WEBVTT 00:07.260 --> 00:08.310 Welcome back. 00:08.310 --> 00:13.230 Now, in all RPGs, just about there's the ability to save your progress. 00:13.380 --> 00:18.720 And this is done in different ways depending on whether it's a single or a multiplayer game. 00:18.720 --> 00:21.030 And there are different ways to go about it. 00:21.060 --> 00:27.360 Now, when saving the game, we need to start thinking about what we need to save, what data is important. 00:27.780 --> 00:33.990 Well, we know that we have an attribute set with some attributes on it, and those attributes, at 00:33.990 --> 00:40.800 least the primary attributes are needed if we want all of the rest of our attributes to have the correct 00:40.800 --> 00:41.670 values. 00:42.270 --> 00:46.950 And as we level up, we spend attribute points on our primary attributes. 00:46.950 --> 00:53.310 So if we're looking for data that we need to save, at least our primary attributes would be part of 00:53.310 --> 00:54.210 that list. 00:54.860 --> 00:58.190 In addition to that, we have variables on our player state. 00:58.190 --> 01:03.890 So the player state contains some data that we're going to want to harvest and save whenever we save 01:03.890 --> 01:04.760 our project. 01:04.760 --> 01:12.590 And in this project, this just consists of four integers the level, the spell points, attribute points, 01:12.590 --> 01:14.210 and the XP. 01:14.860 --> 01:18.250 So those, of course, are data that we would like to save. 01:19.110 --> 01:19.530 Now. 01:19.530 --> 01:26.850 The ability system component itself has data of its own pertaining to our abilities, and luckily, 01:26.850 --> 01:32.340 we've set up our system in a really efficient manner where we can identify abilities by their ability 01:32.340 --> 01:33.180 tags. 01:33.240 --> 01:40.080 So gameplay tags are the only thing that we would need to save in order to keep track of our progress. 01:40.110 --> 01:46.680 Of course, they all have their own ability levels as well, and any other information that we may wish 01:46.680 --> 01:53.370 to save with our gameplay abilities could be lumped in to some kind of data structure, but either way, 01:53.370 --> 01:58.080 we do need to save information pertaining to our gameplay abilities. 01:58.910 --> 02:03.860 Now, these are all data that we would like to save and load for our character. 02:04.280 --> 02:09.530 But there could be additional information not stored in these variables that we would still want to 02:09.530 --> 02:10.100 save. 02:10.640 --> 02:19.820 This can include our location, perhaps the level or map that our character is in, and any other identifying 02:19.820 --> 02:23.750 value that we can use to retrieve our saved data. 02:23.750 --> 02:28.670 Some kind of a slot number or ID associated with the player. 02:29.030 --> 02:32.750 Any of that would be data that we would want to save as well. 02:32.750 --> 02:36.380 So we have a list of things that we're going to want to save. 02:36.380 --> 02:40.100 And now we need to think about how we're going to save it. 02:40.890 --> 02:44.190 Now there are two primary ways to save data. 02:44.220 --> 02:48.780 You could save the data to disk, your actual machine that you're playing on. 02:49.290 --> 02:55.830 So all of those values would now live on your machine and can be loaded from disk, or you could save 02:55.830 --> 03:02.550 to somewhere else, elsewhere in the cloud, or elsewhere on your machine, or onto another machine. 03:02.730 --> 03:06.150 This would be saving to a database of some kind. 03:06.630 --> 03:13.140 All of those values would be streamed across the network and saved somewhere else. 03:13.650 --> 03:16.530 And there are pros and cons to each way. 03:17.290 --> 03:24.070 If you save to an external database, then all of the data for the game is saved in a central location. 03:24.100 --> 03:25.540 This is for all users. 03:25.540 --> 03:32.440 So if this is a multiplayer game, it's the database that contains information pertaining to each user, 03:32.470 --> 03:34.510 not the user themselves. 03:35.080 --> 03:41.560 This is useful because if you save all of your player data to a database on one machine, you could 03:41.560 --> 03:47.920 log out and go to another machine and log in and still retrieve that saved information. 03:47.920 --> 03:52.000 Because it's not local to the machine, it's saved on a database. 03:52.890 --> 03:56.040 Another advantage is databases can be encrypted. 03:56.040 --> 03:58.260 So you could store sensitive information. 03:58.260 --> 04:03.720 And while encryption can be cracked, there's a level of security to it. 04:04.420 --> 04:07.840 Now dedicated servers use databases. 04:07.870 --> 04:14.680 This is typically the way to go for dedicated servers because the dedicated server does not have a player. 04:15.070 --> 04:21.520 The player is connecting to the server from elsewhere, and if the player is connecting to the server, 04:21.520 --> 04:28.090 then the server can connect to the database and have its information ready for the player. 04:28.540 --> 04:32.980 And doing it this way gives the server authority over the data. 04:32.980 --> 04:39.400 You see things that are determined by the client or sent from the client side up to the server. 04:39.400 --> 04:47.020 Run the risk of cheating as clients can be hacked, they can send fake values up to the server. 04:47.020 --> 04:52.510 And so for that reason, the server is typically seen as what should have authority. 04:52.510 --> 04:58.960 So saving to a database and having the server be in charge of saving and loading that data and sending 04:58.960 --> 05:01.960 it to the client is a secure way to do it. 05:02.590 --> 05:06.430 Now, the drawback to this method is it requires APIs. 05:06.430 --> 05:10.150 You need the ability to connect to a database. 05:10.150 --> 05:18.910 This requires expertise and knowledge about databases, how to write to and retrieve data from databases 05:18.910 --> 05:24.640 from within your game, and how to manipulate database data. 05:25.320 --> 05:25.740 Now. 05:25.740 --> 05:27.780 Saving to disk is simpler. 05:27.780 --> 05:30.240 It's typically easier to implement. 05:30.240 --> 05:31.170 It's faster. 05:31.170 --> 05:33.900 It doesn't require an external database. 05:34.290 --> 05:40.170 And for that reason, it's ideal for single player games as you don't really need to connect to a database 05:40.170 --> 05:40.890 elsewhere. 05:40.920 --> 05:47.880 Now, there are single player games that still do connect to dedicated servers and databases in order 05:47.880 --> 05:55.920 to keep track of important things in the game to facilitate in-game purchases, leaderboards, and such. 05:56.160 --> 05:59.580 But in the absence of that need, you could save to disk. 05:59.580 --> 06:05.550 And in reality, most multiplayer games use a combination where important information is stored on the 06:05.550 --> 06:09.240 database, but some information is stored to the disk. 06:09.630 --> 06:15.450 For example, when you have a login and a password and your app remembers the password that you've entered 06:15.450 --> 06:17.820 in that is saved to disk. 06:18.550 --> 06:22.030 Now a con to saving to disk is the data is local. 06:22.180 --> 06:27.640 So you could save your progress in the game on one machine and then go to another machine. 06:27.640 --> 06:34.420 Open up the game and that data is not there because you saved it locally to another machine's disk. 06:35.020 --> 06:36.400 That's a drawback. 06:37.020 --> 06:44.040 And some games again that are single player would still save some data to either a dedicated server 06:44.040 --> 06:46.920 or a database that the server can connect to. 06:47.790 --> 06:48.450 Now. 06:48.450 --> 06:56.340 Saving data externally to a database is outside the scope of this course, as that would require developing 06:56.340 --> 06:59.040 the ability to connect to the database. 06:59.070 --> 07:04.500 Teaching about how to retrieve and send to databases and from them. 07:04.500 --> 07:08.430 And that's really material for a course in itself. 07:08.430 --> 07:15.750 And I am planning on a course on dedicated servers that will talk about this in more detail. 07:16.110 --> 07:18.330 And we'll be creating a system for this. 07:18.330 --> 07:24.570 But in this course, which is primarily about the game play ability system, we're going to devise a 07:24.570 --> 07:26.370 system for saving to disk. 07:26.670 --> 07:33.420 But we'll do it in such a way that it could easily be swapped out for a system that saves to a database. 07:33.840 --> 07:39.780 Really, the only thing that matters is what data you're saving, how you're saving it, and where you're 07:39.780 --> 07:42.120 getting that data from when you load the game. 07:42.720 --> 07:49.530 The only thing that would change in a database based system is that you would add the capability to 07:49.530 --> 07:52.890 connect to the database or the dedicated server, or both. 07:53.430 --> 08:00.300 So in this final section in the course, we're going to implement a save game system where we can save 08:00.300 --> 08:07.710 our progress and load back in in the location where we were when we saved with the stats that we had 08:07.710 --> 08:08.850 when we saved. 08:09.150 --> 08:18.360 And this allows for a much more involved RPG, because if you retain your progress and load it back 08:18.360 --> 08:24.690 up every time you come back into the game, you haven't lost your progression and you can continue moving 08:24.690 --> 08:33.180 deeper into the game and venturing your way through deeper and darker dungeons and more complex levels 08:33.180 --> 08:34.140 and so on. 08:34.680 --> 08:42.150 So we're ready to start implementing a system for this, and we're going to need a way to load into 08:42.150 --> 08:42.930 the game. 08:42.930 --> 08:44.730 We'll need an opening screen. 08:44.730 --> 08:46.920 And we're going to start with that first. 08:46.920 --> 08:52.410 And then we'll work our way into figuring out how we can save our progress. 08:53.140 --> 08:54.100 I'll see you soon.