Ray Tracing Gems: High-Quality and Real-Time Rendering with DXR and Other APIs

622 Pages·2019·34.4 MB·English

by  Eric Haines

RAY
TRACING
GEMS
HIGH-QUALITY AND REAL-TIME RENDERING
WITH DXR AND OTHER APIS
EDITED BY
ERIC HAINES
TOMAS AKENINE-MÖLLER
SECTION EDITORS
ALEXANDER KELLER PETER SHIRLEY
MORGAN MCGUIRE INGO WALD
JACOB MUNKBERG CHRIS WYMAN
MATT PHARR
Ray Tracing Gems
High-Quality and Real-Time Rendering
with DXR and Other APIs
Edited by Eric Haines and Tomas Akenine-Möller
Section Editors 
Alexander Keller
Morgan McGuire
Jacob Munkberg
Matt Pharr
Peter Shirley
Ingo Wald
Chris Wyman
Ray Tracing Gems: High-Quality and Real-Time Rendering
with DXR and Other APIs
Edited by  Jacob Munkberg
Eric Haines Matt Pharr
Tomas Akenine-Möller Peter Shirley
Section Editors:  Ingo Wald
Alexander Keller Chris Wyman
Morgan McGuire
ISBN-13 (pbk): 978-1-4842-4426-5 ISBN-13 (electronic): 978-1-4842-4427-2
https://doi.org/10.1007/978-1-4842-4427-2
Library of Congress Control Number: 2019934207
Copyright © 2019 by NVIDIA
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Table of Contents
Preface ���������������������������������������������������������������������������������������������������xiii
Foreword ������������������������������������������������������������������������������������������������� xv
Contributors ������������������������������������������������������������������������������������������� xxi
Notation �������������������������������������������������������������������������������������������������xliii
PART I: Ray Tracing Basics ���������������������������������������������������������������5
Chapter 1: Ray Tracing Terminology ����������������������������������������������������������7
1.1 Historical Notes ......................................................................................7
1.2 Definitions ...............................................................................................8
Chapter 2: What is a Ray? ������������������������������������������������������������������������15
2.1 Mathematical Description of a Ray .......................................................15
2.2 Ray Intervals..........................................................................................17
2.3 Rays in DXR ...........................................................................................18
2.4 Conclusion .............................................................................................19
Chapter 3: Introduction to DirectX Raytracing �����������������������������������������21
3.1 Introduction ...........................................................................................21
3.2 Overview ................................................................................................21
3.3 Getting Started ......................................................................................22
3.4 The DirectX Raytracing Pipeline ...........................................................23
3.5 New HLSL Support for DirectX Raytracing ...........................................25
3.6 A Simple HLSL Ray Tracing Example ...................................................28
3.7 Overview of Host Initialization for DirectX Raytracing ..........................30
3.8 Basic DXR Initialization and Setup ........................................................31
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3.9 Ray Tracing Pipeline State Objects .....................................................37
3.10 Shader Tables ......................................................................................41
3.11 Dispatching Rays .................................................................................43
3.12 Digging Deeper and Additional Resources .........................................44
3.13 Conclusion ...........................................................................................45
Chapter 4: A Planetarium Dome Master Camera �������������������������������������49
4.1 I ntroduction ...........................................................................................49
4.2 M ethods .................................................................................................50
4.3 Planetarium Dome Master Projection Sample Code ...........................58
Chapter 5: Computing Minima and Maxima of Subarrays ������������������������61
5.1 M otivation ..............................................................................................61
5.2 Naive Full Table Lookup ........................................................................62
5.3 The Sparse Table Method ......................................................................62
5.4 The (Recursive) Range Tree Method .....................................................64
5.5 Iterative Range Tree Queries ................................................................66
5.6 R esults ..................................................................................................69
5.7 S ummary ...............................................................................................69
PART II: Intersections and Efficiency ����������������������������������������������75
Chapter 6: A Fast and Robust Method for Avoiding Self- Intersection ������77
6.1 Introduction ...........................................................................................77
6.2 Method ...................................................................................................78
6.3 Conclusion .............................................................................................84
Chapter 7: Precision Improvements for Ray/Sphere Intersection ����������87
7.1 Basic Ray/Sphere Intersection .............................................................87
7.2 Floating-Point Precision Considerations ..............................................89
7.3 Related Resources ................................................................................93
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Chapter 8: Cool Patches: A Geometric Approach to
Ray/Bilinear Patch Intersections �������������������������������������������������������������95
8.1 Introduction and Prior Art .....................................................................95
8.2 GARP Details .......................................................................................100
8.3 Discussion of Results ..........................................................................102
8.4 Code.....................................................................................................105
Chapter 9: Multi-Hit Ray Tracing in DXR ������������������������������������������������111
9.1 Introduction .........................................................................................111
9.2 Implementation ...................................................................................113
9.3 Results ................................................................................................119
9.4 Conclusions .........................................................................................124
Chapter 10: A Simple Load-Balancing Scheme with
High Scaling Efficiency ��������������������������������������������������������������������������127
10.1 Introduction .......................................................................................127
10.2 Requirements ....................................................................................128
10.3 Load Balancing..................................................................................128
10.4 Results ..............................................................................................132
PART III: Reflections, Refractions, and Shadows ��������������������������137
Chapter 11: Automatic Handling of Materials in Nested Volumes ����������139
11.1 Modeling Volumes .............................................................................139
11.2 Algorithm ..........................................................................................142
11.3 Limitations ........................................................................................146
Chapter 12: A Microfacet-Based Shadowing Function to
Solve the Bump Terminator Problem �����������������������������������������������������149
12.1 Introduction .......................................................................................149
12.2 Previous Work ...................................................................................150
12.3 Method ...............................................................................................151
12.4 Results ..............................................................................................157
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Chapter 13: Ray Traced Shadows: Maintaining Real-Time
Frame Rates ������������������������������������������������������������������������������������������159
13.1 Introduction .......................................................................................159
13.2 Related Work .....................................................................................161
13.3 Ray Traced Shadows .........................................................................162
13.4 Adaptive Sampling ............................................................................164
13.5 Implementation .................................................................................171
13.6 Results ..............................................................................................175
13.7 C onclusion and Future Work ............................................................179
Chapter 14: Ray-Guided Volumetric Water Caustics in
Single Scattering Media with DXR ����������������������������������������������������������183
14.1 Introduction .......................................................................................183
14.2 V olumetric Lighting and Refracted Light ..........................................186
14.3 Algorithm ..........................................................................................189
14.4 Implementation Details.....................................................................197
14.5 Results ..............................................................................................198
14.6 Future Work .......................................................................................200
14.7 Demo .................................................................................................200
PART IV: Sampling ������������������������������������������������������������������������205
Chapter 15: On the Importance of Sampling ������������������������������������������207
15.1 Introduction .......................................................................................207
15.2 Example: Ambient Occlusion ............................................................208
15.3 Understanding Variance ....................................................................213
15.4 Direct Illumination ............................................................................216
15.5 Conclusion .........................................................................................221
Chapter 16: Sampling Transformations Zoo ������������������������������������������223
16.1 T he Mechanics of Sampling ..............................................................223
16.2 I ntroduction to Distributions .............................................................224
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16.3 One-Dimensional Distributions ........................................................226
16.4 Two-Dimensional Distributions ........................................................230
16.5 Uniformly Sampling Surfaces ...........................................................234
16.6 Sampling Directions ..........................................................................239
16.7 Volume Scattering .............................................................................243
16.8 A dding to the Zoo Collection .............................................................244
Chapter 17: Ignoring the Inconvenient When Tracing Rays ��������������������247
17.1 Introduction .......................................................................................247
17.2 Motivation ..........................................................................................247
17.3 Clamping ...........................................................................................250
17.4 Path Regularization...........................................................................251
17.5 Conclusion .........................................................................................252
Chapter 18: Importance Sampling of Many Lights on the GPU ���������������255
18.1 Introduction .......................................................................................255
18.2 R eview of Previous Algorithms .........................................................257
18.3 Foundations .......................................................................................259
18.4 Algorithm ..........................................................................................265
18.5 Results ..............................................................................................271
18.6 Conclusion .........................................................................................280
PART V: Denoising and Filtering ���������������������������������������������������287
Chapter 19: Cinematic Rendering in UE4 with Real-Time
Ray Tracing and Denoising ���������������������������������������������������������������������289
19.1 Introduction .......................................................................................289
19.2 Integrating Ray Tracing in Unreal Engine 4 ...................................... 290
19.3 Real-Time Ray Tracing and Denoising .............................................300
19.4 Conclusions .......................................................................................317
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TABLE OF CONTENTS
Chapter 20: Texture Level of Detail Strategies for
Real-Time Ray Tracing ��������������������������������������������������������������������������321
20.1 Introduction .......................................................................................321
20.2 Background .......................................................................................323
20.3 Texture Level of Detail Algorithms ...................................................324
20.4 Implementation .................................................................................336
20.5 Comparison and Results ...................................................................338
20.6 Code ...................................................................................................342
Chapter 21: Simple Environment Map Filtering Using
Ray Cones and Ray Differentials ������������������������������������������������������������347
21.1 Introduction .......................................................................................347
21.2 Ray Cones ..........................................................................................348
21.3 Ray Differentials ................................................................................349
21.4 Results ..............................................................................................349
Chapter 22: Improving Temporal Antialiasing with
Adaptive Ray Tracing �����������������������������������������������������������������������������353
22.1 Introduction .......................................................................................353
22.2 P revious Temporal Antialiasing ........................................................355
22.3 A New Algorithm ...............................................................................356
22.4 Early Results .....................................................................................363
22.5 Limitations ........................................................................................366
22.6 T he Future of Real-Time Ray Traced Antialiasing ............................367
22.7 Conclusion .........................................................................................368
PART VI: Hybrid Approaches and Systems ������������������������������������375
Chapter 23: Interactive Light Map and Irradiance Volume
Preview in Frostbite �������������������������������������������������������������������������������377
23.1 Introduction .......................................................................................377
23.2 GI Solver Pipeline ..............................................................................378
23.3 Acceleration Techniques ...................................................................393
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23.4 Live Update ........................................................................................398
23.5 Performance and Hardware ..............................................................400
23.6 Conclusion .........................................................................................405
Chapter 24: Real-Time Global Illumination with Photon Mapping ���������409
24.1 Introduction .......................................................................................409
24.2 Photon Tracing ..................................................................................411
24.3 S creen-Space Irradiance Estimation ................................................418
24.4 Filtering .............................................................................................425
24.5 Results ..............................................................................................430
24.6 Future Work .......................................................................................434
Chapter 25: Hybrid Rendering for Real-T ime Ray Tracing ���������������������437
25.1 H ybrid Rendering Pipeline Overview ................................................437
25.2 Pipeline Breakdown ..........................................................................439
25.3 Performance .....................................................................................468
25.4 Future ................................................................................................469
25.5 Code ...................................................................................................469
Chapter 26: Deferred Hybrid Path Tracing ���������������������������������������������475
26.1 Overview ............................................................................................475
26.2 Hybrid Approach ................................................................................476
26.3 BVH Traversal ....................................................................................478
26.4 D iffuse Light Transport .....................................................................481
26.5 S pecular Light Transport ..................................................................485
26.6 Transparency .....................................................................................487
26.7 Performance .....................................................................................488
Chapter 27: Interactive Ray Tracing Techniques for
High-F idelity Scientific Visualization �����������������������������������������������������493
27.1 Introduction .......................................................................................493
27.2 C hallenges Associated with Ray Tracing Large Scenes ...................494
ix