Chapter-11: Shading and Reflection
Structure of the chapter
11.1.1. Light sources
11.2. Diffuse Reflection
11.3. Specular Reflection
11.4. Refracted Light
11.6. Dithering Techniques
11.9. Answers to check your progress/ self assessment questions
11.10. Modal questions
After studying this chapter, the student will be able to:
Explain the concept of illumination in computer graphics.
Explain Diffuse and specular reflections.
Explain refraction of light.
Explain need of halftoning.
Explain various methods of halftoning the images.
Explain dithering techniques.
We can obtain realistic views of a scene by creating perspective projections of objects and by using natural lighting effects to the visible areas. An illumination model which is also called a lighting model or shading model is used to measure the intensity of light on the surface of an object. There is a surface-rendering algorithm that uses the intensity calculations from an illumination model to find out the light…show more content… A very rough surface produces primarily diffuse reflections, so that the surface looks equally dazzling from all viewing directions. Figure 11.4. depicts diffuse light scattering from a surface. The color of an object is the color of the diffuse reflection of the light incident on it. A red object illuminated by a light source, for example, reflects the red component of the white light and completely absorbs all the other components of light. If the red object is viewed under a blue light, it looks black because the entire incident light is absorbed. Along with diffuse reflection, light sources can also create highlights, or bright spots, called specular reflection. The highlighting effect is more pronounced on shiny surfaces than on dull surfaces. Specular reflection is shown in figure