Gather the building input

The project already includes a BuildManager script. Again, take a moment to look at what each method does. Here’s a breakdown of the key points:

• Awake: Makes sure there’s only one instance of the script in the scene.
• Update: If building, it smoothly moves the prefab each frame.
• Build: Instantiates the prefab into the game world.
• MoveAsset: Calculates the new location of the prefab.
• PlaceAsset: Places the model in the world if it has a valid location, a world tile.
• CalculatePosition: Calculates and sets the target position for the model to lerp to.

Most of these methods work behind the scenes. The only two you need to interact with are MoveAsset and Build. InputManager calls MoveAsset. The UI Event System calls Build. Now that you understand how BuildManager operates, it’s time to add the last bit of code to InputManager.

Gathering the input

InputManager interprets the players intent through their touch actions. There are three stages in total:

1. Start Build: A UI OnPointerDown event that starts the building process. It passes the details to BuildManager.Build.
2. Drag: Determines if a touch drag has occurred, and if so, passes the value to BuildManager.MoveAsset.
3. Complete Build: Disables build mode. Passes the details to BuildManager.PlaceAsset.

Add each of the stages. First add a new class variable above the Awake method:

private bool isBuilding;

Second, add a new method:

public void StartBuildOnPointerDown(GameObject model)
{
    if (Touch.activeTouches.Count == 0)
    {
        return;
    }

    isBuilding = true;

    BuildManager.Instance?.Build(model, 
      Touch.activeTouches[0].screenPosition);
}

StartBuildOnPointerDown is called through an Event Trigger setup on the Well and WoodCutterLodge UI game objects. If the finger is still touching the screen, then isBuilding is set to true for tracking. It wraps up by passing the model and screenPosition of the finger to BuildManager.Build for processing. Finally, add the DragAsset and CompleteBuild methods:

 public void DragAsset(Touch touch)
{
    if (touch.phase != TouchPhase.Moved)
    {
        return;
    }

    BuildManager.Instance?.MoveAsset(touch.screenPosition);
}

public void CompleteBuild()
{
    isBuilding = false;
    BuildManager.Instance?.PlaceAsset();
}

Here’s what these methods do:

1. DragAsset is a pass through method. It uses TouchPhase.Moved to confirm the finger moved during the frame. Then it passes the new screenPosition to BuildManager.MoveAsset for processing.
2. CompleteBuild is only called if the finger leaves the screen. It toggles off build mode and notifies BuildManager.

There’s one final change: You need to update Update. :] Replace all the code in Update with the following:

//1
if (Touch.activeFingers.Count == 1)
{
    if (isBuilding)
    {
        DragAsset(Touch.activeTouches[0]);
    }
    else
    {
        MoveCamera(Touch.activeTouches[0]);
    }
}
//2
else if (Touch.activeFingers.Count == 2)
{
    ZoomCamera(Touch.activeTouches[0], Touch.activeTouches[1]);
}
//3
else if (Touch.activeFingers.Count == 0 && isBuilding)
{
    CompleteBuild();
}

Now Update looks for three key conditions:

• One finger is touching: The player is either trying to Move the camera or drag a prefab for building.
• Two fingers are touching: The player is trying to zoom.
• No fingers are touching and they were building: They are trying to place an object.

Save your changes and return to the Unity editor.