[kitKat]

Hey everybody!

 

Is it possible (or is there a function) to check whether an entity is selected and – according to that  – set the bodyType to “static” so that it can’t be moved by the other items?

We would also need a hint on how to move an entity just a fix pixel-length on the onPressed() event in the mouse area!

 

Yours,

KitKat

[ChristianFelgo Team]

Hi,

you cannot change bodyTypes after the entity was created, but you can have a look e.g. at the ColliderBase::gravityScale property if you want to avoid gravity to be applied to the dynamic body.

For moving an entity, you can just change its x or y position (if collisionTestingOnlyMode is set to true), or apply forces or impulses to it (if collisionTestingOnlyMode is set to false, i.e. for physics-based movement).

Cheers, Chris

[kitKat]

Hi!

 

The problem is, that the Boxcollider itself is moved properly, the image not – although we have the Image-anchors.fill:boxCollider.

[kitKat]

Here’s the whole project – Andreas Jakl wasn’t able to find the error.

It seems that the boxcolliders of the serveral entities (from the same type) depend on each other – although they shouldn’t because they are all unique entities???

 

Yours KitKat

// import QtQuick 1.0 // to target S60 5th Edition or Maemo 5
import QtQuick 1.1
import VPlay 1.0

EntityBase {
    entityType: "ball"
   // signal collidedWithBall
    Component.onCompleted: console.debug("Ball.onCompleted()")
    Component.onDestruction: console.debug("Ball.onDestruction()")

    width: 32
    height: 32
    Image {
        source: "../img/ball.png"
        //anchors.fill: boxCollider
        x: boxCollider.x
        y: boxCollider.y
        width: 32
        height: 32
    }
    BoxCollider {
        id:boxCollider

        x: -width/2
        y: -height/2

        Rectangle
        {
            anchors.fill:parent
            color: "blue"
        }

        fixture.onBeginContact: {
            var fixture = other;
            var body = fixture.parent;
            var component = body.parent;
            var collidedEntity = component.owningEntity;
            var collidedEntityType = collidedEntity.entityType;
            if (collidedEntityType === 'ball') {
                removeEntity();
            }
            if (collidedEntityType==='block1' || collidedEntityType==='block2'
                    ||collidedEntityType==='block3' ||collidedEntityType==='block4'
                    ||collidedEntityType==='block5' || collidedEntityType==='ente'
                    ||collidedEntityType==='auto' ||collidedEntityType==='turm' || collidedEntityType==='teddy') {
                    //TODO stehenbleiben!
            }
        }
    }
}






// import QtQuick 1.0 // to target S60 5th Edition or Maemo 5
import VPlay 1.0
import QtQuick 1.1
import "./entities"
import "./levels"

SceneBase{
    id:gameScene

    //property alias level: level1
    //property alias entityContainer: level1

    width: 480
    height: 320


    property string activeLevelStrg
    property variant activeLevel


    PhysicsWorld {
        id:physicsWorld
        gravity.y: -9.81
        z: 10 // draw the debugDraw on top of the entities

        // these are performance settings to avoid boxes colliding too far together
        // set them as low as possible so it still looks good
        updatesPerSecondForPhysics: 30
        //        velocityIterations: 2
        //        positionIterations: 5
    }

    function enterScene() {
        //level1.startGame();
        //loadLevel();
    }


    SimpleButton{
        text:"Back to menu"
        anchors.right: parent.right
        onClicked:backPressed()
    }

    onBackPressed: {
        // it is important to call stopGame() here, because otherwise the entities would not be deleted!
        //level1.stopGame();
        window.state = "main"
    }

    // load levels at runtime
    Loader {
        id: loader
        source: "levels/" + gameScene.activeLevelStrg + ".qml"
        onLoaded: {
            // do not forget to call loadItemWithCocos or the item might not be displayed correct!
            loadItemWithCocos(item)
            activeLevel = item
            item.width = gameScene.width
            item.height = gameScene.height
        }
    }

    // set the name of the current level, this will cause the Loader to load the corresponding level
    function setLevel(level) {
        activeLevelStrg = level
    }

    EntityBase {
        entityId: "ground1"
        entityType: "ground"
        height: 0

        preventFromRemovalFromEntityManager: true

        anchors {
            bottom: gameScene.bottom
            left: gameScene.left
            right: gameScene.right
        }

        Rectangle {
            anchors.fill: parent
            color: "blue"
        }

        BoxCollider {
            anchors.fill: parent
            bodyType: Body.Static // the body shouldnt move
        }
    }

    EntityBase {
        // left wall
        entityId: leftWall
        entityType:"leftWall"
        width: 0
        height: gameScene.height

        preventFromRemovalFromEntityManager: true
        anchors {
            left: gameScene.left
        }
        Rectangle {

            color: "blue"
            anchors.fill: parent
        }
        BoxCollider {
            anchors.fill: parent
            bodyType: Body.Static // the body shouldnt move

        }
    }

    EntityBase {
        // left wall
        entityId: rightWall
        entityType:"rightWall"
        width: 2
        height: gameScene.height
        preventFromRemovalFromEntityManager: true
        anchors {
            right: gameScene.right
            //rightMargin: gameScene.right+288
        }
        Rectangle {

            color: "blue"
            anchors.fill: parent
        }
        BoxCollider {
            anchors.fill: parent
            bodyType: Body.Static // the body shouldnt move

            // fixture.onBeginContact: collidedWithBox()
        }
    }

    MouseArea {
        width:320
        height:320

        property Body selectedBody: null

        property int lastY;
        property int lastX;
        property bool newMove : true;


        onPressed: {
            selectedBody = physicsWorld.bodyAt(Qt.point(mouseX, mouseY)); //nur der Collider!!!
            console.debug("selected body at position", mouseX, mouseY, ":", selectedBody);
            // if the user selected a body, this if-check is true

            if(selectedBody) {

                console.debug("in ONPRESSED - Selected Body: ", selectedBody);

                lastY = mouseY;
                lastX = mouseX;
                newMove=true;

            }
        }

        onPositionChanged: {

            //TODO wenn true und nicht bewegt wird!

            if (newMove===true) {
                if (mouseX < lastX) {
                    // mouseJointWhileDragging.targetPoint = Qt.point(lastX-32, mouseY)
                    selectedBody.x = selectedBody.x-32;

                } else {
                    //mouseJointWhileDragging.targetPoint = Qt.point(lastX+32, mouseY)
                    selectedBody.x = selectedBody.x+32;
                }
                newMove = false;
            }
        }
    }

    Component {
        id: mouseJoint

        MouseJoint {
            // make this high enough so the box with its density is moved quickly
            maxForce: 30000
            // The damping ratio. 0 = no damping, 1 = critical damping. Default is 0.7
            dampingRatio: 1
            // The response speed, default is 5
            frequencyHz: 2
        }
    }
}


// import QtQuick 1.0 // to target S60 5th Edition or Maemo 5
import VPlay 1.0
import QtQuick 1.1
import "../entities"

Item{

    // the size of the Window can be changed at runtime by pressing the number keys 1-7
    // the content of the logical scene size (480x320 by default) gets scaled to the window size based on the scaleMode
    // you can set this size to any resolution you would like your project to start with, most of the times the one of your main target device
    // this resolution is for iPhone 4 & iPhone 4S
    // change this to a portrait resolution (e.g. 640x960) for games in portrait mode

    id:level1

    Block1 {
        x:32
        y:256
    }

    Block4 {
        x:96
        y:128
    }

    Block3 {
        x:128
        y:96
    }

    Block3 {
        x:128
        y:288
    }

    Block1 {
        x:320
        y:256
    }

    Ball {
        x:32
        y:224
    }

    Ball {
        x:64
        y:288
    }

    Ente {
        x:96
        y:98
    }

    Ente {
        x: 64
        y: 224
    }

    Auto {
        x:128
        y:256
    }

    Auto {
        x:96
        y:288
    }

    Auto {
        x:128
        y:64
    }

    Turm {
        x:160
        y:288
    }
}

 

[AlexFelgo Team]

Hi KitKat,

the problem is the following: You are not really “moving” anything at all, all your code does is specify a new x position for the Box2DBody within the BoxCollider within the Entity. That’s why it looks like the collider is moving without the entity, well in fact you are just changing the position of the collider within the entity.

Instead you should move the entity itself, which will cause the collider to move with it. And here is how you do that:
The parent of the body is the boxcollider and the parent of the boxcollider is the entity. This means instead of “selectedBody.x” you need to change “selectedBody.parent.parent.x”. You could of course save the selected entity in a property variant (like the Body), to make it more readable than lots of .parent.parent calls.

Cheers,
Alex

[kitKat]

THAAAANNNKKKSSS!!!! 😀