Upload
vance-giles
View
31
Download
4
Tags:
Embed Size (px)
DESCRIPTION
Efficient Streaming of 3D Scenes with Complex Geometry and Complex Lighting. Romain Pacanowski and M. Raynaud X. Granier P. Reuter C. Schlick P. Poulin. INRIA Bordeaux University. Motivation. Global illumination for remote visualization systems. - PowerPoint PPT Presentation
Citation preview
Efficient Streaming of 3D Scenes with Complex Geometry
and Complex Lighting
Romain Pacanowskiand
M. Raynaud X. Granier P. Reuter C. Schlick P. Poulin
INRIA Bordeaux University
Global illumination (indirect lighting)
• Increases realism of synthetic images
• Very long to compute unless using interactive/real-time techniques
MotivationGlobal illumination for remote visualization systems
All lighting computations done on client• Low data transfer requirements
• Rendering speed depends on scene geometric complexity
MotivationClient approach
• Pre/compute indirect illumination• Stream the indirect illumination to the client
BUT: How to avoid an overhead transfer time proportional to the size of the geometry ?
Need for an illumination representation not correlated to the geometry
MotivationServer approach
• Stochastic methods [Purcell03,Gautron05,…]• Fast but not real time • Depend on geometry
• Radiosity methods [Keller97, Segovia07]• [Dachsbacher07]: scene depth dependent • [Laine07]:
• Real time • Visual quality depends on geometric accuracy
Not suited for streaming context
Previous WorkInteractive/Real time global illumination
Concept: encode light transport effects in a structure
• [Sloan02,Wang04,Pan07]
• Real time even with dynamic scenes • Huge data size
• Direct-to-indirect transfer [Pellacini07]
• Data size is dependent on geometry complexity
Previous WorkPrecomputed radiance transfer approaches
• Most closely related to our work
• 3D regular grid [Mitchell06]
• Irradiance values at vertices• Geometric dependency of irradiance
Storage cost increases
Previous WorkIrradiance Volumes [Greger97]
• New structure for indirect illumination• Geometry independent • GPU friendly
• Streaming technique for our lighting structure• Client/Server visualization system
• Independent streaming of geometry and lighting
• Direct illumination on the client side
Our MethodOverview
Indirect Lighting RepresentationOverview
Regular 3D grid• 6 irradiance vectors at each vertex• Directional interpolation
To reconstruct irradiance for any normal
• Spatial interpolation • Easily compressed• GPU friendly
• Colored irradiance vector for direction : 3x3 matrix
• Compression: • Direction + Color
• If : no artefacts are introduced
Indirect Lighting RepresentationGPU : Irradiance vector compression
• Color 32 bits • R9_G9_B9_E5 GPU compatible format• RGBE [Ward91]
• Direction• XYZ: 24 bits (3x8 bits)• (θ,ϕ): 2x8 bits ([Jensen96])
Quantization used to reduce the transfer size
Indirect Lighting RepresentationGPU : Irradiance vector quantization
• Regular grid
12x3D Textures • 6 for direction • 6 for color • Format GL_RGB16F_ARB
• 6 texture fetches per pixel• Native trilinear interpolation
Indirect Lighting RepresentationGPU issues
Server• Precomputes and stores
• Illumination grids
• LOD for 3D objects
• Stores :
• Materials
• Planar Surfaces
Our Remote Visualization SystemOverview
Client
CPU processes:
• Geometry
• Lighting (Push-Pull)
Direct Transfer
Streaming
• Geometry, and then Lighting
• Lighting, and then Geometry
• Interleave Geometry and Lighting
Our Remote Visualization SystemStreaming strategies
• Initialization: 8 corners• Each client request:
N samples per slice• Not yet received data
vertices
Holes in data =
black spots
Our Remote Visualization SystemIrradiance vector grid streaming
Our Remote Visualization SystemPush-Pull : filling holes in the grid
2. 3D Hierarchical hole filling (PUSH)
1. 3D Hierarchy construction (PULL)
3. For each completed level
=> Pyramidal Filter
Adaptation of [Melax98,Gueziec99] techniques• Vertex split to get a multiresolution mesh • Streaming :
• Vertices• Vertex Indices• Vertex lookup tables
• Mesh is globally updated
Our Remote Visualization SystemGeometry streaming
Our remote system:
• Server: Intel Q6600 with 4GB RAM• Client: Nvidia 8800GTX• Network: Wifi 802.11g
ResultsIndependence of geometry and lighting
New structure to represent indirect lighting:• 3D regular grid with irradiance vectors at
vertices• GPU friendly• Small memory footprint and short transfer
time overhead• Independent of geometric complexity• Easily integrated with geometry streaming
ConclusionSummary
• Server side
• Precomputation to fit cluster architectures• On-line precomputation
• Fast update mechanism for dynamic 3D scenes• Local recomputation in regions of important changes
• Client side: reducing the process timeNew push-pull process (GPU)
Future Work