godot/demos/3d/platformer/follow_camera.gd

extends Camera

# Member variables
var collision_exception = []
export var min_distance = 0.5
export var max_distance = 4.0
export var angle_v_adjust = 0.0
export var autoturn_ray_aperture = 25
export var autoturn_speed = 50
var max_height = 2.0
var min_height = 0

func _fixed_process(dt):
	var target = get_parent().get_global_transform().origin
	var pos = get_global_transform().origin
	var up = Vector3(0, 1, 0)
	
	var delta = pos - target
	
	# Regular delta follow
	
	# Check ranges
	if (delta.length() < min_distance):
		delta = delta.normalized()*min_distance
	elif (delta.length() > max_distance):
		delta = delta.normalized()*max_distance
	
	# Check upper and lower height
	if (delta.y > max_height):
		delta.y = max_height
	if (delta.y < min_height):
		delta.y = min_height
		
	# Check autoturn
	var ds = PhysicsServer.space_get_direct_state(get_world().get_space())
	
	var col_left = ds.intersect_ray(target, target + Matrix3(up, deg2rad(autoturn_ray_aperture)).xform(delta), collision_exception)
	var col = ds.intersect_ray(target, target + delta, collision_exception)
	var col_right = ds.intersect_ray(target, target + Matrix3(up, deg2rad(-autoturn_ray_aperture)).xform(delta), collision_exception)
	
	if (!col.empty()):
		# If main ray was occluded, get camera closer, this is the worst case scenario
		delta = col.position - target	
	elif (!col_left.empty() and col_right.empty()):
		# If only left ray is occluded, turn the camera around to the right
		delta = Matrix3(up, deg2rad(-dt*autoturn_speed)).xform(delta)
	elif (col_left.empty() and !col_right.empty()):
		# If only right ray is occluded, turn the camera around to the left
		delta = Matrix3(up, deg2rad(dt*autoturn_speed)).xform(delta)
	else:
		# Do nothing otherwise, left and right are occluded but center is not, so do not autoturn
		pass
	
	# Apply lookat
	if (delta == Vector3()):
		delta = (pos - target).normalized()*0.0001

	pos = target + delta
	
	look_at_from_pos(pos, target, up)
	
	# Turn a little up or down
	var t = get_transform()
	t.basis = Matrix3(t.basis[0], deg2rad(angle_v_adjust))*t.basis
	set_transform(t)


func _ready():
	# Find collision exceptions for ray
	var node = self
	while(node):
		if (node extends RigidBody):
			collision_exception.append(node.get_rid())
			break
		else:
			node = node.get_parent()
	set_fixed_process(true)
	# This detaches the camera transform from the parent spatial node
	set_as_toplevel(true)