Coordinate Systems - Essentials of Interactive Computer Graphics - page 265

BOOL CTutorialDlg::OnInitDialog()
.
// m _ view is a DrawOnlyHandler (D3DWindowHandler)
if (!m _ view.Initialize( * this , IDC _ PLACEHOLDER))
return FALSE;
UWB _ BoundingBox wcWindow( vec3 (10, 20), vec3 (20, 30)); // initialize the wcWindow
// set the m _ WCWindow of WindowHandler object

m _ view. SetWCWindow( wcWindow ) ;
.

A:

Source file.
TutorialDlg.cpp file in the
Source Files

void CDrawOnlyHandler::DrawGraphics()
.
BeginDraw();

folder of the

D3D _ WCSupport project.

B:

// compute and load the M w 2 n to the VIEW matrix processor

LoadW2NDCXform() ;

. .); // Clears the device for drawing
theApp.GetModel().DrawModel(); // Tells the Model to draw itself
EndDrawAndShow();
.

m _ pD3DDevice->Clear(

Listing 10.10. Working with UWBGL _ D3D _ Lib10 (Tutorial 10.9).

10.4.2 WC Window Position: Panning

Recall that Equation (10.15) defines the transformation of a point from WC space
( x wc , y wc ) to DC space ( x dc , y dc ) :

W dc W dc

2

=(( − )

W wc )+

,

x dc x wc cx wc

( 10 . 15 )

H dc H dc

2

y dc =(( y wc − cy wc )

H wc )+

,

where W dc × H dc is the drawing device dimension and

⎧
⎨

center =( cx wc , cy wc ) ,

WC window = width = W wc , .

⎩

= .

height H wc

In Tutorial 10.8, we observed that by changing the WC center position ( cx wc , cy wc ) ,

we can show different regions of the model defined in the WC system. Based on
our discussions, we can predict that a continuous changing of WC window posi-
tion would create an effect of panning through the WC system.