BarEntity.qml Example File | Qt 3D 5.12.11

- Qt 5.12
- Qt 3D
- Qt 3D: Audio Visualizer Example
- BarEntity.qml Example File
- Qt 5.12.11 Reference Documentation

# BarEntity.qml Example File

audio-visualizer-qml/BarEntity.qml

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     import Qt3D.Core 2.0
     import Qt3D.Render 2.0
     import Qt3D.Extras 2.0
     import QtQuick 2.4 as QQ2

     Entity {
         property int rotationTimeMs: 0
         property int entityIndex: 0
         property int entityCount: 0
         property int startAngle: 0 + 360 / entityCount * entityIndex
         property bool needsNewMagnitude: true
         property real magnitude: 0
         property real animWeight: 0

         property color lowColor: "black"
         property color highColor: "#b3b3b3"
         property color barColor: lowColor

         property string entityAnimationsState: "stopped"
         property bool entityAnimationsPlaying: true

         property var entityMesh: null

         onEntityAnimationsStateChanged: {
             if (animationState == "paused") {
                 if (angleAnimation.running)
                     angleAnimation.pause()
                 if (barColorAnimations.running)
                     barColorAnimations.pause()
             } else if (animationState == "playing"){
                 needsNewMagnitude = true;
                 if (heightDecreaseAnimation.running)
                     heightDecreaseAnimation.stop()
                 if (angleAnimation.paused) {
                     angleAnimation.resume()
                 } else if (!entityAnimationsPlaying) {
                     magnitude = 0
                     angleAnimation.start()
                     entityAnimationsPlaying = true
                 }
                 if (barColorAnimations.paused)
                     barColorAnimations.resume()
             } else {
                 if (animWeight != 0)
                     heightDecreaseAnimation.start()
                 needsNewMagnitude = true
                 angleAnimation.stop()
                 barColorAnimations.stop()
                 entityAnimationsPlaying = false
             }
         }

         property Material barMaterial: PhongMaterial {
             diffuse: barColor
             ambient: Qt.darker(barColor)
             specular: "black"
             shininess: 1
         }

         property Transform angleTransform: Transform {
             property real heightIncrease: magnitude * animWeight
             property real barAngle: startAngle

             matrix: {
                 var m = Qt.matrix4x4()
                 m.rotate(barAngle, Qt.vector3d(0, 1, 0))
                 m.translate(Qt.vector3d(1.1, heightIncrease / 2 - heightIncrease * 0.05, 0))
                 m.scale(Qt.vector3d(0.5, heightIncrease * 15, 0.5))
                 return m;
             }

             property real compareAngle: barAngle
             onBarAngleChanged: {
                 compareAngle = barAngle

                 if (compareAngle > 360)
                     compareAngle = barAngle - 360

                 if (compareAngle > 180) {
                     parent.enabled = false
                     animWeight = 0
                     if (needsNewMagnitude) {
                         // Calculate the ms offset where the bar will be at the center point of the
                         // visualization and fetch the correct magnitude for that point in time.
                         var offset = (90.0 + 360.0 - compareAngle) * (rotationTimeMs / 360.0)
                         magnitude = mediaPlayer.getNextAudioLevel(offset)
                         needsNewMagnitude = false
                     }
                 } else {
                     parent.enabled = true
                     // Calculate a power of 2 curve for the bar animation that peaks at 90 degrees
                     animWeight = Math.min((compareAngle / 90), (180 - compareAngle) / 90)
                     animWeight = animWeight * animWeight
                     if (!needsNewMagnitude) {
                         needsNewMagnitude = true
                         barColorAnimations.start()
                     }
                 }
             }
         }

         components: [entityMesh, barMaterial, angleTransform]

         QQ2.NumberAnimation {
             id: angleAnimation
             target: angleTransform
             property: "barAngle"
             duration: rotationTimeMs
             loops: QQ2.Animation.Infinite
             running: true
             from: startAngle
             to: 360 + startAngle
         }

         QQ2.NumberAnimation {
             id: heightDecreaseAnimation
             target: angleTransform
             property: "heightIncrease"
             duration: 400
             running: false
             from: angleTransform.heightIncrease
             to: 0
             onStopped: barColor = lowColor
         }

         property int animationDuration: angleAnimation.duration / 6

         QQ2.SequentialAnimation on barColor {
             id: barColorAnimations
             running: false

             QQ2.ColorAnimation {
                 from: lowColor
                 to: highColor
                 duration: animationDuration
             }

             QQ2.PauseAnimation {
                 duration: animationDuration
             }

             QQ2.ColorAnimation {
                 from: highColor
                 to: lowColor
                 duration: animationDuration
             }
         }
     }