# CURVATURE-APPROXIMATED ESTIMATION OF REAL-TIME AMBIENT OCCLUSION

### Tomohito Hattori, Hiroyuki Kubo, Shigeo Morishima

#### Abstract

We present a novel technique for computing ambient occlusion (Akenine-Möller et al., 2008) on real-time graphics hardware. Our method approximates the occlusion for a local illumination model by introducing curvature-dependent function. Using our method, we are able to acquire occlusion at lower computational cost than conventional methods such as SSAO (Bavoil et al., 2008). Our method requires a multi-pass algorithm with the graphics processing unit (GPU). In the first pass curvature is acquired, and in the second pass the occlusion is computed from the curvature. In the calculating occlusion from the curvature, we approximate the geometric shape by a quadric surface function, and then obtain a curvature dependent function which is an approximation of geometric surface. This function depends only on local variables and we are able to calculate the ambient occlusion for the local illumination model. According to our results, both the computational and storage costs are sufficiently low for the technique to be applied to current graphics hardware supported computer games.

#### References

- Akenine-Möller, T., Haines, E., and Hoffman, N. (2008). Real-Time Rendering 3rd Edition. A. K. Peters, Ltd., Natick, MA, USA.
- Bavoil, L. and Sainz, M. (2009). Multi-layer dualresolution screen-space ambient occlusion. In SIG-

#### Paper Citation

#### in Harvard Style

Hattori T., Kubo H. and Morishima S. (2012). **CURVATURE-APPROXIMATED ESTIMATION OF REAL-TIME AMBIENT OCCLUSION** . In *Proceedings of the International Conference on Computer Graphics Theory and Applications and International Conference on Information Visualization Theory and Applications - Volume 1: GRAPP, (VISIGRAPP 2012)* ISBN 978-989-8565-02-0, pages 268-273. DOI: 10.5220/0003848402680273

#### in Bibtex Style

@conference{grapp12,

author={Tomohito Hattori and Hiroyuki Kubo and Shigeo Morishima},

title={CURVATURE-APPROXIMATED ESTIMATION OF REAL-TIME AMBIENT OCCLUSION},

booktitle={Proceedings of the International Conference on Computer Graphics Theory and Applications and International Conference on Information Visualization Theory and Applications - Volume 1: GRAPP, (VISIGRAPP 2012)},

year={2012},

pages={268-273},

publisher={SciTePress},

organization={INSTICC},

doi={10.5220/0003848402680273},

isbn={978-989-8565-02-0},

}

#### in EndNote Style

TY - CONF

JO - Proceedings of the International Conference on Computer Graphics Theory and Applications and International Conference on Information Visualization Theory and Applications - Volume 1: GRAPP, (VISIGRAPP 2012)

TI - CURVATURE-APPROXIMATED ESTIMATION OF REAL-TIME AMBIENT OCCLUSION

SN - 978-989-8565-02-0

AU - Hattori T.

AU - Kubo H.

AU - Morishima S.

PY - 2012

SP - 268

EP - 273

DO - 10.5220/0003848402680273