72 lines
3.0 KiB
C
72 lines
3.0 KiB
C
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/****************************************************************************
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* VCGLib o o *
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* Visual and Computer Graphics Library o o *
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* _ O _ *
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* Copyright(C) 2004 \/)\/ *
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* Visual Computing Lab /\/| *
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* ISTI - Italian National Research Council | *
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* \ *
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* All rights reserved. *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
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* for more details. *
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* *
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****************************************************************************/
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#ifndef IO_FAN_TESSELLATOR_H
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#define IO_FAN_TESSELLATOR_H
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namespace vcg {
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namespace tri {
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namespace io {
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/*
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* A face polygon composed of more than three vertices is triangulated
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* according to the following schema:
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* v5
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* / \
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* / \
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* / \
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* v1------v4
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* |\ /
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* | \ /
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* | \ /
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* v2---v3
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*
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* As shown above, the 5 vertices polygon (v1,v2,v3,v4,v5)
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* has been split into the triangles (v1,v2,v3), (v1,v3,v4) e (v1,v4,v5).
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* This way vertex v1 becomes the common vertex of all newly generated
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* triangles, and this may lead to the creation of very thin triangles.
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*
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* This function is intended as a trivial fallback when glutessellator is not available.
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* it assumes just ONE outline
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*/
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template < class PointType>
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void FanTessellator(const std::vector< std::vector<PointType> > & outlines, std::vector<int> & indices)
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{
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indices.clear();
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if(outlines.empty()) return;
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const std::vector<PointType> &points=outlines[0];
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for(size_t i=0;i<points.size()-2;++i)
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{
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indices.push_back(0);
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indices.push_back(i+1);
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indices.push_back(i+2);
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}
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}
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} // end Namespace tri
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} // end Namespace io
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} // end Namespace vcg
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#endif // IO_FAN_TESSELLATOR_H
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