cache font _files_ as well to avoid duplicate buffers

src/rendering/twn_text.c

@@ -31,6 +31,19 @@ typedef struct StringArena {
 static StringArena string_arena;
 
 
+typedef struct FontFileBuffer {
+    size_t len;
+    unsigned char *buffer;
+} FontFileBuffer;
+
+typedef struct FontFileCacheItem {
+    char *key;
+    FontFileBuffer value;
+} FontFileCacheItem;
+
+static FontFileCacheItem *font_file_cache_hash;
+
+
 static void string_arena_init(StringArena *arena) {
     arena->head = cmalloc(sizeof *arena->head);
     arena->current_block = arena->head;
@@ -103,12 +116,22 @@ static FontData *text_load_font_data(const char *path, int height_px) {
 
     {
         unsigned char *buf = NULL;
-        int64_t buf_len = file_to_bytes(path, &buf);
+        int64_t buf_len = 0;
+
+        /* if the file was already loaded just get it */
+        FontFileCacheItem *font_file_ptr = shgetp_null(font_file_cache_hash, path);
+        if (font_file_ptr != NULL) {
+            buf = font_file_ptr->value.buffer;
+            buf_len = font_file_ptr->value.len;
+        } else {
+            buf_len = file_to_bytes(path, &buf);
+            FontFileBuffer buffer = { buf_len, buf };
+            shput(font_file_cache_hash, path, buffer);
+        }
+
         stbtt_InitFont(&font_data->info, buf, stbtt_GetFontOffsetForIndex(buf, 0));
         
         /* might as well get these now, for later */
-        font_data->file_bytes = buf;
-        font_data->file_bytes_len = buf_len;
         font_data->scale_factor = stbtt_ScaleForPixelHeight(&font_data->info, (float)height_px);
         stbtt_GetFontVMetrics(
             &font_data->info,
@@ -142,7 +165,6 @@ static FontData *text_load_font_data(const char *path, int height_px) {
 
 
 static void text_destroy_font_data(FontData *font_data) {
-    SDL_free(font_data->file_bytes);
     delete_gpu_texture(font_data->texture);
     SDL_free(font_data);
 }
@@ -192,7 +214,7 @@ static void text_draw_with(FontData* font_data, char* text, Vec2 position, Color
 
 
 static void ensure_font_cache(const char *font_path, int height_px) {
-    /* HACK: stupid, bad, don't do this */
+    /* HACK: don't */
     bool is_cached = false;
     for (size_t i = 0; i < arrlenu(ctx.text_cache.data); ++i) {
         FontData *font_data = ctx.text_cache.data[i];
@@ -229,6 +251,8 @@ void render_text(const TextPrimitive *text) {
 void text_cache_init(TextCache *cache) {
     arrsetlen(cache->data, 0);
     string_arena_init(&string_arena);
+
+    sh_new_arena(font_file_cache_hash);
 }
 
 
@@ -237,8 +261,13 @@ void text_cache_deinit(TextCache *cache) {
         text_destroy_font_data(ctx.text_cache.data[i]);
     }
 
-    arrfree(cache->data);
+    for (size_t i = 0; i < shlenu(font_file_cache_hash); ++i) {
+        SDL_free(font_file_cache_hash[i].value.buffer);
+    }
+    shfree(font_file_cache_hash);
+
     string_arena_deinit(&string_arena);
+    arrfree(cache->data);
 }
 
 

src/rendering/twn_text_c.h

@@ -22,8 +22,6 @@ typedef struct FontData {
     stbtt_fontinfo info;
 
     const char *file_path;
-    unsigned char *file_bytes;
-    size_t file_bytes_len;
 
     GPUTexture texture;