Introduction



Project Purpose

Graphics model is composed of a huge amount of data and it takes much time to display the whole data. Especially when it is displayed through networks, users sometimes can't stand for the slow display. Therefore, it is necessary to reduce the huge amount of graphics data and refine it gradually. Using progressive refinement, users understand what will happen in the network and what kind of image will be displayed.

There are two purposes of the project.

  1. Graphics Data Reduction
    how to reduce graphics data and merge a set of reduced data into one file

  2. Network Browser
    how to reconstruct the original data and refine it


Graphics Data Format

There are several types of graphics data; however, recently the most popular graphics data format is VRML (Virtual Reality Modeling Language). VRML is defined by VAG (VRML Architecture Group) and used over the world. VAG is composed of 10 computer graphics companies: Virtus Corp., Silicon Graphics, Intervista Software, Sun Microsystems, IBM, Worlds Inc., Integrated Data Systems, Visible Decisions, Strata and Caligari. Several browsers which can display VRML files are created such as Webspace, WebView, Webfx, Worldview and Cosmo Player.

Unfortunately, there is no network browser which supports the idea of progressive refinement. Therefore, a new network browser called GraNet is created in this project.

There are several types of components defined in the form of VRML; however, it takes a lot of time to support all components. Fortunately, the following components are enough to realize the idea of progressive refinement and they are dealt in this project.

  1. Vertex data: including floating point format such as 1.0e-4
  2. Facet data: polygons such as triangle, rectangle and pentagon
  3. Color data: only diffuse color in this project