15. Collectibles, Power-Ups, and Pickups

Overview

In this chapter, we will create collectible coins and potion power-ups for the player. Furthermore, we will design the UI for the collectible coins using the Unreal Motion Graphics UI Designer, or UMG as it is more commonly known. Lastly, we will create bricks that will have these collectibles hidden inside of them. By the end of this chapter, you will be able to implement collectibles and power-ups for a player character to find within a level environment.

Introduction

In the previous chapter, you created the player projectile and used Anim Notifies to spawn the player projectile during the Throw animation. The player projectile will serve as the player's main offensive gameplay mechanic to use against the enemies throughout the level. Due to the combination of default Anim Notifies provided by Unreal Engine 4 and your own custom Anim_ProjectileNotify class, the player projectile mechanic looks and feels great.

The last set of mechanics that we need to develop are the coin collectible and potion power-up. Let's briefly break down how collectibles and power-ups have influenced other games, and what they will accomplish for our SuperSideScroller game.

Coin Collectible

Collectibles give the player an incentive to explore the level thoroughly. In many games, such as Hollow Knight, collectibles also serve as a form of currency that can be used to purchase upgrades for your character and items. In other, more classic platformers...

URotatingMovementComponent

URotatingMovementComponent is one of a few movement components that exist within Unreal Engine 4. You are already familiar with CharacterMovementComponent and ProjectileMovementComponent from the SuperSideScroller game project alone, and RotatingMovementComponent is just that – another movement component. As a refresher, movement components allow different types of movements to occur on actors, or characters, that they belong to.

Note

CharacterMovementComponent, which allows you to control the movement parameters of your character such as their movement speed and jump height, was covered in Chapter 10, Creating a SuperSideScroller Game, when you created the SuperSideScroller player character. ProjectileMovementComponent, which allows you to add projectile-based movement functionality to actors such as speed and gravity, was covered in Chapter 14, Spawning the Player Projectile, when you developed the player projectile.

RotatingMovementComponent...

Logging Variables Using UE_LOG

In Chapter 11, Blend Spaces 1D, Key Bindings, and State Machines, we used and learned about the UE_LOG function in order to log when the player should throw the projectile. We then used the UE_LOG function in Chapter 13, Enemy Artificial Intelligence, to log when the player projectile hit an object. UE_LOG is a robust logging tool we can use to output important information from our C++ functions into the Output Log window inside the editor when playing our game. Up until this point, we have only logged FStrings to display general text in the Output Log window to know that our functions were being called. Now, it is time to learn how to log variables in order to debug how many coins the player has collected.

Note

There is another useful debug function available in C++ with Unreal Engine 4, known as AddOnScreenDebugMessage. You can learn more about this function here: https://docs.unrealengine.com/en-US/API/Runtime/Engine/Engine/UEngine/AddOnScreenDebugMessage...

UMG

UMG, or Unreal Motion Graphics UI Designer, is Unreal Engine 4's main tool for creating UI for things such as menus, in-game HUD elements such as health bars, and other user interfaces you may want to present to the player.

In the SuperSideScroller game, we will only be using the Text widget to construct our Coin Collection UI in Exercise 15.04, Creating the Coin Counter UI HUD Element. We'll learn more about the Text widget in the next section.

Text Widget

The Text widget is one of the simpler widgets that exists. This is because it only allows you to display text information to the user and customize the visuals of this text. Almost every single game uses text in one way or another to display information to its players. Overwatch, for example, uses a text-based UI to display crucial match data to its players. Without the use of text, it would be very difficult – maybe even impossible – to convey key pieces of statistical data to the player, such as total damage dealt, total time playing the game, and many others.

The Text widget appears in the Palette tab within UMG. When you add a Text widget to the Canvas panel, it will display the text Text Block by default. You can customize this text by adding your text to the Text parameter of the widget. Alternatively, you can use Function Binding to display more robust text that can reference internal or external variables. Function Binding should be used whenever...

Adding and Creating UMG User Widgets

Now that we have created the Coin Collection UI in UMG, it is time to learn how to add and remove the UI to and from the player screen. By adding the Coin Collection UI to the player screen, the UI becomes visible to the player and can be updated as the player collects coins.

In Blueprints, there is a function called Create Widget, as shown in the following screenshot. Without a class assigned, it will be labeled Construct None, but do not let this confuse you:

Figure 15.17: The Create widget as it is by default, without a class applied

This function requires the class of the User widget to be created and requires a Player Controller that will be referenced as the owning player of this UI. This function then returns the spawned user widget as its Return Value, where you can then add to the player's viewport using the Add to Viewport function. The Create Widget function only instantiates the widget object; it does...

Timers

Timers in Unreal Engine 4 allow you to perform actions after a delay or every X number of seconds. In the case of the SuperSideScroller potion power-up, a timer will be used to restore the player's movement and jump to their defaults after 8 seconds.

Note

In Blueprints, you can use a Delay node in addition to Timer Handles to achieve the same results. However, in C++, Timers are the best means to achieve delays and reoccurring logic.

Timers are managed by Timer Manager, or FTimerManager, which exists in the UWorld object. There are two main functions that you will be using from the FTimerManager class, called SetTimer() and ClearTimer():

void SetTimer
(
    FTimerHandle & InOutHandle,
    TFunction < void )> && Callback,
    float InRate,
    bool InbLoop,
    float InFirstDelay
)
void ClearTimer(FTimerHandle& InHandle)

You may have...

Summary

In this chapter, you put your knowledge to the test to create the remaining gameplay mechanics for the SuperSideScroller game project. Using a combination of C++ and Blueprints, you developed the potion power-up and coins for the player to collect in the level. Also, by using your knowledge from Chapter 14, Spawning the Player Projectile, you added unique audio and visual assets to these collectible items to add a nice layer of polish to the game.

You learned and took advantage of the UMG UI system within Unreal Engine 4 to create a simple, yet effective, UI feedback system to display the number of coins that the player has collected. By using the binding feature of the Text widget, you were able to keep the UI updated with the number of coins the player has currently collected. Lastly, you created a Brick class using the knowledge you learned from the SuperSideScroller project to hide coins for the player so that they can collect and find them.

The SuperSideScroller...