/// <summary>
/// Un-projects a 2D screen point.
/// </summary>
/// <param name="viewport">The viewport.</param>
/// <param name="point2d">The input point.</param>
/// <returns>The ray.</returns>
public static Ray UnProject(this Viewport3DX viewport, Vector2 point2d)//, out Vector3 pointNear, out Vector3 pointFar)
{
var camera = viewport.CameraCore as ProjectionCameraCore;
if (camera != null)
{
var px = (float)point2d.X;
var py = (float)point2d.Y;
var viewMatrix = camera.GetViewMatrix();
Vector3 v = new Vector3();
var matrix = MatrixExtensions.PsudoInvert(ref viewMatrix);
float w = (float)viewport.ActualWidth;
float h = (float)viewport.ActualHeight;
var aspectRatio = w / h;
var projMatrix = camera.GetProjectionMatrix(aspectRatio);
Vector3 zn, zf;
v.X = (2 * px / w - 1) / projMatrix.M11;
v.Y = -(2 * py / h - 1) / projMatrix.M22;
v.Z = 1 / projMatrix.M33;
Vector3.TransformCoordinate(ref v, ref matrix, out zf);
if (camera is PerspectiveCameraCore)
{
zn = camera.Position;
}
else
{
v.Z = 0;
Vector3.TransformCoordinate(ref v, ref matrix, out zn);
}
Vector3 r = zf - zn;
r.Normalize();
return(new Ray(zn + r * camera.NearPlaneDistance, r));
}
throw new HelixToolkitException("Unproject camera error.");
}
public static Matrix GetInversedViewMatrix(this CameraCore camera)
{
var viewMatrix = GetViewMatrix(camera);
return(MatrixExtensions.PsudoInvert(ref viewMatrix));
}