Turn on the Lights: Reflectance

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Turn on the Lights: Reflectance"

Transcription

1 Turn on the Lights: Reflectance Part 2: Shading Tuesday, October Lecture #14 Goal of Shading Model simple light sources Point light sources Extended light sources Ambient lighting Model lighting geometry Angle between light ray and surface normal Angle between surface normal and viewing ray Model surface reflections Diffuse (Lambertian) reflections Specular reflections Phong reflectance 2

2 Reflectance - 3 Kinds Ambient reflection. Models perfectly even illumination. Lambertian reflection. Matte surfaces, dull rather than shiny. Specular reflection. Bright highlights seen on polished surfaces. Slide 3 Reflectance - Geometry Reflectance functions are defined in terms of: The position of a (point) light source The orientation of the reflecting surface The viewing position. angle of incidence viewing angle surface normal 4

3 Reflectance Functions (III) Light rays, surface normals, and colors are expressed using vectors Light often described as illumination I Three components to illumination: Ir I = Ig Ib 10/10/13 Ross Beveridge Bruce Draper, CSU CS 410 Slide 5 Lambertian Reflection. The moon is cited as a good example of lambertion reflection Image by Dmitry, dzz at Morgefile. Maybe not such a great example large dark patches. 10/10/13 Ross Beveridge Bruce Draper, CSU CS 410 Slide 6

4 Lambertion Reflection Consider a point light source and a Diffuse (Lambertian) Surface. Diffuse surfaces reflect light with equal intensity in all directions. L R 7 A Touch of Physics Light per unit area arriving depends upon angle to light source. Light leaves in all directions, reflected off micro surfaces. 8

5 Diffuse Reflection Illumination/area drops when tilted from a point light source. I = I p1 K d cos K is a (usually diagonal) 3x3 matrix of reflectance parameters (material property) L N 9 Material Properties A full-blown diffuse reflectance matrix looks like:! # K = # # " # k rr k gr k br k rg k gg k bg k rb k gb k bb $ % Most surfaces reflect red light as red, etc.:! # K = # # "# k rr k gg k bb $ % For example, k gr modulates the percentage of incoming green light reflected back as red light. 10

6 Material Properties (II) There are some pragmatic constraints: No term in K may exceed 1.0 No term in K may be negative No column may have a sum exceeding 1 But, These constraints are not always enforced There is an art to lighting a scene! 11 Diffuse Reflection (III) The final term in diffuse reflection is cos(). This is the angle between the incoming light ray L and the surface normal N L = (P pos S)/ (P pos S), where P pos is the position of the light source. S is the position of the surface point. N = E 1 E 2 / E 1 E 2 for two surface edges Remember, the surface is planar. Avoid parallel edges! cos() = N L 12

7 Surface Normals - Sphere What about the surface normal for a sphere? N circlecenteredat P C surface point onsphere S S P C N = S P C S P C 13 Diffuse Reflection (IV) For a single point light source p1: I = I p1 K d ( N L ) p1 For many point light sources I = I p K ( d N L ) p p 14

8 Ambient Reflection Ambient reflection is just diffuse reflection of light from the ambient light source Ambient light models background light It is the same intensity everywhere It is the same color everywhere It comes from every angle So I = I a K d 15 Specular Reflection Most surfaces do more. Consider two extremes: a diffuse surface, and a Mirror. Specular reflection component Mirrors are extreme Mirrors reflect around an angle Metals, for example, combine Diffuse and specular components. 16

9 Only Skin Deep Diffuse models light deep reflection Enters through micro-holes in the surface Bounced from facet to facet, changing color Exits at a random angle Specular reflection is surface reflection Light hits a single surface facet, skips off. The color of the light is unchanged. The exit angle depends on the entry angles. 17 Limiting Case - Mirror The angle of incidence equals the angle of reflection. Idealized form only applies to mirrors. L N R 18

10 Mirrors are hard. Thinking about mirrors helps. One place difference between polygon pipelines and ray tracing differ greatly! For example: Return only when the viewing angle equals the angle of reflection. Generally, need to think about: What is the angle of reflection R? What is the viewing ray V? 19 Reflection and Viewer V is the unit vector from the surface point to the camera: V = (C Q)/ C Q Calculating R is more involved L S N S R V C Q 20

11 Reflection Vector Let N L be the projection of L onto N Assume N is a unit vector N L = (L N)N S is defined as S = N L L = (L N)N L R is L + 2S ( ) = 2 L N R = L + 2 ( L N)N L ( )N L 21 Back to Perfect (for now) If V R, there is no (pure) specular reflection. If V = R, then I = I p1 k s Note that k s is a scalar, measuring the percent of light reflected specularly. Color reflected is that of the light source. 22

12 Close Counts - Phong In Phong s model, reflection strongest in the direction of the angle of reflection Drops off with the cosine of the deviation from the angle of reflection L S N S R 23 Phong Specular Highlights I = I p1 k s ( cosφ) α Φ is the angle between the viewing ray and the angle of reflection. α is the so-called Phong constant, expressing how shiny an object is Mirrors: α = 200 Dull objects: α =

13 Phong - The Algebra cos(φ) = V R = V (2(L N)N L) I = I p1 k s ( V R) α I = I p1 k ( s V ( 2( L N) N L) ) α 25 Total Reflectance Reflectance off a surface point is the sum of: Diffuse reflection from the ambient light Diffuse reflection off of every point light Specular reflection off of every point light ( ) + I p k s ( V R p ) p lights( α ) I = I a K d + I p K d L p N 26

CS5620 Intro to Computer Graphics

CS5620 Intro to Computer Graphics So Far wireframe hidden surfaces Next step 1 2 Light! Need to understand: How lighting works Types of lights Types of surfaces How shading works Shading algorithms What s Missing? Lighting vs. Shading

More information

Illumination & Shading

Illumination & Shading Illumination & Shading Goals Introduce the types of light-material interactions Build a simple reflection model---the Phong model--- that can be used with real time graphics hardware Why we need Illumination

More information

Comp 410/510 Computer Graphics. Spring Shading

Comp 410/510 Computer Graphics. Spring Shading Comp 410/510 Computer Graphics Spring 2017 Shading Why we need shading Suppose we build a model of a sphere using many polygons and then color it using a fixed color. We get something like But we rather

More information

Lighting and Shading. Slides: Tamar Shinar, Victor Zordon

Lighting and Shading. Slides: Tamar Shinar, Victor Zordon Lighting and Shading Slides: Tamar Shinar, Victor Zordon Why we need shading Suppose we build a model of a sphere using many polygons and color each the same color. We get something like But we want 2

More information

CSE 167: Lecture #7: Color and Shading. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011

CSE 167: Lecture #7: Color and Shading. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011 CSE 167: Introduction to Computer Graphics Lecture #7: Color and Shading Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2011 Announcements Homework project #3 due this Friday,

More information

CPSC 314 LIGHTING AND SHADING

CPSC 314 LIGHTING AND SHADING CPSC 314 LIGHTING AND SHADING UGRAD.CS.UBC.CA/~CS314 slide credits: Mikhail Bessmeltsev et al 1 THE RENDERING PIPELINE Vertices and attributes Vertex Shader Modelview transform Per-vertex attributes Vertex

More information

Introduction to Computer Graphics. Farhana Bandukwala, PhD Lecture 14: Light Interacting with Surfaces

Introduction to Computer Graphics. Farhana Bandukwala, PhD Lecture 14: Light Interacting with Surfaces Introduction to Computer Graphics Farhana Bandukwala, PhD Lecture 14: Light Interacting with Surfaces Outline Computational tools Reflection models Polygon shading Computation tools Surface normals Vector

More information

Lighting and Shading Computer Graphics I Lecture 7. Light Sources Phong Illumination Model Normal Vectors [Angel, Ch

Lighting and Shading Computer Graphics I Lecture 7. Light Sources Phong Illumination Model Normal Vectors [Angel, Ch 15-462 Computer Graphics I Lecture 7 Lighting and Shading February 12, 2002 Frank Pfenning Carnegie Mellon University http://www.cs.cmu.edu/~fp/courses/graphics/ Light Sources Phong Illumination Model

More information

Computer Graphics. Illumination and Shading

Computer Graphics. Illumination and Shading () Illumination and Shading Dr. Ayman Eldeib Lighting So given a 3-D triangle and a 3-D viewpoint, we can set the right pixels But what color should those pixels be? If we re attempting to create a realistic

More information

Illumination & Shading I

Illumination & Shading I CS 543: Computer Graphics Illumination & Shading I Robert W. Lindeman Associate Professor Interactive Media & Game Development Department of Computer Science Worcester Polytechnic Institute gogo@wpi.edu

More information

CMSC427 Shading Intro. Credit: slides from Dr. Zwicker

CMSC427 Shading Intro. Credit: slides from Dr. Zwicker CMSC427 Shading Intro Credit: slides from Dr. Zwicker 2 Today Shading Introduction Radiometry & BRDFs Local shading models Light sources Shading strategies Shading Compute interaction of light with surfaces

More information

Overview: Ray Tracing & The Perspective Projection Pipeline

Overview: 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 information

Color and Light. CSCI 4229/5229 Computer Graphics Summer 2008

Color and Light. CSCI 4229/5229 Computer Graphics Summer 2008 Color and Light CSCI 4229/5229 Computer Graphics Summer 2008 Solar Spectrum Human Trichromatic Color Perception Are A and B the same? Color perception is relative Transmission,Absorption&Reflection Light

More information

Lecture 22: Basic Image Formation CAP 5415

Lecture 22: Basic Image Formation CAP 5415 Lecture 22: Basic Image Formation CAP 5415 Today We've talked about the geometry of scenes and how that affects the image We haven't talked about light yet Today, we will talk about image formation and

More information

CS 5625 Lec 2: Shading Models

CS 5625 Lec 2: Shading Models CS 5625 Lec 2: Shading Models Kavita Bala Spring 2013 Shading Models Chapter 7 Next few weeks Textures Graphics Pipeline Light Emission To compute images What are the light sources? Light Propagation Fog/Clear?

More information

Orthogonal Projection Matrices. Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015

Orthogonal Projection Matrices. Angel and Shreiner: Interactive Computer Graphics 7E Addison-Wesley 2015 Orthogonal Projection Matrices 1 Objectives Derive the projection matrices used for standard orthogonal projections Introduce oblique projections Introduce projection normalization 2 Normalization Rather

More information

CSE 681 Illumination and Phong Shading

CSE 681 Illumination and Phong Shading CSE 681 Illumination and Phong Shading Physics tells us What is Light? We don t see objects, we see light reflected off of objects Light is a particle and a wave The frequency of light What is Color? Our

More information

CENG 477 Introduction to Computer Graphics. Ray Tracing: Shading

CENG 477 Introduction to Computer Graphics. Ray Tracing: Shading CENG 477 Introduction to Computer Graphics Ray Tracing: Shading Last Week Until now we learned: How to create the primary rays from the given camera and image plane parameters How to intersect these rays

More information

Illumination and Shading

Illumination and Shading Illumination and Shading Computer Graphics COMP 770 (236) Spring 2007 Instructor: Brandon Lloyd 2/14/07 1 From last time Texture mapping overview notation wrapping Perspective-correct interpolation Texture

More information

Classic Rendering Pipeline

Classic Rendering Pipeline CS580: Classic Rendering Pipeline Sung-Eui Yoon ( 윤성의 ) Course URL: http://sglab.kaist.ac.kr/~sungeui/gcg/ Course Objectives Understand classic rendering pipeline Just high-level concepts, not all the

More information

Illumination. Illumination CMSC 435/634

Illumination. Illumination CMSC 435/634 Illumination CMSC 435/634 Illumination Interpolation Illumination Illumination Interpolation Illumination Illumination Effect of light on objects Mostly look just at intensity Apply to each color channel

More information

Lessons Learned from HW4. Shading. Objectives. Why we need shading. Shading. Scattering

Lessons Learned from HW4. Shading. Objectives. Why we need shading. Shading. Scattering Lessons Learned from HW Shading CS Interactive Computer Graphics Prof. David E. Breen Department of Computer Science Only have an idle() function if something is animated Set idle function to NULL, when

More information

Why we need shading?

Why we need shading? Why we need shading? Suppose we build a model of a sphere using many polygons and color it with glcolor. We get something like But we want Light-material interactions cause each point to have a different

More information

Reflection and Refraction

Reflection and Refraction Reflection and Refraction Lecture #22 Tuesday, ovember 19, 2013 (Major Updates 12/06/13) How about Interreflections ote reflections Granite tabletop Visible on base Also on handle This is a featured picture

More information

Shading and Illumination

Shading and Illumination Shading and Illumination OpenGL Shading Without Shading With Shading Physics Bidirectional Reflectance Distribution Function (BRDF) f r (ω i,ω ) = dl(ω ) L(ω i )cosθ i dω i = dl(ω ) L(ω i )( ω i n)dω

More information

Three-Dimensional Graphics V. Guoying Zhao 1 / 55

Three-Dimensional Graphics V. Guoying Zhao 1 / 55 Computer Graphics Three-Dimensional Graphics V Guoying Zhao 1 / 55 Shading Guoying Zhao 2 / 55 Objectives Learn to shade objects so their images appear three-dimensional Introduce the types of light-material

More information

Ø Sampling Theory" Ø Fourier Analysis Ø Anti-aliasing Ø Supersampling Strategies" Ø The Hall illumination model. Ø Original ray tracing paper

Ø Sampling Theory Ø Fourier Analysis Ø Anti-aliasing Ø Supersampling Strategies Ø The Hall illumination model. Ø Original ray tracing paper CS 431/636 Advanced Rendering Techniques Ø Dr. David Breen Ø Korman 105D Ø Wednesday 6PM 8:50PM Presentation 6 5/16/12 Questions from ast Time? Ø Sampling Theory" Ø Fourier Analysis Ø Anti-aliasing Ø Supersampling

More information

Light Sources. Spotlight model

Light Sources. Spotlight model lecture 12 Light Sources sunlight (parallel) Sunny day model : "point source at infinity" - lighting - materials: diffuse, specular, ambient spotlight - shading: Flat vs. Gouraud vs Phong light bulb ambient

More information

COMP environment mapping Mar. 12, r = 2n(n v) v

COMP environment mapping Mar. 12, r = 2n(n v) v Rendering mirror surfaces The next texture mapping method assumes we have a mirror surface, or at least a reflectance function that contains a mirror component. Examples might be a car window or hood,

More information

Shading, lighting, & BRDF Theory. Cliff Lindsay, PHD

Shading, lighting, & BRDF Theory. Cliff Lindsay, PHD Shading, lighting, & BRDF Theory Cliff Lindsay, PHD Overview of today s lecture BRDF Characteristics Lights in terms of BRDFs Classes of BRDFs Ambient light & Shadows in terms of BRDFs Decomposing Reflection

More information

Lets assume each object has a defined colour. Hence our illumination model is looks unrealistic.

Lets assume each object has a defined colour. Hence our illumination model is looks unrealistic. Shading Models There are two main types of rendering that we cover, polygon rendering ray tracing Polygon rendering is used to apply illumination models to polygons, whereas ray tracing applies to arbitrary

More information

Interpolation using scanline algorithm

Interpolation using scanline algorithm Interpolation using scanline algorithm Idea: Exploit knowledge about already computed color values. Traverse projected triangle top-down using scanline. Compute start and end color value of each pixel

More information

LIGHTING AND SHADING

LIGHTING AND SHADING DH2323 DGI15 INTRODUCTION TO COMPUTER GRAPHICS AND INTERACTION LIGHTING AND SHADING Christopher Peters HPCViz, KTH Royal Institute of Technology, Sweden chpeters@kth.se http://kth.academia.edu/christopheredwardpeters

More information

Ambient reflection. Jacobs University Visualization and Computer Graphics Lab : Graphics and Visualization 407

Ambient reflection. Jacobs University Visualization and Computer Graphics Lab : Graphics and Visualization 407 Ambient reflection Phong reflection is a local illumination model. It only considers the reflection of light that directly comes from the light source. It does not compute secondary reflection of light

More information

Announcement. Lighting and Photometric Stereo. Computer Vision I. Surface Reflectance Models. Lambertian (Diffuse) Surface.

Announcement. Lighting and Photometric Stereo. Computer Vision I. Surface Reflectance Models. Lambertian (Diffuse) Surface. Lighting and Photometric Stereo CSE252A Lecture 7 Announcement Read Chapter 2 of Forsyth & Ponce Might find section 12.1.3 of Forsyth & Ponce useful. HW Problem Emitted radiance in direction f r for incident

More information

Shading , Fall 2004 Nancy Pollard Mark Tomczak

Shading , Fall 2004 Nancy Pollard Mark Tomczak 15-462, Fall 2004 Nancy Pollard Mark Tomczak Shading Shading Concepts Shading Equations Lambertian, Gouraud shading Phong Illumination Model Non-photorealistic rendering [Shirly, Ch. 8] Announcements Written

More information

Illumination and Shading

Illumination and Shading Illumination and Shading Illumination (Lighting) Model the interaction of light with surface points to determine their final color and brightness OpenGL computes illumination at vertices illumination Shading

More information

Methodology for Lecture. Importance of Lighting. Outline. Shading Models. Brief primer on Color. Foundations of Computer Graphics (Spring 2010)

Methodology for Lecture. Importance of Lighting. Outline. Shading Models. Brief primer on Color. Foundations of Computer Graphics (Spring 2010) Foundations of Computer Graphics (Spring 2010) CS 184, Lecture 11: OpenGL 3 http://inst.eecs.berkeley.edu/~cs184 Methodology for Lecture Lecture deals with lighting (teapot shaded as in HW1) Some Nate

More information

Year 6 Science Unit 6F - How we see things

Year 6 Science Unit 6F - How we see things Year 6 Science Unit 6F - How we see things ABOUT THE UNIT In this unit children learn that mirrors and shiny surfaces alter the direction in which light travels and that when they see objects, light enters

More information

CS4670/5760: Computer Vision Kavita Bala Scott Wehrwein. Lecture 23: Photometric Stereo

CS4670/5760: Computer Vision Kavita Bala Scott Wehrwein. Lecture 23: Photometric Stereo CS4670/5760: Computer Vision Kavita Bala Scott Wehrwein Lecture 23: Photometric Stereo Announcements PA3 Artifact due tonight PA3 Demos Thursday Signups close at 4:30 today No lecture on Friday Last Time:

More information

So far, we have considered only local models of illumination; they only account for incident light coming directly from the light sources.

So far, we have considered only local models of illumination; they only account for incident light coming directly from the light sources. 11 11.1 Basics So far, we have considered only local models of illumination; they only account for incident light coming directly from the light sources. Global models include incident light that arrives

More information

Lecture 4: Reflection Models

Lecture 4: Reflection Models Lecture 4: Reflection Models CS 660, Spring 009 Kavita Bala Computer Science Cornell University Outline Light sources Light source characteristics Types of sources Light reflection Physics-based models

More information

Photorealism: Ray Tracing

Photorealism: 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 information

Global Illumination. Global Illumination. Direct Illumination vs. Global Illumination. Indirect Illumination. Soft Shadows.

Global Illumination. Global Illumination. Direct Illumination vs. Global Illumination. Indirect Illumination. Soft Shadows. CSCI 480 Computer Graphics Lecture 18 Global Illumination BRDFs Raytracing and Radiosity Subsurface Scattering Photon Mapping [Ch. 13.4-13.5] March 28, 2012 Jernej Barbic University of Southern California

More information

SEOUL NATIONAL UNIVERSITY

SEOUL NATIONAL UNIVERSITY Fashion Technology 5. 3D Garment CAD-1 Sungmin Kim SEOUL NATIONAL UNIVERSITY Overview Design Process Concept Design Scalable vector graphics Feature-based design Pattern Design 2D Parametric design 3D

More information

Surface Reflection Models

Surface Reflection Models Surface Reflection Models Frank Losasso (flosasso@nvidia.com) Introduction One of the fundamental topics in lighting is how the light interacts with the environment. The academic community has researched

More information

Global Illumination and Radiosity

Global Illumination and Radiosity Global Illumination and Radiosity CS434 Daniel G. Aliaga Department of Computer Science Purdue University Recall: Lighting and Shading Light sources Point light Models an omnidirectional light source (e.g.,

More information

Color and Shading. Color. Shapiro and Stockman, Chapter 6. Color and Machine Vision. Color and Perception

Color and Shading. Color. Shapiro and Stockman, Chapter 6. Color and Machine Vision. Color and Perception Color and Shading Color Shapiro and Stockman, Chapter 6 Color is an important factor for for human perception for object and material identification, even time of day. Color perception depends upon both

More information

Illumination and Shading ECE 567

Illumination and Shading ECE 567 Illumination and Shading ECE 567 Overview Lighting Models Ambient light Diffuse light Specular light Shading Models Flat shading Gouraud shading Phong shading OpenGL 2 Introduction To add realism to drawings

More information

Lighting/Shading II. Week 7, Mon Mar 1

Lighting/Shading II. Week 7, Mon Mar 1 University of British Columbia CPSC 314 Computer Graphics Jan-Apr 2010 Tamara Munzner Lighting/Shading II Week 7, Mon Mar 1 http://www.ugrad.cs.ubc.ca/~cs314/vjan2010 News Homework 3 out today Homework

More information

CEng 477 Introduction to Computer Graphics Fall

CEng 477 Introduction to Computer Graphics Fall Illumination Models and Surface-Rendering Methods CEng 477 Introduction to Computer Graphics Fall 2007 2008 Illumination Models and Surface Rendering Methods In order to achieve realism in computer generated

More information

Objectives. Continue discussion of shading Introduce modified Phong model Consider computation of required vectors

Objectives. Continue discussion of shading Introduce modified Phong model Consider computation of required vectors Objectives Continue discussion of shading Introduce modified Phong model Consider computation of required vectors 1 Lambertian Surface Perfectly diffuse reflector Light scattered equally in all directions

More information

CG Surfaces: Materials, Shading, and Texturing

CG Surfaces: Materials, Shading, and Texturing CG Surfaces: Materials, Shading, and Texturing ART/CSC/FST 220 Spring 2007 From text: 3D for Beginners, Chapter 7 Art of Maya (pages 116-126, 185-194) Shading and texturing involves materials and their

More information

Objectives. Shading II. Distance Terms. The Phong Reflection Model

Objectives. Shading II. Distance Terms. The Phong Reflection Model Shading II Objectives Introduce distance terms to the shading model. More details about the Phong model (lightmaterial interaction). Introduce the Blinn lighting model (also known as the modified Phong

More information

Ray Casting. Outline. Similar to glulookat derivation. Foundations of Computer Graphics

Ray Casting. Outline. Similar to glulookat derivation. Foundations of Computer Graphics Foundations of omputer Graphics Online Lecture 10: Ray Tracing 2 Nuts and olts amera Ray asting Outline amera Ray asting (choose ray directions) Ravi Ramamoorthi Outline in ode Image Raytrace (amera cam,

More information

Precomputed Radiance Transfer: Theory and Practice

Precomputed Radiance Transfer: Theory and Practice 1 Precomputed Radiance Transfer: Peter-Pike Sloan Microsoft Jaakko Lehtinen Helsinki Univ. of Techn. & Remedy Entertainment Jan Kautz MIT 2 Introduction Jan Kautz MIT 3 Introduction We see here an example

More information

Computer Graphics I. Assignment 3

Computer Graphics I. Assignment 3 UNIVERSITÄT DES SAARLANDES Dr.-Ing. Hendrik P.A. Lensch Max Planck Institut Informatik Art Tevs (tevs@mpi-inf.mpg.de) Boris Ajdin (bajdin@mpi-inf.mpg.de) Matthias Hullin (hullin@mpi-inf.mpg.de) 12. November

More information

Announcements. Written Assignment 2 out (due March 8) Computer Graphics

Announcements. Written Assignment 2 out (due March 8) Computer Graphics Announcements Written Assignment 2 out (due March 8) 1 Advanced Ray Tracing (Recursive) Ray Tracing Antialiasing Motion Blur Distribution Ray Tracing Ray Tracing and Radiosity Assumptions Simple shading

More information

Light source estimation using feature points from specular highlights and cast shadows

Light source estimation using feature points from specular highlights and cast shadows Vol. 11(13), pp. 168-177, 16 July, 2016 DOI: 10.5897/IJPS2015.4274 Article Number: F492B6D59616 ISSN 1992-1950 Copyright 2016 Author(s) retain the copyright of this article http://www.academicjournals.org/ijps

More information

Introduction to 3D Graphics

Introduction to 3D Graphics Introduction to 3D Graphics Using OpenGL 3D 1/46 Classical Polygon Graphics (H/W) Pipeline Mesh objects with 3D polygons (triangles or quads usually) Apply material properties to each object (for reflectance

More information

CSE Intro to Computer Graphics. ANSWER KEY: Midterm Examination. November 18, Instructor: Sam Buss, UC San Diego

CSE Intro to Computer Graphics. ANSWER KEY: Midterm Examination. November 18, Instructor: Sam Buss, UC San Diego CSE 167 - Intro to Computer Graphics ANSWER KEY: Midterm Examination November 18, 2003 Instructor: Sam Buss, UC San Diego Write your name or initials on every page before beginning the exam. You have 75

More information

Motivation. Monte Carlo Path Tracing. Monte Carlo Path Tracing. Monte Carlo Path Tracing. Monte Carlo Path Tracing

Motivation. Monte Carlo Path Tracing. Monte Carlo Path Tracing. Monte Carlo Path Tracing. Monte Carlo Path Tracing Advanced Computer Graphics (Spring 2013) CS 283, Lecture 11: Monte Carlo Path Tracing Ravi Ramamoorthi http://inst.eecs.berkeley.edu/~cs283/sp13 Motivation General solution to rendering and global illumination

More information

Summary. What is Computer Graphics? IRISA 2. Coordinate systems. 4. Geometric transformations for display

Summary. What is Computer Graphics? IRISA   2. Coordinate systems. 4. Geometric transformations for display Summary Basic Computer Graphics Kadi Bouatouch IRISA Email: kadi@irisa.fr 1. Introduction 2. Coordinate systems 3. Geometric transformations 4. Geometric transformations for display 5. Choosing the camera

More information

CS 410: Computer Graphics

CS 410: Computer Graphics CS 410: Computer Graphics Professor: Bruce Draper Room 440 CSB (970) 491-7873 Office Hours: Mon 10:00 11:00 Tues 10:00 11:00 or by appointment draper@cs.colostate.edu 1-slide Overview This is what you

More information

4) Finish the spline here. To complete the spline, double click the last point or select the spline tool again.

4) Finish the spline here. To complete the spline, double click the last point or select the spline tool again. 1) Select the line tool 3) Move the cursor along the X direction (be careful to stay on the X axis alignment so that the line is perpendicular) and click for the second point of the line. Type 0.5 for

More information

Recall: Basic Ray Tracer

Recall: Basic Ray Tracer 1 Recall: Ray Tracing Generate an image by backwards tracing the path of light through pixels on an image plane Simulate the interaction of light with objects Recall: Basic Ray Tracer Trace a primary ray

More information

CS 431/636 Advanced Rendering Techniques

CS 431/636 Advanced Rendering Techniques CS 431/636 Advanced Rendering Techniques Dr. David Breen Matheson 308 Thursday 6PM 8:50PM Presentation 7 5/23/06 Questions from Last Time? Hall Shading Model Shadows Reflections Refractions Slide Credits

More information

Shadow Algorithms. CSE 781 Winter Han-Wei Shen

Shadow Algorithms. CSE 781 Winter Han-Wei Shen Shadow Algorithms CSE 781 Winter 2010 Han-Wei Shen Why Shadows? Makes 3D Graphics more believable Provides additional cues for the shapes and relative positions of objects in 3D What is shadow? Shadow:

More information

Illumination and Shading

Illumination and Shading Illumination and Shading Light sources emit intensity: assigns intensity to each wavelength of light Humans perceive as a colour - navy blue, light green, etc. Exeriments show that there are distinct I

More information

Chapter 4- Blender Render Engines

Chapter 4- Blender Render Engines Chapter 4- Render Engines What is a Render Engine? As you make your 3D models in, your goal will probably be to generate (render) an image or a movie as a final result. The software that determines how

More information

Lecture 17: Recursive Ray Tracing. Where is the way where light dwelleth? Job 38:19

Lecture 17: Recursive Ray Tracing. Where is the way where light dwelleth? Job 38:19 Lecture 17: Recursive Ray Tracing Where is the way where light dwelleth? Job 38:19 1. Raster Graphics Typical graphics terminals today are raster displays. A raster display renders a picture scan line

More information

SAMPLING AND NOISE. Increasing the number of samples per pixel gives an anti-aliased image which better represents the actual scene.

SAMPLING AND NOISE. Increasing the number of samples per pixel gives an anti-aliased image which better represents the actual scene. SAMPLING AND NOISE When generating an image, Mantra must determine a color value for each pixel by examining the scene behind the image plane. Mantra achieves this by sending out a number of rays from

More information

Visual cues The human headway

Visual cues The human headway Visual cues The human headway Overlapping objects Quantized scenes Lo sposalizio della Vergine Raffaello Sanzio Pinacoteca di Brera Perspective geometry Depth from shading Multi-presence Depth from texture

More information

CS452/552; EE465/505. Lighting & Shading

CS452/552; EE465/505. Lighting & Shading CS452/552; EE465/505 Lighting & Shading 2-17 15 Outline! More on Lighting and Shading Read: Angel Chapter 6 Lab2: due tonight use ASDW to move a 2D shape around; 1 to center Local Illumination! Approximate

More information

Basic Computer Graphics. Kadi Bouatouch IRISA

Basic Computer Graphics. Kadi Bouatouch IRISA Basic Computer Graphics Kadi Bouatouch IRISA Email: kadi@irisa.fr 1 Summary 1. Introduction 2. Coordinate systems 3. Geometric transformations 4. Geometric transformations for display 5. Choosing the camera

More information

Shading Languages. Seminar Computer Graphics. Markus Kummerer

Shading Languages. Seminar Computer Graphics. Markus Kummerer Shading Languages Markus Kummerer ABSTRACT Shading Languages provide a highly flexible approach for creating visual structures in computer imagery. The RenderMan Interface provides an API for scene description,

More information

DH2323 DGI13. Lab 2 Raytracing

DH2323 DGI13. Lab 2 Raytracing DH2323 DGI13 Lab 2 Raytracing In this lab you will implement a Raytracer, which draws images of 3D scenes by tracing the light rays reaching the simulated camera. The lab is divided into several steps.

More information

Illumination and Shading

Illumination and Shading Illumination and Shading Illumination and Shading z Illumination Models y Ambient y Diffuse y Attenuation y Specular Reflection z Interpolated Shading Models y Flat, Gouraud, Phong y Problems CS4451: Fall

More information

Last Time? Ray Casting. Administrivia: Lab & Office Hours. Notes on Assignments. Ray Casting. Overview of Today

Last Time? Ray Casting. Administrivia: Lab & Office Hours. Notes on Assignments. Ray Casting. Overview of Today Ray Casting Last Time? Luxo Jr. Applications of Computer Graphics Overview of the semester IFS Assignment 0 due tomorrow @ 11:59pm Questions? 1 2 Notes on Assignments Make sure you turn in a linux or windows

More information

Illumination Models and Surface-Rendering Methods. Chapter 10

Illumination Models and Surface-Rendering Methods. Chapter 10 Illumination Models and Surface-Rendering Methods Chapter 10 Illumination and Surface- Rendering Given scene specifications object positions, optical properties of the surface, viewer position, viewing

More information

CSE 167: Lecture #8: GLSL. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2012

CSE 167: Lecture #8: GLSL. Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2012 CSE 167: Introduction to Computer Graphics Lecture #8: GLSL Jürgen P. Schulze, Ph.D. University of California, San Diego Fall Quarter 2012 Announcements Homework project #4 due Friday, November 2 nd Introduction:

More information

3D Programming. 3D Programming Concepts. Outline. 3D Concepts. 3D Concepts -- Coordinate Systems. 3D Concepts Displaying 3D Models

3D Programming. 3D Programming Concepts. Outline. 3D Concepts. 3D Concepts -- Coordinate Systems. 3D Concepts Displaying 3D Models 3D Programming Concepts Outline 3D Concepts Displaying 3D Models 3D Programming CS 4390 3D Computer 1 2 3D Concepts 3D Model is a 3D simulation of an object. Coordinate Systems 3D Models 3D Shapes 3D Concepts

More information

Lecture 7 - Path Tracing

Lecture 7 - Path Tracing INFOMAGR Advanced Graphics Jacco Bikker - November 2016 - February 2017 Lecture 7 - I x, x = g(x, x ) ε x, x + S ρ x, x, x I x, x dx Welcome! Today s Agenda: Introduction Advanced Graphics 3 Introduction

More information

Glossy Reflection. Objectives Modeling

Glossy Reflection. Objectives Modeling 25 Glossy Reflection 25.1 Modeling 25.2 Implementation 25.3 Results Objectives By the end of this chapter, you should: understand what glossy reflection is; understand how it can be modeled in ray tracing;

More information

Shading II. Ed Angel Professor of Computer Science, Electrical and Computer Engineering, and Media Arts University of New Mexico

Shading II. Ed Angel Professor of Computer Science, Electrical and Computer Engineering, and Media Arts University of New Mexico Shading II Ed Angel Professor of Computer Science, Electrical and Computer Engineering, and Media Arts University of New Mexico 1 Objectives Continue discussion of shading Introduce modified Phong model

More information

CIS 536/636 Introduction to Computer Graphics. Kansas State University. CIS 536/636 Introduction to Computer Graphics

CIS 536/636 Introduction to Computer Graphics. Kansas State University. CIS 536/636 Introduction to Computer Graphics 2 Lecture Outline Surface Detail 3 of 5: Mappings OpenGL Textures William H. Hsu Department of Computing and Information Sciences, KSU KSOL course pages: http://bit.ly/hgvxlh / http://bit.ly/evizre Public

More information

Image Formation: Light and Shading. Introduction to Computer Vision CSE 152 Lecture 3

Image Formation: Light and Shading. Introduction to Computer Vision CSE 152 Lecture 3 Image Formation: Light and Shading CSE 152 Lecture 3 Announcements Homework 1 is due Apr 11, 11:59 PM Homework 2 will be assigned on Apr 11 Reading: Chapter 2: Light and Shading Geometric image formation

More information

6.837 Introduction to Computer Graphics Assignment 5: OpenGL and Solid Textures Due Wednesday October 22, 2003 at 11:59pm

6.837 Introduction to Computer Graphics Assignment 5: OpenGL and Solid Textures Due Wednesday October 22, 2003 at 11:59pm 6.837 Introduction to Computer Graphics Assignment 5: OpenGL and Solid Textures Due Wednesday October 22, 2003 at 11:59pm In this assignment, you will add an interactive preview of the scene and solid

More information

EDAN30 Photorealistic Computer Graphics. Seminar 1, Whitted Ray Tracing (And then some!) Magnus Andersson, PhD student

EDAN30 Photorealistic Computer Graphics. Seminar 1, Whitted Ray Tracing (And then some!) Magnus Andersson, PhD student EDAN30 Photorealistic Computer Graphics Seminar, 203 Whitted Ray Tracing (And then some!) Magnus Andersson, PhD student (magnusa@cs.lth.se) Today s Agenda Structure of Assignments Quick prtracer walkthrough

More information

Objectives Shading in OpenGL. Front and Back Faces. OpenGL shading. Introduce the OpenGL shading methods. Discuss polygonal shading

Objectives Shading in OpenGL. Front and Back Faces. OpenGL shading. Introduce the OpenGL shading methods. Discuss polygonal shading Objectives Shading in OpenGL Introduce the OpenGL shading methods - per vertex shading vs per fragment shading - Where to carry out Discuss polygonal shading - Flat - Smooth - Gouraud CITS3003 Graphics

More information

The Question. What are the 4 types of interactions that waves can have when they encounter an object?

The Question. What are the 4 types of interactions that waves can have when they encounter an object? The Question What are the 4 types of interactions that waves can have when they encounter an object? Waves, Wave fronts and Rays Wave Front: Crests of the waves. Rays: Lines that are perpendicular to the

More information

Property of: Entrada Interactive. PBR Workflow. Working within a PBR-based environment

Property of: Entrada Interactive. PBR Workflow. Working within a PBR-based environment Property of: Entrada Interactive PBR Workflow Working within a PBR-based environment Ryan Manning 8/24/2014 MISCREATED PBR WORKFLOW CryDocs on Physically Based Shading/Rendering: http://docs.cryengine.com/display/sdkdoc4/physically+based+rendering

More information

The Reflection of Light

The Reflection of Light King Saud University College of Applied Studies and Community Service Department of Natural Sciences The Reflection of Light General Physics II PHYS 111 Nouf Alkathran nalkathran@ksu.edu.sa Outline Introduction

More information

6.837 Introduction to Computer Graphics Assignment 5: OpenGL and Solid Textures Due Wednesday October 22, 2003 at 11:59pm

6.837 Introduction to Computer Graphics Assignment 5: OpenGL and Solid Textures Due Wednesday October 22, 2003 at 11:59pm 6.837 Introduction to Computer Graphics Assignment 5: OpenGL and Solid Textures Due Wednesday October 22, 2003 at 11:59pm In this assignment, you will add an interactive preview of the scene and solid

More information

STEEL SURFACE CHARACTERIZATION USING 3D PROFILOMETRY

STEEL SURFACE CHARACTERIZATION USING 3D PROFILOMETRY STEEL SURFACE CHARACTERIZATION USING 3D PROFILOMETRY Prepared by Andrea Novitsky 6 Morgan, Ste156, Irvine CA 92618 P: 949.461.9292 F: 949.461.9232 nanovea.com Today's standard for tomorrow's materials.

More information

A Brief Overview of. Global Illumination. Thomas Larsson, Afshin Ameri Mälardalen University

A Brief Overview of. Global Illumination. Thomas Larsson, Afshin Ameri Mälardalen University A Brief Overview of Global Illumination Thomas Larsson, Afshin Ameri Mälardalen University 1 What is Global illumination? Global illumination is a general name for realistic rendering algorithms Global

More information

CS201 Computer Vision Lect 4 - Image Formation

CS201 Computer Vision Lect 4 - Image Formation CS201 Computer Vision Lect 4 - Image Formation John Magee 9 September, 2014 Slides courtesy of Diane H. Theriault Question of the Day: Why is Computer Vision hard? Something to think about from our view

More information

Introduction to Computer Vision. Introduction CMPSCI 591A/691A CMPSCI 570/670. Image Formation

Introduction to Computer Vision. Introduction CMPSCI 591A/691A CMPSCI 570/670. Image Formation Introduction CMPSCI 591A/691A CMPSCI 570/670 Image Formation Lecture Outline Light and Optics Pinhole camera model Perspective projection Thin lens model Fundamental equation Distortion: spherical & chromatic

More information

2/1/10. Outline. The Radiance Equation. Light: Flux Equilibrium. Light: Radiant Power. Light: Equation. Radiance. Jan Kautz

2/1/10. Outline. The Radiance Equation. Light: Flux Equilibrium. Light: Radiant Power. Light: Equation. Radiance. Jan Kautz Outline Jan Kautz Basic terms in radiometry Radiance Reflectance The operator form of the radiance equation Meaning of the operator form Approximations to the radiance equation 2005 Mel Slater, 2006 Céline

More information

Rendering Algorithms: Real-time indirect illumination. Spring 2010 Matthias Zwicker

Rendering 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 information