Soft Shadow Maps for Linear Lights

Heidrich, Wolfgang; Brabec, Stefan; Seidel, Hans‐Peter

doi:10.1007/978-3-7091-6303-0_24

Cited by 28 publications

(28 citation statements)

References 15 publications

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“…Moreover, standard shadow maps cannot be used for heterogeneous media. Nevertheless, dedicated shadow techniques for linear lights exist [Heidrich et al 2000] and seem to be worth investigating. Furthermore, incorporating mutual visibility into sampling could possibly speedup the convergence for highly occluded scenes.…”

Section: Discussion and Future Workmentioning

confidence: 99%

Virtual ray lights for rendering scenes with participating media

et al. 2012

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Figure 1: The FRUIT JUICE scene featuring both single and multiple scattering (left). We evaluate the quality of multiple scattering. Our approach can compute the multiple scattering within the media in about a minute (middle-left), while in equal time, both the previous stateof-the-art approaches for general media (progressive photon beams, middle-right; virtual point lights, right) contain significant artifacts. AbstractWe present an efficient many-light algorithm for simulating indirect illumination in, and from, participating media. Instead of creating discrete virtual point lights (VPLs) at vertices of random-walk paths, we present a continuous generalization that places virtual ray lights (VRLs) along each path segment in the medium. Furthermore, instead of evaluating the lighting independently at discrete points in the medium, we calculate the contribution of each VRL to entire camera rays through the medium using an efficient Monte Carlo product sampling technique. We prove that by spreading the energy of virtual lights along both light and camera rays, the singularities that typically plague VPL methods are significantly diminished. This greatly reduces the need to clamp energy contributions in the medium, leading to robust and unbiased volumetric lighting not possible with current many-light techniques. Furthermore, by acting as a form of final gather, we obtain higher-quality multiple-scattering than existing density estimation techniques like progressive photon beams.

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Section: Discussion and Future Workmentioning

confidence: 99%

Virtual ray lights for rendering scenes with participating media

et al. 2012

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“…In this case, shadows are created from a wide light source. In this case, shadows are created by extending the shadow pattern outward from the center of the light source [16][17][18][19].…”

Section: Real-time Shadow Techniquesmentioning

confidence: 99%

Survey of Shadow Volume Algorithms in Computer Graphics

Kolivand¹,

Sunar²

2013

IETE Tech Rev

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This study will provide an overview of popular and famous algorithms and techniques in shadow generation based on shadow volumes. It characterizes well-known techniques, describing each of them in detail, and discusses the advantages and drawbacks of each. Basic ideas, improvements, and future works of the techniques are also comprehensively summarized and analyzed in depth. Often, programmers have difficulty selecting an appropriate shadow generation algorithm based on shadow volumes that is specific to their purpose. We have classified and systemized these techniques. The main goal of this paper is to provide researchers with background on a progress of shadow volume techniques so as to make it easier for researchers to choose the method best suited to their aims. It is also hoped that our analysis will help researchers find solutions to the shortcomings of each technique.

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“…By using more than one shadow map, and interpolating visibility, soft shadows can be generated as well [Heidrich et al 2000]. Linear lights were used, and more shadow maps had to be generated in complex visibility situations to guarantee a good result.…”

Section: Previous Workmentioning

confidence: 99%

A geometry-based soft shadow volume algorithm using graphics hardware

Assarsson

Akenine-Möller

2003

ACM SIGGRAPH 2003 Papers

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Most previous soft shadow algorithms have either suffered from aliasing, been too slow, or could only use a limited set of shadow casters and/or receivers. Therefore, we present a strengthened soft shadow volume algorithm that deals with these problems. Our critical improvements include robust penumbra wedge construction, geometry-based visibility computation, and also simplified computation through a four-dimensional texture lookup. This enables us to implement the algorithm using programmable graphics hardware, and it results in images that most often are indistinguishable from images created as the average of 1024 hard shadow images. Furthermore, our algorithm can use both arbitrary shadow casters and receivers. Also, one version of our algorithm completely avoids sampling artifacts which is rare for soft shadow algorithms. As a bonus, the four-dimensional texture lookup allows for small textured light sources, and, even video textures can be used as light sources. Our algorithm has been implemented in pure software, and also using the GeForce FX emulator with pixel shaders. Our software implementation renders soft shadows at 0.5-5 frames per second for the images in this paper. With actual hardware, we expect that our algorithm will render soft shadows in real time. An important performance measure is bandwidth usage. For the same image quality, an algorithm using the accumulated hard shadow images uses almost two orders of magnitude more bandwidth than our algorithm.

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Soft Shadow Maps for Linear Lights

Cited by 28 publications

References 15 publications

Virtual ray lights for rendering scenes with participating media

Virtual ray lights for rendering scenes with participating media

Survey of Shadow Volume Algorithms in Computer Graphics

A geometry-based soft shadow volume algorithm using graphics hardware

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