Graphics Programming in 3D - Essentials of Interactive Computer Graphics - page 434

class UWBD3D _ PrimitiveMesh : public UWB _ Primitive {

Source file.
uwbgl _ D3DPrimitiveMesh1.h
file in the D3D Files/
D3D_Primitives

public :

subfolder

UWBD3D _ PrimitiveMesh( meshFileName ); // .x file name
.
protected :

A:

UWBGL _ D3D _ Lib15 of the

project.

B: void DrawPrimitive( ...); // To draw the Mesh object

.

std::wstring m _ resource _ filename; C: // Internal representation of mesh object

.

void UWBD3D _ PrimitiveMesh::DrawPrimitive( ... ) {
.
// access mesh resource using the file name

UWBD3D _ MeshResource * pMesh=...GetMeshResource(m _ resource _ filename.c _ str());
// Calling D3D Mesh Rendering function

D:

E:

pMesh->DrawMesh( ... );
.

Listing 16.4. UWBGL primitive abstraction over mesh file object.

class. As expected, being a simple Primitive , we can work with the new Primi
tiveMesh just as we have worked with the PrimitivePoint or the Primitive
Circle classes! However, notice the D3D in the UWBD3D _ PrimitiveMesh class
name, and notice that we have placed the source file in the D3D Files subfolder.
This new primitive class defines a D3D-specific object. The most important
implication of this observation is that the drawing of the primitive will not be
handled by the DrawHelper class. Label B shows that we must override the
DrawPrimitive() class. The bottom half of Listing 16.4 shows the implemen-
tation of PrimitiveMesh . At label D, the GraphicsSystem class is invoked to
GetMeshResoruce() , and at label E we call the MeshResoruce::DrawMesh()
function directly to render the mesh object. There is no new mesh drawing sup-
port in the DrawHandler class. Listing 16.5 shows the MeshArrow class. Once Source file.

uwbgl _ D3DPrimitiveArrow1.h
file in the D3D Files/
D3D_Primitives

again, this class defines a D3D-specific object. At label A, as in the case of
PrimitiveMesh , we see that we must override the DrawPrimitive() function.
In this case, we will approximate an arrow with appropriately scaled cone and
cylinder meshes. During DrawPrimitive() , at label B, references to the cone
and cylinder mesh resources are obtained via the GraphicsSystem::GetMeshRe
source() function. At labels C and D, the matrix stack is set up to scale and

subfolder

UWBGL _ D3D _ Lib15 of the

project.