我们使用3DTools(http://3dtools.codeplex.com)绘制一条3d线,它允许用户通过鼠标旋转它。我有疑问,如何限制用户只能在Z轴上旋转它?或在X轴上,仅Y轴?
<tool:TrackballDecorator >
<tool:Interactive3DDecorator
ContainsInk="True">
<Viewport3D>
<Viewport3D.Camera>
<PerspectiveCamera x:Name="camera1" Position="4.89,-11,5" LookDirection="-4.89,11,-5"
FieldOfView="45" UpDirection="-4,9,-1"/>
</Viewport3D.Camera>
<ModelVisual3D x:Name="modelVisual3D">
<ModelVisual3D.Children>
<tool:ScreenSpaceLines3D x:Name="axisX" Color="Cyan"
Thickness="2.0"
Points="0, 0, 0, 5, 0, 0" />
<tool:ScreenSpaceLines3D Color="LightCyan"
Thickness="2.0"
Points="-5, 0, 0, 0, 0, 0" />
<tool:ScreenSpaceLines3D x:Name="axisY" Color="Green"
Thickness="2.0"
Points="0,0,0, 0,5,0"/>
<tool:ScreenSpaceLines3D Color="LightGreen"
Thickness="2.0"
Points="0,-5,0, 0,0,0"/>
<tool:ScreenSpaceLines3D x:Name="axisZ" Color="Red"
Thickness="2.0"
Points="0,0,0, 0,0,5"/>
<tool:ScreenSpaceLines3D Color="LightPink"
Thickness="2.0"
Points="0,0,-5, 0,0,0"/>
</ModelVisual3D.Children>
</ModelVisual3D>
</Viewport3D>
</tool:Interactive3DDecorator>
</tool:TrackballDecorator>
答案 0 :(得分:1)
使用以下方法替换'Trackball.cs'中的Trackball.Track()方法:
private void Track(Point currentPosition)
{
Vector3D currentPosition3D = ProjectToTrackball(
EventSource.ActualWidth, EventSource.ActualHeight, currentPosition);
Vector3D axisToRotate = new Vector3D(0, 1, 0); // Rotation around Y only
Vector3D currProjected = Vector3D.CrossProduct(axisToRotate, currentPosition3D);
Vector3D prevProjected = Vector3D.CrossProduct(axisToRotate, _previousPosition3D);
double angle = Vector3D.AngleBetween(currProjected, prevProjected);
int sign = Math.Sign(Vector3D.DotProduct(
axisToRotate,
Vector3D.CrossProduct(_previousPosition3D, currentPosition3D)));
if (sign != 0)
{
Quaternion delta = new Quaternion(axisToRotate * sign, -angle);
AxisAngleRotation3D r = _rotation;
Quaternion q = new Quaternion(_rotation.Axis, _rotation.Angle);
q *= delta;
_rotation.Axis = q.Axis;
_rotation.Angle = q.Angle;
}
_previousPosition3D = currentPosition3D;
}