INTRODUCTION TO OPTIX. Martin Stich, Engineering Manager

Transcription

1 INTRODUCTION TO OPTIX Martin Stich, Engineering Manager

2 OptiX Basics AGENDA Advanced Topics Case Studies Feature Outlook 2

3 OPTIX BASICS 3

4 IN A NUTSHELL The OptiX Ray Tracing SDK State-of-the-art performance: 500M+ rays/sec Algorithm and hardware agnostic Shaders with single-ray programming model, recursion Available free for private and commercial use 4

5 RELEASE TIMELINE OptiX 1.0 Hello World!... OptiX 3.9 Pascal Support OptiX 4.0 LLVM Pipeline NVLINK Scaling OptiX 4.1 Performance CUDA 8, VS Jan 2016 Summer 2016 TODAY! 5

6 MODERN RAY TRACING Rasterization: 6

7 MODERN RAY TRACING Rasterization: Ray Tracing: 7

8 THE RAY TRACING PIPELINE INTERSECTION ANY-HIT Programmable: Ray Generation Closest Hit, Any Hit, Miss Intersection Launch entry Shading Geometry RAY GENERATION INTERSECTION ANY-HIT CLOSEST-HIT 8

9 MAIN OPERATIONS RAY GEN INTERSECT ANY HIT CLOSEST HIT MISS rttrace rtpotentialintersection rtreportintersection rtignoreintersection rtterminateray 9

10 SHADER COMMUNICATION Variables similar to uniforms in other systems constants, system values, buffers, textures, Example: Textures Current ray 10

11 SHADER COMMUNICATION Variables Ray Payload similar to uniforms in other systems constants, system values, buffers, textures, arbitrary data associated with ray in/out from rttrace to Any-hit, Closest-hit, Miss Example: Textures Current ray Example: Color data 11

12 SHADER COMMUNICATION Variables Ray Payload Attributes similar to uniforms in other systems constants, system values, buffers, textures, arbitrary data associated with ray in/out from rttrace to Any-hit, Closest-hit, Miss arbitrary data associated with hit generated in Intersection program consumed by Any-hit, Closest-hit Example: Textures Current ray Example: Color data Example: Barycentrics 12

13 EXAMPLE Miniature Path Tracer See optixpathtracer SDK sample for a slightly less minimalistic version 13

14 GLOBAL ILLUMINATION 14

15 GLOBAL ILLUMINATION 15

16 GLOBAL ILLUMINATION 16

17 GLOBAL ILLUMINATION 17

18 HOWEVER 18

19 RAY PAYLOAD Path State Definition struct RayPayload { float3 radiance; // stores contribution after we hit the light source float3 attenuation; // accumulated attenuation of radiance due to materials float3 next_origin; // reflection ray to be traced for the next float3 next_direction; //..segment of the path unsigned seed; // random number generator state }; bool done; // whether we re done tracing this path 19

20 INTEGRATION RT_PROGRAM void ray_generation() { unsigned int seed = tea<16>( launch_index.x + launch_index.y*output_buffer.size().x, frame_number ); float3 ray_origin = eye; float3 ray_direction = compute_jittered_ray_dir( seed ); RayPayload payload; payload.radiance = make_float3(0,0,0); payload.attenuation = make_float3(1,1,1); payload.seed = seed; payload.done = false; int depth = 0; while(!payload.done && depth++ < 10 ) { Ray ray = make_ray( ray_origin, ray_direction, 0, 0.001f, RT_DEFAULT_MAX ); } rttrace( scene, ray, payload ); ray_origin = payload.next_origin; ray_direction = payload.next_direction; } const float3 result = payload.radiance * payload.attenuation; const float lerp_t = frame_number > 1? 1.0f / frame_number : 1.0f; const float3 prev_col = make_float3( output_buffer[launch_index] ); output_buffer[launch_index] = make_float4( lerp( prev_col, result, lerp_t ), 1.0f ); 4 20

21 DIFFUSE MATERIAL rtdeclarevariable( float3, diffuse_color,, ); rtdeclarevariable( float3, normal, attribute normal, ); rtdeclarevariable( optix::ray, ray, rtcurrentray, ); rtdeclarevariable( float, t_hit, rtintersectiondistance, ); rtdeclarevariable( RayPayload, current_payload, rtpayload, ); RT_PROGRAM void closest_hit_diffuse() { const float3 hitpoint = ray.origin + t_hit * ray.direction; const float z1 = rnd( current_payload.seed ); const float z2 = rnd( current_payload.seed ); float3 dir; cosine_sample_hemisphere( z1, z2, dir ); optix::onb onb( normal ); onb.inverse_transform( dir ); current_payload.next_origin = hitpoint; current_payload.next_direction = dir; } current_payload.attenuation *= diffuse_color; 21

22 LIGHT MATERIAL AND MISS rtdeclarevariable( RayPayload, current_payload, rtpayload, ); rtdeclarevariable( float3, emission_color,, ); RT_PROGRAM void closest_hit_light() { current_payload.radiance = emission_color; current_payload.done = true; } RT_PROGRAM void miss() { current_payload.radiance = make_float3(0,0,0); current_payload.done = true; } 22

23 SCENE GEOMETRY rtdeclarevariable( float3, anchor,, ); rtdeclarevariable( float3, v1,, ); rtdeclarevariable( float3, v2,, ); rtdeclarevariable( float4, plane,, ); rtdeclarevariable( float3, normal, attribute normal, ); rtdeclarevariable( optix::ray, ray, rtcurrentray, ); RT_PROGRAM void intersect( int primidx ) { const float3 n = make_float3( plane ); const float dt = dot( ray.direction, n ); const float t = (plane.w - dot(n, ray.origin)) / dt; const float3 p = ray.origin + ray.direction * t; const float3 vi = p - anchor; const float a1 = dot( v1, vi ); const float a2 = dot( v2, vi ); } if( a1 >= 0 && a1 <= 1 && a2 >= 0 && a2 <= 1 ) { if( rtpotentialintersection( t ) ) { normal = n; rtreportintersection( 0 ); } } 23

24 RESULT Accumulation Over Time 24

25 NEXT STEP IDEAS Mini Path Tracer Reader Exercises Next event estimation Russian roulette Sphere primitives Mirror material Glass material Triangle meshes Environment maps... 25

26 NODE GRAPH Context Group Geometry Group Geometry Instance Geometry Material Variables Intersection Program Any Hit + Closest Hit 26

27 ADVANCED TOPICS 27

28 INTEROP Share CUDA and OpenGL Resources OpenGL Share textures and vertex buffers rtbuffercreatefromglbo rttexturesamplercreatefromglimage CUDA Share CUDA allocations rtbuffersetdevicepointer rtbuffergetdevicepointer 28

29 BINDLESS OBJECTS Bindless : powerful concept to dynamically select textures, buffers, and programs at runtime Allows efficient implementation of large shading networks Reduces code size, compile times, and number of compiles Pixar Animation Studio s Flow material editing tool. Visit the NVIDIA website to watch a SIGGRAPH 2015 talk describing the system in detail. 29

30 PTX GENERATION Options Offline CUDA-C++ nvcc.exe CUDA-C++ nvrtc.dll PTX OptiX JIT LLVM-IR NVVM/ NVPTX 30

31 MULTI-GPU AND NVLINK Automatic Scaling 110M Triangles 23M Grass Blades 15GB Textures 2 x GP100 Monsters University data set courtesy of Pixar Studios 31

32 REMOTE RENDERING On Quadro VCA or DGX-1 Incremental updates OptiX App Progressive video stream ETHERNET INTERNET OptiX Server(s) 32

33 OPTIX PRIME Simple intersection-only API Rays Triangles OptiX Prime GPU or CPU Intersections (primidx, t, u, v) Supports instancing, async operations, ray masks Performance similar to OptiX Same semantics via OptiX: See optixraycasting sample 33

34 CASE STUDIES 34

35 PERFORMANCE Raw Traversal on Titan X Pascal +3% in OptiX % in OptiX

36 NVIDIA: IRAY & MENTAL RAY 36

37 NVIDIA: GVDB Sparse Volume Rendering OpenVDB format support Image Property of DreamWorks Animation Live interaction with multiplebounce GI scattering, 10x-30x faster than CPU Introduction and Techniques with NVIDIA GVDB Voxels Monday, 9:00 AM Room

38 AAA-STUDIO: FURRYBALL PRODUCTION RENDERING 38

39 VISUAL MOLECULAR DYNAMICS (VMD) Molecular Visualization package with hundreds of thousands of users Developed by John Stone of U Illinois Cutting Edge OptiX Ray Tracing Techniques for Visualization of Biomolecular and Cellular Simulations in VMD Tuesday, 3:30 PM Room 230C 39

40 OLCF: SCIENTIFIC VISUALIZATION Visualizing laser interaction with metals, hundreds of millions of primitives on DGX-1 Developed by Benjamin Hernandez, OLCF-ORNL Exploratory Visualization of Petascale Particle Data in NVIDIA DGX-1 Tuesday, 3:30 PM Room 212B Simulation: OLCF INCITE 2017 "Petascale Simulations of Short Pulse Laser Interaction with Metals" PI Leonid Zhigilei, University of Virginia 40

41 NVIDIA: VRWORKS AUDIO Sound waves reflect off of the environment Path traced audio NVIDIA VRWORKS AUDIO - Improving VR Immersion with acoustic fidelity Thursday, 11:00 AM Room 230B 41

42 BUNGIE: LIGHT BAKING FOR GAMES Light and occlusion baking is a major bottleneck in game design Workflow-changing speedups by switching from CPU render farms to OptiX 42

43 LIGHTMASS Light baking in Unreal Engine 4 Total Time on Titan X CPU GPU 1X GPU 2X 1638s 426s 298s 43

44 ADVANCED SAMPLES Maintained on Github A collection of larger, more sophisticated sample applications than the ones that come with the SDK Available at: nvpro-samples/optix_advanced_samples 44

45 FEATURE OUTLOOK 45

46 UNDER DEVELOPMENT SEPARATE COMPILATION MOTION BLUR PERFORMANCE Shorter per-shader compile times Fast incremental addition and removal of programs Overall speedup through parallel compilation Transform and deformation blur Performance is always a focus Tackling some big ticket ideas over the next ~year 46

47 THANK YOU! Related Talks: S LEVERAGING NVRTC RUNTIME COMPILATION FOR DYNAMICALLY BUILDING OPTIX SHADERS FROM MDL MATERIALS S NVIDIA ADVANCED RENDERING S CUTTING EDGE OPTIX RAY TRACING TECHNIQUES FOR VISUALIZATION OF BIOMOLECULAR AND CELLULAR SIMULATIONS IN VMD S EXPLORATORY VISUALIZATION OF PETASCALE PARTICLE DATA IN NVIDIA DGX-1 S GPU-CLOUD PHOTOREALISTIC RENDERING FOR THE NEXT GENERATION OF CLOUD CAD TOOLS H PHYSICALLY BASED RAY TRACING WITH OPTIX S TURBOCHARGING VMD MOLECULAR VISUALIZATIONS WITH STATE-OF-THE-ART RENDERING AND VR TECHNOLOGIES S INTRODUCTION AND TECHNIQUES WITH NVIDIA GVDB VOXELS S NVIDIA VRWORKS AUDIO - IMPROVING VR IMMERSION WITH ACOUSTIC FIDELITY 47

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