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Guide pratique pour animer des propriétés de matériau dans une scène 3D

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Cet exemple montre comment animer la propriété Opacity de l'Material appliquée à un modèle 3D.

L’exemple de code suivant définit la LinearGradientBrush utilisée en tant que Material appliquée à l’objet 3D.

<!-- The material specifies the material applied to the plane. In this case it is a linear gradient.-->
<GeometryModel3D.Material>
  <MaterialGroup>
    <DiffuseMaterial>
      <DiffuseMaterial.Brush>

        <!-- The Opacity property of this LinearGradient is animated. See Storyboard below. -->
        <LinearGradientBrush x:Name="myGradientBrush"  StartPoint="0,0.5" EndPoint="1,0.5">
          <LinearGradientBrush.GradientStops>
            <GradientStop Color="Yellow" Offset="0" />
            <GradientStop Color="Red" Offset="0.25" />
            <GradientStop Color="Blue" Offset="0.75" />
            <GradientStop Color="LimeGreen" Offset="1" />
          </LinearGradientBrush.GradientStops>
        </LinearGradientBrush>
      </DiffuseMaterial.Brush>
    </DiffuseMaterial>
  </MaterialGroup>
</GeometryModel3D.Material>

La propriété Opacity de cette LinearGradientBrush est animée à l’aide de l’exemple de code ci-dessous.

<!-- Trigger the animation when the 3D object loads. -->
<Viewport3D.Triggers>
  <EventTrigger RoutedEvent="Viewport3D.Loaded">
    <BeginStoryboard>
      <Storyboard>

        <!-- This animation animates the opacity of the material applied to the 3D Object. -->
        <DoubleAnimation
         Storyboard.TargetName="myGradientBrush" 
         Storyboard.TargetProperty="Opacity" 
         Duration="0:0:2" 
         To="0.1" 
         AutoReverse="True" RepeatBehavior="Forever" />

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

Exemple

Le code suivant montre l’ensemble de l’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">

        <!-- The Viewport3D provides a rendering surface for 3-D visual content. -->
        <Viewport3D Name="MyAnimatedObject"
          ClipToBounds="True" Width="150" Height="150"
          Canvas.Left="0" Canvas.Top="10">

          <!-- Defines the camera used to view the 3D object. -->
          <Viewport3D.Camera>
            <PerspectiveCamera x:Name="myPerspectiveCamera" Position="0,0,2" LookDirection="0,0,-1" 
             FieldOfView="60" />
          </Viewport3D.Camera>

          <!-- The ModelVisual3D children contain the 3D models -->
          <Viewport3D.Children>

            <!-- This ModelVisual3D defines the lights cast in the scene. Without light, the
                 3D object cannot be seen. Also, the direction of the light affect shadowing. -->
            <ModelVisual3D>
              <ModelVisual3D.Content>
                <DirectionalLight Color="#FFFFFF" Direction="-0.612372,-0.5,-0.612372" />
              </ModelVisual3D.Content>
            </ModelVisual3D>
            <ModelVisual3D>
              <ModelVisual3D.Content>
                <GeometryModel3D>

                  <!-- The geometry specifes the shape of the 3D plane. In this case, a flat sheet is created. -->
                  <GeometryModel3D.Geometry>
                    <MeshGeometry3D
                     TriangleIndices="0,1,2 3,4,5 "
                     Normals="0,0,1 0,0,1 0,0,1 0,0,1 0,0,1 0,0,1 "
                     TextureCoordinates="0,0 1,0 1,1 1,1 0,1 0,0 "
                     Positions="-0.5,-0.5,0.5 0.5,-0.5,0.5 0.5,0.5,0.5 0.5,0.5,0.5 -0.5,0.5,0.5 -0.5,-0.5,0.5 " />
                  </GeometryModel3D.Geometry>
                  <!-- The material specifies the material applied to the plane. In this case it is a linear gradient.-->
                  <GeometryModel3D.Material>
                    <MaterialGroup>
                      <DiffuseMaterial>
                        <DiffuseMaterial.Brush>

                          <!-- The Opacity property of this LinearGradient is animated. See Storyboard below. -->
                          <LinearGradientBrush x:Name="myGradientBrush"  StartPoint="0,0.5" EndPoint="1,0.5">
                            <LinearGradientBrush.GradientStops>
                              <GradientStop Color="Yellow" Offset="0" />
                              <GradientStop Color="Red" Offset="0.25" />
                              <GradientStop Color="Blue" Offset="0.75" />
                              <GradientStop Color="LimeGreen" Offset="1" />
                            </LinearGradientBrush.GradientStops>
                          </LinearGradientBrush>
                        </DiffuseMaterial.Brush>
                      </DiffuseMaterial>
                    </MaterialGroup>
                  </GeometryModel3D.Material>
                  <!-- The Transform specifies how to transform the 3D object. In this sample, the object is rotated.-->
                  <GeometryModel3D.Transform>
                    <RotateTransform3D>
                      <RotateTransform3D.Rotation>
                        <AxisAngleRotation3D Axis="0,3,0" Angle="40" />
                      </RotateTransform3D.Rotation>
                    </RotateTransform3D>
                  </GeometryModel3D.Transform>
                </GeometryModel3D>
              </ModelVisual3D.Content>
            </ModelVisual3D>
          </Viewport3D.Children>
          <!-- Trigger the animation when the 3D object loads. -->
          <Viewport3D.Triggers>
            <EventTrigger RoutedEvent="Viewport3D.Loaded">
              <BeginStoryboard>
                <Storyboard>

                  <!-- This animation animates the opacity of the material applied to the 3D Object. -->
                  <DoubleAnimation
                   Storyboard.TargetName="myGradientBrush" 
                   Storyboard.TargetProperty="Opacity" 
                   Duration="0:0:2" 
                   To="0.1" 
                   AutoReverse="True" RepeatBehavior="Forever" />

                </Storyboard>
              </BeginStoryboard>
            </EventTrigger>
          </Viewport3D.Triggers>
        </Viewport3D>
      </Canvas>
    </Viewbox>
  </DockPanel>
</Page>

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