Francesc Castro

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Acknowledgements I have many people to thank. First of all, I want to express my gratitude to Jordi Levy, the supervisor of this dissertation, who introduced me to the world of computer science research. By contaminating me with the virus of Context Unification he gave me a marvellous research line, although not free of suffering. We have worked together in(More)
In this paper we extend the reuse of paths to the shot from a moving light source. In the classical algorithm new paths have to be cast from each new position of a light source. We show that we can reuse all paths for all positions, obtaining in this way a theoretical maximum speed-up equal to the average length of the shooting path
The ambient term in a renderer is a constant color added to all points which is a crude global approximation to indirect lighting. Because the ambient term ignores geometric occlusion conditions, it is computationally inexpensive. We present an extended ambient term that provides better results than the constant term but is still inexpensive because it also(More)
h this paper we address the problem of extracting representative point samples from polygonal mod&. The goal of such a sampling algorithm is to jind points that are evenly distributed. We propose star-discrepancy as a measure for sampling quality and propose new sampling methods based on global line distributions. We investigate several line generation(More)
This paper presents an efficient acceleration technique for the global line radiosity Multipath method. In this approach, the scene is subdivided in a hierarchy of box bounded subscenes, the boxes subdivided in a grid of virtual patches which store angular information. A new recursive (according to the hierarchy of subscenes) function allows to execute the(More)
We present a strategy to solve the problem of light positioning in a closed environment. We aim at obtaining, for a global illumination radiosity solution, the position and emission power for a given number of lights that provide a desired illumination at a minimum total emission power. Such a desired illumination is expressed using minimum and/or maximum(More)
In this paper we extend our previous result on reusing shooting paths when dealing with moving light sources in radiosity to the final gathering step algorithm, which combines a shooting solution and a gathering step. Paths are reused for each frame in both shooting and gathering steps, obtaining a noticeable reduction of cost in the computation of the(More)