[s4ge]

Hello again,

today I’m trying to setup a little scene with an actor, an obstacle and a simple floor. all of them are visually and physically represented by rectangles/box colliders. The floor and the obstacle are static bodies. There are two things i want to happen:

 

1) Everytime, the dynamic actor hits the floor rectangle, the actor should jump (negative y force impulse). This works so far.

2) Everytime, the screen is touched/clicked somewhere, the force of the actor body should be adjusted the reach this point on the X axis only (the Y force should keep untouched as far as possible). This does not work at all, and a tried alot of configurations to achieve this effect. Here is the code i gave up for now, it includes everything what for the behavior is needed.

 

import VPlay 1.0
import QtQuick 1.1

EntityBase {
    id: actor
    entityType: "actor"

    width: 50
    height: 80

    transformOrigin: Item.TopLeft

    MoveToPointHelper {
      id: moveToPointHelper
    }

    Rectangle {
        id: rectangle
        anchors.fill: parent

        color: "red"
    }

    BoxCollider {
        id: boxCollider

        anchors.fill: parent

        force: Qt.point(moveToPointHelper.outputXAxis * 1, force.y)

        fixture.onBeginContact: {
            actor.jump();
        }
    }

    function jump(){
        boxCollider.body.applyLinearImpulse(
            boxCollider.body.getWorldVector(Qt.point(0,-300)),
            boxCollider.body.getWorldCenter()
        );
    }

    function moveTo(mouseX, mouseY){
        moveToPointHelper.targetPoint = Qt.point(mouseX, actor.y);
    }
}

 

• This topic was modified 10 years, 2 months ago by  Christian.
• This topic was modified 10 years, 2 months ago by  Christian.

[ChristianFelgo Team]

Hi,

I found your problems, see the comments in-line for an explanation and for a working solution.

import VPlay 1.0
import QtQuick 1.1

GameWindow {

  Scene {
    id: scene

    PhysicsWorld {

      gravity.y: -10
    }

    MouseArea {
      anchors.fill: parent
      onClicked: {
        actor.moveTo(mouseX, mouseY)
      }
    }


    EntityBase {
        id: actor
        entityType: "actor"

        width: 50
        height: 80

        transformOrigin: Item.TopLeft

        MoveToPointHelper {
          id: moveToPointHelper

          onOutputXAxisChanged: console.debug("outputXAxis changed to:", outputXAxis)
        }

        Rectangle {
            id: rectangle
            anchors.fill: parent

            color: "red"
        }

        BoxCollider {
            id: boxCollider

            anchors.fill: parent

            // !!! this causes a binding loop! this is the error output:
            // QML BoxCollider: Binding loop detected for property "force"
            // the reason: you are referencing force.y in the property binding
            //force: Qt.point(moveToPointHelper.outputXAxis * 1, force.y)

            // with this it works:
            // outputYAxis is needed, because the XAsis of MoveToPointHelper is looking at 0° initally, which means to the right
            // so if the yAxis is 1 this means your entity (looking up) should move right
            force.x: moveToPointHelper.outputYAxis * 1

            fixture.onBeginContact: {
                actor.jump();
            }
        }

        function jump(){
            boxCollider.body.applyLinearImpulse(
                boxCollider.body.getWorldVector(Qt.point(0,-300)),
                boxCollider.body.getWorldCenter()
            );
        }

        function moveTo(mouseX, mouseY){
            moveToPointHelper.targetPoint = Qt.point(mouseX, actor.y);
        }
    }

    EntityBase {
      id: floor

      width: scene.width
      height: 20
      anchors.bottom: parent.bottom

      BoxCollider {
        anchors.fill: parent
        bodyType: Body.Static
      }
      Rectangle {
        anchors.fill: parent
        color: "green"
      }
    }


  }
}

 

Looks funny already, I’m looking forward to your game! 😉

Cheers, Chris