Fix issue with 'Bodies.circle' usage.

[eezz4]

#1242

Bug reproduction path:

The issue arises when creating two circles with a radius of 0 passed into Bodies.circle().

In this scenario, the body.mass becomes 0, leading to a NaN in the logic within Body.js as shown below:

// update velocity with Verlet integration
body.velocity.x = (velocityPrevX * frictionAir) + (body.force.x / body.mass) * deltaTimeSquared;
body.velocity.y = (velocityPrevY * frictionAir) + (body.force.y / body.mass) * deltaTimeSquared;

The occurrence of NaN in the above code subsequently triggers a vertexA is undefined error in Collision._findSupports().

Fix:

To resolve this issue, throw an explicit Error message when a radius of 0 is provided as input in Bodies.circle().

• "The radius of Bodies.circle must be non-zero."

Trade-offs:

Performance:

• Introduce a constant-time condition check in Bodies.circle().
  • Does not significantly impact performance for bulk generation calls.
  • This appears to be a minimal modification since it does not handle exceptions in engine operations.

Alternative:

Annotate only:

• Note that providing a radius of 0 as input may lead to a bug.
  • "Avoid using a radius of 0 in dynamic logic; opt for uncalled logic instead."
• User issue management is required since it is unclear where the issue may occur.