/// <summary>
/// Traverse from the bottom right of the scene graph (top visible node)
/// up the tree determining which parent nodes are occluded by their children
/// nodes.
/// </summary>
/// <param name="n">The node to find occlusions for.</param>
/// <param name="pickPath">
/// A pick path representing the bounds of <c>n</c> in parent coordinates.
/// </param>
/// <remarks>
/// Note that this is only detecting a subset of occlusions (parent, child),
/// others such as overlapping siblings or cousins are not detected.
/// </remarks>
public void DetectOcclusions(PNode n, PPickPath pickPath) {
if (n.FullIntersects(pickPath.PickBounds)) {
pickPath.PushMatrix(n.MatrixReference);
int count = n.ChildrenCount;
for (int i = count - 1; i >= 0; i--) {
PNode each = n[i];
if (n.Occluded) {
// if n has been occluded by a previous decendent then
// this child must also be occluded
each.Occluded = true;
} else {
// see if child each occludes n
DetectOcclusions(each, pickPath);
}
}
// see if n occludes it's parents
if (!n.Occluded) {
if (n.Intersects(pickPath.PickBounds)) {
if (n.IsOpaque(pickPath.PickBounds)) {
PNode p = n.Parent;
while (p != null && !p.Occluded) {
p.Occluded = true;
}
}
}
}
pickPath.PopMatrix(n.MatrixReference);
}
}
/// <summary>
/// Try to pick this node and all of its descendents.
/// </summary>
/// <param name="pickPath">The pick path to add the node to if its picked.</param>
/// <returns>True if this node or one of its descendents was picked; else false.</returns>
/// <remarks>
/// <b>Notes to Inheritors:</b> Most subclasses should not need to override this
/// method. Instead they should override <c>Pick</c> or <c>PickAfterChildren</c>.
/// </remarks>
public virtual bool FullPick(PPickPath pickPath) {
if ((Pickable || ChildrenPickable) && FullIntersects(pickPath.PickBounds)) {
pickPath.PushNode(this);
pickPath.PushMatrix(matrix);
bool thisPickable = Pickable && pickPath.AcceptsNode(this);
if (thisPickable && Pick(pickPath)) {
return true;
}
if (ChildrenPickable) {
int count = ChildrenCount;
for (int i = count - 1; i >= 0; i--) {
if (children[i].FullPick(pickPath)) {
return true;
}
}
}
if (thisPickable && PickAfterChildren(pickPath)) {
return true;
}
pickPath.PopMatrix(matrix);
pickPath.PopNode(this);
}
return false;
}
/// <summary>
/// Overridden. After the direct children of the camera have been given a chance
/// to be picked objects viewed by the camera are given a chance to be picked.
/// </summary>
/// <param name="pickPath">The pick path used for the pick operation.</param>
/// <returns>
/// True if an object viewed by the camera was picked; else false.
/// </returns>
protected override bool PickAfterChildren(PPickPath pickPath) {
if (Intersects(pickPath.PickBounds)) {
pickPath.PushMatrix(viewMatrix);
if (PickCameraView(pickPath)) {
return true;
}
pickPath.PopMatrix(viewMatrix);
return true;
}
return false;
}
/// <summary>
/// Overridden. Only picks this node's children if the pick bounds intersects the
/// clip.
/// </summary>
/// <param name="pickPath">The pick path to add the node to if its picked.</param>
/// <returns>
/// True if this node or one of its descendents was picked; else false.
/// </returns>
public override bool FullPick(PPickPath pickPath) {
if (Pickable && FullIntersects(pickPath.PickBounds)) {
pickPath.PushNode(this);
pickPath.PushMatrix(MatrixReference);
if (Pick(pickPath)) {
return true;
}
if (ChildrenPickable && PUtil.PathIntersectsRect(PathReference, pickPath.PickBounds)) {
int count = ChildrenCount;
for (int i = count - 1; i >= 0; i--) {
PNode each = this.GetChild(i);
if (each.FullPick(pickPath))
return true;
}
}
if (PickAfterChildren(pickPath)) {
return true;
}
pickPath.PopMatrix(MatrixReference);
pickPath.PopNode(this);
}
return false;
}
//****************************************************************
// Picking - Methods for picking the camera and it's view.
//****************************************************************
/// <summary>
/// Generate and return a PPickPath for the point x,y specified in the local
/// coordinate system of this camera.
/// </summary>
/// <param name="x">The x coordinate of the pick point.</param>
/// <param name="y">The y coordinate of the pick point.</param>
/// <param name="halo">
/// The value to use for the width and height of the rectangle used for picking.
/// </param>
/// <returns>A PPickPath for the given point.</returns>
/// <remarks>
/// Picking is done with a rectangle, halo specifies how large that rectangle
/// will be.
/// </remarks>
public virtual PPickPath Pick(float x, float y, float halo) {
RectangleF b = PUtil.InflatedRectangle(new PointF(x, y), halo, halo);
PPickPath result = new PPickPath(this, b);
FullPick(result);
// make sure this camera is pushed.
if (result.NodeStackReference.Count == 0) {
result.PushNode(this);
result.PushMatrix(MatrixReference);
}
return result;
}
