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- Barrera, Tony, et al.
(författare)
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Connected Minimal Acceleration Trigonometric Curves
- 2005
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Ingår i: SIGRAD 2005 The Annual SIGRAD Conference Special Theme – Mobile Graphics November 23-24, 2005 Lund, Sweden.
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Konferensbidrag (refereegranskat)abstract
- We present a technique that can be used to obtain a series of connected minimal bending trigonometric splines that will intersect any number of predefined points in space. The minimal bending property is obtained by a least square minimization of the acceleration. Each curve segment between two consecutive points will be a trigonometric Hermite spline obtained from a Fourier series and its four first terms. The proposed method can be used for a number of points and predefined tangents. The tangent length will then be optimized to yield a minimal bending curve. We also show how both the tangent direction and length can be optimized to give as smooth curves as possible. It is also possible to obtain a closed loop of minimal bending curves. These types of curves can be useful tools for 3D modelling, etc.
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| 3. |
- Barrera, Tony, et al.
(författare)
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Trigonometric splines
- 2008. - 1
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Ingår i: Game programming Gems 7. - Boston : Charles River Media. - 9781584505273 - 1584505273 ; , s. 191-198
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Bokkapitel (populärvet., debatt m.m.)
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| 8. |
- Hast, Anders, 1966-
(författare)
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Improved Algorithms for Fast Shading and Lighting
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Shading is a technique that is used in computer graphics to make faceted objects appear smooth and more realistic. In the research presented in this thesis we have investigated how shading can be generated as efficiently as possible without sacrificing quality.In the classical approach to high quality shading proposed by Phong, the illumination equation is computed per pixel using an interpolated normal. The normals at the vertices are bi-linearly interpolated over the polygon to obtain a normal per pixel. Correct shading requires normalization of these normals, which is computationally demanding involving a square root. In our research we have shown how this normalization can be eliminated through the use of spherical interpolation and the Chebyshev recurrence formula, reducing the calculation to a few single arithmetic operations per pixel.Still a substantial setup operation is needed for each scanline. We have studied how also this can be made more efficient, with some limited progress so far. An alternative approach is to do the most of the setup on polygon level and incrementally compute the setup needed per scanline. In particular, we have studied quadratic shading approaches, i.e. fitting second degree surfaces to the polygons. The most successful approach has been through what we have called X-shading, where the setup is calculated by using an efficient approximation for the mid-edge normals. This setup is about four times faster than previously known methods.In the process of studying shading methods we have also made some contributions to improving bump-mapping and simulation of different kinds of light sources.The developed methods will be of interest in future generations of computer graphics software and hardware systems, ranging from high end systems to generate realistic movies and 3D games, to handheld devices such as mobile phones with graphics displays.
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| 10. |
- Hast, Anders, et al.
(författare)
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Improved Diffuse Anisotropic Shading
- 2004
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Ingår i: Sigrad Conference 2004. ; , s. 57-58, s. 57-58
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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