Lua API

Author: EmperorPenguin18

example/hello.lua

@@ -1 +1,19 @@
-print("Hello World")
+function hello(e, instance)
+	print("Hello World")
+end
+
+function destruction(e, instance)
+	while (true)
+	do
+		print("go to link")
+	end
+end
+
+function create_room(e, instance)
+	action(e, instance, '{ "type": "music", "file": "background.ogg" }')
+	action(e, instance, '{ "type": "gravity", "h": 0, "v": 50 }')
+	action(e, instance, '{ "type": "spawn", "object": "rocket.json", "x": 50, "y": 240 }')
+	action(e, instance, '{ "type": "spawn", "object": "obstacle_t.json", "x": 400, "y": 50 }')
+	action(e, instance, '{ "type": "spawn", "object": "obstacle.json", "x": 400, "y": 400 }')
+	action(e, instance, '{ "type": "timer", "num": 0, "time": 10 }')
+end

example/rocket.json

@@ -65,6 +65,10 @@
 				"type": "uri",
 				"link": "https://github.com/EmperorPenguin18"
 			},
+			{
+				"type": "lua_async",
+				"function": "destruction"
+			},
 			{
 				"type": "destroy"
 			}

example/room.json

@@ -10,36 +10,8 @@
 		],
 		"creation": [
 			{
-				"type": "music",
-				"file": "background.ogg"
-			},
-			{
-				"type": "gravity",
-				"h": 0,
-				"v": 50
-			},
-			{
-				"type": "spawn",
-				"object": "rocket.json",
-				"x": 50,
-				"y": 240
-			},
-			{
-				"type": "spawn",
-				"object": "obstacle_t.json",
-				"x": 400,
-				"y": 50
-			},
-			{
-				"type": "spawn",
-				"object": "obstacle.json",
-				"x": 400,
-				"y": 400
-			},
-			{
-				"type": "timer",
-				"num": 0,
-				"time": 10
+				"type": "lua",
+				"function": "create_room"
 			}
 		],
 		"timer_0": [

src/actions.c

@@ -211,6 +211,30 @@ static void action_reload(Engine* e, Instance* instance, char* args) {
 	action_close(e, NULL, NULL);
 }
 
+/* Run a Lua function. See action documentation. */
+static void action_lua(Engine* e, Instance* instance, char* args) {
+	char* function = args;
+	lua_getglobal(e->L, function);
+	lua_pushlightuserdata(e->L, e);
+	lua_pushlightuserdata(e->L, instance);
+	lua_pcall(e->L, 2, 0, 0);
+}
+
+static int thread_function(void* L) {
+	lua_pcall(L, 2, 0, 0);
+	return 0;
+}
+
+/* Run a Lua function in another thread. See action documentation. */
+static void action_lua_async(Engine* e, Instance* instance, char* args) {
+	char* function = args;
+	/*lua_getglobal(e->L, function);
+	lua_pushlightuserdata(e->L, e);
+	lua_pushlightuserdata(e->L, instance);
+	SDL_CreateThread(thread_function, function, e->L);*/
+	SDL_Log("Not implemented");
+}
+
 /* Fill in memory with specified structure.
  * Variadic arguments must be in pairs of two.
  * STRING is string, INTEGER is number, and REAL is bool.
@@ -274,6 +298,7 @@ static char* args_generator(zpl_json_object* json, size_t n, ...) {
 /* Based on the type provided, setup args so calling an action is faster. */
 static int action_handler(Action* action, zpl_json_object* json, Asset* assets, const size_t assets_num) {
 	char* type = args_generator(json, 1, "type", ZPL_ADT_TYPE_STRING);
+	if (type == NULL) return -1;
 
 	if (strcmp(type, "spawn") == 0) {
 		action->args =
@@ -388,6 +413,18 @@ static int action_handler(Action* action, zpl_json_object* json, Asset* assets,
 		action->args = NULL;
 		action->run = &action_reload;
 
+	} else if (strcmp(type, "lua") == 0) {
+		action->args =
+			args_generator(json, 1, "function", ZPL_ADT_TYPE_STRING);
+		if (action->args == NULL) return ERROR("Args generator failed");
+		action->run = &action_lua;
+
+	} else if (strcmp(type, "lua_async") == 0) {
+		action->args =
+			args_generator(json, 1, "function", ZPL_ADT_TYPE_STRING);
+		if (action->args == NULL) return ERROR("Args generator failed");
+		action->run = &action_lua_async;
+
 	} else return ERROR("Invalid action type found");
 	return 0;
 }
@@ -403,3 +440,20 @@ int action_init(Action* action, zpl_json_object* json, Asset* assets, const size
 void action_cleanup(Action* action) {
 	free(action->args);
 }
+
+int action_api(lua_State *L) {
+	Engine* e = lua_touserdata(L, 1);
+	Instance* instance = lua_touserdata(L, 2);
+	const char* string = luaL_checkstring(L, 3);
+	char* str = malloc(strlen(string)+1);
+	strcpy(str, string);
+	Action action;
+	zpl_json_object json;
+	zpl_json_parse(&json, str, zpl_heap());
+	if (action_init(&action, &json, e->assets, e->assets_num) < 0) return 0; //should improve error handling later
+	free(str);
+	zpl_json_free(&json);
+	action.run(e, instance, action.args);
+	action_cleanup(&action);
+	return 0;
+}

src/common.c

@@ -52,7 +52,7 @@ int ERROR(const char* format, ...) {
 	va_list arg;
 	va_start(arg, format);
 	//fprintf(stderr, "[%s: %d] ", __FILE__, __LINE__);
-	SDL_LogError(SDL_LOG_CATEGORY_ERROR, format, arg);
+	SDL_LogMessageV(SDL_LOG_CATEGORY_ERROR, SDL_LOG_PRIORITY_ERROR, format, arg);
 	va_end(arg);
 	return -1;
 }

src/engine.c

@@ -45,6 +45,8 @@ static unsigned char collisionCallback(cpArbiter *arb, cpSpace *space, void *dat
 	return 0;
 }
 
+int action_api(lua_State* L);
+
 /* Setup libraries */
 static int setup_env(Engine* e) {
 	time_t t;
@@ -85,6 +87,8 @@ static int setup_env(Engine* e) {
 	col_hand->userData = e; //Set the collision handler's user data to the context
 	e->L = luaL_newstate();
 	luaL_openlibs(e->L);
+	lua_pushcfunction(e->L, action_api);
+	lua_setglobal(e->L, "action");
 #ifndef NDEBUG
 	e->fps = malloc(sizeof(float));
 	e->vars = realloc(e->vars, sizeof(var));
@@ -258,6 +262,8 @@ static int spawn_level(Engine* e) {
 				e->first_layer = layer;
 			}
 			e->inert_ins_num++;
+		} else if (strcmp(getextension(e->assets[i].name), "lua") == 0) {
+			luaL_dostring(e->L, e->assets[i].data);
 		}
 	}
 	if (e->first) {