Scripting: Allow multiple global step callbacks and improve documentation

2 files changed, 89 insertions, 15 deletions

diff --git a/data/scripts/default.lua b/data/scripts/default.lua
index 0b9f8b913..eda7cd25e 100644
--- a/data/scripts/default.lua
+++ b/data/scripts/default.lua
@@ -72,13 +72,47 @@ function dump(o, dumped)
 	end
 end
 
+-- Global functions:
+-- minetest.register_entity(name, prototype_table)
+-- minetest.register_globalstep(func)
+--
+-- Global objects:
+-- minetest.env - environment reference
+--
+-- Global tables:
+-- minetest.registered_entities
+-- ^ List of registered entity prototypes, indexed by name
+-- minetest.object_refs
+-- ^ List of object references, indexed by active object id
+-- minetest.luaentities
+-- ^ List of lua entities, indexed by active object id
+--
+-- EnvRef methods:
+-- - add_node(pos, content); pos={x=num, y=num, z=num}
+--
+-- ObjectRef methods:
+-- - remove(): remove object (after returning from Lua)
+-- - getpos(): returns {x=num, y=num, z=num}
+-- - setpos(pos); pos={x=num, y=num, z=num}
+-- - moveto(pos, continuous=false): interpolated move
+-- - add_to_inventory(itemstring): add an item to object inventory
+--
+-- Registered entities:
+-- - Functions receive a "luaentity" as self:
+--   - It has the member .object, which is an ObjectRef pointing to the object
+--   - The original prototype stuff is visible directly via a metatable
+--
+
 print("omg lol")
 print("minetest dump: "..dump(minetest))
 
 -- Global environment step function
 function on_step(dtime)
+	-- print("on_step")
 end
 
+minetest.register_globalstep(on_step)
+
 local TNT = {
 	-- Maybe handle gravity and collision this way? dunno
 	physical = true,
@@ -112,6 +146,15 @@ function TNT:on_rightclick(clicker)
 	pos = {x=pos.x, y=pos.y+0.1, z=pos.z}
 	self.object:moveto(pos, false)
 end
+
+print("TNT dump: "..dump(TNT))
+
+print("Registering TNT");
+minetest.register_entity("TNT", TNT)
+
+print("minetest.registered_entities:")
+dump2(minetest.registered_entities)
+
 --[[
 function TNT:on_rightclick(clicker)
 	print("TNT:on_rightclick()")
@@ -125,15 +168,6 @@ function TNT:on_rightclick(clicker)
 end
 --]]
 
-print("TNT dump: "..dump(TNT))
-
-print("Registering TNT");
-minetest.register_entity("TNT", TNT)
-
---print("minetest.registered_entities: "..dump(minetest.registered_entities))
-print("minetest.registered_entities:")
-dump2(minetest.registered_entities)
-
 --[=[
 
 register_block(0, {
diff --git a/src/scriptapi.cpp b/src/scriptapi.cpp
index 6d0522000..27f46a8ac 100644
--- a/src/scriptapi.cpp
+++ b/src/scriptapi.cpp
@@ -170,8 +170,35 @@ static int l_register_entity(lua_State *L)
 	return 0; /* number of results */
 }
 
+// Register a global step function
+// register_globalstep(function)
+static int l_register_globalstep(lua_State *L)
+{
+	luaL_checktype(L, 1, LUA_TFUNCTION);
+	infostream<<"register_globalstep"<<std::endl;
+
+	lua_getglobal(L, "table");
+	lua_getfield(L, -1, "insert");
+	int table_insert = lua_gettop(L);
+	// Get minetest.registered_globalsteps
+	lua_getglobal(L, "minetest");
+	lua_getfield(L, -1, "registered_globalsteps");
+	luaL_checktype(L, -1, LUA_TTABLE);
+	int registered_globalsteps = lua_gettop(L);
+	// table.insert(registered_globalsteps, func)
+	lua_pushvalue(L, table_insert);
+	lua_pushvalue(L, registered_globalsteps);
+	lua_pushvalue(L, 1); // push function from argument 1
+	// Call insert
+	if(lua_pcall(L, 2, 0, 0))
+		script_error(L, "error: %s\n", lua_tostring(L, -1));
+
+	return 0; /* number of results */
+}
+
 static const struct luaL_Reg minetest_f [] = {
 	{"register_entity", l_register_entity},
+	{"register_globalstep", l_register_globalstep},
 	{NULL, NULL}
 };
 
@@ -567,6 +594,9 @@ void scriptapi_export(lua_State *L, Server *server)
 	lua_setfield(L, -2, "registered_entities");
 
 	lua_newtable(L);
+	lua_setfield(L, -2, "registered_globalsteps");
+
+	lua_newtable(L);
 	lua_setfield(L, -2, "object_refs");
 
 	lua_newtable(L);
@@ -684,12 +714,22 @@ void scriptapi_environment_step(lua_State *L, float dtime)
 	//infostream<<"scriptapi_luaentity_step: id="<<id<<std::endl;
 	StackUnroller stack_unroller(L);
 
-	lua_getglobal(L, "on_step");
-	if(lua_type(L, -1) != LUA_TFUNCTION)
-		return; // If no on_step function exist, do nothing
-	lua_pushnumber(L, dtime);
-	if(lua_pcall(L, 1, 0, 0))
-		script_error(L, "error: %s\n", lua_tostring(L, -1));
+	// Get minetest.registered_globalsteps
+	lua_getglobal(L, "minetest");
+	lua_getfield(L, -1, "registered_globalsteps");
+	luaL_checktype(L, -1, LUA_TTABLE);
+	int table = lua_gettop(L);
+	// Foreach
+	lua_pushnil(L);
+	while(lua_next(L, table) != 0){
+		// key at index -2 and value at index -1
+		luaL_checktype(L, -1, LUA_TFUNCTION);
+		// Call function
+		lua_pushnumber(L, dtime);
+		if(lua_pcall(L, 1, 0, 0))
+			script_error(L, "error: %s\n", lua_tostring(L, -1));
+		// value removed, keep key for next iteration
+	}
 }
 
 /*