townengine/src/game_object/twn_linux_game_object.c

161 lines
3.8 KiB
C

#include "twn_game_object_c.h"
#include "twn_engine_context_c.h"
#include "twn_util_c.h"
#include <x-watcher.h>
#include <SDL2/SDL.h>
#include <dlfcn.h>
#define GAME_OBJECT_NAME "libgame.so"
#define MODIFIED_TICKS_MERGED 10
static void (*game_tick_callback)(void);
static void (*game_end_callback)(void);
static x_watcher *watcher;
static void *handle = NULL;
static uint64_t last_tick_modified;
static bool loaded_after_modification = true;
static SDL_mutex *lock;
static char *game_object_path;
static void load_game_object(void) {
/* needs to be closed otherwise symbols aren't resolved again */
if (handle) {
dlclose(handle);
handle = NULL;
game_tick_callback = NULL;
game_end_callback = NULL;
}
void *new_handle = dlopen(game_object_path, RTLD_LAZY);
if (!new_handle) {
log_critical("Hot Reload Error: Cannot open game code shared object (%s)", dlerror());
goto ERR_OPENING_SO;
}
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic"
game_tick_callback = (void (*)(void))dlsym(new_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))dlsym(new_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
handle = new_handle;
if (ctx.game.frame_number != 0)
log_info("Game object was reloaded\n");
return;
ERR_GETTING_PROC:
dlclose(new_handle);
game_tick_callback = NULL;
game_end_callback = NULL;
ERR_OPENING_SO:
SDL_UnlockMutex(lock);
}
static void watcher_callback(XWATCHER_FILE_EVENT event,
const char *path,
int context,
void *data)
{
(void)context;
(void)path;
(void)data;
switch(event) {
case XWATCHER_FILE_CREATED:
case XWATCHER_FILE_MODIFIED:
SDL_LockMutex(lock);
last_tick_modified = ctx.game.frame_number;
loaded_after_modification = false;
SDL_UnlockMutex(lock);
break;
case XWATCHER_FILE_UNSPECIFIED:
case XWATCHER_FILE_REMOVED:
case XWATCHER_FILE_OPENED:
case XWATCHER_FILE_ATTRIBUTES_CHANGED:
case XWATCHER_FILE_NONE:
case XWATCHER_FILE_RENAMED:
default:
break;
}
}
void game_object_load(void) {
SDL_asprintf(&game_object_path, "%s%s", ctx.base_dir, GAME_OBJECT_NAME);
watcher = xWatcher_create();
xWatcher_reference dir;
dir.path = game_object_path;
dir.callback_func = watcher_callback;
xWatcher_appendFile(watcher, &dir);
xWatcher_start(watcher);
lock = SDL_CreateMutex();
load_game_object();
}
void game_object_unload(void) {
game_end_callback();
xWatcher_destroy(watcher);
watcher = NULL;
dlclose(handle);
handle = NULL;
game_tick_callback = NULL;
game_end_callback = NULL;
SDL_DestroyMutex(lock);
}
bool game_object_try_reloading(void) {
bool result = false;
/* only load the modified library after some time, as compilers make a lot of modifications */
SDL_LockMutex(lock);
if (ctx.game.frame_number - last_tick_modified > MODIFIED_TICKS_MERGED &&
!loaded_after_modification) {
load_game_object();
loaded_after_modification = true;
result = true;
} SDL_UnlockMutex(lock);
return result;
}
void game_object_tick(void) {
game_tick_callback();
}
void *game_object_get_game_tick_address(void) {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic"
return (void *)&game_tick_callback;
#pragma GCC diagnostic pop
}