/// <summary>
/// Un-projects a 2D screen point.
/// </summary>
/// <param name="viewport">The viewport.</param>
/// <param name="pointIn">The input point.</param>
/// <param name="pointNear">The point at the near clipping plane.</param>
/// <param name="pointFar">The point at the far clipping plane.</param>
/// <returns>The ray.</returns>
public static Ray UnProject(this Viewport3DX viewport, Vector2 point2d)//, out Vector3 pointNear, out Vector3 pointFar)
{
var camera = viewport.Camera as ProjectionCamera;
if (camera != null)
{
var p = new Vector3((float)point2d.X, (float)point2d.Y, 1);
//var wvp = GetViewProjectionMatrix(viewport);
//Vector3 r = Vector3.Unproject(p, 0f, 0f, (float)viewport.ActualWidth, (float)viewport.ActualHeight, 0f, 1f, wvp);
//r.Normalize();
var vp = GetScreenViewProjectionMatrix(viewport);
var vpi = Matrix.Invert(vp);
Vector3 zn, zf;
p.Z = 0;
Vector3.TransformCoordinate(ref p, ref vpi, out zn);
p.Z = 1;
Vector3.TransformCoordinate(ref p, ref vpi, out zf);
Vector3 r = zf - zn;
r.Normalize();
if (camera is PerspectiveCamera)
{
return(new Ray(camera.Position.ToVector3(), r));
}
else if (camera is OrthographicCamera)
{
return(new Ray(zn, r));
}
}
throw new HelixToolkitException("Unproject camera error.");
}
public static global::SharpDX.Matrix Inverted(this global::SharpDX.Matrix m)
{
m.Invert();
return(m);
}
