CODEWITHSUNDEEP
flameforge2d
Chris G.
Chris G.

Reputation: 25974

revoluteJointDef.localAnchorA y-axes looks wrong

From this, I would expect the following RevoluteJoint bodyB, to be higher up than the blue box on the y-axe - setting revoluteJointDef.localAnchorA?

flame_forge2d: ^0.11.0

    class Box extends BaseBox { // just a BodyComponent for same shape
      BaseBox? boxB;
      Box(position, paint, [this.boxB]) : super(position, paint);
    
      @override
      Body createBody() {
        super.createBody();
    
        if (this.boxB != null) {
          paint.color = Colors.blue;

          final revoluteJointDef = RevoluteJointDef();
          revoluteJointDef.bodyA = body;
          revoluteJointDef.bodyB = this.boxB!.body;

          revoluteJointDef.localAnchorA.setFrom(Vector2(1, 1));

          RevoluteJoint joint = RevoluteJoint(revoluteJointDef);
          world.createJoint(joint);
        }
        return body;
      }
    }

enter image description here

I would expect it to be like this:

enter image description here

Upvotes: 0

Views: 22

Answers (1)

spydon
spydon

Reputation: 11562

In flame_forge2d 0.11.0 the coordinate system was flipped on the y-axis to be the same coordinate system as Flame, so larger y-values will result in further down, instead of further up like it is in normal forge2d.

Just negate the y-value of the anchor and you should get your intended result:

revoluteJointDef.localAnchorA.setFrom(Vector2(1, -1));

Upvotes: 1

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