Computer Graphics Flashcards
What is Modelling?
Effective representation and efficient computational modification of geometric shapes.
What is Animation and Simulation?
Generation and representation of dynamic imagery on a computer.
What is Image Synthesis?
Display of models and scenes on a computer.
What is Imaging and Computer Vision?
Manipulation of images and extraction of information from images.
What Is Visualisation?
Methods to visually represent the information content of large-scale, multi-dimensional data sets.
What is a Raster Display?
A display that consists of pixels with a defined colour and intensity. It also contains a framebuffer.
What is the RGB colour theory?
The theory that every colour can be made up of red, green and blue
What is a Framebuffer?
An in-memory representation of pixel states used to store the image displayed.
What is double buffering?
Having two framebuffers, draw into one while displaying the other then swap.
What are Primitives?
Simple geometric elements such as a line, point, boundary or polygon, that make up more complex shapes and images. They are specified by location and dimension.
What are Complex Objects?
Objects built from primitives, but with visual attributes such as colour, line-style, and fill style.
What are local and world coordinates?
Local coordinates define objects individually, while world coordinates describe these objects place in the world.
What is a clipping window in computer graphics?
The area of a scene, defined in world coordinates, that you choose to display.
What is a viewport?
An area on the display device (screen) where the clipped portion of the scene is rendered, defined in device coordinates.
Outline the main stages of the 2D Graphics Pipeline.
Model Scene: Construct objects from primitives in local coordinates and place them into world coordinates.
View Scene: Specify window (scene area) and viewport (display area), then clip and map the scene.
Output: Rasterise primitives to pixels using attributes for display.
What are Device Coordinates?
Coordinates specifying pixel locations on the physical device or screen, typically measured in pixels or physical units.
What is a Linear Transformation?
A transformation represented by multiplying vectors by matrices, such as rotation, scaling, and shear.
What linear transformation is
[ cosθ -sinθ ]
[ sinθ cosθ ]
and what would the effect be?
Rotation by θ
What linear transformation is
[ λ1 0 ]
[ 0 λ2 ]
and what would the effect be?
Scaling x by λ1, and y by λ2
What linear transformation is
[ 1 λ ]
[ 0 1 ]
and what would the effect be?
Shear, and it adds λy to every x value
What is the key difference between linear and affine transformations?
Affine transformations include translation; linear ones do not.
How do you combine two affine transformations (M1, t1) and (M2, t2)?
M = M2M1 and T = M2t1 + t2
What is an affine transformation
A linear transformation plus a translation
What are Homogeneous Coordinates?
They add a 3rd component to 2D points (x, y) → (x, y, 1), which allows affine transformations to be handled with a single matrix multiplication.
What is the advantage of using homogeneous coordinates?
Allows all affine transformations to be combined in one matrix multiplication.
What is the form of a 2D affine transformation matrix in homogeneous coordinates?
[m11
