🚀 Feature: Allow angle-directed physics gravity

[JoshuaKGoldberg]

Feature Request Checklist

• I have pulled the latest main branch of the repository.
• I have searched for related issues and found none that matched my issue.

Overview

Right now, physics.gravity is a number:

gravity (_0.35`_): How much to increase y-velocity downward each tick.

That allows users to specify different vertical amounts. That includes negative gravities such as in the Inverse Gravity demo.

But, what if users want to rotate gravity at an arbitrary angle? Say, make it horizontal (90 degrees) or directly diagonal (45 degrees)? There's no clean way to do that right now.

Proposal: how about allowing gravity to alternately be an object containing:

• acceleration: what the number currently represents, with the same 0.35 default
• angle: a number in [0, 360), currently defaulting to 180 (down)

Additional Info

This would not be a breaking change as proposed. The default should still be number with the current angle.

🎆