State warnock algorithm, Data Structure & Algorithms

Assignment Help:

Warnock's Algorithm

An interesting approach to the hidden-surface problem was presented by Warnock. His method does not try to decide exactly what is happening in the scene but rather just tries to get the display right. As the resolution of the display increases, the amount of work which the algorithm must do to get the scene right also increases, (this is also true for scan-line algorithms). The algorithm divides the screen up into sample areas. In some sample areas it will be easy to decide what to do. If there are no faces within the area, then it is left blank. If the nearest polygon completely covers it, then it can be filled in with the colour of that polygon. If neither of these conditions holds, then the algorithm subdivides the sample area into smaller sample areas and considers each of them in turn. This process is repeated as needed. It stops when the sample area satisfies one of the two simple cases or when the sample area is only a single pixel (which can be given the colour of the foremost polygon). The process can also be allowed to continue to half or quarter pixel-sized sample areas, whose colour may be average over a pixel to provide antialiasing.  

The test for whether a polygon surrounds or is disjoint from the sample area is much like a clipping test to see if the polygon sides cross the sample-area boundaries. Actually the minimax test can be employed to identify many of the disjoint polygons. A simple test for whether a polygon is in front of another is a comparison of the z coordinates of the polygon planes at the corners of the sample area. At each subdivision, information learned in the previous test can be used to simplify the problem. Polygons which are disjoint from the tested sample area will also be disjoint from all of the sub-areas and do not need further testing. Likewise, a polygon which surrounds the sample area will also surround the sub-areas.

 


Related Discussions:- State warnock algorithm

Write stream analogues of list processing functions, (a) Write (delay ) as...

(a) Write (delay ) as a special form for (lambda () ) and (force ), as discussed in class. (b) Write (stream-cons x y) as a special form, as discussed in class. (c) Write

How do collisions happen during hashing, How do collisions happen during ha...

How do collisions happen during hashing? Usually the key space is much larger than the address space, thus, many keys are mapped to the same address. Assume that two keys K1 an

Quick sort, This is the most extensively used internal sorting algorithm. I...

This is the most extensively used internal sorting algorithm. In its fundamental form, it was invented by C.A.R. Hoare in the year of 1960. Its popularity lies in the easiness of i

Which data structure is used for implementing recursion, Which data structu...

Which data structure is used for implementing recursion Stack.

Acyclic graph, Tree is a widely used data structure employed for representi...

Tree is a widely used data structure employed for representing several problems. We studied tree like a special case of acyclic graph. Though, rooted trees are most prominent of al

Programs, Develop a program that accepts the car registration( hint: LEA 43...

Develop a program that accepts the car registration( hint: LEA 43242010)

Complexity of an algorithm, What do you mean by complexity of an algorithm?...

What do you mean by complexity of an algorithm? The complexity of an algorithm M is the function f(n) which gives the running time and/or storage space need of the algorithm i

Multiple queue, algorithm for multiple queue with example program

algorithm for multiple queue with example program

C++ function, Write c++ function to traverse the threaded binary tree in in...

Write c++ function to traverse the threaded binary tree in inorder traversal

Addressing modes, Compare zero-address, one-address, two-address, and three...

Compare zero-address, one-address, two-address, and three-address machines by writing programs to compute: Y = (A – B X C) / (D + E X F) for each of the four machines. The inst

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd