WPF 3D基础(2)

目标:画一个立方体

根据上篇画三角形的步骤,我们知道2个三角形可以画1个四边形,一个立方体有6个面,如果伪3D的话则只需要画3个平面就可以了(背后隐藏着3个平面),如下

如果给立方体添加动画(如旋转动画,那么就需要看到背面的平面),这时候就需要画6个平面.

我们需要给每个平面都构造2三角形,即6个点,比如其中一个

                        <GeometryModel3D>
                            <GeometryModel3D.Geometry>
                                <MeshGeometry3D 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>
                            <GeometryModel3D.Material>
                                <DiffuseMaterial>
                                    <DiffuseMaterial.Brush>
                                        <SolidColorBrush Color="Red" Opacity="1"/>
                                    </DiffuseMaterial.Brush>
                                </DiffuseMaterial>
                            </GeometryModel3D.Material>
                        </GeometryModel3D>

画6个面

        <Viewport3D>
            <Viewport3D.Camera>
                <PerspectiveCamera FarPlaneDistance="20" FieldOfView="50" NearPlaneDistance="0"
                    Position="-5,2,3" LookDirection="5,-2,-3" UpDirection="0,1,0"/>
            </Viewport3D.Camera>
            
            <ModelVisual3D>
                <ModelVisual3D.Content>
                    <Model3DGroup>
                        <!--side 5 top-->
                        <GeometryModel3D>
                            <GeometryModel3D.Geometry>
                                <MeshGeometry3D 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>
                            <GeometryModel3D.Material>
                                <DiffuseMaterial Brush="Blue" />
                            </GeometryModel3D.Material>
                        </GeometryModel3D>
                        <!--side 6 front-->
                        <GeometryModel3D>
                            <GeometryModel3D.Geometry>
                                <MeshGeometry3D 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>
                            <GeometryModel3D.Material>
                                <DiffuseMaterial>
                                    <DiffuseMaterial.Brush>
                                        <SolidColorBrush Color="Red" Opacity="1"/>
                                    </DiffuseMaterial.Brush>
                                </DiffuseMaterial>
                            </GeometryModel3D.Material>
                        </GeometryModel3D>
                        <AmbientLight Color="White"/>
                        <!--side 2 Right-->
                        <GeometryModel3D>
                            <GeometryModel3D.Geometry>
                                <MeshGeometry3D 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>
                            <GeometryModel3D.Material>
                                <DiffuseMaterial Brush="Yellow" />
                            </GeometryModel3D.Material>
                        </GeometryModel3D>
                        <!--side 1-->
                        <GeometryModel3D>
                            <GeometryModel3D.Geometry>
                                <MeshGeometry3D 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>
                            <GeometryModel3D.Material>
                                <DiffuseMaterial Brush="Green" />
                            </GeometryModel3D.Material>
                        </GeometryModel3D>
                        <!--side 3-->
                        <GeometryModel3D>
                            <GeometryModel3D.Geometry>
                                <MeshGeometry3D 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>
                            <GeometryModel3D.Material>
                                <DiffuseMaterial Brush="LightSlateGray" />
                            </GeometryModel3D.Material>
                        </GeometryModel3D>
                        <!--side 4-->
                        <GeometryModel3D>
                            <GeometryModel3D.Geometry>
                                <MeshGeometry3D 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>
                            <GeometryModel3D.Material>
                                <DiffuseMaterial Brush="DarkOrange" />
                            </GeometryModel3D.Material>
                        </GeometryModel3D>
                    </Model3DGroup>
                </ModelVisual3D.Content>
            </ModelVisual3D>
        </Viewport3D>

效果图上面已经看到了

旋转立方体

添加一个RotateTransform3D

                <ModelVisual3D.Transform>
                    <RotateTransform3D>
                        <RotateTransform3D.Rotation>
                            <AxisAngleRotation3D x:Name="myAngleRotation" Axis="0,3,3" />
                        </RotateTransform3D.Rotation>
                    </RotateTransform3D>
                </ModelVisual3D.Transform>

就不用动画了.直接Timer演示

public Window2()
{
    InitializeComponent();
    DispatcherTimer timer = new DispatcherTimer();
    timer.Interval = TimeSpan.FromSeconds(0.001);
    timer.Tick += new EventHandler(timer_Tick);
    timer.Start();
}

private int i = 0;
void timer_Tick(object sender, EventArgs e)
{
    if (myAngleRotation.Angle + 5 == 360)
    {
        i++;
        if (i % 2 == 1)
            myAngleRotation.Axis = new Vector3D(3, 3, 0);
        else
            myAngleRotation.Axis = new Vector3D(0, 3, 3);
    }
    myAngleRotation.Angle = (myAngleRotation.Angle + 5) % 360;
}

完毕,一个旋转的立方体就出来了