2.Introduction to image synthesis

Question 1

The user moves the mouse, where does opengl fit in?

Answer 1

Input device -> OpenGLAPI->App program->App model (and then back again ending in display)

Question 2

What can a vector based display draw?

Answer 2

Lines, text and points

Question 3

In a graphics pipeline what is a fragment?

Answer 3

A candidate pixel which may or may not be displayed

Question 4

What is the fundamental difference between a fixed and a programmable pipeline?

Answer 4

In a programmable pipeline the user has to program some parts themselves (SHADERS)

Question 5

Which statement best describes OpenGL?

Answer 5

An API for doing 3D computer graphics

Question 6

What dimension of matrix does opengl use for 3d transformations?

Answer 6

4x4

Question 7

Who oversees the development of OpenGL?

Answer 7

Khronos

Question 8

Name 7 features of OpenGL

Answer 8

1. 3D Graphics
2. Coordinate Transformations
3. Viewing “camera”
4. Hidden Surface Removal
5. Lighting & Shading
6. Texturing
7. Pixel (image) operations

Question 9

Name the support libraries of OpenGL

Answer 9

GLU & GLUT

Question 10

The graphics pipeline flows from ____ to _____

Answer 10

Application’s 3D vertices —->pixels

Question 11

Last two stages (of 5) in the graphics pipeline

Answer 11

4.RASTERIZATION (scan conversion):
Primitives -> Fragments
5.FRAGMENT OPERATIONS (blending, depth test)
Fragments -> Pixels

Question 12

First two stages (/5) in the graphics pipeline

Answer 12

1. Transformations & viewing

2. Lighting (Gouraud/Phong)

Question 13

Middle stage of the graphics pipeline

Answer 13

3.Primitive assembly (clipping)

Question 14

Name the two types of shader in the programmable pipeline that must be provided

Answer 14

Vertex shader and fragment shader

Question 15

Algorithm to scan convert a line?

Answer 15

Bresenham’s algorithm

Question 16

How does Bresenham’s algorithm scan convert a line?

Answer 16

Approximate with newarest available pixels

Question 17

What algorithm to scan convert a polygon?

Answer 17

Sweepline algorithm

Question 18

Data structure of hidden surface removal? What does it store?

Answer 18

Z-buffer (stores pixel z-depth)

Question 19

What’s a problem that can happen when numbers in z-buffer aren’t precise enough?

Answer 19

Z-fighting or stiching

Question 20

What are raster graphics?

Answer 20

A raster graphics or bitmap image is a DOT MATRIX DATA STRUCTURE that represent a rectangular grid of pixels stored in an IMAGE FILE

Question 21

When working with a fixed pipeline what does the programmers application provide through the API?

Answer 21

PARAMETER CHANGES