Lập sa bàn trên máy tính? (Quà đầu năm kính gữi Thầy Xuân Vũ và Cô Kim Nguyên PCT.UBND Tỉnh ĐN nhân ngày mùng ba tết Thầy; và các Em lớp Chuyên Tin Đồng nai: Đại Học Lạc Hồng và Trường Chuyên Lương Thế Vinh). (Từ năm 1992 đến nay mình không còn đứng trên bục giãng mong các Bạn thông cảm) PHẦN I: LÀM QUEN THỰC TẠI ẢO TRÊN MÁY TÍNH: I.1.-Thực tại Ảo (virtual reality - Computer Science): A computer simulation of a real or imaginary system that enables a user to perform operations on the simulated system and shows the effects in real time. Virtual Reality (VR), system that enables users to move and react in a computer-simulated environment. Various types of devices allow users to sense and manipulate virtual objects much as they would real objects. This natural style of interaction gives participants the feeling of being immersed in the simulated world. Virtual worlds are created by mathematical models and computer programs. Virtual reality simulations differ from other computer simulations in that they require special interface devices that transmit the sights, sounds, and sensations of the simulated world to the user. These devices also record and send the speech and movements of the participants to the simulation program. To see in the virtual world, the user wears a head-mounted display (HMD) with screens directed at each eye. The HMD contains a position tracker to monitor the location of the user''s head and the direction in which the user is looking. Using this information, a computer recalculates images of the virtual world to match the direction in which the user is looking and displays these images on the HMD. Users hear sounds in the virtual world through earphones in the HMD. The haptic interface, which relays the sense of touch and other physical sensations in the virtual world, is the least developed feature. Currently, with the use of a glove and position tracker, the user can reach into the virtual world and handle objects but cannot actually feel them. In recent years, virtual reality devices have improved dramatically as the result of various technological advances. Computers now are more powerful, have a higher memory capacity, are smaller, and are less expensive than in the past. These developments, along with the advent of small liquid crystal displays (LCDs) that can be used in HMDs, have made it possible for scientists to develop virtual reality simulations. xem URL: http://fusionanomaly.net/virtualreality.html I.2.-Làm quen Thực tại Ảo qua VRML (Virtual Reality Modeling Language) với dem.wrl: - VRML: Acronym for Virtual Reality Modeling Language. A scene description language for creating 3-D interactive Web graphics similar to those found in some video games, allowing the user to "move around" within a graphic image and interact with objects. VRML, a subset of Silicon Graphics'' Inventor File Format (ASCII), was created by Mark Pesce and Tony Parisi in 1994. While VRML files can be created in a text e***or, CAD packages, modeling and animation packages, and VRML authoring software are the tools preferred by most VRML authors. VRML files reside on an HTTP server; links to these files can be embedded in HTML documents, or users can access the VRML files directly. To view VRML Web pages, users need a VRML-enabled browser, such as WebSpace from Silicon Graphics, or a VRML add-in for Internet Explorer and a VRML plug-in for Netscape Navigator. When virtual reality suddenly appeared on the scene with a big whizbang, Timothy Leary appeared at a conference in New York with Jaron Lanier and a couple of other cybernauts. Leary was wearing the goggles on stage and declared, "Oooh, I have been here before." As that suggests, from the start a connection was established between virtual reality and the LSD experience - or as some of us prefer to call it, ''the entheogenic experience,'' which is just a fancy way of not using the word psychedelic because it alerts the police. xem URL: http://fusionanomaly.net/virtualreality.html - Tãi về tập tin dem.wrl tại URL: http://www.ablesw.com/r2v/dem.wrl Tập tin dem.wrl có nội dung: # VRML V2.0 utf8 # Created by R2V software, http://www.ablesw.com/r2v # start object Shape { geometry IndexedFaceSet { colorPerVertex TRUE coord Coordinate { point [ -540.000000 40.000000 -530.000000, -530.000000 40.000000 -530.000000, -530.000000 38.536987 -520.000000, -540.000000 40.000000 -520.000000, ..................................................... -130.000000 46.562012 -520.000000, ] } } # End object I.3.-Cài đặt phần hổ trợ đọc VRML cho trình duyệt WEB: -Tìm tập tin "Vrml2c.exe" trong đĩa cài đặt Ie (.IeXVrml2c.exe) hoặc hạ tãi về từ URL: http://www.intervista.com/ (Intervista Software) -Khởi động Vrml2c.exe để cài đặt Microsoft VRML 2.0 Viewer (version 1.0) is based on WorldView 2.0. I.4.-Khởi động dem.wrl để vào thế giới Thực tại Ảo. (còn tiếp)
