Hierarchical Modeling - Essentials of Interactive Computer Graphics - page 313

Source file. Model.h file

class CModel { // ... similar to Tutorial 11.6 ...

in the Model folder of the

D3D _ SceneNodePicking
project.

public :
// sets the currently selected scene node
A: void SetActiveSceneNode(UWB _ SceneNode * );
// test if (wcX, wcY) is inside the WC Bbox of the currently
// selected scene node
B: void PickNodeAt( float wcX, float wcY);
private :
// root of the enture human model hierarchy

UWB _ SceneNode m _ Body;
// pointer to the scene node that is selected in the
// SceneTreeControl GUI element

C:

UWB _ SceneNode * m _ pActiveNode;
.

D:

};

Listing 11.15. The CModel class of Tutorial 11.7.

Source file. Model.cpp
file in the Model folder of
the D3D _ SceneNodePicking
project.

void CModel::PickNodeAt( float worldX, float worldY)

// bbox of the currently selected scene node

UWB _ BoundingBox bbox;
// mouse click position in WC
vec3 pick _ point(worldX, worldY, 0);
// initialize matrix stack for OC-to-WC computation

A:

m _ DrawHelper.InitializeModelTransform();
// compute WC bbox for the selected scene node

B:

m _ Body.GetNodeBounds(m _ pActiveNode, bbox ...);
// test if bbox contains the mouse click position

C:

if (bbox.ContainsPoint( pick _ point ) )
.
// all positions are in WC space
sets bbox draw color and prints appropriate message

D:

Listing 11.16. The implementation CModel class of Tutorial 11.7.

initialized at label B for the proper concatenation of the OC-to-WC transformation
matrix. At label C, we call the GetNodeBounds() function on the m _ Body node.
As illustrated in Listing 11.14, the GetNodeBounds() function will maintain a
correct OC-to-WC transformation matrix on the matrix stack while traversing the
hierarchy in search of the target node. In this case, the m _ pActiveNode is the tar-