Character Animation with Direct3D- P1 pdf

For your lifelong learning solutions, visit courseptr.com Visit our corporate website at cengage.com Character Animation with Direct3D Carl Granberg Publisher and General Manager, Cours

C HARACTER A NIMATION

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Character Animation with Direct3D

Carl Granberg

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eISBN-10: 1-58450-630-X

To Aino… again.

About the Author

Carl Granberg has been creating games on a hobby basis since the old DOS-based

Mode 13h graphics, after which he moved on to DirectDraw and finally Direct3D graphics He received his master of science in computing at Curtin University, Perth, Australia, and has since been working in the Finnish game industry for 3 years

He is currently working as a Tools programmer at Remedy Entertainment in Finland He’s also involved with a group of hobby game developers that goes by

the name of BugFactory (www.bugfactory.fi), which has just released its first

title, The Tales of Bingwood.

For matters relating to this book, he can be contacted at carl@bugfactory.fi.

Acknowledgments

As always with a project such as this, there’s a long list of people deserving my thanks Writing a book is not a small feat (yes, patting myself on the back), and it is also some-thing I could not have done alone So first off I must thank the people of Charles River Media for wanting to publish this hunk of technical mumbo jumbo, and especially Emi Smith, my editor Big thanks also to Dan Foster, my project editor, and Henrik Enqvist of Remedy Entertainment, my technical editor Henrik also supplied the code for the Inverse Kinematics chapter and the Wrinkle Maps example, for which I owe him thanks

Next I’d like to thank my friend Markus Tuppurainen for supplying some of the art for this book—sketches and pixel characters—as well as for helping me make the Soldier model

Finally I’d like to thank my wife and my family for their support through this last year, which has been challenging in many ways

Last, but not least, thank you for buying this book I hope you enjoy it and also

learn something from it

Introduction .xi

1 Introduction to Character Animation 1

What Is Character Animation? 2

A Brief History of Character Animation 2

Morphing Animation and Skeletal Animation 5

The Soldier 7

Coding Conventions 8

Conclusions 10

Further Reading 10

2 A Direct3D Primer 11

DirectX 9 versus DirectX 10 12

STL and the D3DX Library 13

Setting Up a Project in Visual Studio Express 2008 15

VC++ Directories 15

Creating a New Project 17

Linking DirectX Libraries 18

Application Framework 19

WinMain 21

Creating the Window 22

Basic Rendering 24

Creating the DirectX Device 25

Direct3D Rendering Loop 26

Loading a Mesh 27

Loading an Effect 28

Rendering a Mesh with an Effect 30

Conclusions 32

Further Reading 32

3 Skinned Meshes 33

Skinned Meshes Overview 34

Bone Hierarchies 35

The D3DXFRAME Structure 37

Loading a Bone Hierarchy 40

The CreateFrame() Function 41

The CreateMeshContainer() Function 41

The DestroyFrame() Function 42

The DestroyMeshContainer() Function 42

The ID3DXAllocateHierarchy 42

Applying a Mesh to the Bone Hierarchy 47

Software Skinning Overview 49

Hardware Skinning Overview 49

Software Skinning Implementation 50

Hardware Skinning Implementation 59

Rendering Static Meshes in Bone Hierarchies 67

Conclusions 71

Chapter 3 Exercises 72

Further Reading 72

4 Skeletal Animation 73

Keyframe Animation 74

Animation Sets 76

The ID3DXAnimationController Interface 79

Loading the Animation Data 79

Multiple Animation Controllers 82

Conclusions 83

Chapter 4 Exercises 84

vi Contents

5 Advanced Skeletal Animation Techniques 85

The Track Structure 86

Blending Multiple Animations 88

Compressing Animation Sets 90

Animation Callback Events 92

Motion Capture (Mocap) 96

Optical Motion Capture Systems 97

Magnetic Motion Capture Systems 98

Mechanical Motion Capture Systems .99

Comparison of the Different Mocap Systems 100

Lapland Studio Interview 101

Conclusions 107

Chapter 5 Exercises 107

Further Reading 107

6 Physics Primer 109

Introduction to Rigid Body Physics 110

Forces 111

The Effect of Forces on a Rigid Body 112

Quaternions 114

Describing the World 119

The Oriented Bounding Box Class 120

Physics Simulation 124

Position, Velocity, and Acceleration 126

The Particle 128

The Spring 131

Conclusions 134

Chapter 6 Exercises 135

Further Reading 135

Contents vii

7 Ragdoll Simulation 137

Introduction to the Bullet Physics Engine 139

Integrating the Bullet Physics Library 140

Download Bullet 140

Build the Bullet Libraries 141

Setting Up a Custom Direct3D Project 142

Hello btDynamicsWorld 144

Constraints 147

Constructing the Ragdoll 150

Updating the Character Mesh from the Ragdoll 158

Getting a Bone’s Position from an OBB 159

Getting a Bone’s Orientation from an OBB 161

Updating the Bone Hierarchy 162

Conclusions 164

Chapter 7 Exercises 165

8 Morphing Animation 167

Basics of Morphing Animation 168

Using Multiple Morph Targets 170

Morphing Animation on the GPU 173

Custom Vertex Formats 174

Creating the Morph Vertex Declaration 177

The Morphing Vertex Shader 180

Combining Skeletal and Morphing Animation 183

Skeletal/Morphing Vertex Format 185

Skeletal/Morphing Vertex Shader 188

Conclusions 191

Chapter 8 Exercises 192

viii Contents

9 Facial Animation 193

Facial Animation Overview 194

Facial Expressions 194

The Eye of the Beholder 196

The Face Class 198

Loading Multiple Targets from One X File 200

Extracting Meshes from a D3DXFRAME Hierarchy 201

Implementing the Face Class 202

The Face Controller Structure 205

Animation Channels 205

Face Factory 208

Conclusions 215

Chapter 9 Exercises 216

10 Making Characters Talk 217

Phonemes 218

Visemes 221

Basics of Speech Analysis 225

Sound Data 227

The WAVE Format 227

Automatic Lip-Syncing 232

Conclusions 234

Further Reading 235

11 Inverse Kinematics 237

Introduction to Inverse Kinematics 238

Solving the IK Problem 240

Look-At Inverse Kinematics 240

Two-Joint Inverse Kinematics 246

Conclusions 252

Chapter 11 Exercises 253

Further Reading 253

Contents ix

12 Wrinkle Maps 255

Introduction to Normal Mapping 256

What Are Normal Maps? 258

Encoding Normals as Color 261

Putting the Normal Map to Use 262

The TBN-Matrix 265

Converting a Mesh to Support Normal Mapping 265

The Normal Mapping Shader 270

Creating Normal Maps 277

Creating Normal Maps in Practice 280

Specular Highlight 281

Specular Maps 284

Wrinkle Maps 288

Conclusions 292

Chapter 12 Exercises 292

Further Reading 293

13 Crowd Simulation 295

Flocking Behaviors 296

Boids 297

Introduction to Crowd Simulation 304

Smart Objects 308

Following a Terrain 310

Conclusions 313

Chapter 13 Exercises 313

Further Reading 313

x Contents

14 Character Decals 315

Introduction to Decals 316

Picking a Hardware-Rendered Mesh 318

Creating Decal Geometry 325

Calculating the Exact Hit Position 328

Selecting Triangles for the Decal Mesh 330

Copying the Skinning Information 331

The CharacterDecal Class 337

Calculating Decal UV Coordinates 339

Conclusions 346

Chapter 14 Exercises 347

15 Hair Animation 349

Hair Representation 350

Hair Modeling 351

The Control Hair Class 352

The HairPatch Class 356

Growing the Hair 359

Rendering the Hair Patch 362

Creating a Haircut 367

Animating the Control Hairs 370

The Hair Class 373

Conclusions 376

Chapter 15 Exercises 377

Further Reading .377

Contents xi

16 Putting It All Together 379

Attaching the Head to the Body 380

The Character Class 387

Future Work 389

Character Level-of-Detail 390

Root Motion versus Non-Root Motion 392

Animation Trees/Animation Graph 393

Track Masks 395

Separate Mesh and Animation Files 395

Alan Wake Case Study 396

Interview with Sami Vanhatalo, Senior Technical Artist 397

Interview with Henrik Enqvist, Animation Programmer 402

Final Thoughts 408

Further Reading 408

Index .409

xii Contents

INTENDED AUDIENCE

This book is primarily aimed at teaching indie and hobby game developers how to create character animation with Direct3D Also, the seasoned professional game developer may find some interesting things in this book

You will need a solid understanding of the C++ programming language as well

as general object-oriented programming skills

As for DirectX, you will need to know the very basics at least In other words, you will need to have completed at least an introductory book on DirectX before starting this one

On top of all these prerequisites, you should also have basic knowledge of the High Level Shading Language (HLSL), since many of the effects done in this book will use it

If you feel that you can’t honestly say you meet these prerequisites, I suggest you brush up on these topics before continuing with this book rather than trying to learn them as you go You will quite quickly be faced with some advanced topics, and, if you are faced with them for the first time, they will be quite hard to handle without trying to learn HLSL or similar topics as well

But, hey, this is just my suggestion After all, that certainly wasn’t how I learned the stuff I know today

USING THIS BOOK

This book has been divided into 16 chapters, each of which usually focuses on one

or a few related components I aim to keep this book very “hands-on,” so a lot of code will be covered throughout You’re probably best off reading the book from cover to cover, since a lot of stuff covered in the earlier chapters will be built upon

in later chapters

Introduction

The topic of character animation is a very general one that can be applied to all game genres It doesn’t matter if you are making your own role-playing games (RPG), real-time strategy games (RTS), first-person shooter games (FPS), or a game from another genre As long as you plan to include characters in your game, you will benefit greatly from learning the topics covered in this book

Because the topic is extremely code intensive, you won’t find most of the code written out in full throughout this book Rather, use the book as a manual to un-derstand the code found on the accompanying CD-ROM Also, if you have time I suggest that you try to implement the topics covered here completely on your own, and use the code provided only as guidelines or a helping hand Even though this might seem like a tedious waste of time, I can guarantee that it will greatly increase your understanding of the different techniques (although, of course, I know that 95% of readers will pay no attention whatsoever to this recommendation)

To get to the fun stuff as soon as possible, I won’t waste time covering simple things like basic Direct3D rendering, basic data structures, and so on There are more books available on these topics than absolutely necessary, so if you feel you’re lacking in knowledge about basic DirectX programming, I suggest you go and pick up such a book before getting back to this one Also, I’ll rely heavily on the Standard Template Library (STL) for all basic data structures such as vectors, stacks, queues, etc For all generic 3D math functions, mesh and texture loading, and more, I will be using the D3DX library This is a part of Direct3D and is a great help when developing 3D applications (as you’ll soon see)

You’ll find all the examples on the CD-ROM together with their executables, models, textures, and more The examples are ordered according to the chapter number and the example number Usually the examples are fairly simple and focus only on one specific thing At the end of the book, however, there will be a character that can walk, talk, collide with objects, fall, and more

SYSTEM REQUIREMENTS

Windows Vista/Windows XP DirectX SDK

Graphic card supporting Vertex and Pixelshader version 2.0

A decent processor Not too little RAM

xiv Introduction