Body properties are incorrect after switching from static to dynamic

[0yz]

After updating to the latest version (0.20.0) i have an issue where when i switch my body from static to dynamic with Matter.Body.setStatic(ball, false); it disappears. When looking at the body it seems like the values of its properties are set incorrectly. The body seems to be still there because the collision logic still triggers. I think the body just shoots off outside of view.

When adding the body with isStatic: false it spawns and behaves as it should.

I really don't know where to go from here.

Here is a basic example of the issue:

        const Engine = Matter.Engine,
              Render = Matter.Render,
              Runner = Matter.Runner,
              Bodies = Matter.Bodies,
              Composite = Matter.Composite;
        const engine = Engine.create();
        const render = Render.create({
            element: document.body,
            engine: engine,
            options: {
                width: window.innerWidth,
                height: window.innerHeight,
                wireframes: false
            }
        });
        const ball = Bodies.circle(400, 200, 50, {
            isStatic: true, // change this to false and it works
            render: {
            	fillStyle: 'blue'
            }
        });
        Composite.add(engine.world, ball);
        runner = Runner.create();
        Runner.run(runner,engine);
        Render.run(render);
        document.addEventListener('click', function(event) {
            Matter.Body.setStatic(ball, false);
            console.log(ball);
        });

[ggorlen]

See this Stack Overflow snippet for another reproduction of the issue. The snippet is currently running 0.19.0. When the box hits the static platform, the platform falls when struck by disabling static with Matter.Body.setStatic(wall, false). Behavior is as expected. But if you bump the version to 0.20.0, the platform disappears when struck, a clear bug.

[a-studio-named-desire]

Just ran into the same issue with version 20. I saw that the Body.setStatic = function(body, isStatic) on line 1887 of matter.js v20 has a line of code that is causing the issue. After I removed if (!part.isStatic) { the shapes worked as before; if the shape changed to non-static it retains its properties, This avoids the conditional check that could skip setting isStatic properly.

[hylarucoder]

For users upgrading from version 0.19 to 0.20, some code may exhibit unexpected behavior and break.

You can try this

const textBody = Matter.Bodies.rectangle(
  pivotX + textWidth / 2,
  pivotY,
  textWidth,
  textHeight,
  {
    isStatic: true, // remove this
    friction: 0.8,
    frictionStatic: 0.9,
    restitution: 0.4,
    density: 0.001,
  }
);

Matter.Body.setStatic(textBody, true); // add this

[ggorlen]

@hylarucoder Surprisingly, that does seem to make a difference! Nice find.

Nonetheless, the behavior of the falling body is still quite a bit different (and less desirable) in v.20 relative to v.19. It may be a different issue, but if you apply that setStatic approach to this snippet, the green bar falls much faster in v.20 than v.19.