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

Explain in detail about the ruby arrays, Explain in detail about the Ruby a...

Explain in detail about the Ruby arrays Ruby arrays have many interesting and powerful methods. Besides indexing operations which go well beyond those discussed above, arrays h

How do you rotate a binary tree, How do you rotate a Binary Tree?  Rot...

How do you rotate a Binary Tree?  Rotations in the tree: If after inserting a node in a Binary search tree, the balancing factor (height of left subtree - height of right

Explain the halting problem, Explain the halting problem Given a comput...

Explain the halting problem Given a computer program and an input to it, verify whether the program will halt on that input or continue working indefinitely on it.

Hash function, Q. Define the graph, adjacency matrix, adjacency list, hash ...

Q. Define the graph, adjacency matrix, adjacency list, hash function, adjacency matrix, sparse matrix, reachability matrix.

Explain open addressing, Open addressing The easiest way to resolve a c...

Open addressing The easiest way to resolve a collision is to start with the hash address and do a sequential search by the table for an empty location.

Depth First Search Through Un-weighted Connected Graph , Q. Write down the ...

Q. Write down the algorithm which does depth first search through an un-weighted connected graph. In an un-weighted graph, would breadth first search or depth first search or neith

Explain backtracking, Explain Backtracking The  principal idea is to co...

Explain Backtracking The  principal idea is to construct solutions single component  at a time  and evaluate such  partially constructed candidates as follows. If a partiall

Illustrate hls colour model, HLS Colour Model  This model has the doub...

HLS Colour Model  This model has the double-cone representation shown in Figure 3.40. The three colour parameters in this model are called hue (H), lightness (L), and Saturati

Design a framework of a genetic algorithm, You have to design a framework o...

You have to design a framework of a Genetic Algorithm (GA) with basic functionality. The basic functionality includes representation, recombination operators, tness function and se

Sorting, Define Hashing. Store the following values in a hash table of tabl...

Define Hashing. Store the following values in a hash table of table size 11 using division method: 25, 42, 96, 101, 102, 162, and 197. In case of collision, use other hash functio

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