Go, Go, Godot!
  • 0

Projectiles going through collision objects

October 27, 2022

Ever had the problem where you’re firing a bullet or some kind of projectile at high speeds, and it just goes right through the collision object, instead of hitting it?

Here’s a weapon that fires a bullet at random velocities, to demonstrate the issue:

The bullets impact the character in various places, rather than at the first point of contact. I haven’t found a way to enable any kind of continuous contact option, outside of playing with the safe_margin setting. I ended up adding a raycast:

The ray cast looks somewhat like this:

func _physics_process(delta):
	ttl -= delta
	match state:
		STATES.FIRED:
			var collision: KinematicCollision2D = move_and_collide(velocity * delta)
			if collision: _on_collision(collision.get_collider(), collision.get_position())
			
			var rq = PhysicsRayQueryParameters2D.create(_last_pos, position, collision_mask)
			rq.collide_with_areas = true
			var res: Dictionary = get_world_2d().direct_space_state.intersect_ray(rq)
			if res.has("collider"):
				_on_collision(res.collider, res.position)
				position = res.position
			elif ttl <= 0:
				state = STATES.EXPIRED
		# ...

It’s definitely a hack, though. The move_and_collide should be replaced by the ray query. Using both instructions together could result in an even weirder situation; move_and_collide could skip a collision object (the issue we’re trying to fix with the ray query), but then still collide with a different collision object. Then the ray query redoes the same movement and collides with the first object that was missed by move_and_collide . Depending on the game, that could mean something like randomly shooting through shields or walls under specific circumstances.

The current approach is essentially a two-pass solution, where the first pass is sloppy, and the second pass works as intended, but doesn’t move the projectile.

Posted in Godot.
Share
PreviousMaking videos for the web with Godot 4’s Movie Writer
NextAudio Manager to handle the loading of sound effects in bulk

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Related Posts

  • February 16, 2024

    Inventory System v1.8.1 available

    A quick update to yesterday’s release with a few fixes:

  • January 27, 2023

    Dynamically finding and loading resources from the Filesystem for Android and Web Exports

    A little while ago, I created a type of AudioManager to make it easier to work with sound files in bulk: Rather than assigning audio streams by hand, I was doing it programmatically; reading the contents of a directory and using load() to get the resources. It worked great and saved a lot of time …

  • March 12, 2025

    Inventory System 2 Alpha 3 available

    This release improves weight management. Inventories can now configure an option weight limit, and item stacking and item transfer strategies are weight-aware. The crafting demo and crafting mechanic in the inventory tour have been improved. Auto-crafting is limited to the crafting slide, so that items don’t automatically and unexpectedly get crafted while stepping through the …

  • July 30, 2024

    Inventory System v1.15 available

    This inventory system release refines a lot of architecture guide sections based on customer feedback and adds over 100 additional pages to the PDF guide. Features: Bug fixes:

    © 2025 GoGoGodot.io. All rights reserved.