Moving the player with code (2024)

It's time to code! We're going to use the input actions we created in the lastpart to move the character.

Right-click the Player node and select Attach Script to add a new script toit. In the popup, set the Template to Empty before pressing the Createbutton. We set it to Empty because we want to write our own code forplayer movement.

Let's start with the class's properties. We're going to define a movement speed,a fall acceleration representing gravity, and a velocity we'll use to move thecharacter.

extends CharacterBody3D# How fast the player moves in meters per second.@export var speed = 14# The downward acceleration when in the air, in meters per second squared.@export var fall_acceleration = 75var target_velocity = Vector3.ZERO

These are common properties for a moving body. The target_velocity is a 3D vectorcombining a speed with a direction. Here, we define it as a property becausewe want to update and reuse its value across frames.

Let's code the movement. We start by calculating the input direction vectorusing the global Input object, in _physics_process().

func _physics_process(delta): # We create a local variable to store the input direction. var direction = Vector3.ZERO # We check for each move input and update the direction accordingly. if Input.is_action_pressed("move_right"): direction.x += 1 if Input.is_action_pressed("move_left"): direction.x -= 1 if Input.is_action_pressed("move_back"): # Notice how we are working with the vector's x and z axes. # In 3D, the XZ plane is the ground plane. direction.z += 1 if Input.is_action_pressed("move_forward"): direction.z -= 1

Here, we're going to make all calculations using the _physics_process()virtual function. Like _process(), it allows you to update the node everyframe, but it's designed specifically for physics-related code like moving akinematic or rigid body.

We start by initializing a direction variable to Vector3.ZERO. Then, wecheck if the player is pressing one or more of the move_* inputs and updatethe vector's x and z components accordingly. These correspond to theground plane's axes.

These four conditions give us eight possibilities and eight possible directions.

In case the player presses, say, both W and D simultaneously, the vector willhave a length of about 1.4. But if they press a single key, it will have alength of 1. We want the vector's length to be consistent, and not move faster diagonally. To do so, we cancall its normalized() method.

#func _physics_process(delta): #... if direction != Vector3.ZERO: direction = direction.normalized() # Setting the basis property will affect the rotation of the node. $Pivot.basis = Basis.looking_at(direction)

Here, we only normalize the vector if the direction has a length greater thanzero, which means the player is pressing a direction key.

We compute the direction the $Pivot is looking by creating a Basisthat looks in the direction direction.

Then, we update the velocity. We have to calculate the ground velocity and thefall speed separately. Be sure to go back one tab so the lines are inside the_physics_process() function but outside the condition we just wrote above.

func _physics_process(delta): #... if direction != Vector3.ZERO: #... # Ground Velocity target_velocity.x = direction.x * speed target_velocity.z = direction.z * speed # Vertical Velocity if not is_on_floor(): # If in the air, fall towards the floor. Literally gravity target_velocity.y = target_velocity.y - (fall_acceleration * delta) # Moving the Character velocity = target_velocity move_and_slide()

The CharacterBody3D.is_on_floor() function returns true if the body collided with the floor in this frame. That's whywe apply gravity to the Player only while it is in the air.

For the vertical velocity, we subtract the fall acceleration multiplied by thedelta time every frame.This line of code will cause our character to fall in every frame, as long as it is not on or colliding with the floor.

The physics engine can only detect interactions with walls, the floor, or otherbodies during a given frame if movement and collisions happen. We will use thisproperty later to code the jump.

On the last line, we call CharacterBody3D.move_and_slide() which is a powerfulmethod of the CharacterBody3D class that allows you to move a charactersmoothly. If it hits a wall midway through a motion, the engine will try tosmooth it out for you. It uses the velocity value native to the CharacterBody3D

And that's all the code you need to move the character on the floor.

Here is the complete Player.gd code for reference.

extends CharacterBody3D# How fast the player moves in meters per second.@export var speed = 14# The downward acceleration when in the air, in meters per second squared.@export var fall_acceleration = 75var target_velocity = Vector3.ZEROfunc _physics_process(delta): var direction = Vector3.ZERO if Input.is_action_pressed("move_right"): direction.x += 1 if Input.is_action_pressed("move_left"): direction.x -= 1 if Input.is_action_pressed("move_back"): direction.z += 1 if Input.is_action_pressed("move_forward"): direction.z -= 1 if direction != Vector3.ZERO: direction = direction.normalized() $Pivot.basis = Basis.looking_at(direction) # Ground Velocity target_velocity.x = direction.x * speed target_velocity.z = direction.z * speed # Vertical Velocity if not is_on_floor(): # If in the air, fall towards the floor. Literally gravity target_velocity.y = target_velocity.y - (fall_acceleration * delta) # Moving the Character velocity = target_velocity move_and_slide()