Computer Graphics

Computer Graphics

The technology associated with the use of computer technology to convert created or collected data into visual representations /
Using a computer to convert a model into an image

Explicit geometry

Geometry Modeling:
Triangle meshes, Patches, Subdivision surfaces,…

Implicit geometry

Geometry Modeling:
Surface defined by x2 + y2 + z2 = 10
Fractal sets, procedural definition, …

Volume data

Geometry Modeling:
Samples from MRI, ultra-sound, simulation…

Frame Buffer

A block of memory, dedicated that contains the pixel array to be passed to the optical display system

Pixel

One element of frame buffer
- uniquely accessible point in image

Resolution

Width x Height (in pixels)
- 640x480, 1280x1024, 1920x1080

Color depth

Number of bits per-pixel in the buffer
- 8, 16, 24, 32-bits for RGBA

Buffer size

Total memory allocated for buffer

Alpha

Frame Buffer Opacity:
Used for compositing or merging images

Alpha channel

Frame Buffer Opacity:
Added to color, Holds the alpha value for every pixel
8 bit range: 0 (transparent) – 255 (opaque)

Buffer size

____ ____ = width x height x color depth

921600 bytes

If width = 640, height = 480, color depth = 24 bits
Buffer size = ?
(No commas, include measurement)

6220800 bytes

If width = 1920, height = 1080, color depth = 24 bits
Buffer size = ?
(No commas, include measurement)

Physical device

That can be described by their real-world physical properties
(mouse, keyboard, joystick…)

Logical Device

Application abstraction

Transformations

Create object in convenient coordinates, Reuse basic shape multiple times, Hierarchical modeling, System independent, Virtual cameras

2D Rotations

Type of Transformation:

3D Rotations

Type of Transformation:

Scaling

Type of Transformation:

Translation

Type of Transformation:

Homogeneous Coordinates

Image:

Deformations

Transformations that do not preserve shape
EX: Non-uniform scaling, Shearing, Tapering, Twisting, Bending

Shearing

Type of Deformation:

Tapering

Type of Deformation:

Twisting

Type of Deformation:

Bending

Type of Deformation:

Object Coordinates

Convenient place to model the object

World Coordinates

Common coordinates for the scene