Character Animation with Direct3D- P1

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Character Animation with Direct3D- P1: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.

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CHARACTER ANIMATION WITH DIRECT3D ® CARL GRANBERG Charles River Media A part of Course Technology, Cengage Learning Australia, Brazil, Japan, Korea, Mexico, Singapore, Spain, United Kingdom, United States ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
Character Animation with Direct3D® © 2009 Course Technology, a part of Cengage Learning. ALL RIGHTS RESERVED. No part of this work covered by the copyright Carl Granberg herein may be reproduced, transmitted, stored, or used in any form or by any means graphic, electronic, or mechanical, including but not limited to photocopying, recording, scanning, digitizing, taping, Web distribution, Publisher and General Manager, information networks, or information storage and retrieval systems, except Course Technology PTR: as permitted under Section 107 or 108 of the 1976 United States Copyright Stacy L. Hiquet Act, without the prior written permission of the publisher. Associate Director of Marketing: For product information and technology assistance, contact us at Sarah Panella Cengage Learning Customer & Sales Support, 1-800-354-9706 For permission to use material from this text or product, Content Project Manager: submit all requests online at cengage.com/permissions Jessica McNavich Further permissions questions can be emailed to permissionrequest@cengage.com Marketing Manager: Jordan Casey Microsoft, Windows, Direct3D, and DirectX are either registered trademarks Senior Acquisitions Editor: Emi Smith or trademarks of Microsoft Corporation in the United States and/or other countries. All other trademarks are the property of their respective owners. Project Editor and Copy Editor: Library of Congress Control Number: 2008931080 Dan Foster, Scribe Tribe ISBN-13: 978-1-58450-570-9 Technical Reviewer: Henrik Enqvist ISBN-10: 1-58450-570-2 CRM Editorial Services Coordinator: eISBN-10: 1-58450-630-X Jennifer Blaney Course Technology, a part of Cengage Learning 20 Channel Center Street Editorial Services Coordinator: Jen Blaney Boston, MA 02210 USA Interior Layout: Jill Flores Cengage Learning is a leading provider of customized learning solutions with office locations around the globe, including Singapore, the United Kingdom, Cover Designer: Mike Tanamachi Australia, Mexico, Brazil, and Japan. Locate your local office at: international. cengage.com/region CD-ROM Producer: Brandon Penticuff Cengage Learning products are represented in Canada by Nelson Education, Ltd. Indexer: Valerie Haynes Perry For your lifelong learning solutions, visit courseptr.com Proofreader: Ruth Saavedra and Visit our corporate website at cengage.com Mike Beady Printed in the United States of America 1 2 3 4 5 6 7 11 10 09 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
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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. 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. iv Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
Contents 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 v ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
vi Contents 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 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
Contents vii 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 ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
viii Contents 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 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
Contents ix 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 ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
x Contents 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 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
Contents xi 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 ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
xii Contents 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 Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
Introduction I NTENDED A UDIENCE 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. U SING T HIS B OOK 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. xiii ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
xiv 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. S YSTEM R EQUIREMENTS Windows Vista/Windows XP DirectX SDK Graphic card supporting Vertex and Pixelshader version 2.0 A decent processor Not too little RAM Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
1 Introduction to Character Animation Hello, dear reader, and welcome to this book about character animation! I hope you enjoy it and find it useful. In this chapter, I’ll start you off slow by looking at character animation in general as well as a brief history of the same topic. You won’t get to do any coding in this chapter, but toward the end I’ll include a brief overview of the coding conventions used in this book. In this first chapter, you’ll find the following: What is character animation? A brief history of character animation Comparison of skeletal animation and morphing animation Coding conventions 1 ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
2 Character Animation with Direct3D W HAT I S C HARACTER A NIMATION ? This somewhat silly question may seem pretty easy to answer at a first glance, but is it really? Wikipedia defines it as follows: “Character animation is a specialized area of the animation process concerning the animation of one or more characters featured in an animated work.” -Wikipedia Animated work. Well, I guess games falls under that category. However, I would probably have tried to define it along the lines of “Making a character move in a realistic way.” Although, I suppose that better answers the question, “What is the goal of character animation?” Historically, characters were drawn (or pixeled) and animated by making multiple pictures showing the character at a slightly different pose. These pictures would then loop to give the impression of movement. With today’s video cards, it is possible to have full three-dimensional characters and animate them with some of the various techniques covered in this book. New ways of animating character models pop up each year, pushing the evolu- tion of the field forward. The techniques covered in this book are by no means cutting edge; rather, they are the foundational techniques that all (or most) cutting- edge technologies are based upon. Techniques such as skeletal animation, morphing, ragdoll physic simulation, and inverse kinematics have already existed for a long time (in terms of game evolution at least). Still, at the end of this book you will have all the tools you need to create your own game featuring realistic character animation. A B RIEF H ISTORY OF C HARACTER A NIMATION Let’s start from the beginning! Say hello to one of the first well-known computer game characters of our time: Pac-Man (Figure 1.1). This 28 28 pixel character (developed by Namco) was released in Japan in 1980 and is still today the most famous arcade game of all time. This character (looking more like a pizza missing a slice) slowly gave way to more humanoid characters. Four years later, Sierra On-Line released Kings Quest: Quest for the Crown, staring Sir Graham (Figure 1.2). Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
Chapter 1 Introduction to Character Animation 3 FIGURE 1.1 Pac-Man. FIGURE 1.2 Sir Graham. ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
4 Character Animation with Direct3D Sir Graham might not feature many more pixels than Pac-Man did, but at least he was more colorful and had a great set of animations. Characters continued along the same lines through the late ’80s, with steadily increasing pixel count and/or color. In 1987, LucasArts developed its first version of the SCUMM engine (Script Creation Utility for Maniac Mansion) and with it they released several adventure games, including Maniac Mansion, Monkey Island, Loom, and many more. The characters of this era (late ’80s to early ’90s) pretty much shared the same complexity—Figure 1.3 shows an example. FIGURE 1.3 An animation sequence of Tom (The Tales of Bingwood). © BugFactory 2008. Suddenly the ’90s hit, and with the new decade the first 3D games brought a whole new set of problems. Some of the more famous games included Wolfenstein 3D and, later, DOOM—although these games can’t really be called proper 3D games since they still used 2D sprites for enemies and characters (usually drawn from eight angles, depending on their orientation to the player). The first real 3D character was seen in the game Alone in the Dark, which was released in 1992. It featured charac- ters in full 3D with interpolated animations. These characters had an extremely low polygon count and were built from several blocks (one for each limb). An example character from this era can be seen in Figure 1.4. You can easily see the obvious gaps between the joints in this character, but back then there was usually no lighting of the models and the resolution was so small that these gaps were often hidden from the player. Jumping ahead in time a few years, we reach 1996, when 3dfx launched the first Voodoo chipset and with it brought affordable 3D accelerator cards to the masses. One of the first reputable games taking advantage of this new technology was the game Quake. With Quake came seamless characters (albeit low-poly) animated using vertex morphing. Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark.
Chapter 1 Introduction to Character Animation 5 FIGURE 1.4 A character built from blocks. M ORPHING A NIMATION AND S KELETAL A NIMATION Morphing animation (or per-vertex animation) works by blending two (or more) meshes together on a per-vertex basis. The two meshes need to have the same amount of vertices, and their polygons need to be arranged in the same way for this technique to work. Each mesh representing a pose of the character is referred to as a morph target. More than one morph target may be used to blend the final mesh. The main use of morphing animation these days is facial animation. But in the past it was also used to create full-body character animations. For instance, the Quake I and II engines used this approach for their characters using the popular but slightly outdated MD2 file format [Schoenblum07, Leimbach02]. See Figure 1.5 for an example of morphing animation. In this figure, only the HAPPY and ANGRY frames are the actual target meshes. The meshes in between are created by interpolating the vertex positions smoothly over time. ease purchase PDF Split-Merge on www.verypdf.com to remove this watermark.