Material and Illumination - Essentials of Interactive Computer Graphics - page 470

Tutorial A.1. Simple Example with Lighting Computation

Tutorial A.1.
Project Name:
D3D _ SimpleLighting
Library Support:
UWB _ MFC _ Lib1

• Goal. Examine how to work with the illumination model.

• Approach. Implement a simple program independent of the UWBGL to
demonstrate the effect of lighting computation.

Figure A.1 is a screenshot of running Tutorial A.1. This program is similar to
Tutorial 14.1 where the source code is independent of the UWBGL library. However,
this tutorial includes three extra checkboxes at the lower part of the application
window. Each of these checkboxes controls the on/off switch of the corresponding
light source. By switching each of the light sources on, we can observe that the
point light is green in color, the directional light is purple, and the spot light is
blue. All the changes from Tutorial 14.1 are in the GrfxWindowD3D.cpp file, in
the OnPaint() function.

UWBGL_D3D_Lib18

Change summary. See p. 533
for a summary of changes to
the library.

This library includes support for working with the default Phong illumination
model. The new classes introduced by this library are UWB _ Material and the
UWBD3D _ Light hierarchy. UWB _ Primitive is modified to contain a UWB _ Material
as an attribute. This new attribute describes the material property of the prim-
itive. As in any other attribute, before rendering the primitive, the material at-
tribute is copied to the UWB _ DrawHelper to be programmed into the graphics
API. To observe the results of illumination, a program should create instances
of UWBD3D _ Light objects, initialize the UWB _ Material , and enable the lighting
attributes of UWB _ Primitive objects.

Tutorial A.2. Lighting with UWBGL

Tutorial A.2.
Project Name:
D3D _ Lighting
Library Support:
UWB _ MFC _ Lib1
UWB _ D3D _ Lib18

• Goal. Demonstrate the support of the illumination model and lighting com-
putation in the UWBGL .

• Approach. Implement a simple program based on the UWBGL .

Figure A.2 is a screenshot of running Tutorial A.2. Notice the brighter circular

region in the middle of the rendered image; this is the illumination effect from a
spot light. You can bring up the “Light Control” window by clicking on the “Light
Control” checkbox. On the “Light Control” window, select the “Spot Light” radio
button and toggle the “On/Off” checkbox. Notice the circular region appear/dis-
appear with the on/off of the spot light. Now, click on the “Draw Lgt” checkbox
and see a blue sphere being drawn. This is the position of the spot light. In similar
fashion, we can switch on/off each of the point and directional lights and enable

Figure A.2. Tutorial

A.2.