Lecture Computer graphics: Lecture 19 - Fasih ur Rehman

This chapter discuss the purpose of the components required for successful communications; describe these uses of computer communications: wireless messaging services, wireless Internet access points, cybercafés, global positioning systems, collaboration, groupware, voice mail, and Web services;

Computer Graphics

Lecture 19 Fasih ur Rehman

Last Class

• Rasterization

• Fragment Processing

• Clipping

Today’s Agenda

• Clipping

• Identification of the portions of geometric primitives by analytical calculations within the view windows

• Not to clip means

be wasted

Clipping Approach

• For each line segment

• The process of determining which

primitives, or parts of primitives, fit within the clipping or view volume

• The portions of all primitives that can

possibly be displayed (lie in the cube)

Line Clipping

• A clipper decides which primitives, or parts

of primitives can possibly be displayed and

be passed on to rasterizer

volume pass through the clipper, or are

accepted

are eliminated, or rejected or culled

volume must be clipped such that any part

lying outside the volume is removed

Accepted

Rejected

Clipped

Clipping Algorithms

• Test both end points of line

(same) edge

Clipping Algorithms

• Test both end points of line

(same) edge

Clipping Algorithms

• Combining the above two

view window, accept the line “trivially”

view window, reject the line “trivially”

accept and reject each segment trivially

• Clipping

• Fundamentals of Computer Graphics Third Edition by Peter Shirley and Steve

Marschner

• Interactive Computer Graphics, A

Top-down Approach with OpenGL (Sixth

Edition) by Edward Angel.