TiledMap * tiledMap);
 
-void setTiledMapTile(TiledMap tiledMap, int pos[2], char tile);
-
-char getTiledMapTile(TiledMap tiledMap, int pos[2]);
-
-TiledMap loadTiledMap(char * filename);
-
-void saveTiledMap(char * filename, TiledMap tiledMap);
-
-TiledMap newTiledMap(Image atlas, int tileSize, int width, int height);