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Procedura: Animare una rotazione 3D usando quaternioni

  • Articolo

Questo esempio illustra come animare una rotazione di un oggetto 3D usando quaternioni.

Il codice seguente mostra un QuaternionRotation3D usato come valore per la proprietà Rotation di un RotateTransform3D.

<!-- The Transform specifies how to transform the 3D object. The rotation
     is animated using the Storyboard below. -->
<GeometryModel3D.Transform>
  <RotateTransform3D>
    <RotateTransform3D.Rotation>
      <QuaternionRotation3D x:Name="myQuaternionRotation3D" />
    </RotateTransform3D.Rotation>
  </RotateTransform3D>
</GeometryModel3D.Transform>

Questa QuaternionRotation3D viene animata con un QuaternionAnimation all'interno di un Storyboard usando il codice riportato di seguito.

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

        <!-- This animation animates the Rotation property of the RotateTransform3D
             causing the 3D shape to rotate. -->
        <QuaternionAnimation
         Storyboard.TargetName="myQuaternionRotation3D"
         Storyboard.TargetProperty="Quaternion" From="0,0,1,0" To="0.3, 0.3, 1, 0" 
         Duration="0:0:2" />

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

Esempio

Il codice seguente illustra l'intero esempio.

<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 lights 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>
                          <LinearGradientBrush 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. The rotation
                       is animated using the Storyboard below. -->
                  <GeometryModel3D.Transform>
                    <RotateTransform3D>
                      <RotateTransform3D.Rotation>
                        <QuaternionRotation3D x:Name="myQuaternionRotation3D" />
                      </RotateTransform3D.Rotation>
                    </RotateTransform3D>
                  </GeometryModel3D.Transform>
                </GeometryModel3D>
              </ModelVisual3D.Content>
            </ModelVisual3D>
          </Viewport3D.Children>
          <!-- Trigger the rotation animation when the 3D object loads. -->
          <Viewport3D.Triggers>
            <EventTrigger RoutedEvent="Viewport3D.Loaded">
              <BeginStoryboard>
                <Storyboard>

                  <!-- This animation animates the Rotation property of the RotateTransform3D
                       causing the 3D shape to rotate. -->
                  <QuaternionAnimation
                   Storyboard.TargetName="myQuaternionRotation3D"
                   Storyboard.TargetProperty="Quaternion" From="0,0,1,0" To="0.3, 0.3, 1, 0" 
                   Duration="0:0:2" />

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

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