[proq]

Is it possible to use multi-touch with mouseJoint? I need to swipe two balls in same time.

[AlexFelgo Team]

Hi,

I see no reason why it is not possible.

You can take the Code from the StackTheBox demo game as a base, especially this part (i added some TODO comments about what i think needs to be added for your case):

    Component {
      id: mouseJoint
      MouseJoint {
        // make this high enough so the box with its density is moved quickly
        maxForce: window.maxForce
        // The damping ratio. 0 = no damping, 1 = critical damping. Default is 0.7
        dampingRatio: window.dampingRatio
        // The response speed, default is 5
        frequencyHz: window.frequencyHz
      }
    }

    // when the user presses a box, move it towards the touch position
    MouseArea {
      anchors.fill: parent
      // TODO add 2nd Body and MouseJoint property
      property Body selectedBody: null
      property MouseJoint mouseJointWhileDragging: null

      onPressed: {
        // TODO check if one of the joint properties is null (this is the case if only one or no ball is already being swiped)
        // if yes, create a new joint with the available (null) properties
        selectedBody = physicsWorld.bodyAt(Qt.point(mouseX, mouseY));
        console.debug("selected body at position", mouseX, mouseY, ":", selectedBody);
        // if the user selected a body, this if-check is true
        if(selectedBody) {
          // create a new mouseJoint
          mouseJointWhileDragging = mouseJoint.createObject(physicsWorld)

          // set the target position to the current touch position (initial position)
          mouseJointWhileDragging.targetPoint = Qt.point(mouseX, mouseY)

          // connect the joint with the body
          mouseJointWhileDragging.movingBody = selectedBody

          // set the physicsWorld where the joint should be created
          mouseJointWhileDragging.world = physicsWorld
        }
      }

      onPositionChanged: {
        // TODO also add the 2nd joint
        // this check is necessary, because the user might also drag when no initial body was selected
        if (mouseJointWhileDragging)
          mouseJointWhileDragging.targetPoint = Qt.point(mouseX, mouseY)
      }
      onReleased: {
        // TODO check which one of the bodies was released and destroy the corresponding joint
        // if the user pressed a body initially, remove the created MouseJoint
        if(selectedBody) {
          selectedBody = null
          if (mouseJointWhileDragging)
            mouseJointWhileDragging.destroy()
        }
      }
    }

I hope this helps you a little bit, let me know if you managed to make it work.

Cheers,
Alex

 

[proq]

Thank you very much for reply!

We’ve tried this code, with two balls and MultiTouchArea instead of MouseArea. Unfortunately, we still have problem, when one ball is selected, second touch always change same ball position (we can select another ball only, when first touch was released). Is it possible to identify which touch was called for onPositionChanged event. Is there any properties like touchID ?