Method polarCubicTo

src/main/java/field/graphics/FLine.java:377–401

draws a curve that starts by heading in the `theta1` angle for a distance of roughly `r1` then ends up heading to `destination` coming in at angle `theta2` from roughly `r2` away

(float r1, float theta1, float r2, float theta2, Vec2 destination)

		Vec2 a = last().to.toVec2();

		Vec2 d = Vec2.sub(destination, a, new Vec2());

		Vec2 c1 = new Vec2(d).mul(r1 / 3);
		Vec2 c2 = new Vec2(d).mul(-r2 / 3);

		c1 = new Quat().setAngleAxis(Math.PI * theta1 / 180, new Vec3(0, 0, 1))
			.transform(c1.toVec3())
			.toVec2();
		c2 = new Quat().setAngleAxis(Math.PI * theta2 / 180, new Vec3(0, 0, 1))
			.transform(c2.toVec3())
			.toVec2();

		Vec2.add(c1, a, c1);
		Vec2.add(c2, destination, c2);

		cubicTo(c1, c2, destination);
		return this;
	}

	public FLine polarCubicTo3(float r1, float theta1, float r2, float theta2, Vec3 destination) {

		if (nodes.size() == 0)
			return moveTo(destination);

		Vec3 a = last().to;

		Vec3 d = Vec3.sub(destination, a, new Vec3());