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Charles University Prague
Rendering Parametrizable Planetary Atmospheres with Multiple Scattering in Real-Time Oskar Elek Charles University Prague
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Motivation Why atmosphere? Oskar Elek CESCG’09
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Motivation Why real-time? Oskar Elek CESCG’09
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Outline Introduction Related work Model and its precomputation
Rendering Results Conclusion Interactive demonstration Oskar Elek CESCG’09
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Outline Introduction Related work Model and its precomputation
Rendering Results Conclusion Interactive demonstration Oskar Elek CESCG’09
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Introduction Participating media Oskar Elek CESCG’09
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Introduction Participating media Light scattering Rayleigh / Mie
Multiple scattering Oskar Elek CESCG’09
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Introduction Participating media Light scattering Parametrizability
Rayleigh / Mie Multiple scattering Parametrizability Oskar Elek CESCG’09
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Outline Introduction Related work Model and its precomputation
Rendering Results Conclusion Interactive demonstration Oskar Elek CESCG’09
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Related work Scattering physics Non-realtime methods Real-time methods
Rayleigh (1871) Mie (1908) Non-realtime methods Nishita et al. (1993, 1996) Haber et al. (2005) Real-time methods Schafhitzel et al. (2007) Bruneton and Neyret (2008) Oskar Elek CESCG’09
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Outline Introduction Related work Model and its precomputation
Rendering Results Conclusion Interactive demonstration Oskar Elek CESCG’09
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Scattering model Oskar Elek CESCG’09
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Scattering model Oskar Elek CESCG’09
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Precomputation We need scattering for: Every position
Every view direction Every sun direcion Oskar Elek CESCG’09
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Precomputation We need scattering for: Naïve implementation - 9 DoF!
Every position Every view direction Every sun direcion Naïve implementation DoF! Oskar Elek CESCG’09
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Precomputation We need scattering for: Naïve implementation - 9 DoF!
Every position Every view direction Every sun direcion Naïve implementation DoF! Improved parametrization Polar coordinates Observer altitude Without azimuth Oskar Elek CESCG’09
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Precomputation We need scattering for: Naïve implementation - 9 DoF!
Every position Every view direction Every sun direcion Naïve implementation DoF! Improved parametrization Polar coordinates Observer altitude Without azimuth Oskar Elek CESCG’09
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Multiple scattering Oskar Elek CESCG’09
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Multiple scattering Computational complexity Ck*(n2+n3)k Oskar Elek
CESCG’09
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Multiple scattering Computational complexity Ck*(n2+n3)k
Higher scattering orders – similar to IS for P Oskar Elek CESCG’09
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… Multiple scattering Solution – iterative computation
Scattering texture contains previous order … Oskar Elek CESCG’09
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… Multiple scattering Solution – iterative computation +
Scattering texture contains previous order … + Oskar Elek CESCG’09
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… Multiple scattering Solution – iterative computation
Scattering texture contains previous order … + New complexity C*n2 + (k-1)*C*(n2+n3) n3 term now fast Oskar Elek CESCG’09
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Outline Introduction Related work Model and its precomputation
Rendering Results Conclusion Interactive demonstration Oskar Elek CESCG’09
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Rendering On graphics hardware Fragment shader evaluation
Simple spherical geometry Terrain taken into account in Schafhitzel et al. Oskar Elek CESCG’09
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Rendering On graphics hardware Fragment shader evaluation
Simple spherical geometry Terrain taken into account in Schafhitzel et al. Atmosphere Evaluate h, θ and δ Fetch sky colour Front face culling enabled Oskar Elek CESCG’09
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Rendering On graphics hardware Fragment shader evaluation
Simple spherical geometry Terrain taken into account in Schafhitzel et al. Atmosphere Evaluate h, θ and δ Fetch sky colour Front face culling enabled Oskar Elek CESCG’09
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Rendering Planet Scattering Direct illumination Water reflection
Ambient light Oskar Elek CESCG’09
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Rendering Planet Scattering Direct illumination Water reflection
Ambient light (precomputed in texture) Oskar Elek CESCG’09
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Rendering Planet Scattering Direct illumination Water reflection
Ambient light (precomputed in texture) Oskar Elek CESCG’09
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Outline Introduction Related work Model and its precomputation
Rendering Results Conclusion Interactive demonstration Oskar Elek CESCG’09
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Results 0.2x Earth atmosphere density 5x Earth’s atmosphere density
Oskar Elek CESCG’09
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Results Single scattering Multiple scattering Oskar Elek CESCG’09
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Outline Introduction Related work Model and its precomputation
Rendering Results Conclusion Interactive demonstration Oskar Elek CESCG’09
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Conclusion We present:
Precomputation scheme for multiple scattering in parametrizable atmosphere 5 MB for whole dataset Real-time rendering algorithm for entire planet x768 (GeForce 8800GT) Oskar Elek CESCG’09
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Demonstration Oskar Elek CESCG’09
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End Thank you for your attention Questions? Oskar Elek CESCG’09
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