Illumination and Shading

Slides:



Advertisements
Similar presentations
SI31 Advanced Computer Graphics AGR
Advertisements

Polygon Rendering Flat Rendering Goraud Rendering Uses Phong Reflectance Phong Rendering.
1 Graphics CSCI 343, Fall 2013 Lecture 18 Lighting and Shading.
Virtual Realism LIGHTING AND SHADING. Lighting & Shading Approximate physical reality Ray tracing: Follow light rays through a scene Accurate, but expensive.
Ray Tracing & Radiosity Dr. Amy H. Zhang. Outline  Ray tracing  Radiosity.
1. What is Lighting? 2 Example 1. Find the cubic polynomial or that passes through the four points and satisfies 1.As a photon Metal Insulator.
Illumination Model & Surface-rendering Method 박 경 와.
1 Angel: Interactive Computer Graphics 5E © Addison-Wesley 2009 Shading I.
IMGD 1001: Illumination by Mark Claypool
Computer Graphics (Fall 2005) COMS 4160, Lecture 16: Illumination and Shading 1
Lighting and Shading Wen-Chieh (Steve) Lin
(conventional Cartesian reference system)
1 CSCE 641: Computer Graphics Lighting Jinxiang Chai.
Global Illumination May 7, Global Effects translucent surface shadow multiple reflection.
7M836 Animation & Rendering
CSCE 641 Computer Graphics: Radiosity Jinxiang Chai.
The Radiosity Method Donald Fong February 10, 2004.
CSCE 641 Computer Graphics: Radiosity Jinxiang Chai.
CSCE 441 Computer Graphics: Radiosity Jinxiang Chai.
Coordinate Systems X Y Z (conventional Cartesian reference system) X Y Z.
1 Angel: Interactive Computer Graphics 4E © Addison-Wesley 2005 Shading I Ed Angel Professor of Computer Science, Electrical and Computer Engineering,
CS 480/680 Computer Graphics Shading I Dr. Frederick C Harris, Jr.
Fundamentals of Computer Graphics Part 6 Shading prof.ing.Václav Skala, CSc. University of West Bohemia Plzeň, Czech Republic ©2002 Prepared with Angel,E.:
Shading (introduction to rendering). Rendering  We know how to specify the geometry but how is the color calculated.
COMPUTER GRAPHICS CS 482 – FALL 2014 AUGUST 27, 2014 FIXED-FUNCTION 3D GRAPHICS MESH SPECIFICATION LIGHTING SPECIFICATION REFLECTION SHADING HIERARCHICAL.
COLLEGE OF ENGINEERING UNIVERSITY OF PORTO COMPUTER GRAPHICS AND INTERFACES / GRAPHICS SYSTEMS JGB / AAS 1 Shading (Shading) & Smooth Shading Graphics.
Shading & Texture. Shading Flat Shading The process of assigning colors to pixels. Smooth Shading Gouraud ShadingPhong Shading Shading.
COLLEGE OF ENGINEERING UNIVERSITY OF PORTO COMPUTER GRAPHICS AND INTERFACES / GRAPHICS SYSTEMS JGB / AAS Global illumination algorithms Graphics.
CS447/ Realistic Rendering -- Radiosity Methods-- Introduction to 2D and 3D Computer Graphics.
Rendering Overview CSE 3541 Matt Boggus. Rendering Algorithmically generating a 2D image from 3D models Raster graphics.
University of Texas at Austin CS 378 – Game Technology Don Fussell CS 378: Computer Game Technology Basic Rendering Pipeline and Shading Spring 2012.
Illumination and Shading How to shade surfaces based on the position,orientation,characteristics of the surfaces and the light sources illuminating them.
CPSC 641 Computer Graphics: Radiosity Jinxiang Chai.
Computer Graphics: Programming, Problem Solving, and Visual Communication Steve Cunningham California State University Stanislaus and Grinnell College.
Illumination and Shading
CS 325 Introduction to Computer Graphics 03 / 29 / 2010 Instructor: Michael Eckmann.
Graphics Graphics Korea University cgvr.korea.ac.kr 1 Surface Rendering Methods 고려대학교 컴퓨터 그래픽스 연구실.
High detail models, depth of field, soft shadows, reflective surfaces. (Image created by Toxic Studios using Brazil R/S)
CS 445 / 645 Introduction to Computer Graphics Lecture 15 Shading Shading.
CS 376 Introduction to Computer Graphics 04 / 02 / 2007 Instructor: Michael Eckmann.
Illumination and Shading Prof. Lizhuang Ma Shanghai Jiao Tong University.
Render methods. Contents Levels of rendering Wireframe Plain shadow Gouraud Phong Comparison Gouraud-Phong.
Illumination Models. Introduction 1 Illumination model: Given a point on a surface, what is the perceived color and intensity? Known as Lighting Model,
CS552: Computer Graphics Lecture 33: Illumination and Shading.
Computer Graphics Ken-Yi Lee National Taiwan University (the slides are adapted from Bing-Yi Chen and Yung-Yu Chuang)
Computer Graphics (Fall 2006) COMS 4160, Lecture 16: Illumination and Shading 1
Illumination and Shading. Illumination (Lighting) Model the interaction of light with surface points to determine their final color and brightness OpenGL.
Illumination and Shading Prof. Lizhuang Ma Shanghai Jiao Tong University.
Chapter 10: Computer Graphics
Rendering Process of producing “realistic” images or pictures
3D Graphics Rendering PPT By Ricardo Veguilla.
Unit-7 Lighting and Shading
Chapter 10: Computer Graphics
Chapter 14 Shading Models.
CSC461: Lecture 23 Shading Computation
CSCE 441 Computer Graphics: Radiosity
Fundamentals of Computer Graphics Part 6 Shading
Isaac Gang University of Mary Hardin-Baylor
CS5500 Computer Graphics May 29, 2006
Last Time Liang-Barsky Details Weiler-Atherton clipping algorithm
GR2 Advanced Computer Graphics AGR
Texture Mapping 고려대학교 컴퓨터 그래픽스 연구실.
Chapter 14 Shading Models.
Illumination Model 고려대학교 컴퓨터 그래픽스 연구실.
Illumination Model 고려대학교 컴퓨터 그래픽스 연구실.
Adding Surface Detail 고려대학교 컴퓨터 그래픽스 연구실.
CS 480/680 Computer Graphics Shading.
Adding Surface Detail 고려대학교 컴퓨터 그래픽스 연구실.
Lighting Calculations
Presentation transcript:

Illumination and Shading Prof. Lizhuang Ma Shanghai Jiao Tong University

Contents Illumination Models Shading Models for Polygons Surface Detail Shadows Transparency Global Illumination Recursive Ray Tracing Radiosity The Rendering Pipeline

Illumination Models Ambient Light: :intensity of the ambient light :ambient-reflection coefficient: 0~1 Diffuse reflection: :point light source’s intensity :diffuse-reflection coefficient: 0~1 :angle:

Diffuse Reflection

Examples

Illumination Models :light-source attenuation factor If the light is a point source Diffuse reflection: where is the distance the light travels from the point source to the surface

Examples

Colored Lights and Surfaces If an object’s diffuse color is where for the red component however, it should be generally where is the wavelength then

Specular Reflection

The Phong Illumination Model : specular-reflection coefficient: 0~1 So, the Eq. can be rewritten as: Consider the object’s specular color: : specular color

The Phong Model

The Phong Illumination Model

Examples

Calculating the Reflection Vector

The Halfway Vector

Multiple Light Sources If there are m light sources, then

Shading Models for Polygons Constant Shading Faceted Shading Flat Shading Gouraud Shading Intensity Interpolation Shading Color Interpolation Shading Phong Shading Normal-Vector Interpolation Shading

Constant Shading Assumption The light source is at infinity The viewer is at infinity The polygon represents the actual surface being modeled and is not an approximation to a curved surface: Note that N.L ,N.V are constant across the polygon face

Gouraud Shading

Gouraud v.s. Phong Shading

Phong Shading

Texture Mapping = Pattern Mapping

Bump Mapping & Displacement Mapping

Shadows If light I is blocked at this point If light I is not blocked at this point

Shadows If light I is blocked at this point If light I is not blocked at this point

Scan-Line Generation of Shadows

Shadow Volumes

Shadow Volumes

Shadow

Transparency Interpolated transparency : transparency: 0~1 Filtered transparency :transparency color

Global Illumination Direct & indirect (reflected) light sources

The Rendering Equation : intensity passing from to : emitted light intensity from to : intensity of light reflected from to from the surface at (indirect light sources) : the distance between and : all surfaces if is invisible from if is visible from

Recursive Ray Tracing surface normal reflected ray shadow ray transmitted ray

Recursive Ray Tracing surface normal reflected ray shadow ray transmitted ray

Traditional Ray Tracing

Ray Tracing + Soft Shadows

The Ray Tree Intensity of reflected ray Transmission coefficient :0~1 Intensity of transmitted ray

The Radiosity Equation : radiosity of patch i : rate at which light is emitted form patch i : reflectivity of patch i : form factor (configuration factor) : area of patch i Since Thus

The Radiosity Equation Rearranging terms Therefore Progressive refinement

Radiosity vs. Ray Tracing Ray traced image. Image rendered with radiosity. Original

Computing Form Factors

Hemisphere

Hemicube

The Rendering Pipeline Local Illumination Pipelines z-buffer and Gouraud shading z-buffer and Phong shading List-priority algorithm and Phong shading Global Illumination Pipelines Radiosity Ray tracing

Rendering Pipeline for z-buffer & Gouraud Shading

Rendering Pipeline for z-buffer & Phone shading

Rendering Pipeline for List-priority Algorithm & Gouraud Shading

Rendering Pipeline for List-priority Algorithm & Phong Shading

Rendering Pipeline for Ray Tracing