The Model-View-Controller Architecture - Essentials of Interactive Computer Graphics - page 130

class UWBD3D _ GraphicsSystem {

Source file.
uwbgl _ D3DGraphicsSystem2
.h file in the D3D Files/
GraphicsSystem subfolder of
the UWBGL _ D3D _ Lib3 project.

.
bool CreateGraphicsContext(HWND hMainWindow);
// similar to verion 1 from UWB _ D3D _ Lib1
.

Create an additional Swap Chain for the RC (m_pD3DDevice).
LPDIRECT3DSWAPCHAIN9 CreateSwapChain(HWND hWindow);
private :
.
LPDIRECT3DDEVICE9 m _ pD3DDevice;

};

Listing 5.20. GraphicsSystem class (Tutorial 5.4).

create multiple hardware drawing buffers in the GHC to be associated with the
rendering states of each RC. So far, our GraphicsSystem class creates only one
hardware drawing buffer during the creation of GHC/RC in CreateGraphics
Context() . We need to extend the GraphicsSystem class to support the creation
of multiple hardware drawing buffers.

OpenGL. OpenGL dictates that each RC must be associated with one unique
hardware drawing buffer. In this case, a new RC ( HGLRC ) must be created for
each GUI drawing area. The data type representing OpenGL rendering contexts
is HGLRC . To support multiple GUI drawing areas, we create a new HGLRC for each
GUI drawing area by calling the wglCreateContext() function.

D3D. D3D supports the creation of swap chains to associate multiple drawing
buffers with each RC. For D3D release 9, the data type representing a swap chain
is DIRECT3DSWAPCHAIN9 , and the data type representing the RC is Direct3D
Device9 . To support multiple GUI drawing areas, we create one RC ( DIRECT3D
Device9 ), and then for each GUI drawing area, we create a new DIRECT3DSWAP
CHAIN9 object based on the same RC. Listing 5.20 shows that version 2 of the
UWBD3D _ GraphicsSystem class supports the creation of additional swap chains
for each RC. The detailed procedure of creating the swap chain is D3D-specific
and is not shown here.

Interface to GUI: The WindowHandler Class
In Figure 5.4, we saw that the WindowHandler class is designed to bridge the
graphics API and GUI API to implement the view/controller functionality.