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

Deletion of any element from the queue, Program segment for the deletion of...

Program segment for the deletion of any element from the queue delmq(i)  /* Delete any element from queue i */ { int i,x; if ( front[i] == rear[i]) printf("Queue is

Depth-First Traversal, With the help of a program and a numerical example e...

With the help of a program and a numerical example explain the Depth First Traversal of a tree.

Define order of growth, Define order of growth The  efficiency  analysi...

Define order of growth The  efficiency  analysis  framework  concentrates   on  the  order  of  growth  of  an  algorithm's   basic operation count as the principal indicator o

What are the advantages of using assertions, Using Assertions When writ...

Using Assertions When writing code, programmer must state pre- and subtle post conditions for public operations, state class invariants and insert unreachable code assertions a

Define the carrier set of the symbol abstract data type, Define the Carrier...

Define the Carrier set of the Symbol ADT Carrier set of the Symbol ADT is the set of all finite sequences of characters over Unicode characters set (Unicode is a standard char

Explain in detail about the abstract data type, Abstract data type The ...

Abstract data type The thing which makes an abstract data type abstract is that its carrier set and its operations are mathematical entities, like geometric objects or numbers;

Test whether a binary tree is a binary search tree, Q. Write down an algori...

Q. Write down an algorithm to test whether a Binary Tree is a Binary Search Tree.              A n s . The algorithm to check whether a Binary tree is as Binary Search

Sorting, Sort the following array of elements using quick sort: 3, 1, 4, 1,...

Sort the following array of elements using quick sort: 3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5, 8.

Explain graph traversal, Graph Traversal In many problems we wish to in...

Graph Traversal In many problems we wish to investigate all the vertices in a graph in some systematic order. In graph we often do not have any single vertex singled out as spe

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