1 files changed, 173 insertions, 0 deletions
diff --git a/src/chunkedtiledmap.c b/src/chunkedtiledmap.c
new file mode 100644
index 0000000..ce6be57
--- /dev/null
+++ b/src/chunkedtiledmap.c
@@ -0,0 +1,173 @@
+#include <raylib.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <wchar.h>
+
+#include "chunkedtiledmap.h"
+
+//! 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) {
+    int noChunks;
+
+    // 4 bytes for number of chunks
+    readb((char *)&noChunks, 4, tiledMap->file);
+    size_t chunkSizeBytes = tiledMap->chunkWidth * tiledMap->chunkHeight;
+    for (int n = 0; n < noChunks; n++) {
+        int x, y;
+        readb((char *)&x, 4, tiledMap->file);
+        readb((char *)&y, 4, tiledMap->file);
+        long pointer = ftell(tiledMap->file);
+        // TODO casting to pointer here is maybe unsafe
+        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);
+    
+    buildChunkTree(&tiledMap);
+    return tiledMap;
+}
+
+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);
+    fseek(tiledMap.file, pos, SEEK_SET);
+    fread(chunk, 1, chunkSizeBytes, tiledMap.file);
+    return chunk;
+}
+
+void 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, chunk);
+
+    writeb((char *) &x, 4, tiledMap->file);
+    writeb((char *) &y, 4, tiledMap->file);
+    fwrite(chunk, 1, chunkSizeBytes, tiledMap->file);
+}
+
+
+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 newTiledMap(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);
+
+    if (!(tiledMap.file = fopen(filename, "r+b"))) {
+        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);
+        }
+    }
+
+    return tiledMap;
+}
+
+void closeTiledMap(ChunkedTiledMap tiledMap) {
+    kdtree_free(&tiledMap.chunkTree);
+    UnloadImageColors(tiledMap.atlasData);
+    fclose(tiledMap.file);
+}
+
+
+