| Abstract [eng] |
VRML (Virtual Reality Modeling Language) is a hierarchical three-dimensional (3D) computer graphic format used in the web browsers that defines the behavior and geometry of 3D scenes. However, while in the past VRML was very popular, now it’s not widely used. Currently, the popularity of 3D graphics in the web is very closely related to WebGL technology. WebGL is an application programming interface (API) that uses JavaScript programming language to determine the interactivity of 3D graphics. In this thesis we examined the possibilities of converting threedimensional computer graphic formats - VRML to WebGL. At first, we analyze the main working principles of VRML format and compared it toWebGL technology in order to choose the platform for software that would be able to convert 3D objects with their geometry, materials, animations and navigation system. We also reviewed other similar technologies that can be used to display 3D graphics on web browsers. After examined various 3D graphics development programs we selected the Three.js library that uses JavaScript language. This library was used to create the converter. In this thesis we shown algorithms that can be used to analyze to mediate X3D file format converted VRML file and display geometries, textures and normals described in indexed face set. In order to verify in practice whether the algorithms that were created are working well, various VRML objects have been converted from VRML to WebGL, including a VRML files containing a complex indexed face set nodes - Vilnius St. Nicholas Church and Vilnius university courtyards. We also evaluated WebGL objects impact to web browser performance and the sizes of the WebGL files saved. After analyzing VRML and Three.js library animation models we presented VRML animation conversion toWebGL action scheme. We also changed standard Three.js library camera control functionality to more accurately convert VRML format navigation system. The proposed Three.js converter has been compared to another widely used X3DOM converter that also have been used to display VRML and X3D files in a web browser. We compared both algorithms geometry’s, textures, animation and navigation conversion options. Performance in frames per seconds was measured on various web browsers. The ability to save created WebGL scene to other 3D graphics formats was analyzed as well. |
