07 - Waypoints
In this section, you will create a Waypoint script that you will use to define positions in your world for your enemies to move between.
Creating a Waypoint Prefab
It is possible to create a Prefab directly in the Project explorer.
- Navigate to your Prefabs folder
- Right Click
- Select Create > Scene > Prefab
- Name the Prefab "Waypoint"
- Double click the Waypoint prefab to open it
If all went well, you should be in the Scenes | Prefab editor with an Empty Game Object named "Waypoint":
To make it easy to know where the Waypoint is when you add it to a Scene, you can add a 3D Sphere (or another shape if you prefer).
- In the Waypoint's Hierarchy, Right Click
- Select 3D Object > Sphere
This will add a child object to the Waypoint called Sphere that is positioned at the center of the Waypoint. You can verify this by ensuring the Transform's position is (0, 0, 0)
You may have also noticed that the defaults Sphere generated comes with 3 additional components that are visible in the Inspector.
- Mesh Filter - Used to specify the mesh of this object
- Mesh Renderer - Used to specify how the mesh is rendered
- Sphere Collider - Used by Unity's 3D Physics system to detect collisions
Because the Waypoint does not need to collide with other objects, you can safely remove this component.
- Locate the Sphere Collider component in the Inspector
- Click the 3 dots on the top right of the component
- Select Remove Component
Another way you can exit the Prefab editor is by clicking the Scenes text that appears in the top left of the Scene view.
- Exit the Prefab editor and return to your Scene
Adding Waypoints to Your Level
You can add a Prefab directly into your Scene by dragging it into the Scene view.
- Add a Waypoint at the starting point of your path
- Add a Waypoint at each corner of your path
- Add a Waypoint at the end of your path
Grid Snapping
Once again, you might find it difficult to precisely place the objects in the Scene view. To help with placement, you can enable Grid Snapping.
- In the Scene view, enable the Grid and Snapping settings from the Overlay Menu
Clicking this button will show the Grid and Snap settings at the top of the Scene View
This menu allows you to specify the size of the Grid and allows you to turn on Snapping.
- Set your Grid Size to
0.5
- Enable Grid Snapping
- Ensure that you have your Tool Handle settings are set to Pivot and Global
With Grid Snapping enabled, you should now be able to place your waypoints more precisely on your tile map using the Move Tool.
- With Grid Snapping enabled, use the Move Tool position your Waypoints
If you're having trouble selecting your Waypoints, you can disable the ability to click your Tile Grid elements by hovering to the left of the Grid Game Object in the Hierarchy and clicking the finger icon.
This will disable your ability to click on that Game Object in the Scene View. You can re-enable interactions by clicking the finger icon again.
Hiding the Waypoints
Currently, your Waypoints are visible in your Game View which means your player will see them during game play. You can test this by Entering Play Mode.
One way you could hide the Waypoints would be to disable the Mesh Renderer. (Don't do this)
However, it is very convenient to be able to see the Waypoints in the Scene view so we can adjust them.
Another option is to tell our Main Camera to ignore rendering them. This can be done by setting adding the Waypoints to a special rendering layer and then updating the Main Camera's Culling Mask to ignore that layer.
Creating a Waypoint Layer
- Open your Project Settings
- From the top menu Edit > Project Settings
- Select the Tags and Layers tab on the left
- Verify you're editing the Layers drop down
- Select Layer 6
- Enter the name "Waypoint"
- Close the Project Settings Window
Specifying the Waypoint Layer
In the Inspector you can see and modify the layer of a Game Object.
- Select a Waypoint from your Hierarchy
- Alternatively you could open it in Prefab mode
- Set the Layer to Waypoint
- When prompted select "Yes, Change Children"
- This will set the layer of all children objects to the selected layer
- If you are not editing in Prefab mode, don't forget to apply the Override
Camera the Culling Mask
Culling refers to the process of determining which objects in a scene are not visible to the camera and excluding them from rendering to improve performance. Next, you will update the Main Camera's Culling Mask to exclude the Waypoint layer.
- Select the Main Camera
- In the Inspector locate the Camera components Rendering settings
By default, the camera's Culling Mask will render everything.
- Select the Drop Down and unselect the Waypoint layer
You can verify that the camera is no longer rendering your Waypoints by entering the Game View.
Waypoint Component
With your Waypoints placed on your map, it is now time to make them aware of their order. You can accomplish this by creating a Waypoint component that knows which Waypoint comes next in the sequence.
- Create a Waypoint MonoBehaviour
- Delete the Start and Update methods from the template, you won't need them
- Add a Waypoint property called Next
- Remember to use good programming practices and us a
private set
- Remember to use good programming practices and us a
- Serialize the Next property using the
[field: SerializeField]attribute
Practice
Can you remember how to add your new component to your Waypoint prefab? If you're having trouble, you can review how you added the EnemyMovement component in 06 - Adding an Enemy
- Add the Waypoint component to your Waypoint Prefab
- Verify that each Waypoint object in your scene has the component
Set the Waypoint Sequence in the Inspector
By creating a Next property that has the type Waypoint , you have made it possible to specify the Next property of each Waypoint in the Inspector.
- Select your starting Waypoint Game Object from the Hierarchy
- In the Inspector click the small circle next to the Next property
- Select the second Waypoint Game Object from the list
Note: If you click the object in the Next field, it will highlight in the Hierarchy. If you double-click the object in the Next field, it will select that object.
You can also set the an object property in the Inspector by dragging a game object into the property field.
Sometimes this can be challenging to do because you can accidentally click the object you're trying to drag, changing the selected object in the Inspector. To help with this, you can open a new inspector window for a specific game object by Right Clicking on it and select Properties.
Practice
Test out each of the methods for setting the Next for each of your Waypoints property to figure out which one works best for you. You should leave the final Waypoint's Next property as None. You will use this to signal to the Enemy that it has reached the end of the path.
Organizing the Hierarchy
Depending on the number of Waypoints you have created, your Hierarchy might be feeling a bit crowded. To help with this, create an Empty Parent that contains all of the Waypoints as children object.
When you're finished, your Hierarchy should look similar to the image below:
Drawing the Waypoint Path in the Scene View
While setting each of the Next properties, you may have sensed that this process could be error prone. That is, it is easy to set the wrong Waypoint. To help with this, you can use the OnDrawGizmos and OnDrawGizmosSelected methods to draw additional information in the Scene View.
OnDrawGizmosSelected
The OnDrawGizmosSelect method is used to draw information in the Scene View when a Game Object is selected.
- Read the Friendly Manual
- Add
using UnityEditor;to yourusingstatements- Note: This will allow you to access the Handles API
- Add the void OnDrawGizmosSelected() to your Waypoint script
- Note: Spelling and casing must match exactly
- Set the Handles.color property to Color.red
- Use the Handles.DrawLine method to draw a line between the Waypoint and its Next
With your new gizmo in place, you can now more easily verify that your Waypoints are connected properly:
Null Check
You most likely encountered NullReferenceException when you selected your final Waypoint. This is because the Next property is set to None. For class objects, this is the equivalent to a null value. To prevent this, you should add a null check to your code that exists your method early if Next == null.
Using OnDrawGizmos
If you prefer, you can also use the OnDrawGizmos method which is executed in the Scene View even when the Game Object is not selected.
- Rename your OnDrawGizmosSelected method to OnDrawGizmos
In the Scene View verify your path is correct
Binary Waypoint Challenge
It is important to review what you've learned in this lesson and apply it in a new context. Before continuing, I encourage you to attempt the Binary Waypoint Challenge in which you will be challenged to create a new script to accommodate splitting paths.
What's Next
With your Waypoints set up, it is now time to update your Enemy Movement script to move between each Waypoint.