1. Chapter 10: Computer Graphics

2. Chapter 10: Computer Graphics
The Scope of Computer Graphics
Overview of 3D Graphics
Modeling
Rendering
Dealing with Global Lighting
Animation
OpenGL

3. 2D Versus 3D Graphics
2D Graphics: Deals with manipulating two-dimensional images
3D Graphics: Deals with producing and displaying images of three-dimensional virtual scenes.

4. 2D graphics and image processing
2D graphics focuses on the task of converting two-dimensional shapes (circles, rectangles, letters, etc.) into patterns of pixels to produce an image. Image processing, an area of artificial intelligence, focuses on analyzing the pixels in an image in order to identify patterns that can be used to enhance or perhaps “understand” the image.

5. A “photograph” of a virtual world produced using 3D graphics (from Toy Story by Walt Disney Pictures/Pixar Animation Studios)

6. Rendering
Producing a 2D image of the scene by computing how the objects in the scene would appear in a photograph made by a camera at a specified position.

7. The 3D graphics paradigm

8. Modeling Objects Shape: Represented by a polygonal mesh obtained from
Traditional mathematical equations
Berzier curves and surfaces
Procedural models
Other methods being researched
Surface: Can be represented by a texture map

9. Pixel-by-pixel process is computationally complex and requires determining how the objects in the scene interact with light. A hard, shiny surface in bright light should be rendered differently than a soft, transparent surface in indirect light.

10. A polygonal mesh for a sphere

11. A Bezier curve

12. Some shapes may be so complex that obtaining realistic models by geometric modeling or manual digitizing is unfeasible. Such as trees, complex terrain such as mountain ranges, and gaseous substances such as clouds, smoke, or the flames of a fire. In these cases, polygonal meshes can be obtained by writing programs that construct the desired shape automatically. Such programs are collectively known as procedural models. A program unit that applies an algorithm to generate a desired structure.

13. Growing a polygonal mesh for a mountain range

14. Texture mapping is similar to the process of applying wallpaper in that it associates a predefined image with the surface of an object.

15. A scene from Shrek 2 by Dreamworks SKG (© Dreamworks/The Kobal Collection)

16. Reflection Versus Refraction
Reflection: Light rays bounce off surface.
Refraction: Light rays penetrate surface.

17. Reflected light

18. Specular versus diffuse light
Reflected light is called specular light
Many rays will be scattered in different directions. This scattered light is called diffuse light

19. Refracted light

20. Rendering
Clipping: Restricts attention to objects within view volume. Trimming.
Scan Conversion: Associates pixel positions with points in scene
Shading: Determines appearance of points associated with pixels

21. Identifying the region of the scene that lies inside the view volume

23. Scan conversion
The process of associating pixel positions with points in the scene is called scan conversion or rasterization. An array of pixels is known as a raster.

24. The scan conversion of a triangular patch

25. Shading Techniques Flat Shading: Creates faceted appearance
Gouraud and Phong Shading: Creates smooth, rounded appearance
Bump Mapping: Creates bumpy, rounded appearance

26. A sphere as it might appear when rendered by flat shading

27. A conceptual view of a polygonal mesh with normal vectors at its vertices

28. A sphere as it might appear when rendered using bump mapping

29. Rendering Pipeline
Consists of traditional algorithms for clipping, scan conversion, and shading
Used as an abstract tool in graphics applications

30. Identifying and discarding points in a scene that are blocked from view is the process called hidden-surface removal.

31. Z-buffer
A popular technique uses an extra storage area, called a z-buffer (also a depth buffer), which contains an entry for each pixel in the image. Each position in the z-buffer is used to store the distance along the appropriate projector from the camera to the object currently represented by the corresponding entry in the frame buffer.

32. Local Versus Global Lighting
Local Lighting Model: Does not account for light interactions among objects
Global Lighting Model: Accounts for light interactions among objects
Ray Tracing
Radiosity

33. Ray tracing

34. Animation
Storyboard: A sequence of sketches summarizing the entire animation
Frame: One of many images used to create animation
Key Frames: Frames capturing the scene at specified points in time
In-betweening: Producing frames to fill the gaps between key frames

35. Simulating Motion
Dynamics: Applies laws of physics to determine position of objects
Kinematics: Applies characteristics of joints and appendages to determine position of objects
Avars
Motion Capture

36. Graphics software interfaces
Examples include OpenGL (short for Open Graphics Library) is a nonproprietary system developed by Silicon Graphics and widely used in the video game industry. Direct3D, which was developed by Microsoft for use in Microsoft Windows environments.

37. https://www. youtube. com/watch. v=xKVS_81Op5A https://www. youtube