Chapter 15, Illumination Models and Surface-Rendering Methods Video Solutions, Computer Graphics with Open GL

Problem 1

Write a routine to implement Equation 12 for diffuse reflection using a single point light source and constant surface rendering for the faces of a tetrahedron. The object description is to be given in polygon tables, including surface normal vectors for each of the polygon faces. Additional input parameters include the ambient intensity, light-source intensity, and surface reflection coefficients. All coordinate information can be specified directly in the viewing reference frame.

Charles Carter

Numerade Educator

06:26

Problem 2

Modify the routine in Exercise 1 to render the polygon facets of a tessellated spherical surface.

Chris Trentman

Numerade Educator

01:59

Problem 3

Modify the routine in Exercise 2 to display the spherical surface using Gouraud surface rendering.

Linh Vu

Numerade Educator

01:02

Problem 4

Modify the routine in Exercise 3 to display the spherical surface using Phong surface rendering.

Carson Merrill

Numerade Educator

03:33

Problem 5

Use the routines developed in the previous exercises to write a program that displays an input set of objects given as polygon meshes using the same parameters as described in Exercise $1 .$ The program should allow the user to switch between constant surface rendering. Gouraud shading, and Phong shading via keyboard input. Run the program with a sample set of objects and the light source in various positions and examine the visual differences between the three different rendering schemes.

Morgan Cheatham

Numerade Educator

02:45

Problem 6

Write a routine to implement Equation 17 for diffuse and specular reflections using a single point light source and Gouraud surface rendering for the polygon facets of a tessellated spherical surface. The object description is to be given in polygon tables, including surface normal vectors for each of the polygon faces. Additional input includes values for the ambient intensity, lightsource intensity, surface reflection coefficients, and specular-reflection parameter. All coordinate information can be specified directly in the viewing reference frame.

Charles Carter

Numerade Educator

03:56

Problem 7

Modify the routine in preceding exercise to display the polygon facets using Phong surface rendering

Willis James

Numerade Educator

02:41

Problem 8

Modify the routine in the preceding exercise to include a linear intensity attenuation function.

Sheryl Ezze

Numerade Educator

03:11

Problem 9

Modify the routine in the preceding exercise to include two light sources in the scene.

Suhas Katkar

Numerade Educator

03:28

Problem 10

Modify the routine in the preceding exercise so that the spherical surface is viewed through a pane of glass.

Vipender Rao

Numerade Educator

02:21

Problem 11

Discuss the differences you might expect to see in the appearance of specular reflections modeled with $(\mathrm{N}-\mathrm{H})^{\mathrm{n}_{4}}$ compared to specular reflections modeled with $(\mathrm{V} \cdot \overline{\mathbf{R}})^{\mathrm{H}_{n}}$.

Mayukh Banik

Numerade Educator

View

Problem 12

Verify that $2 \alpha=\phi$ in Figure 18 when all vectors are coplanar, but that, in general, $2 \alpha \neq \phi$.

Eduard Sanchez

Numerade Educator

01:17

Problem 13

Discuss how the different visable-surface detection methods can be combined with an intensity model for displaying a set of polyhedrons with opaque surfaces.

Hunza Gilgit

Numerade Educator

02:16

Problem 14

Discuss how the various visible-surface detection methods can be modified to process transparent objects. Are there any visible-surface detection methods that cannot handle transparent surfaces?

Sanjeev Kumar

Numerade Educator

01:40

Problem 15

Set up an algorithm, based on one of the visiblesurface detection methods, that will identify shadow areas in a scene illuminated by a distant point source.

Khoobchandra Agrawal

Numerade Educator

05:12

Problem 16

How many intensity levels can be displayed with halftone approximations using $n \times n$ pixel grids, where each pixel can be displayed with $m$ different intensities?

Bruce Edelman

Numerade Educator

00:43

Problem 17

How many different color combinations can be generated using halftone approximations on a four-level RGB system with a $3 \times 3$ pixel grid?

Amy Jiang

Numerade Educator

00:43

Problem 18

How many different color combinations can be generated using halftone approximations on a two-level RGB system with a $4 \times 4$ pixel grid?

Amy Jiang

Numerade Educator

22:52

Problem 19

Write a routine to display a given set of surfaceintensity variations using halftone approximations with $4 \times 4$ pixel grids and two intensity levels ( 0 and 1) per pixel.

Brian Ketelobeter

Numerade Educator

08:30

Problem 20

Write a routine to generate ordered-dither matrices using the recurrence relation in Equation 48 .

Chris Trentman

Numerade Educator

03:15

Problem 21

Write a procedure to display a given array of intensity values using the ordered-dither method.

Ava Perkins

Numerade Educator

02:06

Problem 22

Write a procedure to implement the errordiffusion algorithm for a given $m \times n$ array of intensity values.

Adriano Chikande

Numerade Educator

02:45

Problem 23

Write an OpenGL program to display a scene containing a sphere, a cube, and a tetrahedron illuminated by two light sources: one is to be a local green source and the other a distant whitelight source. Set surface parameters for both diffuse and specular reflections with Gouraud surface rendering, and apply a linear intensityattenuation function.

Charles Carter

Numerade Educator

01:20