Kỹ thuật đồ họa vầ hiện thực ảo

(c) SE/FIT/HUT 2002 Lesson 1: Kӻ thuұt ÿӗ hӑa và HiӋn thӵc ҧo Computer Graphics And Virtual Reality „ Kӻ Thuұt ÿӗ hӑa cѫ sӣ „ Kӻ Thuұt ÿӗ hӑa tiên tiӃn „ HiӋn thӵc ҧo - VRML Le Tan Hung hunglt@it-hut.edu.vn (c) SE/FIT/HUT 2003 2 Tәng quan vӅ kӻ thuұt ÿӗ hoҥ ‰ Các khái niӋm tәng quan cӫa kӻ thuұt ÿӗ hoҥ máy tính ‰ Các kӻ thuұt ÿӗ hoҥ ‰ Phân loҥi các lƭnh vӵc cӫa kӻ thuұt ÿӗ hoҥ ‰ HӋ ÿӗ hӑa tѭѫng tác (interactive) ‰ Phҫn cӭng ÿӗ hoҥ (Graphics Hardware) (c) SE/FIT/HUT 2003 3 A Brief History of Computer Graphics 1885 - CRT (Cathode Ray Tube) 1887 - Edison patents motion picture camera 1888 - Edison and Dickson record motion picture photos on a wax cylinder (c) SE/FIT/HUT 2003 4 A Brief History of Computer Graphics 1926 – J.L. Baird invents the television. 30 line vertical, black and red scan. (c) SE/FIT/HUT 2003 5 A Brief History of Computer Graphics 1963 „ IBM creates the 360 models „ One of the First General Purpose Mainframes „ SRI develops the mouse. (c) SE/FIT/HUT 2003 6 A Brief History of Computer Graphics 1966 „ Ralph Baer creates the 1st comsumer CG product: Odyssey Pinball (c) SE/FIT/HUT 2003 7 A Brief History of Computer Graphics 1967 „ GE introduces first full colour real time flight simulator for NASA (c) SE/FIT/HUT 2003 8 A Brief History of Computer Graphics 1968 „ John Whitney: Permutations In "Permutations," (1968) he delineates a marvellous and exciting new world. One senses a choreographer. The movements are reminiscent of traditional ballet. The shapes follow the dictates of formal geometry more than those of abstract painting. Movement is three- dimensional and the ambition for a more polished three-dimensional shaded space is apparent. (c) SE/FIT/HUT 2003 9 A Brief History of Computer Graphics 1973 „ Michael Crichton’s “Westworld” uses 2D graphics „ First time computer is used for image manipulation. „ Featured scenes that showed audiences the world viewed by the eye circuitry of a synthetic human (played by a very real Yul Brenner) in a future Western theme park. This effect was achieved with 2D computer graphics tools mostly derived from image processing techniques. (c) SE/FIT/HUT 2003 10 A Brief History of Computer Graphics 1974 „ Intel develop the 8080 processor. 1975 „ Mandelbrot plots fractals „ Bill Gates starts Microsoft (c) SE/FIT/HUT 2003 11 A Brief History of Computer Graphics 1976 „ Steve Jobs and Steve Wozniak start Apple. 1977 „ Academy of Motion Pictures Art and Sciences introduces Visual Effects category for Oscars. (c) SE/FIT/HUT 2003 12 A Brief History of Computer Graphics 1977 „ Star Wars wins oscar for special effects. 1978 •Superman wins oscar for special effects. (c) SE/FIT/HUT 2003 13 A Brief History of Computer Graphics 1979 „ Alien wins oscar for visual effects. 1980 •The Empire Strikes Back wins oscar for visual effects. (c) SE/FIT/HUT 2003 14 A Brief History of Computer Graphics 1980 „ Disney’s TRON is the first live action film with over 20 mins of computer animations. „ Seagate Technology releases the HDD for PCs (c) SE/FIT/HUT 2003 15 A Brief History of Computer Graphics 1981 IBM introduces the first IBM PC (16 bit 8088 chip) • Raiders of the Lost Ark wins an oscar for visual effects. (c) SE/FIT/HUT 2003 16 A Brief History of Computer Graphics 1982 „ The Genesis Effect (ILM) for Startrek II is the first all computer animated visual effects shot for film. (c) SE/FIT/HUT 2003 17 A Brief History of Computer Graphics 1983 „ First Coke Polar Bears Commercial „ 1984 PIXAR Opens (c) SE/FIT/HUT 2003 18 A Brief History of Computer Graphics 1985 „ The Last Starfighter is the first live action feature film with realistic computer animation of highly detailed models. (c) SE/FIT/HUT 2003 19 A Brief History of Computer Graphics 1989 „ The Abyss is the first movie to include convincing 3D character animation. (c) SE/FIT/HUT 2003 20 A Brief History of Computer Graphics 1990 „ Windows 3.0 ships 1993 „ Myst 1994 „ Playstation and N64 released (c) SE/FIT/HUT 2003 21 A Brief History of Computer Graphics 1995 „ Quake Released by Id Software „ Toy Story becomes the first fully 3D computer animation feature film. (c) SE/FIT/HUT 2003 22 A Brief History of Computer Graphics 1996 „ Independence Day wins oscar for visual effects. (c) SE/FIT/HUT 2003 23 A Brief History of Computer Graphics 1997 „ Titanic wins oscar for visual effects. „ PIXAR wins oscar for best short film: Geri’s Game. (c) SE/FIT/HUT 2003 24 A Brief History of Computer Graphics 1998 „ Armageddon „ Mouse Hunt „ Bugs Life 1999 „ The Matrix „ Star Wars: The Phantom Menace „ Disney’s Tarzan (c) SE/FIT/HUT 2003 25 A Brief History of Computer Graphics 2000 „ Sony Playstation II „ Walking with Dinosaurs „ Disney’s Shrek 2002 Microsoft’s XBOX (c) SE/FIT/HUT 2003 26 Kӻ thuұt ÿӗ hӑa vi tính. „ Definition (ISO) „ Computer Graphics (KͿ thu̵t ÿ͛ ho̩ máy tính) „ Computer graphics deals with all aspects of creating images with a computer model – Interactive Computer Graphics: (c) SE/FIT/HUT 2003 27 Kӻ thuұt ÿӗ hoҥ ÿiӇm (Sample based-Graphics) „ Các mô hình, hình ҧnh cӫa các ÿӕi tѭӧng ÿѭӧc hiӇn thӏ thông qua tӯng pixel (tӯng mүu rӡi rҥc) „ Ĉһc ÿiӇm: „ Phѭѫng pháp ÿӇ tҥo ra các pixel (c) SE/FIT/HUT 2003 Bitmap lines,areas,... SRGP library Pascal / C program X Window System Graphics hardware Image image formats, compression, transfer graphics algorithms colourpositions (c) SE/FIT/HUT 2003 29 Graphical Model Rendering Output Device Rendering Parameters Kӻ thuұt ÿӗ hoҥ vector „ Vector = geometrical model + rendering (c) SE/FIT/HUT 2003 30 Ví dө vӅ hình ҧnh ÿӗ hoҥ Vector (c) SE/FIT/HUT 2003 31 Muscle ModelWireframe Model Skeletal Model Skin Hair Render and Touch up © Walt Disney and TSL (c) SE/FIT/HUT 2003 32 Raster and Vector Graphics „ Raster „ Hình ҧnh và mô hình cӫa các vұt thӇ ÿѭӧc biӇu diӉn bӣi tұp hӧp các ÿiӇm cӫa grid „ Thay ÿәi thuӝc tính cӫa các pixel => thay ÿәi tӯng phҫn và tӯng vùng cӫa hình ҧnh. „ Copy ÿѭӧc các pixel tӯmӝt hình ҧnh này sang hình ҧnh khác. „ Vector „ Không thay ÿәi thuӝc tính cӫa tӯng ÿiӇm trӵc tiӃp „ Xӱ lý vӟi tӯng thành phҫn hình hӑc cѫ sӣ cӫa nó và thӵc hiӋn quá trình tô trát và hiӇn thӏ lҥi. „ Quan sát hình ҧnh và mô hình cӫa hình ҧnh và sӵ vұt ӣ nhiӅu góc ÿӝ khác nhau bҵng cách thay ÿәi ÿiӇm nhìn và góc nhìn. (c) SE/FIT/HUT 2003 33 Phân loҥi các lƭnh vӵc cӫa Computer Graphics Kü thuËt ph©n tÝch vμ t¹o ¶nh §å ho¹ ho¹t h×nh vμ nghÖ thuËt Kü thuËt nhËn d¹ng Xö lý ¶nh §å ho¹ minh ho¹ CAD/CAM System Kü thuËt ®å ho¹ KiÕn t¹o ®å ho¹ Xö lý ®å ho¹ (c) SE/FIT/HUT 2003 34 Phân loҥi theo hӋ toҥ ÿӝ Kü thuËt ®å ho¹ Kü thuËt ®å ho¹ 2 chiÒu Kü thuËt ®å ho¹ ba chiÒu (c) SE/FIT/HUT 2003 35 Phân loҥi theo chӭc năng „ Kӻ thuұt xӱ lý ҧnh (COMPUTER IMAGING) „ Kӻ thuұt nhұn dҥng (Computer Vision techniques attempt to provide meaning to computer) images. „ Kӻ thuұt tәng hӧp ҧnh (Computer Graphics) „ Geometry modelling (c) SE/FIT/HUT 2003 36 Các ӭng dөng tiêu biӇu cӫa kӻ thuұt ÿӗ hӑa „ Xây dӵng giao diӋn ngѭӡi dùng (User Interface) „ Tҥo các biӇu ÿӗ trong thѭѫng mҥi, khoa hӑc, kӻ thuұt „ Tӵ ÿӝng hoá văn phòng và chӃ bҧn ÿiӋn tӱ „ ThiӃt kӃ vӟi sӵ trӧ giúp cӫa máy tính (CAD_CAM) „ Lƭnh vӵc giҧi trí, nghӋ thuұt và mô phӓng „ ĈiӅu khiӇn các quá trình sҧn xuҩt (Process Control) „ Lƭnh vӵc bҧn ÿӗ (Cartography) (c) SE/FIT/HUT 2003 37 (c) SE/FIT/HUT 2003 38 (c) SE/FIT/HUT 2003 39 CAD-CAM application (c) SE/FIT/HUT 2003 40 HӋ ÿӗ hӑa tѭѫng tác ƒ Mô hình hӋ ÿӗ hoҥ tѭѫng tác ƒ Các thành phҫn cӫa hӋ ÿӗ hoҥ tѭѫng tác ƒ Bӝ xӱ lý tѭѫng tác vӟi ngѭӡi sӱ dөng ƒ Các chuҭn cӫa hӋ ÿӗ hoҥ (c) SE/FIT/HUT 2003 41 concerned with: - hardware - how to display (rasterization) concerned with: - modeling - modeling transf. - color models - material property - lighting property G U I MODELING RENDERING DISPLAYING what is a table, a car, x x x ( to describe) to the computer Geometric Engine (to capture) the description create 2D image from 2D / 3D models Rendering Engine generate image on screen (to show) the image Raster & Display Engine concerned with : - viewing & projection - drawing & clipping primitives - local illumination & shading - texture mapping - global rendering Thành phҫn trong chӭc năng cӫa kӻ thuұt ÿӗ hoҥ (c) SE/FIT/HUT 2003 42 Các thành phҫn cӫa hӋ ÿӗ hoҥ tѭѫng tác Application Data Structure Application Program Graphics System Computer Graphics Devices (c) SE/FIT/HUT 2003 43 Model of RGP Application model Application program SRGP Display Hardware output pipeline input pipeline output primitives output attributes Canvascontrol copyPixel Input device measures Input device control (c) SE/FIT/HUT 2003 3D Graphics Over World Wide Web SRGP library Pascal / C program X Window System Graphics hardware Image image formats, compression, transfer graphics algorithms colour Drawing packages transformation of objects 3D Graphics projections lighting,shading lines,areas,...positions Video WWW Animation WWW VRML (c) SE/FIT/HUT 2003 45 Thành phҫn thѭ viӋn ÿӗ hoҥ „ Các thӵc thӇ cѫ sӣ ƒ ĈiӇm (pixel) ƒ Ĉѭӡng thҷng (line) ƒ Ĉѭӡng tròn (circle) „ Ĉa giác (polygon) ..v..v. „ Các thuӝc tính ƒ Màu sҳc (color) ƒ KiӇu ÿѭӡng vӁ (line style) ƒ KiӇu văn bҧn (text style) „ Mүu tô (pattern). (c) SE/FIT/HUT 2003 46 Bӝ xӱ lý tѭѫng tác vӟi ngѭӡi sӱ dөng „ HӋ thӕng ÿӗ hoҥ thông thѭӡng phҧi chӭa mӝt tұp hӧp các thӫ tөc (chѭѫng trình con) ÿӇ xӱ lý vӟi các thiӃt bӏ vào ra (I/O System). „ hӋ thӕng ÿӗ hoҥ sinh ra các thiӃt bӏ ngoҥi vi lôgic ÿӇ tѭѫng tác giӳa ngѭӡi sӱ dөng và thiӃt bӏ ngoҥi vi này. „ Mӝt chu trình ÿiӇn hình cӫa các chѭѫng trình ӭng dөng quҧn lý các thiӃt bӏ ngoҥi vi ÿѭӧc gӑi là vòng lһp sӵ kiӋn tӯ thiӃt bӏ (event-driven loop ) (c) SE/FIT/HUT 2003 47 HӋ thӕng ÿӗ hoҥ (Graphics System) „ Interface between application software and graphics hardware system „ Consists of input subroutines and output subroutines accepting input data or commands from a user and converting internal representations into external pictures on screen, respectively „ Ph̯n m͉m ÿ͛ ho̩ h͏ th͙ng: „ Là tұp hӧp các lӋnh ÿӗ hoҥ cӫa hӋ thӕng (graphics output commands), „ Thӵc hiӋn công viӋc hiӇn thӏ cái gì (what object) và chúng sӁ ÿѭӧc hiӇn thӏ nhѭ thӃ nào (how). „ Phҫn mӅm ÿӗ hoҥ hӋ thӕng là phҫn mӅm xây dӵng trên cѫ sӣ mӝt thӇ loҥi phҫn cӭng nhҩt ÿӏnh và phө thuӝc vào phҫn cӭng. „ Ph̯n cͱng ÿ͛ ho̩: „ Là tұp hӧp các thiӃt bӏ ÿiӋn tӱ (CPU, bӝ nhӟ màn hình) giúp cho viӋc thӵc hiӋn các phҫn mӅm ÿӗ hoҥ. (c) SE/FIT/HUT 2003 48 Application program Graphics system Graphics hardware Input and output devices Core, GKS, GKS-3D CGI (device interface) CGM (metafile) PHIGS (3D and realtime) X-window PHIGS+ (PEX) IGES OpenGL DirectX Metafiles Operating system Giao diӉn hӉ thӓng ÿӕhӏa Interface of Graphics System (c) SE/FIT/HUT 2003 49 Các chuҭn giao diӋn cӫa hӋ ÿӗ hoҥ „ GKS (Graphics Kernel System): „ GKS Functional Description, ANSI X3.124 - 1985. „ GKS - 3D Functional Description, ISO Doc #8805:1988. „ CGI (Computer Graphics Interface System): „ CGM (Computer Graphics Metafile): „ VRML (Virtual Reality Modeling Language): „ PHIGS (Programmers Hierarchical Interactive „ PHIGS Functional Description, ANSI X3.144 - 1985. „ PHIGS+ Functional Description, 1988, 1992. „ IGES (c) SE/FIT/HUT 2003 50 Non-official industry standards Các chuҭn cӫa hӋ ÿӗ hoҥ „ OPENGL SGI’s OpenGL 1993 „ DIRECTX Direct X/Direct3D 1997 (c) SE/FIT/HUT 2003 51 OpenGL „ Software interface to graphics hardware „ Client-server model „ 250 distinct commands „ Object specification + image generation „ Simple primitives: points, lines, polygons (pixels, images, bitmaps) „ 3D rendering „ Commands interpreted using client-server model „ Client (Application) issues commands „ Server (OpenGL) interprets and processes commands „ Frame buffer configuration done by the window system (c) SE/FIT/HUT 2003 52 „ Direct control of graphics hardware „ Direct control of input/output devices, and sound Application programApplication progra Windows systemindows syste Direct sound Direct draw Direct 3D Direct input Windows APIindows API Direct X …….. DirectX (c) SE/FIT/HUT 2003 53 Các thiӃt bӏ vào ra dӳ liӋu „ Máy in ƒ Dot size: ÿѭӡng kính cӫa mӝt ÿiӇm in bé nhҩt mà máy in có thӇ in ÿѭӧc ƒ Addressability: khҧ năng ÿӏa chӍ hoá các ÿiӇm in có thӇ có trên mӝt ÿѫn vӏ ÿӝ dài (dot per inch) ƒ Sӕ lѭӧng màu có thӇ vӁ trên mӝt ÿiӇm „ Dot size Point per inch „ InkJet 8 - 20/ 100 inch 200 y600 „ Laser 5/1000 inch 1500 „ Máy vӁ 6 y 15/1000 inch 1000 y 2000 (c) SE/FIT/HUT 2003 54 Phҫn cӭng ÿӗ hoҥ (Graphics Hardware) „ Các thành phҫn phҫn cӭng cӫa hӋ ÿӗ hoҥ tѭѫng tác (c) SE/FIT/HUT 2003 55 Màn hình CRT (c) SE/FIT/HUT 2003 56 Màn hình CRT SONY Trinitron CRT NEC Hybrid Mask Hitachi EDP Standard Dot-trio (c) SE/FIT/HUT 2003 57 Các thiӃt bӏ hiӇn thӏ dҥng vector „ MOVE 10,15 „ LINE 400,300 „ LINE 600,800 „ Refesh Buffer DrawLine(A, B): Turn beam off, move to A. Turn beam on, move to B. A B (c) SE/FIT/HUT 2003 58 Graphics Devices Display processor CRT Alphanumeric keyboard Stylus Data tablet Interface to host computer … … MOVE 10 15 LINE 100 25 CHAR LU CY LINE … … JMP Refresh buffer memory (Display commands) (interaction data) (c) SE/FIT/HUT 2003 59 Display processor CRT Interface to host computer (Display commands) (interaction data) Keyboard Data input00000000000000000000000001000000 00000000000000000000000001000000 00000000000000000000000111110000 00000000011000000001111111111111 00000000111100000000000111110000 00000011111111000000000001000000 00001111111111110000000001000000 00111111111111111100000000000000 00011111111111111000000000000000 00011111111111111000000000000000 00011111111111111000000000000000 00000000000000000000000000000000 Bitmap refresh buffer (the 1’s are accentuated for contrast) Typical raster graphics display showing a house and a star (c) SE/FIT/HUT 2003 60 Các thiӃt bӏ hiӇn thӏ dҥng ÿiӇm (c) SE/FIT/HUT 2003 61 LCD-Liquid Crystal Display „ A transmissive technology „ Works by letting varying amounts of a fixed-intensity white backlight through an active filter „ Organnic crystals that lign themselves together „ When external force is applied they realign themselves „ This is used to change polarisation and filter light (c) SE/FIT/HUT 2003 62 CRT Displays Advantages „ Fast repsonse (high resolution possible) „ Full color (large modulation depth of E-beam) „ Saturated and natural colors „ Inexpensive, matured technology „ Wide angle, high contrast and brightness Disadvantages „ Large and heavy (typ. 70x70 cm, 15 kg) „ High power consumption (typ. 140W) „ Harmful DC and AC electric and magnetic fields „ Flickering at 50-80 Hz (no memory effect) „ Geometrical errors at edges (c) SE/FIT/HUT 2003 63 LCD Displays Advantages „ Small footprint (approx 1/6 of CRT) „ Light weight (typ. 1/5 of CRT) „ Low power consumption (typ. 1/4 of CRT) „ Completely flat screen - no geometrical errors „ Crisp pictures - digital and uniform colors „ No electromagnetic emission „ Fully digital signal processing possible „ Large screens (>20 inch) on desktops Disadvantages „ High price (presently 3x CRT) „ Poor viewing angle (typ. +/- 50 degrees) „ Low contrast and luminance (typ. 1:100) „ Low luminance (typ. 200 cd/m2) (c) SE/FIT/HUT 2003 64 Future Research Areas Hѭӝng nghiên cӫu „ Graphics accelerators „ parallel processing „ Geometric modeling „ physically-based modeling „ level of detail „ Motion control / synthesis „ kinematics / dynamics „ motion capture/ modification „ Rendering „ photo-realism „ real-time „ image-based rendering „ non-photorealistic rendering „ Scientific visualization „ Geometric algorithms „ User interface