Qt 3D: Audio Visualizer Example▲
Audio Visualizer demonstrates how to implement an application that combines the use of Qt 3D rendering with Qt Quick 2D elements. The example uses media player to play music and it visualizes the magnitude of the music as animated bars.
Running the Example▲
To run the example from Qt Creator, open the Welcome mode and select the example from Examples. For more information, visit Building and Running an Example.
Qt Quick 2D Implementation▲
The Qt Quick Implementation in audio-visualizer-qml/main.qml of the example uses MediaPlayer to play audio content.
MediaPlayer {
id: mediaPlayer
source: "qrc:/music/tiltshifted_lost_neon_sun.mp3"
audioOutput: AudioOutput {}The player is controlled with the playButton and c{stopButton}. Based on the clicked buttons the state of the mainview changes.
The 3D content is rendered using the Scene3D type. The state of the Audio Visualizer is maintained in the mainview. It's passed on to the visualizer as it's needed for the bar animations.
Scene3D {
anchors.fill: parent
Visualizer {
id: visualizer
animationState: mainview.state
numberOfBars: 120
barRotationTimeMs: 8160 // 68 ms per bar
}
}Qt 3D Implementation▲
The 3D elements of the example are created in audio-visualizer-qml/Visualizer.qml. The camera is set to a fixed position to show the visualized bars from a correct angle.
Camera {
id: camera
projectionType: CameraLens.PerspectiveProjection
fieldOfView: 45
aspectRatio: 1820 / 1080
nearPlane: 0.1
farPlane: 1000.0
position: Qt.vector3d(0.014, 0.956, 2.178)
upVector: Qt.vector3d(0.0, 1.0, 0.0)
viewCenter: Qt.vector3d(0.0, 0.7, 0.0)
}A NodeInstantiator is used to create the bars that visualize the magnitude of the music.
// Bars
CuboidMesh {
id: barMesh
xExtent: 0.1
yExtent: 0.1
zExtent: 0.1
}
NodeInstantiator {
id: collection
property int maxCount: parent.numberOfBars
model: maxCount
delegate: BarEntity {
id: cubicEntity
entityMesh: barMesh
rotationTimeMs: sceneRoot.barRotationTimeMs
entityIndex: index
entityCount: sceneRoot.numberOfBars
entityAnimationsState: animationState
magnitude: 0
}
}The visualizer also contains an Entity to show the progress. This element has a curve shaped mesh and it's rotated on a level to show the progress based on the duration of the played track.
// Progress
Mesh {
id: progressMesh
source: "qrc:/meshes/progressbar.obj"
}
Transform {
id: progressTransform
property real defaultStartAngle: -90
property real progressAngle: defaultStartAngle
rotationY: progressAngle
}
Entity {
property Material progressMaterial: PhongMaterial {
ambient: "#80C342"
diffuse: "black"
}
components: [progressMesh, progressMaterial, progressTransform]
}In audio-visualizer-qml/BarEntity.qml there are animations for rotating the bars and changing the bar color. The bars are rotated on a level following a ring form. At the same time the color of the bars is animated.
QQ2.NumberAnimation {
id: angleAnimation
target: angleTransform
property: "barAngle"
duration: rotationTimeMs
loops: QQ2.Animation.Infinite
running: true
from: startAngle
to: 360 + startAngle
}
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
}
}The magnitude of each bar is read from a separate .raw file that is based on the track being played. As the bars rotate around the ring the height is scaled to highlight currently played position. After a full round of rotation, a new value is fetched for the bar.