tutorials/physics/physics_introduction

[giscus[bot]]

tutorials/physics/physics_introduction

In game development, you often need to know when two objects in the game intersect or come into contact. This is known as collision detection. When a collision is detected, you typically want somet...

https://docs.godotengine.org/en/latest/tutorials/physics/physics_introduction.html

[jerryjrowe]

Area2D will only detect StaticBody2D when calling get_overlapping_bodies() if the Area2D has monitorable set to true. You'd think it'd only need monitoring set to true, but it also needs to be monitorABLE for StaticBody2D.

[jh2952]

Thanks for this comment - helped me solve my issue :)

[miketvo]

The documentation is not clear about this:

Non-moving Area will not fire body_entered and body_exited signals for moving StaticBody and frozen RigidBody, because those physics bodies are not intended to be moved. Use AnimatableBody instead if you want to move them and have them be detected by Area.

A moving Area however will detect non-moving StaticBody and frozen RigidBody.

See godotengine/godot#81883

[gargantuan]

Three hours I've wasted trying to figure this one out. Thank you!

[cucumberlush]

Makes more sense great Job figuring that one out

[gargantuan]

An easy way to remember the difference between collision layers and collisions masks that I find useful.

Collision Layer: I live here
Collision Mask: I will look here

[JuhaW]

Display/View Layer: This displays/Views objects
Collision Layer: Here collision happens

:)

[thenicksager]

If the collision layer is "I live here", what kinds of objects could (or should) ever have multiple collision layers set? What kind of objects can "be" in more than one place at once?

[flowstate]

You're misunderstanding what "I live here" means. It's not referring to a physical location, it's referring to a physics layer.

For a contrived example, let's say I have a layer for 'terrain' (floors, walls, etc) and another for 'hazards' (spikes, acid). If I want my player to be hurt by spikes, but to be able to walk on them while invincible or if they have a specific item, then my spikes could live in both 'terrain' and 'hazards'.

This would allow my spikes to behave as a hazard AND be walkable like terrain. Does that make sense?

[v1993]

I feel like the example where pow is used to compute collision masks would be better off using bit shifts, at least since these are semantically bit operations on integers and pow works with floats. That would make it

(1 << 1 - 1) + (1 << 3 - 1) + (1 << 4 - 1)

[Calinou]

Pull request opened:

• Use bitshift and binary OR operator in to set layers in Physics introduction godot-docs#10943

[mj2068]

That Asteroid example was not good, the code only calls apply_force() and apply_torque(), just through the state argument, didn't actually directly change any properties which it was mainly talking about prior to the snippet. These calls we can already use in _physics_process(). This didn't convey the main advantages of _integrate_forces(). It's confusing for people trying to understand the difference.

[backslash-enn]

Exactly, this was the only part that really threw me off.

To put it concisely, they say "only use _PhysicsProcess for abc, dont use it for xyz. If you want to do xyz, use _IntegrateForces instead". Sounds good

Then they say "here's an example of us using _IntegrateForces"....and in the example they only do abc

Then they double down in the footnote below that example and say "note how we're only doing abc here, not xyz"

...isnt the entire reason _IntegrateForces exists so that we can do xyz? I think that section would benefit from a rewrite

[Calinou]

This is being tracked in godotengine/godot-docs#10029.

[Vitorgus]

I think it would be nice to explain and include some reference to the Joint2D nodes (DampedSpringJoint2D, GrooveJoint2D and PinJoint2D). Or even a separated page just talking about the 2D and 3D Joints, since they are related to the physics system. They are only mentioned in the documentation, but never really explained or shown examples of use.