Extra: Boost

Boost

Section titled Boost

If you want a little extra help with speed, here we go!

1. In the hud.tscn scene: Add a ColorRect node under the main Control node.

   • Rename it to Boost and change it’s size to an upright rectangle on the right side of the screen.
   • Change the colour to transparent(ish) dark green.
   • Add another ColorRect node under the main ColorRect Boost node. Rename this to BoostIndicator.
   • Add BoostIndicator to the labels global group (in Node > Signals).
   • Add a Label as a child of the Boost node and set the text to Boost. Set the scale to 1.5.

2. Bind a ‘Boost’ to your Space Bar in the Settings > Input Map.

3. Inside our car.gd, add in these changes.

   car.gd

   var boost_multiplier = 1.5 # Factor to increase acceleration during boost
   var boost_duration = 2.0 # Boost lasts for 2 seconds
   var boost_cooldown = 5.0 # 5 seconds cooldown between boosts
   var is_boosting = false # Tracks if boost is active
   var boost_timer = 0.0 # Timer to track boost duration
   var cooldown_timer = 0.0 # Timer for boost cooldown
   var boost_rect_size = 370 # Change this to your rectangles current size!
   var boost_indicator
   
   func _ready() -> void:
       # (exisiting code)
       boost_indicator = labels.filter(func(label): return label.name == "BoostIndicator")[0]
   
   func _process(delta: float) -> void:
       # Handle boost activation with space bar
       if Input.is_action_just_pressed("Boost") and cooldown_timer <= 0.0:
           start_boost()
   
       # Update timers if boosting or in cooldown
       if is_boosting:
           boost_timer -= delta
           # the lerp function maps the timer to the boost bar.
           boost_indicator.size.y = lerp(0, boost_rect_size, boost_timer / 2.0)
           if boost_timer <= 0.0:
               end_boost() # End boost when timer runs out
       elif cooldown_timer > 0.0:
           cooldown_timer -= delta
           boost_indicator.size.y = lerp(boost_rect_size, 0, cooldown_timer / 5.0)
           boost_indicator.color = Color('ca7566a5') # transparent red
       else:
           boost_indicator.color = Color('caff66a5') # transparent green
   
   func _physics_process(delta: float):
     # steering & speed physics
       # (exisiting code)
       var acceleration = Input.get_axis("Backward", "Forward")
       # Add a check if the car is boosting between acceleration declaration
       # and before the rpm declaration
       if is_boosting:
           acceleration *= boost_multiplier # Apply boost multiplier
   
       var rpm = abs($BackLeftWheel.get_rpm())
       # (exisiting code)
   
   func start_boost():
       is_boosting = true # Activate boosting
       boost_timer = boost_duration # Set the boost duration timer
       cooldown_timer = boost_cooldown # Set the cooldown timer
   
   func end_boost():
       is_boosting = false # Deactivate boosting

You should now have something like this: When pressing space bar:

When the boost is reloading:

Checklist

Section titled Checklist

• I’ve built a boost bar!