ilimination of system code, removal of x-watcher and replacement of it by dmon, fixes in audio code, dynamic asset reload

src/game_object/twn_dynamic_game_object.c

@@ -0,0 +1,98 @@
+#include "twn_game_object_c.h"
+#include "twn_engine_context_c.h"
+#include "twn_filewatch_c.h"
+#include "twn_util_c.h"
+#include "twn_util.h"
+#include "twn_loop_c.h"
+
+#include <SDL2/SDL.h>
+
+#ifdef _WIN32
+#define GAME_OBJECT_NAME "libgame.dll"
+#else
+#define GAME_OBJECT_NAME "libgame.so"
+#endif
+
+static void (*game_tick_callback)(void);
+static void (*game_end_callback)(void);
+
+static void *handle = NULL;
+
+
+static void game_object_file_action(char const *path, enum FilewatchAction action) {
+    (void)action;
+
+    if (action == FILEWATCH_ACTION_FILE_DELETED)
+        return;
+
+    if (handle) {
+        SDL_UnloadObject(handle);
+        game_tick_callback = NULL;
+        game_end_callback = NULL;
+        handle = NULL;
+    }
+
+    handle = SDL_LoadObject(path);
+    if (!handle) {
+        CRY_SDL("Hot Reload Error: Cannot open game code shared object");
+        return;
+    }
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+
+    game_tick_callback = (void (*)(void))SDL_LoadFunction(handle, "game_tick");
+    if (!game_tick_callback) {
+        CRY("Hot Reload Error", "game_tick_callback() symbol wasn't found");
+        goto ERR_GETTING_PROC;
+    }
+
+    game_end_callback = (void (*)(void))SDL_LoadFunction(handle, "game_end");
+    if (!game_end_callback) {
+        CRY("Hot Reload Error", "game_end_callback() symbol wasn't found");
+        goto ERR_GETTING_PROC;
+    }
+
+#pragma GCC diagnostic pop
+
+    if (fabsf(0.0f - ctx.game.frame_number) > 0.00001f) {
+        log_info("Game object was reloaded\n");
+        reset_state();
+    }
+
+    return;
+
+ERR_GETTING_PROC:
+    SDL_UnloadObject(handle);
+    handle = NULL;
+    game_tick_callback = NULL;
+    game_end_callback = NULL;
+}
+
+
+void game_object_load(void) {
+    static bool filewatch_attached;
+    if (!filewatch_attached) {
+        char *game_object_path;
+        SDL_asprintf(&game_object_path, "%s%s", ctx.base_dir, GAME_OBJECT_NAME);
+        filewatch_add_file(game_object_path, game_object_file_action);
+        game_object_file_action(game_object_path, FILEWATCH_ACTION_FILE_MODIFIED);
+        SDL_free(game_object_path);
+        filewatch_attached = true;
+    }
+}
+
+
+void game_object_unload(void) {
+    game_end_callback();
+    /* needs to be closed otherwise symbols aren't resolved again */
+    SDL_UnloadObject(handle);
+    game_tick_callback = NULL;
+    game_end_callback = NULL;
+    handle = NULL;
+}
+
+
+void game_object_tick(void) {
+    game_tick_callback();
+}