Eikonal Rendering: Efficient Light Transport in Refractive

Eikonal
Rendering: View
Renderer
refEiko - View renderer
“Eikonal Rendering: Efficient Light Transport in Refractive Objects”,
Ivo Ihrke, Gernot Ziegler, Art Tevs, Christian Theobalt, Marcus Magnor,
Hans-Peter Seidel
Overview: 2 main components
System capable of Refractive Object Rendering:
• Light Simulator (pre-process, ~10 secs)
• View Renderer (real-time, 5-60 fps)
Renderer
• Shader Model >= 3.0 GPU
• Use OpenSceneGraph (v1.2) for the low level tasks, e.g.
transparency sorting, mesh rendering, etc.
• nrEngine: script handling, resource management, …
• Volume Ray Casting
Scene Graph based rendering
(depth and transparency sorting)
Renderer
• Full HDR color
along complete
rendering pipeline
• Post processing by
PPUG (post-processing
units graph)
• Completely scriptable
Scene Representation
• XML description of a complete scene
• Supported objects:
– Camera
– Light
– Shader
– Texture
– Model (Mesh)
– Entity (Static, Voxel Volume)
– Environment Map (CubeMap, PlaneMap, ShadowCubeMap)
– Post Processing Unit
Scene graph
Root Node
Environment
Map
Renderable
Root Node
Light Group
Light 1
Light 2
Entity
Mesh (Geode)
Entity
Entity
Mesh (Geode)
Volume rendering
• Volume rendering is required for our approach
• VoxelVolume class stays for an osg node handling volume rendering
• VoxelVolumeDrawable derived from osg::Drawable, implements
volume rendering by a shader program
• Rendering by a proxy geometry (ray casting)
– Box primitive (default)
– Geode as a child-node
Post Processing Effects
• Post processing by a so called PPU, post processing unit
• PPUs are combined into a graph
• Multiple inputs for each of PPU (osg::Texture)
• Multiple outputs (MRT) are implemented, but not well tested ;-(
• PPUG could contribute to osg as a new node kit
PP Effects (HDR bloom, Depth of Field,
Motion Blur, [+ tone mapping])
Post Processing Units Graph (Depth of
Field)
DoF resample
0.5
DoF resample
0.5
DoF blur
vertical
DoF blur
horizontal
DoF blur
vertical
DoF blur
horizontal
Color bypass
Depthmap
bypass
DoF Result
Taken from http://www.daionet.gr.jp/~masa/archives/GDC2003_DSTEAL.ppt
Post Processing Units Graph (HDR
Bloom + tone mapping)
DoF Result
Downsample
Compute avg.
luminance
Compute scaled
luminance
Downsample
Blur vertical
Brightpass
Blur horizontal
Tone mapping
Based on http://msdn2.microsoft.com/en-us/library/bb173484.aspx
Summary & Future work
• Nice renderer for our approach
• HDR rendering and scripting
• Osg 2.x is supported, but not well tested
• osgLua implementation required
• Possible contribution to the community by developing
a new node kit osgPPU
• New SH4.0 features are in development, hence new contribution to
osg will follow: Texture2DArray, GeometryProgram, …
Advertisement
• Visit our implementation sketch at Thursday, 9th August, Room 3 at
San Diego Convention Center:
GPU-based Light Wavefront Simulation for Real-Time Refractive
Object Rendering
• Google for Eikonal Rendering or just go to :
http://www.mpi-inf.mpg.de/resources/EikonalRendering/
and download slides, videos and source code.
• Visit my Homepage http://www.tevs.eu ;-)
Discussion & Demo

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