Computing & Information Sciences Kansas State University Advanced CG 1 of 8: TexturingCIS 636/736:...

Computing & Information SciencesKansas State University

Advanced CG 1 of 8: TexturingCIS 636/736: (Introduction to) Computer Graphics

CIS 736Computer Graphics

William H. Hsu

Department of Computing and Information Sciences, KSU

KSOL course pages: http://snipurl.com/1y5gc

Course web site: http://www.kddresearch.org/Courses/CIS736

Instructor home page: http://www.cis.ksu.edu/~bhsu

Readings:

Handout 1: Texturing

Sections 20.3 – 20.4, Eberly 2e – see http://snurl.com/1ye72

NeHe tutorials 6 (basics), 11 (flag), 15 & 17 (fonts) – http://nehe.gamedev.net

More NeHe texturing tutorials: 35 (rendering), 42 (coloring)

Advanced CG Topics 1 of 8:Filters for Texturing



Online Recorded Lectures for CIS 736

Computer Graphics Project Topics for CIS 736

Advanced Topics in Computer Graphics (8) 1. Filters for Texturing – first month

2. More Mappings – second month

3. Advanced Lighting Models – second month

4. Advanced Ray-Tracing – first month

5. Advanced Ray-Tracing, concluded – second month

6. Global Illumination: Photon Maps (Radiosity) – third month

7. More on Scientific, Data, Info Visualization – third month

8. Terrain – first month

Recommended Background Reading for CIS 736

Shared Lectures with CIS 636 (Computer Graphics) Regular in-class lectures (35) and labs (7)

Guidelines for paper reviews – week of Mon 25 Feb 2008

Preparing term project presentations and demos for graphics – April



Background Expected

Both Courses Proficiency in C/C++ or strong proficiency in Java and ability to learn

Strongly recommended: matrix theory or linear algebra (e.g., Math 551)

At least 120 hours for semester (up to 150 depending on term project)

Textbook: 3D Game Engine Design, Second Edition (2006), Eberly

Angel’s OpenGL: A Primer recommended

CIS 636 Introduction to Computer Graphics Fresh background in precalculus: Algebra 1-2, Analytic Geometry

Linear algebra basics: matrices, linear bases, vector spaces

Watch background lectures

CIS 736 Computer Graphics Recommended: first course in graphics (background lectures as needed)

OpenGL experience helps

Read up on shaders and shading languages

Watch advanced topics lectures; see list before choosing project topic



Lecture Outline

References: Gröller & Jeschke (2002), Isenberg (2005), Jacobs (2007)

Texture Mapping Explained Definitions

Design principles

Texture Pipeline

Using Simple Intermediate Surfaces (Cylinder, Sphere, Plane, Box)

Procedural Textures Simple regular patterns (e.g., checkerboard)

Terrain

Clouds

Perlin Noise Models Interpolation

Turbulence

Later: Relation to Fractals, Fractional Brownian Motion (fBm)

Anisotropic Filtering



Source Material: Gröller & JeschkeICGA, Vienna Institute of

Technology

Source Material: Gröller & JeschkeICGA, Vienna Institute of

Technology

Adapted from slides

© 2002 Gröller, E. & Jeschke, S. Vienna Institute of Technology



Other Source Material: Other Source Material:

CMSC 427 Computer Graphics

University of Maryland – College Park (UMD)

Fall 2007

Course: http://snurl.com/20csv

Instructor: http://www.cs.umd.edu/~djacobs

Tobias IsenbergScientific Visualization and Computer Graphics Group

Department of Mathematics and Computing Science

University of Groningen

Formerly

Graphics Jungle Lab

Department of Computer Science

University of Calgary

CPSC 599.64/601.64 Computer Graphics

Fall 2005

Course: http://snurl.com/20cu0

Instructor: http://www.cs.rug.nl/~isenberg



Why Texturing?Why Texturing?

Adapted from slides




Introduction [1]:Motivation

Introduction [1]:Motivation

Adapted from slides

© 2005 Isenberg, T., University of Calgary (now at U. Groningen)



Adapted from slides


Introduction [2]:Properties and their Mappings

Introduction [2]:Properties and their Mappings



Concerning TexturesConcerning Textures

Adapted from slides

© 2007 Jacobs, D. W., University of Maryland



Without TexturesWithout Textures

Adapted from slides


From Computer Graphics: Principles and Practice

© 1991 Foley, van Dam, Feiner, Hughes



With TexturesWith Textures

Adapted from slides


From Computer Graphics: Principles and Practice

© 1991 Foley, van Dam, Feiner, Hughes



Texture ImageTexture Image

Adapted from slides


u

v



Adapted from slides


Texture Mapping How-To [1]:Goals and Texture Elements

(Texels)

Texture Mapping How-To [1]:Goals and Texture Elements

(Texels)



Adapted from slides


Texture Mapping How-To [2]:Adapting Polygons-to-Pixels

Pipeline

Texture Mapping How-To [2]:Adapting Polygons-to-Pixels

Pipeline



Adapted from slides


Texture Mapping How-To [3]: Mapping Definition

Texture Mapping How-To [3]: Mapping Definition

u = s(x, y, z)

v = t(x, y, z)



Adapted from slides


Texture Mapping How-To [4]:General Procedure

Texture Mapping How-To [4]:General Procedure



Adapted from slides


Texture Mapping How-To [5]: Projective Textures, Projector

Functions

Texture Mapping How-To [5]: Projective Textures, Projector

Functions



Adapted from slides


Texture Mapping How-To [6]: (Manual) Surface Parameterization

Texture Mapping How-To [6]: (Manual) Surface Parameterization



Adapted from slides


Texture Mapping How-To [6]: Inherent (u, v) Coordinates

Texture Mapping How-To [6]: Inherent (u, v) Coordinates



Adapted from slides


Two-Step Approach [1]:Duality (Again)

Two-Step Approach [1]:Duality (Again)



Adapted from slides


Two-Step Approach [2]:Example – Cylindrical Mapping

Two-Step Approach [2]:Example – Cylindrical Mapping



Adapted from slides


Two-Step Approach [3]:Example – Spherical Mapping

Two-Step Approach [3]:Example – Spherical Mapping



Adapted from slides


Two-Step Approach [4]:Example – Planar Mapping

Two-Step Approach [4]:Example – Planar Mapping



Adapted from slides


Two-Step Approach [5]:Example – Cuboid/Box Mapping

Two-Step Approach [5]:Example – Cuboid/Box Mapping



Adapted from slides


O Mapping [1]:Object-to-Surface

O Mapping [1]:Object-to-Surface



Adapted from slides


O Mapping [2]:Illustrations

O Mapping [2]:Illustrations

1. Reflected Ray 2. Object Normal

3. Object Center 4. Normal of Intermediate Surface



Adapted from slides


Correspondence Functions [1]:Texture Coordinates

Correspondence Functions [1]:Texture Coordinates

u = s(x, y, z)

v = t(x, y, z)



Adapted from slides


Correspondence Functions [2]:Tiling, Mirroring, Clamping,

Borders

Correspondence Functions [2]:Tiling, Mirroring, Clamping,

Borders



Adapted from slides


Correspondence Functions [3]:Clamping and Borders IllustratedCorrespondence Functions [3]:

Clamping and Borders Illustrated



Adapted from slides


Application of Texture Values:Combining Texturing and Lighting

Application of Texture Values:Combining Texturing and Lighting



Adapted from slides


The End…?The End…?

Done! … well, almost



Adapted from slides


AcknowledgementsAcknowledgements



Surface Detail: Imitating Complexity by Texturing Smooth

Objects

Surface Detail: Imitating Complexity by Texturing Smooth

Objects

Adapted from slides




Texture PropertiesTexture Properties

Adapted from slides


Procedural: either

Procedural: either



Procedural Texture [1]Procedural Texture [1]

Adapted from slides

© 2007 Jacobs, D. W., University of Maryland… how to get this?




Adapted from slides




Adapted from slides


Procedural Models:Example [1]






Adapted from slides




What is Texture?What is Texture?

Adapted from slides




Perlin Noise [1]:How to Simulate Variation

Perlin Noise [1]:How to Simulate Variation

Adapted from slides




Perlin Noise [2]:Properties

Perlin Noise [2]:Properties

Adapted from slides




Procedural Textures:Strategy

Procedural Textures:Strategy

Adapted from slides




1-D Perlin Noise1-D Perlin Noise

Adapted from slides




2-D Perlin Noise2-D Perlin Noise

Adapted from slides




Smooth NoiseSmooth Noise

Adapted from slides




Linear InterpolationLinear Interpolation

Adapted from slides




Cubic InterpolationCubic Interpolation

Adapted from slides


… more on this later:

Splines

Bezier curves

Bicubic surfaces



Gradient (Perlin) NoiseGradient (Perlin) Noise

Adapted from slides




Perlin Noise:Example

Perlin Noise:Example

Adapted from slides




Perlin Noise Mixtures [1]:Idea

Adapted from slides




Perlin Noise Mixtures [2]:Example

Adapted from slides




Perlin Noise Mixtures [3]:Texture

Adapted from slides




Procedural Turbulence [1]:Using Perlin Noise

Adapted from slides




Procedural Turbulence [2]:Example

Adapted from slides




Procedural Turbulence [3]:Texture

Adapted from slides




More Procedural Textures

Adapted from slides




Example with Illumination

Adapted from slides




Nonlinear Changes in Intensity

Adapted from slides




3-D Textures

Adapted from slides


© 2007 Feiner, S. & Nayar, S. K.

Computer Vision Lab

Department of Computer Science

Columbia University

http://snurl.com/20swn



OpenGL Texturing [1]:Steps

Adapted from slides




OpenGL Texturing [2]:Specify 2-D Texture Object

Adapted from slides




OpenGL Texturing [3]:Specify How Texture Is Applied

Adapted from slides




OpenGL Texturing [4]:Enable Texture and Draw

Adapted from slides




OpenGL Texturing [5]:Create Texture Object

Adapted from slides




OpenGL Texturing [6]:Putting It All Together

Adapted from slides




Texture Synthesis:Goal

Adapted from slides




Texture Synthesis:Probabilistic Modeling

Adapted from slides




Texturing:Like Copying, but Not Just

Repetition

Adapted from slides




Texturing with Blocks [1]:Technique

Adapted from slides




Texturing with Blocks [2]:Examples

Adapted from slides




Summary

Textures Definitions

Design principles

Texture Pipeline Part of polygons-to-pixels

Uses same spaces (coordinate systems) and more

Using Simple Intermediate Surfaces (Cylinder, Sphere, Plane, Box)

Procedural Textures Simple regular patterns (e.g., checkerboard)

Other textures: terrain, clouds, etc.

Perlin Noise Models Interpolation approach

Turbulence for material properties


References:

Gröller & Jeschke (2002), Isenberg (2005), Jacobs (2007)



Terminology

Texture

Coordinate Systems (Spaces) Model / Object: 3-D (x, y, z)

World / Scene: 3-D (x, y, z)

Camera / Eye: 3-D (u, v, n)

Window / Screen: 2-D (u, v)

Texture: 1-D, 2-D, or 3-D; (s, t) for 2-D

Texture Pipeline

Perlin Noise Interpolation

Turbulence for material properties


References: Gröller & Jeschke (2002), Isenberg (2005), Jacobs (2007)



Next:Animation (Class), Ray Tracing (736)

Vicki Shreiner: Animation and Depth Buffering Double buffering

Lights: positioning

Illumination: light models, attenuation

Material properties

Animation basics in OpenGL

Vicki Schreiner: Imaging and Raster Primitives

Ed Angel: Texture Mapping

Dave Shreiner: Advanced Topics Display lists and vertex arrays

Accumulation buffer

Fog

Stencil buffering

Fragment programs (to be concluded in Tutorial 3)

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