Week 1 - Definitions, Displays, Building Objects, Primitives, Attributes and Coordiates/2D Graphics Flashcards
Define modelling.
Effective representation and efficient computational modification of geometric shapes.
Define animation and simulation.
Generation and representation of dynamic imagery on a computer.
Define image synthesis.
Display of models and scenes on a computer.
Define imaging and computer vision.
Manipulation of images and extraction of information from images.
Define visualisation.
Methods to visually represent the information content of large-scale, multi-dimensional data sets.
What are all images made up of?
Pixels (Picture Elements)
What is image resolution?
The density of points describing the image.
What can the property of a pixel define?
Its colour or intensity.
Based on physics, what is a pure colour?
A wave with Wavelength (λ) and Amplitude (intensity or energy) (I).
What is the tri-stimulus colour theory?
The receptor performance implies that colours do not have a unique energy distribution.
Colours which are a distribution over all wavelengths can be matched by mixing three: RGB
Describe colour matching.
Given any colour light source, regardless of the distribution of wavelengths that it contains, we can try to match it with a mixture of three light sources:
X = rR + gG + bB, where R, G and B are pure light sources, and r, g and b are their intensities.
What are the three primary colours of subtractive colour mixing?
Cyan, magenta and yellow.
What are the three primary colours of additive colour mixing?
Red, blue and green.
How are coordinates defined in raster displays?
Pictures or scenes specified in Cartesian coordinates (with infinite precision), but drawn on display with finite resolution.
What is a framebuffer?
Contains an entry for every pixel in the display. Pixels to be illuminated are written into the frame buffer in arbitrary order but read sequentially by hardware.
What is a framebuffer?
An in-memory image of the display.
What is rasterisation?
Algorithms for converting infinite precision specification into pixels.
What is double buffering?
Two framebuffers - draw into one while displaying the other, then swap.
What is the 2D graphics pipeline?
Model scene -> view scene -> output
Describe the model scene part of the graphics pipeline.
Build objects from primitives.
Object constructed in local coordinates.
Object placed in world coordinates.
Describe the view scene part of the graphics pipeline.
Specify area of scene to view (window).
Specify area of display on which to view viewport.
Clip scene to window.
Map clipped scene to viewport.
Can take output from several scenes.
Describe the output part of the graphics pipeline.
Rasterise vectors to pixels for display.
Rasterisation works on primitives.
Attributes determine the appearance.
Define local coordinates.
Specify locations of primitives in object.
Arbitrary units (chosen by the modeller).
Define world coordinates.
= User coordinates.
Specify locations of objects in scene.
Specify location of clipping window.
Units dependent on graphics API.
