[Manuel]

Hello,

I am trying to make a simple Space-Shooter and can’t get the Bullets animated properly:

This is my Bullet QML File, with the animation.

bullet.qml

import QtQuick 2.0
import Felgo 3.0


EntityBase {
    id: bulletEntity
    entityType: "bullet"
    poolingEnabled: true

    Rectangle {
        color:"transparent"
        anchors.fill: parent
        //debug info
        //border.color: 'green'
        Image {
            id: bulletImage
            smooth: false
            source: "../../assets/img/bullet.png"

            // set the size of the image to the one of the collider and not vice versa, because the physics properties depend on the collider size
            anchors.fill: parent
        }

        // moves the entity to y position 0 within 2 seconds
        NumberAnimation on y {
            to: 0
            duration: 2000
        }

    }


}

I am creating the bullets in my “Main.qml”, like that:

Scene {
        id: scene
        width: 480
        height: 320

        Rectangle {
            color: "black"
            anchors.fill: parent
            //move the Ship according to the mouse position
            MouseArea {
                id:shipInputController
                //enable updating of mouse position without clicking
                hoverEnabled: true
                anchors.fill: parent
                onMouseXChanged: {
                    //positioning the ship in the middle of the mouse position (all items have a top-left origin)
                    ship1.x = mouseX - (ship1.width/2) ;
                }
                onClicked: {
                    clickSound.play()

                    var newEntityProperties = {
                        width: 15,
                        height: 20,
                        x: ship1.x + (ship1.width/2) - 7.5,
                        y: ship1.y - 12, 
                    }

                    entityManager.createEntityFromUrlWithProperties(
                                Qt.resolvedUrl("entities/Bullet.qml"),
                                newEntityProperties);

                }
            }
        }

It seems I am stuck here, I can’t really get a hold of the problem, I only could get Animations to work when using them directly in the scene via “manually created” entities:

Bullet {
  x: 100
  y: 100
  width: 15
  height: 20
  numberAnimation on y {
    to: 0
    duration: 4000
  }
}

Any idea what could be the problem in the above code sample?

Thanks in Advance.

• This topic was modified 8 years ago by  Deathdragon.

[AlexFelgo Team]

Hi,

you have defined your animation on the y property of the Rectangle, not the bullet entity. Since you anchored the Rectangle, I guess you would like to animate the bullet entity instead, so make the NumberAnimation a child of this one instead.

Cheers,
Alex

[Manuel]

Hi,

thanks for your comment. I just tried that, unfortunately it doesn’t fix the issue. :/
Do you have any other idea? The problem is that I can’t see any animation happening and when trying to debug and setting a breakpoint, it seems that the Animation never gets called.

Thanks again.

• This reply was modified 8 years ago by  Deathdragon.
• This reply was modified 8 years ago by  Deathdragon.

[Manuel]

I could get it to work with the following code statement:

 onYChanged: {
        bulletAnim.start()
    }

    // moves the entity to y position 0 within 2 seconds
    NumberAnimation on y {
        id:bulletAnim
        to: 0
        duration: 1000
    }

 

[AlexFelgo Team]

You could also define your animation like this:

NumberAnimation {
target: bulletEntity
property: “y”
to: 0
duration: 2000
running: true // this makes the animation run right after the component is created
}

or simply adding “running: true” to your animation could solve it.

Cheers,
Alex

[AlexFelgo Team]

The onYChanged signal handler will be called every time the y property is changed, I don’t think this will be desired behavior, instead you can use the Component.onCompleted signal handler of the bullet entity, that one will be called after the component has been fully created, it’s a bit like a constructor method.

Cheers,
Alex

[Manuel]

It seems the problem with all of the above suggestions (except the onYchanged one) is that I use Entity Pooling, which means that the animation will not be started, when the entities are reused…I would need to restart it manually by using the entityManager.

When using onYChanged it will be called always as Y is changing even when reusing the entities.

 

Possible Solution with entity Pooling and not using onYChanged:

function startAnimation() {
        bulletAnim.start()
    }

    // moves the entity to y position 0 within 1 second
    NumberAnimation on y {
        id:bulletAnim
        to: 0
        duration: 1000
        running: true
        onStopped: {
            bulletEntity.removeEntity()
        }
    }

and

MouseArea {
                id:shipInputController
                //enable updating of mouse position without clicking
                hoverEnabled: true
                anchors.fill: parent
                onMouseXChanged: {
                    //positioning the ship in the middle of the mouse position (all items have a top-left origin)
                    ship1.x = mouseX - (ship1.width/2) ;
                }
                onClicked: {
                    clickSound.play()

                    var newEntityProperties = {
                        width: 15,
                        height: 20,
                        // vary x between [ safetyZoneHoriztonal ... width-safetyZoneHoriztonal]
                        x: ship1.x + (ship1.width/2) - 7.5,
                        y: ship1.y - 12, // position on top of the scene, at least below the top wall
                    }

                    entityManager.createEntityFromUrlWithProperties(
                                Qt.resolvedUrl("entities/Bullet.qml"),
                                newEntityProperties);
                    entityManager.getLastAddedEntity()["startAnimation"].call()
                }
            }

Thanks again.

• This reply was modified 8 years ago by  Deathdragon.

[AlexFelgo Team]

If you use entity pooling you can also use the onUsedFromPool signal handler of the EntityBase.

Tip: If you place your cursor on an component and press F1 you open the corresponding documentation.

Cheers,
Alex