**The Role of Blueprints and C++ in Unreal Engine**

In the context of Unreal Engine, blueprints are a powerful tool that allows artists to create gameplay elements without needing extensive knowledge of programming languages like C++. The designers at Epic Games have found that blueprints provide an excellent balance between ease of use and performance. When it comes to creating gameplay elements, artists can work with blueprints until they require more advanced functionality.

At this point, the programmer takes over, using C++ code to create a class that is then exposed through the blueprint interface. This allows artists to access the underlying behavior of the class while still being able to modify and extend it without having to write custom code. The programmer can use C++ when they need more control over the performance-critical aspects of their game, such as physics calculations.

One common scenario where programmers take over from blueprints is when working with asynchronous tasks, such as loading assets or interacting with databases. In these cases, C++ provides a more efficient and effective way to manage the underlying operations. On the other hand, blueprints remain a great choice for most gameplay elements that don't require this level of complexity.

**Blending Code and Blueprints**

One key benefit of Unreal Engine is its ability to seamlessly blend code and blueprints. When working on a project, artists can start with blueprints and gradually add more advanced functionality as needed. This approach allows them to get started quickly and make rapid progress on their game without needing extensive programming knowledge.

To illustrate this point, let's consider an example where the designer wants to create a generator that produces power for certain gameplay elements. They might need to create a custom class that handles this behavior, but they don't care about what model is attached or how it works at a fundamental level. In this case, the programmer can create a generic class in C++, expose the necessary hooks through blueprints, and then allow the artist to modify and extend those hooks as needed.

**Blueprints vs. Native Code**

One question that often arises when working with Unreal Engine is whether blueprints can be used to interact with external systems or data sources. In general, it's possible to use blueprints to access external systems, but there are some limitations and potential workarounds.

For example, when it comes to interacting with databases like MySQL, there isn't a native blueprint node that provides direct access to these systems. However, this doesn't mean that artists can't use blueprints to interact with databases at all. Instead, they can create their own custom class that handles the database operations and then expose those hooks through the blueprint interface.

In other words, an artist might need to write a custom class in C++ that interacts with the database, but then exposes those interactions as a set of public functions or variables that can be accessed from within the blueprints. This approach allows artists to use blueprints while still having access to the underlying functionality they need.

**Level Streaming and Asset Management**

In Unreal Engine 4, level streaming is used extensively to manage assets and optimize performance. When working on a project, artists often take on specific sections of the level or even entire tasks, such as creating foliage or decals. These artists typically work with a "stream level" that represents their current work-in-progress.

To illustrate this point, let's consider an example where multiple artists are working together to build a level. Each artist is responsible for a specific section of the level, and they all work on separate stream levels that get loaded into Unreal Engine as needed. When one artist finishes their work, they can save out their changes and then share them with the team.

At any point in this process, an artist can reload the entire level and see the changes made by their colleagues. This approach allows teams to work together more efficiently and make rapid progress on their projects without needing to constantly restart or reload levels.

**Conclusion**

Unreal Engine 4 provides a powerful toolset for artists and programmers alike, with blueprints offering an easy-to-use interface for creating gameplay elements without extensive programming knowledge. While C++ code is used when advanced functionality is required, the two can be seamlessly blended together using blueprint hooks and interfaces. By understanding how to work effectively with both blueprints and C++, developers can create complex, high-performance games that are well-suited to a wide range of projects and workflows.

**Additional Notes**

Unreal Engine 4 can run on PC and Mac, but it's primarily designed for Windows at this time. Epic Games is focused on providing support and updates for the platform, but the engine itself is designed to be flexible and adaptable to different operating systems.

Regarding C++ code on Macs, Xcode is a popular integrated development environment (IDE) that provides a comprehensive set of tools and features for building and managing C++ projects. While some developers may find it more challenging to work with C++ on Mac compared to Windows, the engine itself remains compatible with both platforms.

Finally, Epic Games has made significant investments in supporting level streaming and asset management in Unreal Engine 4. This approach allows artists to work together more efficiently and make rapid progress on their projects without needing to constantly restart or reload levels.

"WEBVTTKind: captionsLanguage: enI'm going to rotate a little bit and you can see it's shining a little bit of light on well we could take the whole thing and scale it a little bit and that might kind of help make it a little more visible oh also when I hit play then make sure that playing to the location of the camera not from the players start that way we don't accidentally jump around a location they don't really want again so what I'd like to have happen here to be able to walk up to this light and just turn it on and off using the e key right now when i hit a all the cow blow up to let's fix that first i'm going over to my project settings once again you remember on my inputs we took those action let's change that over to our push that one key over and then we're going to add a new action mapping which i will call use expand that what's actually set this one to the e key so a little more conventional so when you might have actually seen in one two or five thousand different names you might have played now here's the deal our cows Boughner we set up earlier week she did we told that it should always be listening out from inputs from the player but general that's not how I handle things it wouldn't be a lot more I guess elegant with how you handled inputs and how you pass them off between different players so let's start there let's set up our little waltz cons here so that it can dynamically handoff control to the player and take it away and a common way to handle that is by approximate only when the player is close to something should they be able to actually use it when they step away from it they shouldn't be able to use it anymore now it's pretty easy to set up in blueprint it's affecting a lot of ways it's very similar to how used to do things in kismet if and you've ever played with that that things like trigger volumes and whatnot we're going to do something really similar let's go over to our components list and here we could see the wall sconce leads to the light component that makes it up chooses list of components we're going to add a box component now we're going to resize this a little bit so we can move it around freely we can scale it we have all the same types of controls that we have in viewport it'll make us a little bit wider or something to be super wide and pull that in just a little and will kick up its thickness and then I'm going to try to make it kind of flush with the back of the light fixture it does not have to be perfect this is necessarily need to be an exact science but if you get a lot of these overlapping you could run into problems you want to keep this clearly trimmed down to just the object you want to interact with let's call this essentially give us a amzil rename it trigger perfect now back over here in our crap we're not going to worry about the construction script in this case just to show off what the construction script is doing is allowing us to set some public variables for our lights you see over here i have the brightness that i can adjust and get real time feedback you take the light color and make that really anything we want and that's because each time I make a property change the construction script is fire now in terms of gameplay the construction script will only fire the moment this is spawned when you play and then it will never fire again so it's a way for you to have some in editor behavior as well as using the event graph or your in-game name so in terms of that let's take our trigger which i just added a moment ago I'll drag that in except let's not drag it on I'm sorry we're just going to select it over here the mindprint list right click it at the very top you see we can add events for it and one of these events is called on the component begin overlap which is a little bit of a mouthful but what that means is when we have entered the space of this volume when it is overlapping with us we want to do something on that note that reminds me over in our components we want to make sure that that trigger has some specific collision properties an easy way to do that is just change its preset will tell it to behave like a trigger so it's just that happens to be one of the names of presets if you want to know what that does if you're the kind of person says I hate presets because I never know what's going on in the hood all it's doing is changing a series of checkboxes about how you're going to collide with objects already got a walk stuff are you going to register overlaps and stuff what types of objects do you want to collide with a non collided and so on we're going to use the trigger preset to save a speed and then on our component begin overlap we want something to happen what we're going to do is we're going to enable input we are going to tell this light a when something steps into your volume we want you to start listening out for inputs and that's fine the note said that's cool but where we're listening to it was from it's going to ask you to provide a player controller now in my case I'm going to again cheat for the sake of speed and we are going to say get player controller and it will feed us one by default this is hard code into player index zero right now we're we have a single player game so player and x0 is perfect if you started having multiple players there are some note that you have access to that would allow you to dynamically check which player just entered into the volume and then set your player controller accordingly we're not going to worry about that in this case so we have enabled input and we can already kind of test this out we just need to set up the rest of our actual toggling behavior so remember earlier we made that action input for the use event so we slay that to the inky so here I can right click and let's type use and I get an event for that just like we did earlier with the cow self-destruct system so what we'll do is just say when we hit this button we are going to take our light component which is point like to in this case and we are going to toggle it we'll plug that in like step and toggle is going to go either way so that's fine don't worry among other than that there is one problem still remaining but I'd rather show it to you to tell you what it is so let's go ahead and hit play and now I can walk up to the light actually let's get way back here for starters so I'm hitting the key key and nothing's happening let's walk up to the light and now when I hit the e key we can turn it on and on but there's a problem now if I get away from the light really far away from light and still turn it on and off that's because we enabled that in we never disabled it we never told the light to stop listening to the player so let's do that really quick it's pretty easy to do we need to select our trigger right click one more time and this time add an event this one will be called on component and overlap so now we're stepping out of the volume and what are we going to do we are going to disable input and just as before it's going to say so who should we stop listening to well I'll stop listening to that player controller we set up a moment ago compile play and I hit from back here head everything's just lock any question on excuse me any questions about this so far yes sir so at it at this time there's not that is something that we have been discussing but I mean until we have like actual plans on the table I can't really talk further about it but it does get to be compiled code so I mean it exists somewhere we just haven't really gone to that other step however the good news is you have access to the source code so if you want to go ahead and write that for us then you totally do that we probably really appreciate it though I'm so sorry I'm supposed to repeat the questions back and I get carried away the question was do you have access to the whatever the blueprint is doing in code meaning like if I create a really cool blueprint network can I see the code that gets created under the hood and then make changes to that the answer is at this time no but it is something we have discussed a little bit here and there I just I can't really promise anything until we have a plan right were there any other questions and I will try to repeat things yes sir not the other way around if you start a sequence of project you get any other visual aspects so if you didn't hear that the question was it can you work the other way you go from code to blueprint and the answer is yes that's actually what we do a lot of the studio so programmer can go in and create a class that can be fairly generic and then start exposing elements of that class by a blueprint and then you can use those bug those hooks if you will and change them around so one of the things we do for instance is a you know the designer will go to a programmer say I need a generator that allows me to create power to power these things but I'm not quite I don't care about what model is going to be attached and so on so the program will create the very basic behavior in a generic class expose the hooks that need to be changed by an artist to blueprint so the artist who knows nothing about program you can go in and make their records and changes and turn it and they want any other questions yes sir so when should a gameplay element B and blueprints what should it be in C++ that's always going to be like a question right so the good news about blueprint is it becomes compiled code you're looking at speeds they're very similar to what you saw with unreal script so just like with any scripting language on well script included once you start having to get really low under the hood like individual physics calculations like let's say you're doing a vehicle I wouldn't necessarily do a vehicle in blueprint because you need a lot of dynamic access to stuff going on in physics so at that point I would be reaching for C++ code for most other things things that tend to run more asynchronously use blueprint whenever you can I mean it's going to remain super fast super performant you can make entire games in it again because it is in effect a compiled scripting language sir can't blueprint reach out and touch a mysql database where you have basically handles i was trying to dig through all of the nodes that i know from blueprint and there's like thousands and thousands there's not a native one bit would be really easy to create you would just create your class that handled your your sequel database and then you just expose the hooks that are artists needed say for instance they need to populate that with an array you would make that array public and accessible to blueprint they can now bring in that know they can execute what it fires and they can now feed an array into it and start setting stuff out the database that make sense cool any other questions yes sir so unreal engine 4 can run on pc and mac we're not calling a unique add any more just and I'm only saying that because I want to make sure I understand what you're saying so unique a is still a pc product on religion for is pc and mac any other questions yes sir oh so what do you do about the c++ code on Matthews Xcode yes I'm noticed a lot of people Mac does have an IDE okay sorry i'll try not to troll the back users any more than that attitude today I need anything else all right yes sir but multiple people so we can do that in a village before the same way we could it on religion 3 you would use something like level streaming and make each artist responsible for a specific section of a level that gets streamed in individually and when you're done if you need to reevaluate how things are strained in of course you can say take this part that the artist was building that was stream and now let's make it a permanent part of this level and maybe reevaluate how everything else get stringed in but that's generally how we do it right you'll take a level bust it up into certain sections or in some cases certain tasks like your you know your high-end final look artists who may just be going in and adding bits of foliage or decals here and there and they're all going to have their own stream levels that represent what they're working on and they can work on all those at the same time at any point you can just reload the map and ever all changes this have been saved out come right in anything else all right well that hits us pretty much right to the mark I want to thank all of you guys for attending please be sure to get your hands on a religion for if you haven't yet remember that once you subscribe even just one time what you get is yours to keep and will not magically stop working so you have really very little excuse to not get your hands on these tool to start making Navy with them thank you all very much enjoy these easyI'm going to rotate a little bit and you can see it's shining a little bit of light on well we could take the whole thing and scale it a little bit and that might kind of help make it a little more visible oh also when I hit play then make sure that playing to the location of the camera not from the players start that way we don't accidentally jump around a location they don't really want again so what I'd like to have happen here to be able to walk up to this light and just turn it on and off using the e key right now when i hit a all the cow blow up to let's fix that first i'm going over to my project settings once again you remember on my inputs we took those action let's change that over to our push that one key over and then we're going to add a new action mapping which i will call use expand that what's actually set this one to the e key so a little more conventional so when you might have actually seen in one two or five thousand different names you might have played now here's the deal our cows Boughner we set up earlier week she did we told that it should always be listening out from inputs from the player but general that's not how I handle things it wouldn't be a lot more I guess elegant with how you handled inputs and how you pass them off between different players so let's start there let's set up our little waltz cons here so that it can dynamically handoff control to the player and take it away and a common way to handle that is by approximate only when the player is close to something should they be able to actually use it when they step away from it they shouldn't be able to use it anymore now it's pretty easy to set up in blueprint it's affecting a lot of ways it's very similar to how used to do things in kismet if and you've ever played with that that things like trigger volumes and whatnot we're going to do something really similar let's go over to our components list and here we could see the wall sconce leads to the light component that makes it up chooses list of components we're going to add a box component now we're going to resize this a little bit so we can move it around freely we can scale it we have all the same types of controls that we have in viewport it'll make us a little bit wider or something to be super wide and pull that in just a little and will kick up its thickness and then I'm going to try to make it kind of flush with the back of the light fixture it does not have to be perfect this is necessarily need to be an exact science but if you get a lot of these overlapping you could run into problems you want to keep this clearly trimmed down to just the object you want to interact with let's call this essentially give us a amzil rename it trigger perfect now back over here in our crap we're not going to worry about the construction script in this case just to show off what the construction script is doing is allowing us to set some public variables for our lights you see over here i have the brightness that i can adjust and get real time feedback you take the light color and make that really anything we want and that's because each time I make a property change the construction script is fire now in terms of gameplay the construction script will only fire the moment this is spawned when you play and then it will never fire again so it's a way for you to have some in editor behavior as well as using the event graph or your in-game name so in terms of that let's take our trigger which i just added a moment ago I'll drag that in except let's not drag it on I'm sorry we're just going to select it over here the mindprint list right click it at the very top you see we can add events for it and one of these events is called on the component begin overlap which is a little bit of a mouthful but what that means is when we have entered the space of this volume when it is overlapping with us we want to do something on that note that reminds me over in our components we want to make sure that that trigger has some specific collision properties an easy way to do that is just change its preset will tell it to behave like a trigger so it's just that happens to be one of the names of presets if you want to know what that does if you're the kind of person says I hate presets because I never know what's going on in the hood all it's doing is changing a series of checkboxes about how you're going to collide with objects already got a walk stuff are you going to register overlaps and stuff what types of objects do you want to collide with a non collided and so on we're going to use the trigger preset to save a speed and then on our component begin overlap we want something to happen what we're going to do is we're going to enable input we are going to tell this light a when something steps into your volume we want you to start listening out for inputs and that's fine the note said that's cool but where we're listening to it was from it's going to ask you to provide a player controller now in my case I'm going to again cheat for the sake of speed and we are going to say get player controller and it will feed us one by default this is hard code into player index zero right now we're we have a single player game so player and x0 is perfect if you started having multiple players there are some note that you have access to that would allow you to dynamically check which player just entered into the volume and then set your player controller accordingly we're not going to worry about that in this case so we have enabled input and we can already kind of test this out we just need to set up the rest of our actual toggling behavior so remember earlier we made that action input for the use event so we slay that to the inky so here I can right click and let's type use and I get an event for that just like we did earlier with the cow self-destruct system so what we'll do is just say when we hit this button we are going to take our light component which is point like to in this case and we are going to toggle it we'll plug that in like step and toggle is going to go either way so that's fine don't worry among other than that there is one problem still remaining but I'd rather show it to you to tell you what it is so let's go ahead and hit play and now I can walk up to the light actually let's get way back here for starters so I'm hitting the key key and nothing's happening let's walk up to the light and now when I hit the e key we can turn it on and on but there's a problem now if I get away from the light really far away from light and still turn it on and off that's because we enabled that in we never disabled it we never told the light to stop listening to the player so let's do that really quick it's pretty easy to do we need to select our trigger right click one more time and this time add an event this one will be called on component and overlap so now we're stepping out of the volume and what are we going to do we are going to disable input and just as before it's going to say so who should we stop listening to well I'll stop listening to that player controller we set up a moment ago compile play and I hit from back here head everything's just lock any question on excuse me any questions about this so far yes sir so at it at this time there's not that is something that we have been discussing but I mean until we have like actual plans on the table I can't really talk further about it but it does get to be compiled code so I mean it exists somewhere we just haven't really gone to that other step however the good news is you have access to the source code so if you want to go ahead and write that for us then you totally do that we probably really appreciate it though I'm so sorry I'm supposed to repeat the questions back and I get carried away the question was do you have access to the whatever the blueprint is doing in code meaning like if I create a really cool blueprint network can I see the code that gets created under the hood and then make changes to that the answer is at this time no but it is something we have discussed a little bit here and there I just I can't really promise anything until we have a plan right were there any other questions and I will try to repeat things yes sir not the other way around if you start a sequence of project you get any other visual aspects so if you didn't hear that the question was it can you work the other way you go from code to blueprint and the answer is yes that's actually what we do a lot of the studio so programmer can go in and create a class that can be fairly generic and then start exposing elements of that class by a blueprint and then you can use those bug those hooks if you will and change them around so one of the things we do for instance is a you know the designer will go to a programmer say I need a generator that allows me to create power to power these things but I'm not quite I don't care about what model is going to be attached and so on so the program will create the very basic behavior in a generic class expose the hooks that need to be changed by an artist to blueprint so the artist who knows nothing about program you can go in and make their records and changes and turn it and they want any other questions yes sir so when should a gameplay element B and blueprints what should it be in C++ that's always going to be like a question right so the good news about blueprint is it becomes compiled code you're looking at speeds they're very similar to what you saw with unreal script so just like with any scripting language on well script included once you start having to get really low under the hood like individual physics calculations like let's say you're doing a vehicle I wouldn't necessarily do a vehicle in blueprint because you need a lot of dynamic access to stuff going on in physics so at that point I would be reaching for C++ code for most other things things that tend to run more asynchronously use blueprint whenever you can I mean it's going to remain super fast super performant you can make entire games in it again because it is in effect a compiled scripting language sir can't blueprint reach out and touch a mysql database where you have basically handles i was trying to dig through all of the nodes that i know from blueprint and there's like thousands and thousands there's not a native one bit would be really easy to create you would just create your class that handled your your sequel database and then you just expose the hooks that are artists needed say for instance they need to populate that with an array you would make that array public and accessible to blueprint they can now bring in that know they can execute what it fires and they can now feed an array into it and start setting stuff out the database that make sense cool any other questions yes sir so unreal engine 4 can run on pc and mac we're not calling a unique add any more just and I'm only saying that because I want to make sure I understand what you're saying so unique a is still a pc product on religion for is pc and mac any other questions yes sir oh so what do you do about the c++ code on Matthews Xcode yes I'm noticed a lot of people Mac does have an IDE okay sorry i'll try not to troll the back users any more than that attitude today I need anything else all right yes sir but multiple people so we can do that in a village before the same way we could it on religion 3 you would use something like level streaming and make each artist responsible for a specific section of a level that gets streamed in individually and when you're done if you need to reevaluate how things are strained in of course you can say take this part that the artist was building that was stream and now let's make it a permanent part of this level and maybe reevaluate how everything else get stringed in but that's generally how we do it right you'll take a level bust it up into certain sections or in some cases certain tasks like your you know your high-end final look artists who may just be going in and adding bits of foliage or decals here and there and they're all going to have their own stream levels that represent what they're working on and they can work on all those at the same time at any point you can just reload the map and ever all changes this have been saved out come right in anything else all right well that hits us pretty much right to the mark I want to thank all of you guys for attending please be sure to get your hands on a religion for if you haven't yet remember that once you subscribe even just one time what you get is yours to keep and will not magically stop working so you have really very little excuse to not get your hands on these tool to start making Navy with them thank you all very much enjoy these easy\n"