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//---------------------------------------------------------------------------
//
// <copyright file="HitTestParameters3D.cs" company="Microsoft">
// Copyright (C) Microsoft Corporation. All rights reserved.
// </copyright>
//
// History:
// 03/16/2004 : Microsoft - Created
//
//---------------------------------------------------------------------------
using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using MS.Internal.Media3D;
using CultureInfo = System.Globalization.CultureInfo;
namespace System.Windows.Media.Media3D
{
/// <summary>
/// Encapsulates a set parameters for performing a 3D hit test. This is an
/// abstract base class.
/// </summary>
/// <remarks>
/// Internally the HitTestParameters3D is double as the hit testing "context"
/// which includes such things as the current LocalToWorld transform, etc.
/// </remarks>
public abstract class HitTestParameters3D
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
// Internal to prevent 3rd parties from extending this abstract base class.
internal HitTestParameters3D() {}
#endregion Constructors
//------------------------------------------------------
//
// Public Methods
//
//------------------------------------------------------
//------------------------------------------------------
//
// Public Properties
//
//------------------------------------------------------
//------------------------------------------------------
//
// Public Events
//
//------------------------------------------------------
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
internal void PushVisualTransform(Transform3D transform)
{
Debug.Assert(!HasModelTransformMatrix,
"ModelTransform stack should be empty when pusing a visual transform");
if (transform != null && transform != Transform3D.Identity)
{
_visualTransformStack.Push(transform.Value);
}
}
internal void PushModelTransform(Transform3D transform)
{
if (transform != null && transform != Transform3D.Identity)
{
_modelTransformStack.Push(transform.Value);
}
}
internal void PopTransform(Transform3D transform)
{
if (transform != null && transform != Transform3D.Identity)
{
if (_modelTransformStack.Count > 0)
{
_modelTransformStack.Pop();
}
else
{
_visualTransformStack.Pop();
}
}
}
//------------------------------------------------------
//
// Internal Properties
//
//------------------------------------------------------
#region Internal Properties
internal bool HasWorldTransformMatrix
{
get { return _visualTransformStack.Count > 0 || _modelTransformStack.Count > 0; }
}
internal Matrix3D WorldTransformMatrix
{
get
{
Debug.Assert(HasWorldTransformMatrix,
"Check HasWorldTransformMatrix before accessing WorldTransformMatrix.");
if (_modelTransformStack.IsEmpty)
{
return _visualTransformStack.Top;
}
else if (_visualTransformStack.IsEmpty)
{
return _modelTransformStack.Top;
}
else
{
return _modelTransformStack.Top * _visualTransformStack.Top;
}
}
}
internal bool HasModelTransformMatrix
{
get { return _modelTransformStack.Count > 0; }
}
/// <summary>
/// The ModelTransformMatrix is the transform in the coordinate system
/// of the last Visual hit.
/// </summary>
internal Matrix3D ModelTransformMatrix
{
get
{
Debug.Assert(HasModelTransformMatrix,
"Check HasModelTransformMatrix before accessing ModelTransformMatrix.");
return _modelTransformStack.Top;
}
}
/// <summary>
/// True if the hit test origined in 2D (i.e., we projected a
/// the ray from a point on a Viewport3DVisual.)
/// </summary>
internal bool HasHitTestProjectionMatrix
{
get { return _hitTestProjectionMatrix != null; }
}
/// <summary>
/// The projection matrix can be set to give additional
/// information about a hit test that originated from a camera.
/// When any 3D point is projected using the matrix it ends up
/// at an x,y location (after homogeneous divide) that is a
/// constant translation of its location in the camera's
/// viewpoint.
///
/// All points on the ray project to 0,0
///
/// The RayFromViewportPoint methods will set this matrix up.
/// This matrix is needed to implement hit testing of the magic
/// line, which is not intersected by any rays not produced
/// using RayFromViewportPoint.
///
/// It is being added to HitTestParameters3D rather than
/// RayHitTestParameters3D because it could be generally useful
/// to any sort of hit testing that originates from a camera,
/// including cone hit testing or the full generalization of 3D
/// shape hit testing.
/// </summary>
internal Matrix3D HitTestProjectionMatrix
{
get
{
Debug.Assert(HasHitTestProjectionMatrix,
"Check HasHitTestProjectionMatrix before accessing HitTestProjectionMatrix.");
return _hitTestProjectionMatrix.Value;
}
set
{
_hitTestProjectionMatrix = new Matrix3D?(value);
}
}
internal Visual3D CurrentVisual;
internal Model3D CurrentModel;
internal GeometryModel3D CurrentGeometry;
#endregion Internal Properties
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
private Matrix3D? _hitTestProjectionMatrix = null;
private Matrix3DStack _visualTransformStack = new Matrix3DStack();
private Matrix3DStack _modelTransformStack = new Matrix3DStack();
#endregion Private Fields
}
}
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