Image Formation. Introduction to Computer Graphics. Machiraju/Zhang/Möller/Klaffenböck
|
|
- Tracy Garrett
- 5 years ago
- Views:
Transcription
1 Image Formation Introduction to Computer Graphics Machiraju/Zhang/Möller/Klaffenböck
2 Today Input and displays of a graphics system Raster display basics: pixels, the frame buffer, raster scan, LCD displays Historical perspective Image formation The ray tracing algorithm The z-buffer algorithm Readings: Sections 1, 12.2 (Ray tracing), 5.8 (z-buffering) Machiraju/Zhang/Möller/Klaffenböck 2
3 Overview of a graphics system Output device Input devices Image formed and stored in frame buffer Machiraju/Zhang/Möller/Klaffenböck 3
4 Input devices Pointing/locator devices: indicate location on screen Mouse/trackball/spaceball Data tablet Joystick Touch pad and touch screen Keyboard device: send character input Choice devices: mouse buttons, function keys Machiraju/Zhang/Möller/Klaffenböck 4
5 More sophisticated interaction Machiraju/Zhang/Möller/Klaffenböck 5
6 Input devices for this class our class Use simple keyboard and mouse commands to interact with your WebGL program Machiraju/Zhang/Möller/Klaffenböck 6
7 Output: cathode-ray tube (CRT) Machiraju/Zhang/Möller/Klaffenböck 7
8 Machiraju/Zhang/Möller/Klaffenböck 8
9 CRT basics The screen output is stored in the frame buffer and is converted into voltages across the reflection plates via a digital-to-analog converter (DAG) Light is emitted when electrons hit phosphor But light output from the phosphor decays exponentially with time, typically in microseconds Thus the screen needs to be redrawn or refreshed Refresh rate is typically 60 Hz to avoid flicker ( twinkling ) Flicker: when the eye can no longer integrate individual light pulses from a point on screen, e.g., due to low refresh rate Machiraju/Zhang/Möller/Klaffenböck 9
10 Shadow-mask color CRTs Three different colored phosphors (R, G, B) dots are arranged in very small groups (triads) on coating We see a mixture of three colors Three electron guns (R, G, B) emit electron beams in a controlled fashion so that only phosphors of the proper colors are excited Shadow-mask CRT Machiraju/Zhang/Möller/Klaffenböck 10
11 Flat-panel displays CRTs are no longer the most widely used display devices nowadays Flat-panel displays, e.g., LCDs or liquid-crystal displays and plasma displays dominate Flat-panel displays can be emissive (plasma) or nonemissive (LCD) allowing for light to pass through Colors can be produced using triads (sub-pixels) Screen refresh no longer necessary See Chapter 3.1 of Marschner et al. for more on flat-panel technologies (or check out wikipedia) Machiraju/Zhang/Möller/Klaffenböck 11
12 A generic flat-panel display Figure from Shirley et al. Machiraju/Zhang/Möller/Klaffenböck 12
13 High Dynamic Range Displays High resolution colour LCD Courtesy: High Dynamic Range Display Low resolution Individually Modulated LED array Machiraju/Zhang/Möller/Klaffenböck 13
14 Raster display basics The screen is a rectangular array of picture elements, or pixels Resolution: determines the details you can see number of pixels in an image e.g., , 1280x1024, 1366 x 768, etc. also in ppi or dpi pixel or dot per inch Machiraju/Zhang/Möller/Klaffenböck 14
15 Raster scan pattern Horizontal scan rate: # scan lines per second Interlaced (TV) vs. non-interlaced displays Vertical retrace Scan line Horizontal retrace Machiraju/Zhang/Möller/Klaffenböck 15
16 Video display standards NTSC (National Television System Committee): 525 lines, 30 frames/sec interlaced (visual system tricked into thinking that the refresh rate is 60 f/s) 480 lines visible North America, South America, Japan PAL/SECAM: 625 lines, 25 frames/sec interlaced Europe, Russian, Africa, etc. HDTV: 1,080 lines Machiraju/Zhang/Möller/Klaffenböck 16
17 The frame buffer Stores per-pixel information Depth of a frame buffer: number of bits per pixel E.g. for color representation, 1 bit => 2 colors, 8 bits => 256 colors, 24 bits => true color (16 million colors) Color buffer is only one of many buffers, other information, e.g., depth, can also be used Implemented with special type of memory in standard PCs or on a graphics card for fast redisplay Part of standard memory in earlier systems Machiraju/Zhang/Möller/Klaffenböck 17
18 Today Input and displays of a graphics system Raster display basics: pixels, the frame buffer, raster scan, LCD displays Historical perspective Image formation The ray tracing algorithm The z-buffer algorithm Readings: Sections , 11.2 (Ray tracing), (z-buffering) Machiraju/Zhang/Möller/Klaffenböck 18
19 Comp Graphics: Computer graphics goes back to the earliest days of computing Strip charts Pen plotters Simple displays using A/D converters to go from computer to calligraphic CRT Cost of refresh for CRT too high Computers slow, expensive, unreliable adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 19
20 Comp Graphics: Wireframe graphics Draw only lines Sketchpad Display Processors Storage tube wireframe representation of sun object adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 20
21 Sketchpad Ivan Sutherland s PhD thesis at MIT Recognized the potential of man-machine interaction Loop Display something User moves light pen Computer generates new display Sutherland also created many of the now common algorithms for computer graphics adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 21
22 Interactive Computer Graphics Ivan Sutherland, Sketchpad, 1963 Doug Engelbart, Machiraju/Zhang/Möller/Klaffenböck 22
23 Comp Graphics: Raster Graphics Beginning of graphics standards IFIPS GKS: European effort Becomes ISO 2D standard Core: North American effort 3D but fails to become ISO standard Workstations and PCs adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 23
24 Raster Graphics Allows us to go from lines and wire frame images to filled polygons adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 24
25 Comp Graphics: Realism comes to computer graphics smooth shading environment mapping bump mapping adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 25
26 Comp Graphics: Special purpose hardware Silicon Graphics geometry engine VLSI implementation of graphics pipeline Industry-based standards PHIGS RenderMan Networked graphics: X Window System Human-Computer Interfaction (HCI) adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 26
27 Comp Graphics: OpenGL API Completely computer-generated featurelength movies (Toy Story) are successful New hardware capabilities Texture mapping Blending Accumulation, stencil buffers adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 27
28 Computer Graphics: Photorealism Graphics cards for PCs dominate market Nvidia, ATI Game boxes and game players determine direction of market Computer graphics routine in movie industry: Maya, Lightwave Programmable pipelines adapted Machiraju/Zhang/Möller/Klaffenböck from Angel and Shreiner 28
29 Today Input and displays of a graphics system Raster display basics: pixels, the frame buffer, raster scan, LCD displays Historical perspective Image formation The ray tracing algorithm The z-buffer algorithm Readings: Sections , 11.2 (Ray tracing), (z-buffering) Machiraju/Zhang/Möller/Klaffenböck 29
30 Image formation (aside) In computer graphics, we form 2D images via a process analogous to how images are formed by physical imaging systems Cameras Microscopes Human visual system Machiraju/Zhang/Möller/Klaffenböck 30
31 Elements of image formation Object: Exists independent of image formation and viewer defined in its own object space Formed by geometric primitives, e.g., polygons Viewer: Forms the image of the objects via projection onto an image plane Image is produced in 2D, e.g., on retina, film, etc. Objects need to be transformed into the image space Machiraju/Zhang/Möller/Klaffenböck 31
32 Also, light and color No light => nothing is visible How do we, or the camera, see? Light reflected off objects in the scene, or Light transmitted directly into our eyes, e.g., from light source What is reflected color? Light and object have color When colored light reaches a colored object, some colors are reflected and some absorbed Machiraju/Zhang/Möller/Klaffenböck 32
33 Light Light is the (visible) part of the electromagnetic spectrum that causes a reaction in our visual systems Generally these are wavelengths in the range of about nm (nanometers) Long wavelengths appear as reds and short wavelengths as blues The electromagnetic spectrum Machiraju/Zhang/Möller/Klaffenböck 33
34 Simplistic color representation RGB-color system (R: red, G: green, B: blue) Each displayed color has 3 components: R, G, B 8 bits per component in 24-bit true-color display; component value: (R,G,B) = (255,255,255) (0,0,0) (255,0,0) (255,255,0) (0,255,255) In OpenGL/WebGL, RGB values are in [0,1] More details on lights and colors later in course Machiraju/Zhang/Möller/Klaffenböck 34
35 Imaging system: pinhole camera Use trigonometry to find projection of point at (x,y,z) x p = y p = z p = d dx/z dy/z Machiraju/Zhang/Möller/Klaffenböck 35
36 Synthetic camera model projector image plane center of projection Imaging model adopted by 3D computer graphics Machiraju/Zhang/Möller/Klaffenböck 36
37 First imaging algorithm Directly derived from the synthetic camera model Follow rays of light from a point light source Determine which rays enter the lens of the camera through the imaging window Compute color of projection Why is this not a good idea? Machiraju/Zhang/Möller/Klaffenböck 37
38 Ray tracing When following light from a light source, many (reflected) rays do not intersect the image window and do not contribute to the scene eye reflected ray pixel Image plane shadow ray refracted ray rays Reverse the process Cast one ray per pixel from the eye and shoot it into the scene Machiraju/Zhang/Möller/Klaffenböck 38
39 Ray tracing: the basics A point on an object may be illuminated by Light source directly through shadow ray Light reflected off an object through reflected ray Light transmitted through a transparent object through refracted ray reflected ray eye pixel Image plane shadow ray refracted ray Machiraju/Zhang/Möller/Klaffenböck 39
40 Ray tracing: the algorithm for each pixel on screen determine ray from eye through pixel if ray shoots into infinity, return a background color if ray shoots into light source, return light color appropriately find closest intersection of ray with an object cast off shadow ray (towards light sources) if shadow ray hits a light source, compute light contribution according to some illumination model cast reflected and refracted ray, recursively calculate pixel color contribution return pixel color after some absorption Machiraju/Zhang/Möller/Klaffenböck 40
41 The WingsPov Civilisation Museum by Eric Ouvrard Machiraju/Zhang/Möller/Klaffenböck 41
42 Ray tracing: pros and cons Pros: Follows (approximately) the physics of optical flow High level of visual realism can model both lightobject interactions and inter-surface reflections and refractions Cons expensive: intersection tests and the levels of recursion (rays generated) Inadequate for modeling non-reflective (dulllooking) objects (why is that?) Machiraju/Zhang/Möller/Klaffenböck 42
43 Which is the most important ray? eye reflected ray pixel Image plane shadow ray refracted ray Machiraju/Zhang/Möller/Klaffenböck 43
44 The z-buffer algorithm Per-polygon operations vs. per-pixel for ray tracing Simple and often accelerated with hardware Works regardless of the order in which the polygons are processed no need to sort them back to front A visibility algorithm and not designed to compute colors WebGL implements this fundamental algorithm gl.enable(gl.depth_test); gl.clear(gl.color_buffer_bit gl.depth_buffer_bit); Machiraju/Zhang/Möller/Klaffenböck 44
45 The algorithm for each polygon in the scene project its vertices onto viewing (image) plane for each pixel inside the polygon formed on viewing plane determine point on polygon corresponding to this pixel get pixel color according to some illumination model get depth value for this pixel (distance from point to plane) if depth value < stored depth value for the pixel update pixel color in frame buffer update depth value in depth buffer (z-buffer) end if end if Machiraju/Zhang/Möller/Klaffenböck 45
46 Machiraju/Zhang/Möller/Klaffenböck 46
Image Formation. Introduction to Computer Graphics Torsten Möller. Machiraju/Zhang/Möller
Image Formation Introduction to Computer Graphics Torsten Möller Machiraju/Zhang/Möller Today Input and displays of a graphics system Raster display basics: pixels, the frame buffer, raster scan, LCD displays
More informationIntroduction to Computer Graphics. Overview. What is Computer Graphics?
INSTITUTIONEN FÖR SYSTEMTEKNIK LULEÅ TEKNISKA UNIVERSITET Introduction to Computer Graphics David Carr Fundamentals of Computer Graphics Spring 2004 Based on Slides by E. Angel Graphics 1 L Overview What
More informationMMGD0206 Computer Graphics. Chapter 1 Development of Computer Graphics : History
MMGD0206 Computer Graphics Chapter 1 Development of Computer Graphics : History What is Computer Graphics? Computer graphics generally means creation, storage and manipulation of models and images Such
More informationComputer Graphics. Bing-Yu Chen National Taiwan University
Computer Graphics Bing-Yu Chen National Taiwan University Introduction The Graphics Process Color Models Triangle Meshes The Rendering Pipeline 1 INPUT What is Computer Graphics? Definition the pictorial
More informationNational Chiao Tung Univ, Taiwan By: I-Chen Lin, Assistant Professor
Computer Graphics 1. Graphics Systems National Chiao Tung Univ, Taiwan By: I-Chen Lin, Assistant Professor Textbook: Hearn and Baker, Computer Graphics, 3rd Ed., Prentice Hall Ref: E.Angel, Interactive
More informationINTRODUCTION. Slides modified from Angel book 6e
INTRODUCTION Slides modified from Angel book 6e Fall 2012 COSC4328/5327 Computer Graphics 2 Objectives Historical introduction to computer graphics Fundamental imaging notions Physical basis for image
More informationGraphics Systems and Models
Graphics Systems and Models 2 nd Week, 2007 Sun-Jeong Kim Five major elements Input device Processor Memory Frame buffer Output device Graphics System A Graphics System 2 Input Devices Most graphics systems
More informationLecture 1. Computer Graphics and Systems. Tuesday, January 15, 13
Lecture 1 Computer Graphics and Systems What is Computer Graphics? Image Formation Sun Object Figure from Ed Angel,D.Shreiner: Interactive Computer Graphics, 6 th Ed., 2012 Addison Wesley Computer Graphics
More informationComputer Graphics - Chapter 1 Graphics Systems and Models
Computer Graphics - Chapter 1 Graphics Systems and Models Objectives are to learn about: Applications of Computer Graphics Graphics Systems Images: Physical and Synthetic The Human Visual System The Pinhole
More informationLecturer Athanasios Nikolaidis
Lecturer Athanasios Nikolaidis Computer Graphics: Graphics primitives 2D viewing and clipping 2D and 3D transformations Curves and surfaces Rendering and ray tracing Illumination models Shading models
More informationOverview CS Plans for this semester. References. CS 4600 Fall Prerequisites
Overview CS 4600 What is CS 4600? What should know (pre reqs)? What will you get out of this course? Chuck Hansen Website: www.eng.utah.edu/~cs4600 Thanks to Ed Angel and Jeff Parker for slides and materials
More informationComputer Graphics Lecture 2
1 / 16 Computer Graphics Lecture 2 Dr. Marc Eduard Frîncu West University of Timisoara Feb 28th 2012 2 / 16 Outline 1 Graphics System Graphics Devices Frame Buffer 2 Rendering pipeline 3 Logical Devices
More informationSurvey in Computer Graphics Computer Graphics and Visualization
Example of a Marble Ball Where did this image come from? Fall 2010 What hardware/software/algorithms did we need to produce it? 2 A Basic Graphics System History of Computer Graphics 1200-2008 Input devices
More informationImage Formation. Ed Angel Professor of Computer Science, Electrical and Computer Engineering, and Media Arts University of New Mexico
Image Formation Ed Angel Professor of Computer Science, Electrical and Computer Engineering, and Media Arts University of New Mexico 1 Objectives Fundamental imaging notions Physical basis for image formation
More informationIntroduction to Computer Graphics with WebGL
Introduction to Computer Graphics with WebGL Ed Angel Professor Emeritus of Computer Science Founding Director, Arts, Research, Technology and Science Laboratory University of New Mexico Image Formation
More informationGraphics Hardware and Display Devices
Graphics Hardware and Display Devices CSE328 Lectures Graphics/Visualization Hardware Many graphics/visualization algorithms can be implemented efficiently and inexpensively in hardware Facilitates interactive
More informationVTU QUESTION PAPER SOLUTION UNIT -1 INTRODUCTION
VTU QUESTION PAPER SOLUTION UNIT -1 INTRODUCTION 1. Briefly explain any two applications of computer graphics. (June 2012) 4M Ans: Applications of computer graphics are: Display Of Information Design Simulation
More informationComputer Graphics and Visualization. Graphics Systems and Models
UNIT -1 Graphics Systems and Models 1.1 Applications of computer graphics: Display Of Information Design Simulation & Animation User Interfaces 1.2 Graphics systems A Graphics system has 5 main elements:
More informationIntroduction to Computer Graphics with WebGL
Introduction to Computer Graphics with WebGL Rongkai Guo Assistant Professor at Computer Game Design program Kennesaw State University 1 Overview These lectures are for a senior/graduate elective for computer
More informationComputer Graphics. Chapter 1 (Related to Introduction to Computer Graphics Using Java 2D and 3D)
Computer Graphics Chapter 1 (Related to Introduction to Computer Graphics Using Java 2D and 3D) Introduction Applications of Computer Graphics: 1) Display of Information 2) Design 3) Simulation 4) User
More informationHomework Graphics Input Devices Graphics Output Devices. Computer Graphics. Spring CS4815
Computer Graphics Spring 2016-2017 Outline 1 2 3 Displays To Do 1 Go to Wikipedia http://en.wikipedia.org/ and read the pages on Colour Spaces (http: //en.wikipedia.org/wiki/colour_spaces), Optical Illusions
More informationIntroduction to Computer Graphics with WebGL
Introduction to Computer Graphics with WebGL Ed Angel Professor Emeritus of Computer Science Founding Director, Arts, Research, Technology and Science Laboratory University of New Mexico 1 Overview These
More informationRendering. Converting a 3D scene to a 2D image. Camera. Light. Rendering. View Plane
Rendering Pipeline Rendering Converting a 3D scene to a 2D image Rendering Light Camera 3D Model View Plane Rendering Converting a 3D scene to a 2D image Basic rendering tasks: Modeling: creating the world
More informationCSE4030 Introduction to Computer Graphics
CSE4030 Introduction to Computer Graphics Dongguk University Jeong-Mo Hong Timetable 00:00~00:10 Introduction (English) 00:10~00:50 Topic 1 (English) 00:50~00:60 Q&A (English, Korean) 01:00~01:40 Topic
More informationHomework Graphics Input Devices Graphics Output Devices. Computer Graphics. Spring CS4815
Computer Graphics Spring 2017-2018 Outline 1 2 3 Displays To Do 1 Go to Wikipedia http://en.wikipedia.org/ and read the pages on Colour Spaces (http: //en.wikipedia.org/wiki/colour_spaces), Optical Illusions
More informationModels and Architectures. Ed Angel Professor of Computer Science, Electrical and Computer Engineering, and Media Arts University of New Mexico
Models and Architectures Ed Angel Professor of Computer Science, Electrical and Computer Engineering, and Media Arts University of New Mexico 1 Objectives Learn the basic design of a graphics system Introduce
More informationLast week. Machiraju/Zhang/Möller
Last week Machiraju/Zhang/Möller 1 Overview of a graphics system Output device Input devices Image formed and stored in frame buffer Machiraju/Zhang/Möller 2 Introduction to CG Torsten Möller 3 Ray tracing:
More information3D graphics, raster and colors CS312 Fall 2010
Computer Graphics 3D graphics, raster and colors CS312 Fall 2010 Shift in CG Application Markets 1989-2000 2000 1989 3D Graphics Object description 3D graphics model Visualization 2D projection that simulates
More informationCS452/552; EE465/505. Overview of Computer Graphics
CS452/552; EE465/505 Overview of Computer Graphics 1-13-15 Outline! What is Computer Graphics? a historical perspective! Draw a triangle using WebGL Computer Graphics! Computer graphics deals with all
More informationIntroduction to Computer Graphics with WebGL
Introduction to Computer Graphics with WebGL Ed Angel Professor Emeritus of Computer Science Founding Director, Arts, Research, Technology and Science Laboratory University of New Mexico Models and Architectures
More informationLuxo Jr. (Pixar, 1986) Last Time. Real Cameras and Ray Tracing. Standard Rasterization. Lights, Cameras, Surfaces. Now Playing:
Now Playing: Luxo Jr. (Pixar, 1986) Giant Steps From Giant Steps Recorded May 4-5, 1959 John Coltrane - Tenor Sax Tommy Flanagan - Piano Paul Chambers - Bass Art Taylor - Drums Real Cameras and Ray Tracing
More informationDevelopment of Computer Graphics
1951 Whirlwind, Jay Forrester (MIT) CRT displays mid 1950s SAGE air defense system command & control CRT, light pens late 1950s Computer Art, James Whitney Sr. Visual Feedback loops 1962 Sketchpad, Ivan
More informationModels and Architectures
Models and Architectures Objectives Learn the basic design of a graphics system Introduce graphics pipeline architecture Examine software components for an interactive graphics system 1 Image Formation
More informationCS130 : Computer Graphics Lecture 2: Graphics Pipeline. Tamar Shinar Computer Science & Engineering UC Riverside
CS130 : Computer Graphics Lecture 2: Graphics Pipeline Tamar Shinar Computer Science & Engineering UC Riverside Raster Devices and Images Raster Devices - raster displays show images as a rectangular array
More informationOverview: Ray Tracing & The Perspective Projection Pipeline
Overview: Ray Tracing & The Perspective Projection Pipeline Lecture #2 Thursday, August 28 2014 About this Lecture! This is an overview.! Think of it as a quick tour moving fast.! Some parts, e.g. math,
More informationIntro to Ray-Tracing & Ray-Surface Acceleration
Lecture 12 & 13: Intro to Ray-Tracing & Ray-Surface Acceleration Computer Graphics and Imaging UC Berkeley Course Roadmap Rasterization Pipeline Core Concepts Sampling Antialiasing Transforms Geometric
More informationComputer Graphics 1 Instructor Information. Books. Graphics? Course Goals and Outcomes. Where are computer graphics? Where are computer graphics?
Computer Graphics 1 Instructor Information Books Instructor: Dr. Jessica Bayliss Office: 70-3509 Telephone: (585) 475-2507 Office Hours: see my web site Web page: www.cs.rit.edu/~jdb Teaching Philosophy:
More informationAn Introduction to Computer Graphics
An Introduction to Computer Graphics Joaquim Madeira Beatriz Sousa Santos Universidade de Aveiro 1 Topics What is CG Brief history Main applications CG Main Tasks Simple Graphics system CG APIs 2D and
More informationFor Intuition about Scene Lighting. Today. Limitations of Planar Shadows. Cast Shadows on Planar Surfaces. Shadow/View Duality.
Last Time Modeling Transformations Illumination (Shading) Real-Time Shadows Viewing Transformation (Perspective / Orthographic) Clipping Projection (to Screen Space) Graphics Pipeline Clipping Rasterization
More informationLighting. To do. Course Outline. This Lecture. Continue to work on ray programming assignment Start thinking about final project
To do Continue to work on ray programming assignment Start thinking about final project Lighting Course Outline 3D Graphics Pipeline Modeling (Creating 3D Geometry) Mesh; modeling; sampling; Interaction
More informationLast Time. Why are Shadows Important? Today. Graphics Pipeline. Clipping. Rasterization. Why are Shadows Important?
Last Time Modeling Transformations Illumination (Shading) Real-Time Shadows Viewing Transformation (Perspective / Orthographic) Clipping Projection (to Screen Space) Graphics Pipeline Clipping Rasterization
More informationComputer Graphics CS 543 Lecture 1 (Part I) Prof Emmanuel Agu. Computer Science Dept. Worcester Polytechnic Institute (WPI)
Computer Graphics CS 543 Lecture 1 (Part I) Prof Emmanuel Agu Computer Science Dept. Worcester Polytechnic Institute (WPI) About This Course Computer graphics: algorithms, mathematics, data structures..
More informationDevelopment of Computer Graphics. mid 1950s SAGE air defense system command & control CRT, light pens
1951 Whirlwind, Jay Forrester (MIT) CRT displays mid 1950s SAGE air defense system command & control CRT, light pens late 1950s Computer Art, James Whitney Sr. Visual Feedback loops 1962 Sketchpad, Ivan
More informationReal-Time Shadows. Last Time? Today. Why are Shadows Important? Shadows as a Depth Cue. For Intuition about Scene Lighting
Last Time? Real-Time Shadows Today Why are Shadows Important? Shadows & Soft Shadows in Ray Tracing Planar Shadows Projective Texture Shadows Shadow Maps Shadow Volumes Why are Shadows Important? Depth
More informationChapter 7 - Light, Materials, Appearance
Chapter 7 - Light, Materials, Appearance Types of light in nature and in CG Shadows Using lights in CG Illumination models Textures and maps Procedural surface descriptions Literature: E. Angel/D. Shreiner,
More informationPhotorealism: Ray Tracing
Photorealism: Ray Tracing Reading Assignment: Chapter 13 Local vs. Global Illumination Local Illumination depends on local object and light sources only Global Illumination at a point can depend on any
More informationCS130 : Computer Graphics. Tamar Shinar Computer Science & Engineering UC Riverside
CS130 : Computer Graphics Tamar Shinar Computer Science & Engineering UC Riverside Raster Devices and Images Raster Devices Hearn, Baker, Carithers Raster Display Transmissive vs. Emissive Display anode
More information... Output System Layers. Application 2. Application 1. Application 3. Swing. UIKit SWT. Window System. Operating System
Output: Hardware Output System Layers Application 1 Application 2 Application 3 Swing SWT... UIKit Window System Operating System Hardware (e.g., graphics card) 2 Output Hardware 3 Start with some basics:
More informationComputer Graphics. Bing-Yu Chen National Taiwan University The University of Tokyo
Computer Graphics Bing-Yu Chen National Taiwan University The University of Tokyo Introduction The Graphics Process Color Models Triangle Meshes The Rendering Pipeline 1 What is Computer Graphics? modeling
More informationSUMMARY. CS380: Introduction to Computer Graphics Ray tracing Chapter 20. Min H. Kim KAIST School of Computing 18/05/29. Modeling
CS380: Introduction to Computer Graphics Ray tracing Chapter 20 Min H. Kim KAIST School of Computing Modeling SUMMARY 2 1 Types of coordinate function Explicit function: Line example: Implicit function:
More informationCMP 477 Computer Graphics Module 2: Graphics Systems Output and Input Devices. Dr. S.A. Arekete Redeemer s University, Ede
CMP 477 Computer Graphics Module 2: Graphics Systems Output and Input Devices Dr. S.A. Arekete Redeemer s University, Ede Introduction The widespread recognition of the power and utility of computer graphics
More information2: Introducing image synthesis. Some orientation how did we get here? Graphics system architecture Overview of OpenGL / GLU / GLUT
COMP27112 Computer Graphics and Image Processing 2: Introducing image synthesis Toby.Howard@manchester.ac.uk 1 Introduction In these notes we ll cover: Some orientation how did we get here? Graphics system
More informationComputer Graphics and Visualization. What is computer graphics?
CSCI 120 Computer Graphics and Visualization Shiaofen Fang Department of Computer and Information Science Indiana University Purdue University Indianapolis What is computer graphics? Computer graphics
More informationCHAPTER 1 Graphics Systems and Models 3
?????? 1 CHAPTER 1 Graphics Systems and Models 3 1.1 Applications of Computer Graphics 4 1.1.1 Display of Information............. 4 1.1.2 Design.................... 5 1.1.3 Simulation and Animation...........
More informationEffects needed for Realism. Computer Graphics (Fall 2008) Ray Tracing. Ray Tracing: History. Outline
Computer Graphics (Fall 2008) COMS 4160, Lecture 15: Ray Tracing http://www.cs.columbia.edu/~cs4160 Effects needed for Realism (Soft) Shadows Reflections (Mirrors and Glossy) Transparency (Water, Glass)
More informationReal-Time Shadows. Computer Graphics. MIT EECS Durand 1
Real-Time Shadows Computer Graphics MIT EECS 6.837 Durand 1 Why are Shadows Important? Depth cue Scene Lighting Realism Contact points 2 Shadows as a Depth Cue source unknown. All rights reserved. This
More informationgraphics pipeline computer graphics graphics pipeline 2009 fabio pellacini 1
graphics pipeline computer graphics graphics pipeline 2009 fabio pellacini 1 graphics pipeline sequence of operations to generate an image using object-order processing primitives processed one-at-a-time
More informationCS451Real-time Rendering Pipeline
1 CS451Real-time Rendering Pipeline JYH-MING LIEN DEPARTMENT OF COMPUTER SCIENCE GEORGE MASON UNIVERSITY Based on Tomas Akenine-Möller s lecture note You say that you render a 3D 2 scene, but what does
More informationgraphics pipeline computer graphics graphics pipeline 2009 fabio pellacini 1
graphics pipeline computer graphics graphics pipeline 2009 fabio pellacini 1 graphics pipeline sequence of operations to generate an image using object-order processing primitives processed one-at-a-time
More informationFrom 3D World to 2D Screen. Hendrik Speleers
Hendrik Speleers Overview Synthetic camera Rendering pipeline World window versus viewport Clipping Cohen-Sutherland algorithm Rasterizing Bresenham algorithm Three different actors in a scene Objects:
More informationCS452/552; EE465/505. Clipping & Scan Conversion
CS452/552; EE465/505 Clipping & Scan Conversion 3-31 15 Outline! From Geometry to Pixels: Overview Clipping (continued) Scan conversion Read: Angel, Chapter 8, 8.1-8.9 Project#1 due: this week Lab4 due:
More informationCS230 : Computer Graphics Lecture 4. Tamar Shinar Computer Science & Engineering UC Riverside
CS230 : Computer Graphics Lecture 4 Tamar Shinar Computer Science & Engineering UC Riverside Shadows Shadows for each pixel do compute viewing ray if ( ray hits an object with t in [0, inf] ) then compute
More informationGame Programming. Bing-Yu Chen National Taiwan University
Game Programming Bing-Yu Chen National Taiwan University What is Computer Graphics? Definition the pictorial synthesis of real or imaginary objects from their computer-based models descriptions OUTPUT
More informationPipeline Operations. CS 4620 Lecture 10
Pipeline Operations CS 4620 Lecture 10 2008 Steve Marschner 1 Hidden surface elimination Goal is to figure out which color to make the pixels based on what s in front of what. Hidden surface elimination
More informationRendering: Reality. Eye acts as pinhole camera. Photons from light hit objects
Basic Ray Tracing Rendering: Reality Eye acts as pinhole camera Photons from light hit objects Rendering: Reality Eye acts as pinhole camera Photons from light hit objects Rendering: Reality Eye acts as
More informationReal-Time Shadows. Last Time? Textures can Alias. Schedule. Questions? Quiz 1: Tuesday October 26 th, in class (1 week from today!
Last Time? Real-Time Shadows Perspective-Correct Interpolation Texture Coordinates Procedural Solid Textures Other Mapping Bump Displacement Environment Lighting Textures can Alias Aliasing is the under-sampling
More informationWhat is Output? p Fig. 6-1 Next
Output What is Output? What is output? Data that has been processed into a useful form, called information Output device is any hardware component that can convey information to user p. 6.06 Fig. 6-1 Next
More informationGraphics for VEs. Ruth Aylett
Graphics for VEs Ruth Aylett Overview VE Software Graphics for VEs The graphics pipeline Projections Lighting Shading VR software Two main types of software used: off-line authoring or modelling packages
More informationRendering Algorithms: Real-time indirect illumination. Spring 2010 Matthias Zwicker
Rendering Algorithms: Real-time indirect illumination Spring 2010 Matthias Zwicker Today Real-time indirect illumination Ray tracing vs. Rasterization Screen space techniques Visibility & shadows Instant
More informationPhotorealistic 3D Rendering for VW in Mobile Devices
Abstract University of Arkansas CSCE Department Advanced Virtual Worlds Spring 2013 Photorealistic 3D Rendering for VW in Mobile Devices Rafael Aroxa In the past few years, the demand for high performance
More informationLast Time. Reading for Today: Graphics Pipeline. Clipping. Rasterization
Last Time Modeling Transformations Illumination (Shading) Real-Time Shadows Viewing Transformation (Perspective / Orthographic) Clipping Projection (to Screen Space) Scan Conversion (Rasterization) Visibility
More informationInput: is any data or instructions that are used by a computer.
1 What is input? Input: is any data or instructions that are used by a computer. Input devices: are hardware used to translate words, sounds, images, and actions that people understand into a form that
More informationChapter 1 Introduction
Graphics & Visualization Chapter 1 Introduction Graphics & Visualization: Principles & Algorithms Brief History Milestones in the history of computer graphics: 2 Brief History (2) CPU Vs GPU 3 Applications
More informationComputer Graphics Solved MCQs -Part 2 MCQs Questions
http://itbookshub.com/ Computer Graphics Solved MCQs -Part 2 MCQs Multiple Choice Questions Computer Graphics Solved MCQs -Part 2 Two consecutive scaling transformation s1 and s2 are Additive Multiplicative
More informationBooks: 1) Computer Graphics, Principles & Practice, Second Edition in C JamesD. Foley, Andriesvan Dam, StevenK. Feiner, John F.
Computer Graphics Books: 1) Computer Graphics, Principles & Practice, Second Edition in C JamesD. Foley, Andriesvan Dam, StevenK. Feiner, John F. Huges 2) Schaim s Outline Computer Graphics Roy A. Plastock,
More informationComputer Graphics Shadow Algorithms
Computer Graphics Shadow Algorithms Computer Graphics Computer Science Department University of Freiburg WS 11 Outline introduction projection shadows shadow maps shadow volumes conclusion Motivation shadows
More informationCS452/552; EE465/505. Image Formation
CS452/552; EE465/505 Image Formation 1-15-15 Outline! Image Formation! Introduction to WebGL, continued Draw a colored triangle using WebGL Read: Angel, Chapters 2 & 3 Homework #1 will be available on
More informationLevel of Details in Computer Rendering
Level of Details in Computer Rendering Ariel Shamir Overview 1. Photo realism vs. Non photo realism (NPR) 2. Objects representations 3. Level of details Photo Realism Vs. Non Pixar Demonstrations Sketching,
More informationCSE528 Computer Graphics: Theory, Algorithms, and Applications
CSE528 Computer Graphics: Theory, Algorithms, and Applications Hong Qin State University of New York at Stony Brook (Stony Brook University) Stony Brook, New York 11794--4400 Tel: (631)632-8450; Fax: (631)632-8334
More informationIntroductionto ComputerGraphics
Introductionto ComputerGraphics Frédo Durand, «A Short Introduction to Computer Graphics» MIT Laboratory for Computer Science Torsten Möller «Introduction to Computer Graphic», SFU Computer Science Lecture
More informationSRM INSTITUTE OF SCIENCE AND TECHNOLOGY
SRM INSTITUTE OF SCIENCE AND TECHNOLOGY DEPARTMENT OF INFORMATION TECHNOLOGY QUESTION BANK SUB.NAME: COMPUTER GRAPHICS SUB.CODE: IT307 CLASS : III/IT UNIT-1 2-marks 1. What is the various applications
More informationReal-Time Shadows. Last Time? Schedule. Questions? Today. Why are Shadows Important?
Last Time? Real-Time Shadows The graphics pipeline Clipping & rasterization of polygons Visibility the depth buffer (z-buffer) Schedule Questions? Quiz 2: Thursday November 2 th, in class (two weeks from
More informationOverview of Graphics Systems Hearn & Baker Chapter 2. Some slides are taken from Robert Thomsons notes.
Overview of Graphics Systems Hearn & Baker Chapter 2 Some slides are taken from Robert Thomsons notes. OVERVIEW Video Display Devices Raster Scan Systems Graphics Workstations and Viewing Systems Input
More information3D Rasterization II COS 426
3D Rasterization II COS 426 3D Rendering Pipeline (for direct illumination) 3D Primitives Modeling Transformation Lighting Viewing Transformation Projection Transformation Clipping Viewport Transformation
More informationInteractive Computer Graphics A TOP-DOWN APPROACH WITH SHADER-BASED OPENGL
International Edition Interactive Computer Graphics A TOP-DOWN APPROACH WITH SHADER-BASED OPENGL Sixth Edition Edward Angel Dave Shreiner Interactive Computer Graphics: A Top-Down Approach with Shader-Based
More informationComputer Graphics Introduction. Taku Komura
Computer Graphics Introduction Taku Komura What s this course all about? We will cover Graphics programming and algorithms Graphics data structures Applied geometry, modeling and rendering Not covering
More informationCSE328 Fundamentals of Computer Graphics: Concepts, Theory, Algorithms, and Applications
CSE328 Fundamentals of Computer Graphics: Concepts, Theory, Algorithms, and Applications Hong Qin State University of New York at Stony Brook (Stony Brook University) Stony Brook, New York 11794--4400
More informationC P S C 314 S H A D E R S, O P E N G L, & J S RENDERING PIPELINE. Mikhail Bessmeltsev
C P S C 314 S H A D E R S, O P E N G L, & J S RENDERING PIPELINE UGRAD.CS.UBC.C A/~CS314 Mikhail Bessmeltsev 1 WHAT IS RENDERING? Generating image from a 3D scene 2 WHAT IS RENDERING? Generating image
More informationUlf Assarsson Department of Computer Engineering Chalmers University of Technology
Ulf Assarsson Department of Computer Engineering Chalmers University of Technology Tracing Photons One way to form an image is to follow rays of light from a point source finding which rays enter the lens
More informationComputer Graphics. Si Lu. Fall uter_graphics.htm 11/22/2017
Computer Graphics Si Lu Fall 2017 http://web.cecs.pdx.edu/~lusi/cs447/cs447_547_comp uter_graphics.htm 11/22/2017 Last time o Splines 2 Today o Raytracing o Final Exam: 14:00-15:30, Novermber 29, 2017
More informationRecall: Indexing into Cube Map
Recall: Indexing into Cube Map Compute R = 2(N V)N-V Object at origin Use largest magnitude component of R to determine face of cube Other 2 components give texture coordinates V R Cube Map Layout Example
More informationReal-Time Shadows. MIT EECS 6.837, Durand and Cutler
Real-Time Shadows Last Time? The graphics pipeline Clipping & rasterization of polygons Visibility the depth buffer (z-buffer) Schedule Quiz 2: Thursday November 20 th, in class (two weeks from Thursday)
More informationComputer Graphics. Lecture 1 Introduction to Computer Graphics. Somsak Walairacht - Computer Engineering KMITL
Lecture 1 Introduction to Somsak Walairacht - Computer Engineering KMITL 1 Textbooks with OpenGL - 3Ed, Hearn & Baker, Prentice Hall, 2003. Most of the topics follow this book Interactive : A Top-Down
More informationComputer Graphics. Lecture 9 Environment mapping, Mirroring
Computer Graphics Lecture 9 Environment mapping, Mirroring Today Environment Mapping Introduction Cubic mapping Sphere mapping refractive mapping Mirroring Introduction reflection first stencil buffer
More informationShadows in the graphics pipeline
Shadows in the graphics pipeline Steve Marschner Cornell University CS 569 Spring 2008, 19 February There are a number of visual cues that help let the viewer know about the 3D relationships between objects
More informationEnhancing Traditional Rasterization Graphics with Ray Tracing. October 2015
Enhancing Traditional Rasterization Graphics with Ray Tracing October 2015 James Rumble Developer Technology Engineer, PowerVR Graphics Overview Ray Tracing Fundamentals PowerVR Ray Tracing Pipeline Using
More informationHomeschool Enrichment. Input & Output
Homeschool Enrichment Input & Output Overview This chapter covers: Different types of keyboards and pointing devices Types of scanners, readers, and digital cameras What audio input is Types of display
More informationLocal Illumination. CMPT 361 Introduction to Computer Graphics Torsten Möller. Machiraju/Zhang/Möller
Local Illumination CMPT 361 Introduction to Computer Graphics Torsten Möller Graphics Pipeline Hardware Modelling Transform Visibility Illumination + Shading Perception, Interaction Color Texture/ Realism
More informationCIS 581 Interactive Computer Graphics
CIS 581 Interactive Computer Graphics Instructor: Han-Wei Shen (hwshen@cse.ohio-state.edu) Credit: 4 Class: MWF 2:30 pm 3:18 pm DL 264 Office hours: TuTr 11 am - 12pm DL 789 Web: http://www.cse.ohio-state.edu/~hwshen/581
More informationCOMP371 COMPUTER GRAPHICS
COMP371 COMPUTER GRAPHICS SESSION 15 RAY TRACING 1 Announcements Programming Assignment 3 out today - overview @ end of the class Ray Tracing 2 Lecture Overview Review of last class Ray Tracing 3 Local
More information