Add angular and motor limits to PinJoint2D

[DiamondWolf3393]

Describe the project you are working on

A 2D physics simulation game that makes heavy use of active ragdolls.

Describe the problem or limitation you are having in your project

The node "PinJoint2D" which is what I am using to hold the ragdolls together lacks an angular_limit parameter. This allows the joints to rotate freely, which is not what I want.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

The angular_limit parameter would be paired with some sort of limit strength in order to determine the rotation limits of the joint, and how hard it would pull back once brought out of the limits.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

The angular_limit parameter when non-zero prevents the rotation of node_b relative to node_a beyond a certain point. The angular_limit_strength parameter would determine how hard to pull the node back within the limits. This could possibly work by setting the angular_velocity of node_b if it is out of the limits.

If this enhancement will not be used often, can it be worked around with a few lines of script?

I can imagine this enhancement being used frequently, but I haven't fully figured out the code to create it myself yet. I am still trying though.

Is there a reason why this should be core and not an add-on in the asset library?

This would match the 2D physics systems closer to the 3D physics systems and allow game developers creating 2D ragdolls to have an easier time.

[James103]

See also #1033.