problem 1: Compare the object-space and image-space visibility tests in synthesizing an image for display.
describe one visibility test in detail.
problem 2: When scan-converting items for display, a Z-buffer is sometimes employed to avoid some sorting. Outline its operation and limitations. The use of an A-buffer will enhance matters. Describe why.
problem 3: A certain image comprises a number Q of differently colored pixels. There are not adequate different pixel values accessible to represent these and so a method of approximation is required.
describe an approach and comment on its performance.
problem 4: RasterOp is the name given to operation that produces, from a number of raster’s of pixel values, another raster of pixel values.
describe appropriate versions which could be used:
a) To move a window on screen while preserving the background.
b) To blend two images in proportions given by a mask.