我有一个WPF 3D场景在那里我可以平移，旋转和使用来自TrackballDecorator的3DTools library放大。我想保存相机设置（改造）并能够重新应用它们在应用程序重新启动下一次（这样的观点恢复）。
我试图挽救Camera的每个单独的值：
private void SaveCameraSettings()
{
var d = Properties.Settings.Default;
d.CameraPositionX = camera.Position.X;
d.CameraPositionY = camera.Position.Y;
...
d.Save();
}
这是不行的，我猜是因为根据应用到相机转换（我总是在XAML中设置初始值）不更新这些设置。
我检查了Transformation3D类，但找不到任何方式将其值设置...
问题是，什么样的价值观，我需要从PerspectiveCamera拿到为了能够给它它是当我关闭我的应用程序的最后时间的方式恢复。所述相机被设置为一个默认位置（XAML），然后变换被TrackBallDecorator应用于该相机。我怎样才能挽救这个转变（存储什么值）？而且我怎么能在以后的时间重新申请呢？
这将是一个有点长，所以忍耐一下...
1，您需要修改3DTools库，以便您可以应用转换到TrackballDecorator如下：
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Media3D;
using System.Windows.Input;
namespace _3DTools
{
public class TrackballDecorator : Viewport3DDecorator
{
#region Private Members
private Point m_PreviousPosition2D;
private Vector3D m_PreviousPosition3D = new Vector3D(0, 0, 1);
private Transform3DGroup m_Transform;
private ScaleTransform3D m_Scale = new ScaleTransform3D();
private AxisAngleRotation3D m_Rotation = new AxisAngleRotation3D();
private TranslateTransform3D m_Translate = new TranslateTransform3D();
private readonly Border m_EventSource;
#endregion
#region Constructor
public TrackballDecorator()
{
TranslateScale = 10;
ZoomScale = 1;
RotateScale = 1;
// the transform that will be applied to the viewport 3d's camera
m_Transform = new Transform3DGroup();
m_Transform.Children.Add(m_Scale);
m_Transform.Children.Add(new RotateTransform3D(m_Rotation));
m_Transform.Children.Add(m_Translate);
// used so that we always get events while activity occurs within
// the viewport3D
m_EventSource = new Border { Background = Brushes.Transparent };
PreViewportChildren.Add(m_EventSource);
}
#endregion
#region Properties
/// <summary>
/// A transform to move the camera or scene to the trackball's
/// current orientation and scale.
/// </summary>
public Transform3DGroup Transform
{
get { return m_Transform; }
set
{
m_Transform = value;
m_Scale = m_Transform.GetScaleTransform3D();
m_Translate = m_Transform.GetTranslateTransform3D();
m_Rotation = m_Transform.GetRotateTransform3D().Rotation as AxisAngleRotation3D;
ApplyTransform();
}
}
public double TranslateScale { get; set; }
public double RotateScale { get; set; }
public double ZoomScale { get; set; }
#endregion
#region Event Handling
protected override void OnMouseDown(MouseButtonEventArgs e)
{
base.OnMouseDown(e);
m_PreviousPosition2D = e.GetPosition(this);
m_PreviousPosition3D = ProjectToTrackball(ActualWidth,
ActualHeight,
m_PreviousPosition2D);
if (Mouse.Captured == null)
{
Mouse.Capture(this, CaptureMode.Element);
}
}
protected override void OnMouseUp(MouseButtonEventArgs e)
{
base.OnMouseUp(e);
if (IsMouseCaptured)
{
Mouse.Capture(this, CaptureMode.None);
}
}
protected override void OnMouseMove(MouseEventArgs e)
{
base.OnMouseMove(e);
if (IsMouseCaptured)
{
Point currentPosition = e.GetPosition(this);
// avoid any zero axis conditions
if (currentPosition == m_PreviousPosition2D) return;
// Prefer tracking to zooming if both buttons are pressed.
if (e.LeftButton == MouseButtonState.Pressed)
{
Track(currentPosition);
}
else if (e.RightButton == MouseButtonState.Pressed)
{
Zoom(currentPosition);
}
else if (e.MiddleButton == MouseButtonState.Pressed)
{
Translate(currentPosition);
}
m_PreviousPosition2D = currentPosition;
ApplyTransform();
}
}
private void ApplyTransform()
{
Viewport3D viewport3D = Viewport3D;
if (viewport3D != null)
{
if (viewport3D.Camera != null)
{
if (viewport3D.Camera.IsFrozen)
{
viewport3D.Camera = viewport3D.Camera.Clone();
}
if (viewport3D.Camera.Transform != m_Transform)
{
viewport3D.Camera.Transform = m_Transform;
}
}
}
}
#endregion Event Handling
private void Track(Point currentPosition)
{
var currentPosition3D = ProjectToTrackball(ActualWidth, ActualHeight, currentPosition);
var axis = Vector3D.CrossProduct(m_PreviousPosition3D, currentPosition3D);
var angle = Vector3D.AngleBetween(m_PreviousPosition3D, currentPosition3D);
// quaterion will throw if this happens - sometimes we can get 3D positions that
// are very similar, so we avoid the throw by doing this check and just ignoring
// the event
if (axis.Length == 0) return;
var delta = new Quaternion(axis, -angle);
// Get the current orientantion from the RotateTransform3D
var r = m_Rotation;
var q = new Quaternion(m_Rotation.Axis, m_Rotation.Angle);
// Compose the delta with the previous orientation
q *= delta;
// Write the new orientation back to the Rotation3D
m_Rotation.Axis = q.Axis;
m_Rotation.Angle = q.Angle;
m_PreviousPosition3D = currentPosition3D;
}
private static Vector3D ProjectToTrackball(double width, double height, Point point)
{
var x = point.X / (width / 2); // Scale so bounds map to [0,0] - [2,2]
var y = point.Y / (height / 2);
x = x - 1; // Translate 0,0 to the center
y = 1 - y; // Flip so +Y is up instead of down
var z2 = 1 - x * x - y * y; // z^2 = 1 - x^2 - y^2
var z = z2 > 0 ? Math.Sqrt(z2) : 0;
return new Vector3D(x, y, z);
}
private void Zoom(Point currentPosition)
{
var yDelta = currentPosition.Y - m_PreviousPosition2D.Y;
var scale = Math.Exp(yDelta / 100) / ZoomScale; // e^(yDelta/100) is fairly arbitrary.
m_Scale.ScaleX *= scale;
m_Scale.ScaleY *= scale;
m_Scale.ScaleZ *= scale;
}
private void Translate(Point currentPosition)
{
// Calculate the panning vector from screen(the vector component of the Quaternion
// the division of the X and Y components scales the vector to the mouse movement
var qV = new Quaternion(((m_PreviousPosition2D.X - currentPosition.X) / TranslateScale),
((currentPosition.Y - m_PreviousPosition2D.Y) / TranslateScale), 0, 0);
// Get the current orientantion from the RotateTransform3D
var q = new Quaternion(m_Rotation.Axis, m_Rotation.Angle);
var qC = q;
qC.Conjugate();
// Here we rotate our panning vector about the the rotaion axis of any current rotation transform
// and then sum the new translation with any exisiting translation
qV = q * qV * qC;
m_Translate.OffsetX += qV.X;
m_Translate.OffsetY += qV.Y;
m_Translate.OffsetZ += qV.Z;
}
}
}
该GetXXXTransform3D方法是定义如下扩展方法：
public static ScaleTransform3D GetScaleTransform3D(this Transform3DGroup transform3DGroup)
{
ScaleTransform3D scaleTransform3D = null;
if (transform3DGroup != null)
{
foreach (var transform in transform3DGroup.Children)
{
scaleTransform3D = transform as ScaleTransform3D;
if (scaleTransform3D != null) return scaleTransform3D;
}
}
return scaleTransform3D;
}
public static RotateTransform3D GetRotateTransform3D(this Transform3DGroup transform3DGroup)
{
RotateTransform3D rotateTransform3D = null;
if (transform3DGroup != null)
{
foreach (var transform in transform3DGroup.Children)
{
rotateTransform3D = transform as RotateTransform3D;
if (rotateTransform3D != null) return rotateTransform3D;
}
}
return rotateTransform3D;
}
public static TranslateTransform3D GetTranslateTransform3D(this Transform3DGroup transform3DGroup)
{
TranslateTransform3D translateTransform3D = null;
if (transform3DGroup != null)
{
foreach (var transform in transform3DGroup.Children)
{
translateTransform3D = transform as TranslateTransform3D;
if (translateTransform3D != null) return translateTransform3D;
}
}
return translateTransform3D;
}
2，你需要一个Transform申报您的PerspectiveCamera如下：
（该例子是从萨莎理发的Elements3D项目采取我用来测试这个）
<Tools:TrackballDecorator x:Name="tbViewPort">
<Viewport3D x:Name="vpFeeds">
<Viewport3D.Camera>
<PerspectiveCamera x:Name="camera" Position="-2,2,40" LookDirection="2,-2,-40" FieldOfView="90">
<PerspectiveCamera.Transform>
<Transform3DGroup />
</PerspectiveCamera.Transform>
</PerspectiveCamera>
</Viewport3D.Camera>
<ContainerUIElement3D x:Name="container" />
<ModelVisual3D x:Name="model">
<ModelVisual3D.Content>
<DirectionalLight Color="White" Direction="-1,-1,-1" />
</ModelVisual3D.Content>
</ModelVisual3D>
</Viewport3D>
</Tools:TrackballDecorator>
第三，因为我们要在整个转型的每个部分存储在一个单独的值，你需要创建在你的设置文件，即CameraScaleX，CameraScaleY，CameraScaleZ，CameraTranslateX，CameraTranslateY，CameraTranslateZ，CameraRotateAxisX，CameraRotateAxisY，CameraRotateAxisZ相关属性和CameraRotateAngle。所有的类型double的，并存储在用户范围。
第四和最后一步是实际使用下面的代码保存和加载这些设置到相机：
private void SaveCameraSettings()
{
var transform3DGroup = camera.Transform as Transform3DGroup;
if (transform3DGroup != null)
{
foreach (var transform in transform3DGroup.Children)
{
var scale = transform as ScaleTransform3D;
if (scale != null) SaveCameraSetting(scale);
var rotate = transform as RotateTransform3D;
if (rotate != null) SaveCameraSetting(rotate);
var translate = transform as TranslateTransform3D;
if (translate != null) SaveCameraSetting(translate);
}
Settings.Default.Save();
}
}
private static void SaveCameraSetting(ScaleTransform3D transform)
{
Properties.Settings.Default.CameraScaleX = transform.ScaleX;
Properties.Settings.Default.CameraScaleY = transform.ScaleY;
Properties.Settings.Default.CameraScaleZ = transform.ScaleZ;
}
private static void SaveCameraSetting(RotateTransform3D transform)
{
var axisAngleRotation3D = transform.Rotation as AxisAngleRotation3D;
if (axisAngleRotation3D != null)
{
Properties.Settings.Default.CameraRotateAxisX = axisAngleRotation3D.Axis.X;
Properties.Settings.Default.CameraRotateAxisY = axisAngleRotation3D.Axis.Y;
Properties.Settings.Default.CameraRotateAxisZ = axisAngleRotation3D.Axis.Z;
Properties.Settings.Default.CameraRotateAngle = axisAngleRotation3D.Angle;
}
}
private static void SaveCameraSetting(TranslateTransform3D transform)
{
Properties.Settings.Default.CameraTranslateX = transform.OffsetX;
Properties.Settings.Default.CameraTranslateY = transform.OffsetY;
Properties.Settings.Default.CameraTranslateZ = transform.OffsetZ;
}
private void LoadCameraPosition()
{
var d = Settings.Default;
var transform3DGroup = new Transform3DGroup();
var scaleTransform3D = new ScaleTransform3D(d.CameraScaleX, d.CameraScaleY, d.CameraScaleZ);
var translateTransform3D = new TranslateTransform3D(d.CameraTranslateX, d.CameraTranslateY, d.CameraTranslateZ);
var axisAngleRotation3D = new AxisAngleRotation3D(new Vector3D(d.CameraRotateAxisX, d.CameraRotateAxisY, d.CameraRotateAxisZ),
d.CameraRotateAngle);
var rotateTransform3D = new RotateTransform3D(axisAngleRotation3D);
transform3DGroup.Children.Add(scaleTransform3D);
transform3DGroup.Children.Add(translateTransform3D);
transform3DGroup.Children.Add(rotateTransform3D);
tbViewPort.Transform = transform3DGroup;
}
但愿我没有忘记什么。如果您需要更多的帮助或者不明白的地方，请不要犹豫，问;-)
您将需要两个摄像机视图矩阵数据和投影矩阵数据。视图矩阵将包含关于照相机的位置，旋转，缩放和平移和投影矩阵将包含类似的视图，近平面，远平面和其它数据字段事物的数据。
对不起，我不能与导出/导入的数据，因为我没有用WPF帮助，但也有可能是，如果它使用任何与内置矩阵类AS3的RAWDATA性暴露出来，这是一个usualy AS3载体。对象暴露为行有序浮点值矩阵16倍的值。
我相信，你需要的是位置，LookDirection，UpDirection，fieldOfView域，NearPlaneDistance，FarPlaneDistance。所有上述特性定义了摄像机。