Qt 5.9 | Qt 3D | Qt 3D: Audio Visualizer Example | BarEntity.qml Example File

Qt 5.9.3 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
              }
          }
      }