Italian Chapter Conference 2007
Permanent URI for this collection
Browse
Browsing Italian Chapter Conference 2007 by Subject "Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Line and Curve Generation, Display algorithms, Line and Curve generation I.3.5 [Computer Graphics]: Surface Representation, Geometric Algorithms, Splines"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item An Efficient Algorithm for Adaptive Segmentation and Tessellation with Pixel Precision(The Eurographics Association, 2007) Martinelli, Alessandro; Raffaele De Amicis and Giuseppe ContiWe propose a new algorithm to get a representation of a curved surface with the precision of the image pixel. This technique uses some results from Scan-line algorithms, but it considers also the new functionalities from graphics hardware and takes advantages from it. We explain the general method, with principles common to every kind of surface: then we illustrate how these principles can be applied to quadratic and cubic bezier triangles, showing formulas and some algorithm details.Item Explicit Adaptive Tessellation based on re-parametrization on Graphics Hardware(The Eurographics Association, 2007) Martinelli, Alessandro; Raffaele De Amicis and Giuseppe ContiWe propose to use an explicit function for adaptive tessellation of parametric curves and surfaces. This function behaves as a new parametrization from the surface domain (or curve domain) to the domain itself; it is build using information about derivatives and curvature: a fixed tessellation may be re-arranged in an adaptive tessellation, which takes care of those parts of the curve or surface which need to be tessellated more and those which may use a poorer tessellation. We show how to produce and how to use the kernel function with four example: a simple cubic curve, a spline curve, a cubic bezièr triangle and a cubic quadrilateral patch. For every example, we compare the fixed tessellation with the adaptive one: the number of vertexes used is always the same, but the points are re-arranged in a better way. At the end we show how to use commonly known forward differencing methods to evaluate both the explicit parametrization and the curve or surface; we also show how simply this method may be implemented on common graphics cards.