GodotCourse/week2/exercise2_jumpcontrol.md

The template for the character controller in Godot is very basic.

```
extends CharacterBody2D


const SPEED = 300.0
const JUMP_VELOCITY = -300.0

# Get the gravity from the project settings to be synced with RigidBody nodes.
var gravity = ProjectSettings.get_setting("physics/2d/default_gravity")


func _physics_process(delta):
	# Add the gravity.
	if not is_on_floor():
		velocity.y += gravity * delta

	# Handle jump.
	if Input.is_action_just_pressed("ui_accept") and is_on_floor():
		velocity.y = JUMP_VELOCITY

	# Get the input direction and handle the movement/deceleration.
	# As good practice, you should replace UI actions with custom gameplay actions.
	var direction = Input.get_axis("ui_left", "ui_right")
	if direction:
		velocity.x = direction * SPEED
	else:
		velocity.x = move_toward(velocity.x, 0, SPEED)

	move_and_slide()
```

The basic template uses two helper functions `is_on_floor` and `move_and_slide` along with the `velocity` variable to achieve jumping, falling, and movement.

Let us use some of our newfound knowledge of physics to improve our player character!

### Exported Variables

Exported variables allow us to make changes to them in the Godot editor. This is nice for play testing as it gives us a visual way to tweak our code. Let's take the imortant variables and export them.

```
@export var SPEED = 10400
@export var JUMP_VELOCITY = -300
```
### Collisions with RigidBodies

Each time a PlayerCharacter body moves via `move_and_slide` any colliders it made contact with are stored in an array that can be retrieved via the `get_slide_collision` method.

We can use that to apply an impulse to any RigidBody the player collided with.

```
	# This represents the player's inertia
	# after calling move_and_slide()
	for i in get_slide_collision_count():
		var c = get_slide_collision(i)
		if c.get_collider() is RigidBody2D:
			c.get_collider().apply_central_impulse(-c.get_normal() * PUSH_FORCE)
```
## Creating a Melee Force Push Attack

We can use our new knowledge of impulses to do some pretty cool attacks agains RigidBodies!

To pull off the attack we need to know:

* Is there a target in range?
* What direction is the player facing?
* Is there a target in front of them in range?
* Are they attacking?
* How much force should be applied?

To tell if there is a target in range, we can use a handy feature called a Raycast.

### Raycasts

Raycasts can be used to detect collisions within a very narrow line. They are very helpful for detecting objects within a certain proximity.

We will use them to detect if there are any items we can attack with a force-push within range of the player character.

First we make a reference to our two raycasts:

```
@onready var rightRay = $RightRaycast
@onready var leftRay = $LeftRaycast
var pushRightEnabled = false
var pushLeftEnabled = false

#note no type assigned
var pushTarget
#can not force-push right if facing left
var faceLeft = false
```

When we detect the action of a raycast we need to respond. First of all, we need to track which direction the player is facing, assuming that they can only force-push in the direction they are facing.

```
if direction:
		velocity.x = direction * SPEED
		faceLeft = true if direction<0 else false
```

```
if rightRay.is_colliding():
		var collider = rightRay.get_collider()
		if collider is Node:
			if collider.is_in_group("boxes"):
				pushRightEnabled = true
				pushTarget = collider
	else:
		pushRightEnabled = false
```

And we can do the same for the left ray:

```
if leftRay.is_colliding():
		var collider = leftRay.get_collider()
		if collider is Node:
			if collider.is_in_group("boxes"):
				pushLeftEnabled = true
				pushTarget = collider
	else:
		pushLeftEnabled = false
```

Now we just have to detect if the player is holding the force push button.

```
if Input.is_action_just_pressed("push") && pushRightEnabled && faceLeft == false:
		label.text="shove"
		pushTarget.apply_central_impulse(Vector2(1,0) * PUSH_FORCE * 20)
		pushRightEnabled = false
		
	if Input.is_action_just_pressed("push") && pushLeftEnabled :
		label.text="shove"
		pushTarget.apply_central_impulse(Vector2(-1,0) * PUSH_FORCE * 20)
		pushLeftEnabled = false
```