Add galilean relativity to shooty enemy

ShootyEnemy.gd

@@ -11,23 +11,26 @@ var bullet_scene = preload("res://Bullet.tscn")
 var bullet_velocity = 40.0
 
 var target
+var velocity := Vector3(0.0, 5.0, 10.0)
 
 
 func _ready():
 	$ShotTimer.connect("timeout", self, "shoot_bullet")
 
 
-func _process(delta):
+func _physics_process(delta):
 	# Project the player's position into the future
 	target = _get_future_position(
 		player.get_center(),
-		player.velocity
+		player.velocity - velocity
 	)
 	
 	if target:
 		var gravity = solar_system.get_gravitation_acceleration(global_transform.origin)
 		look_at(target, gravity)
 	
+	global_transform.origin += velocity * delta
+
 
 func shoot_bullet():
 	if not target:
@@ -38,11 +41,12 @@ func shoot_bullet():
 	get_tree().get_root().add_child(instance)
 	
 	instance.global_transform.origin = global_transform.origin
-	instance.velocity = (target - global_transform.origin).normalized() * bullet_velocity
+	instance.velocity = velocity + (target - global_transform.origin).normalized() * bullet_velocity
 
 
 func _get_future_position(position, velocity):
 	# Solution to the quadratic formula gives us the time at which the player would be hit
+	# TODO: Take acceleration into account as well!
 	var a = pow(velocity.x, 2) + pow(velocity.y, 2) + pow(velocity.z, 2) - pow(bullet_velocity, 2)
 	var b = 2 * (velocity.x * (position.x - global_transform.origin.x)
 		+ velocity.y * (position.y - global_transform.origin.y)