.equals in class Spherical

[chenxinhang12345]

Description

We have .equals in Vector classes for all dimensions. Why cant we have .equals in Spherical?

Solution

Add comparison method for class Spherical just like other VectorN classes, should be pretty simple I guess?

Alternatives

Do nothing but we would definitely want to use something like JSON.stringify() or some other workaround to compare two Spherical?

Additional context

No response

[WestLangley]

Spherical and Cylindrical coordinates are not unique, and neither class has an equals() method.

Can you please explain your use case?

[chenxinhang12345]

Yeah you are right. Those classes shouldn't have .equals methods.

[Mugen87]

Spherical and Cylindrical coordinates are not unique, and neither class has an equals() method.

Do you mind explaining this in more detail? Why can we compare euclidian coordinates but not spherical ones? The following does work as expected:

const v1 = new THREE.Vector3( 1, 0, 0 );
const v2 = new THREE.Vector3( 1, 0, 0 );
console.log( v1.equals( v2 ) ); // true

const s1 = new THREE.Spherical().setFromVector3( v1 );
const s2 = new THREE.Spherical().setFromVector3( v2 );
console.log( equals( s1, s2 ) ); // true
 
function equals( s1, s2 ) {

	return ( ( s1.radius === s2.radius ) && ( s1.phi === s2.phi ) && ( s1.theta === s2.theta ) );

}

Demo: https://jsfiddle.net/8fbkpr60/1/

[WestLangley]

... because Spherical and Cylindrical coordinates are not unique, just as 2D polar coordinates are not unique.

const s1 = new THREE.Spherical( 1, 0, 0 );
const s2 = new THREE.Spherical( 1, 0, 2 * Math.PI );

Likewise, quaternion.equals( q ) is also incorrect because quaternions are not unique.

//

As a side note, I am not in favor of methods that compare floating point values using equality. I would have preferred

Vector3.equals( vector, tolerance = 0 ).

[chenxinhang12345]

Instead of adding .equals(), would it be a good idea to add toVector3() so that we could compare the derived Euclidian coordinates?

[WestLangley]

@chenxinhang12345 Do this:

const v1 = new THREE.Vector3().setFromSpherical( s1 );