Optimize the use of Transform API

[GuoLei1990]

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

When I designed the Transform API in the past, I always had a big problem, that is, there is no struct in JS.
Vector3 types like position and rotation in Oasis can only be class.

However, class is a reference type, so when modifying its sub attributes, developers usually think it has taken effect. This is difficult for the design.

After some trade-offs, I think we should make the use of API more natural (even if there is a slight loss of performance). It is not a good decision to blindly pursue performance and ignore ease of use. A good design will strike a balance between ease of use, performance and memory. So we added delegate callback inside vector3 to achieve a more natural design. Obviously, everyone will like the following improvements. In fact, this has a certain performance loss, but I think it has more advantages on the whole.

If we want to increase the Y axis by 0.1, we must do like this before:

const transform = rootEntity.transform;
const position = transform.position;
position.y += 0.1;
transform.position = position;

or

const transform = rootEntity.transform;
const position = transform.position;
transform.position.setValue(position.x, position.y + 0.1, position.z);

But now it has become so simple:

const transform = rootEntity.transform;
transform.position.y += 0.1;

[singlecoder]

+1

[yangfengzzz]

+1

[zhuxudong]

it's better to call function later?

math.ts

set x(value: number){
   ...;
   this._isDirty = true;
}

transform.ts

get worldPosition(){
   if(this._position.isDirty){
       ...
   }
   ...
}