Attributes and Behaviors of Primitives - Essentials of Interactive Computer Graphics - page 158

class CModel {
public :
.
A: void SetObjectColor( const UWB _ Color& color);
void SetCircleFillMode( bool filled);
B: void StartDefineGraphicsObject( float world _ x, float world _ y);
void EndDefineGraphicsObject( float world _ x, float world _ y);
void MoveGraphicsObject( float world _ x, float world _ y);

Source file. Model.h file
in the Model folder of the
D3D _ ObjectsAndAttributes
project.

C: void DrawModel();
.
private :
.

UWB _ CircleGeometry m _ Circle;
UWB _ PointGeometry

D:

m _ Point;

UWB _ LineGeometry m _ Line;

UWBD3D _ DrawHelper m _ DrawHelper;
.

E:

};

Listing 7.5. The CModel class (Tutorial 7.1).

Alternatively, if an OGLDrawHelper ispassedtothe Draw() function, then the
corresponding OpenGL drawing would occur. LineGeometry and CircleGeome
try have similar class structures, and the details are not shown here.

The CModel class. With the functionality defined in UWB _ D3D _ Lib4 ,thecore
application state (or the CModel class) of Tutorial 7.1 can be defined. From
Listing 7.5, we can see that public interface of the model class includes (A)
methods for setting primitive attributes, (B) methods for interactively drawing
the primitives, and (C) drawing of the model. Privately, we see instances of
geometric primitives at label D, and the D3DDrawHelp object ( m _ DrawHelper )
that will support the drawing in D3D. The implementation of these methods is
shown in Listing 7.6. At label A, we see that the attribute-setting methods (e.g.,
SetObjectColor() ) are implemented by straightforward calling of public meth-
ods supported by the corresponding primitive type (e.g., m _ Circle 's SetColor()
method). At label B, we see that to properly support primitive editing, we must
determine the currently active primitive type and then set the vertex/geometric
properties accordingly. Lastly at label C, we see that the D3D graphics API-