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Guide pratique pour animer la position et la direction de la caméra à l’aide d’images clés

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Dans l’exemple suivant, Point3DAnimationUsingKeyFrames est utilisé pour animer la position d’un PerspectiveCamera dans une scène 3D. En outre, Vector3DAnimationUsingKeyFrames est utilisée pour animer la direction que la caméra pointe dans la scène 3D. Ces deux animations utilisent plusieurs images clés qui créent une série d’effets d’animation :

  1. LinearPoint3DKeyFrame et LinearVector3DKeyFrame sont utilisés pour créer une interpolation lisse et linéaire entre les valeurs.

  2. DiscretePoint3DKeyFrame et DiscreteVector3DKeyFrame sont utilisés pour créer des « sauts » soudains entre les valeurs (aucune interpolation).

  3. SplinePoint3DKeyFrame et SplineVector3DKeyFrame sont utilisés pour créer une transition variable entre les valeurs en fonction de la propriété KeySpline. Dans l’exemple ci-dessous, l’animation démarre lentement, mais vers la fin du segment de temps, accélère exponentiellement.

Exemple

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >
  <DockPanel>
    <Viewbox>
      <Canvas Width="321" Height="201">

        <Viewport3D Name="MyAnimatedObject"
          ClipToBounds="True" Width="150" Height="150"
          Canvas.Left="0" Canvas.Top="10">

          <!-- Defines the camera used to view the 3D object. The position and direction of this 
               camera is animated in the Storyboard below. -->
          <Viewport3D.Camera>
            <PerspectiveCamera x:Name="myPerspectiveCamera" Position="0,0,2" LookDirection="0,0,-1" 
             FieldOfView="45" />
          </Viewport3D.Camera>
          <Viewport3D.Children>
            <ModelVisual3D>
              <ModelVisual3D.Children>

                <!-- This resource defines the 3D cube that is used in this example.-->
                <StaticResource ResourceKey="PictureCubeModelVisual3DResource" />
              </ModelVisual3D.Children>

            </ModelVisual3D>
          </Viewport3D.Children>
          <Viewport3D.Triggers>
            <EventTrigger RoutedEvent="Viewport3D.Loaded">
              <BeginStoryboard>
                <Storyboard>

                  <!-- This animation moves the camera around the object. The object is not
                       changing position or rotating but moving the camera makes it appear that
                       it is.-->
                  <Point3DAnimationUsingKeyFrames
                   Storyboard.TargetName="myPerspectiveCamera" 
                   Storyboard.TargetProperty="Position" >
                    <Point3DAnimationUsingKeyFrames.KeyFrames>

                      <!-- Using a LinearPoint3DKeyFrame, the camera moves steadily from its
                           starting position to a new position that is to the upper right and a 
                           little farther away. This happens over the first second of the animation. -->
                      <LinearPoint3DKeyFrame Value="1,2,3" KeyTime="0:0:1" />

                      <!-- Using a DiscretePoint3DKeyFrame, the camera suddenly moves farther away
                           from the object. This happens immdeiately after the first 1 and a half second
                           of the animation. -->
                      <DiscretePoint3DKeyFrame Value="1,2,5" KeyTime="0:0:1.5" />

                      <!-- Using a SplinePoint3DKeyFrame, the camera moves back to its starting point. The
                           animation starts out slowly at first and then speeds up. This KeyFrame ends 
                           after the fourth second. -->
                      <SplinePoint3DKeyFrame KeySpline="0.6,0.0 0.9,0.00" Value="0,0,2" KeyTime="0:0:4" />
                    </Point3DAnimationUsingKeyFrames.KeyFrames>
                  </Point3DAnimationUsingKeyFrames>


                  <!-- As the position of the camera changes using the Point3DAnimation
                       above, the direction the camera is pointing swivels to keep the object
                       within the view of the camera. -->
                  <Vector3DAnimationUsingKeyFrames
                   Storyboard.TargetName="myPerspectiveCamera" 
                   Storyboard.TargetProperty="LookDirection" >
                    <Vector3DAnimationUsingKeyFrames.KeyFrames>

                      <!-- Using a LinearVector3DKeyFrame, the camera swivels steadily from its
                           starting position down and to the left. This happens over the 
                           first second of the animation. -->
                      <LinearVector3DKeyFrame Value="-1,-2,-3" KeyTime="0:0:1" />

                      <!-- Using a DiscreteVector3DKeyFrame, the camera suddenly swivels up. This happens  
                           immdeiately after the first 1 and a half second of the animation. -->
                      <DiscreteVector3DKeyFrame Value="-1,-1,-3" KeyTime="0:0:1.5" />

                      <!-- Using a SplineVector3DKeyFrame, the camera swivels back to its starting point. 
                           The animation starts out slowly at first and then speeds up. This KeyFrame ends 
                           after the fourth second. -->
                      <SplineVector3DKeyFrame KeySpline="0.6,0.0 0.9,0.00" Value="0,0,-1" KeyTime="0:0:4" />
                      
                    </Vector3DAnimationUsingKeyFrames.KeyFrames>
                  </Vector3DAnimationUsingKeyFrames>

                </Storyboard>
              </BeginStoryboard>
            </EventTrigger>
          </Viewport3D.Triggers>
        </Viewport3D>
      </Canvas>

    </Viewbox>
  </DockPanel>
</Page>

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