Switched the space shooter demo from none fixed process to fixed process

(cherry picked from commit a9d246ea6c)

demos/2d/space_shooter/asteroid.gd

@@ -10,7 +10,7 @@ var speed_y = 0.0
 var destroyed = false
 
 
-func _process(delta):
+func _fixed_process(delta):
 	translate(Vector2(SPEED, speed_y)*delta)
 
 
@@ -23,7 +23,7 @@ func destroy():
 		return
 	destroyed = true
 	get_node("anim").play("explode")
-	set_process(false)
+	set_fixed_process(false)
 	get_node("sfx").play("sound_explode")
 	# Accumulate points
 	get_node("/root/game_state").points += 1
@@ -34,7 +34,7 @@ func is_enemy():
 
 
 func _on_visibility_enter_screen():
-	set_process(true)
+	set_fixed_process(true)
 	# Make it spin!
 	get_node("anim").play("spin")
 

demos/2d/space_shooter/enemy1.gd

@@ -7,7 +7,7 @@ const SPEED = -200
 var destroyed=false
 
 
-func _process(delta):
+func _fixed_process(delta):
 	get_parent().translate(Vector2(SPEED*delta, 0))
 
 
@@ -20,14 +20,14 @@ func destroy():
 		return
 	destroyed = true
 	get_node("anim").play("explode")
-	set_process(false)
+	set_fixed_process(false)
 	get_node("sfx").play("sound_explode")
 	# Accumulate points
 	get_node("/root/game_state").points += 5
 
 
 func _on_visibility_enter_screen():
-	set_process(true)
+	set_fixed_process(true)
 	get_node("anim").play("zigzag")
 	get_node("anim").seek(randf()*2.0) # Make it start from any pos
 

demos/2d/space_shooter/enemy2.gd

@@ -9,7 +9,7 @@ var shoot_timeout = 0
 var destroyed=false
 
 
-func _process(delta):
+func _fixed_process(delta):
 	translate(Vector2(SPEED*delta, 0))
 	shoot_timeout -= delta
 	
@@ -33,18 +33,14 @@ func destroy():
 		return
 	destroyed = true
 	get_node("anim").play("explode")
-	set_process(false)
+	set_fixed_process(false)
 	get_node("sfx").play("sound_explode")
 	# Accumulate points
 	get_node("/root/game_state").points += 10
 
 
-func _ready():
-	set_fixed_process(true)
-
-
 func _on_visibility_enter_screen():
-	set_process(true)
+	set_fixed_process(true)
 
 
 func _on_visibility_exit_screen():

demos/2d/space_shooter/rail.gd

@@ -7,13 +7,13 @@ var offset = 0
 
 
 func stop():
-	set_process(false)
+	set_fixed_process(false)
 
 
-func _process(delta):
+func _fixed_process(delta):
 	offset += delta*SPEED
 	set_pos(Vector2(offset, 0))
 
 
 func _ready():
-	set_process(true)
+	set_fixed_process(true)

demos/2d/space_shooter/ship.gd

@@ -9,7 +9,7 @@ var prev_shooting = false
 var killed = false
 
 
-func _process(delta):
+func _fixed_process(delta):
 	var motion = Vector2()
 	if Input.is_action_pressed("move_up"):
 		motion += Vector2(0, -1)
@@ -53,7 +53,7 @@ func _process(delta):
 
 func _ready():
 	screen_size = get_viewport().get_rect().size
-	set_process(true)
+	set_fixed_process(true)
 
 
 func _hit_something():