454 lines
13 KiB
C++
454 lines
13 KiB
C++
/****************************************************************************
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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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/****************************************************************************
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History
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$Log: not supported by cvs2svn $
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Revision 1.6 2007/02/02 04:11:00 tarini
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added parameter theta (from conformal to equiareal) to AreaPresTextureOptimizer.
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Improved feature lists (comments).
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Revision 1.5 2007/02/02 01:39:58 tarini
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added three general-utility global functions for texture coordinates: SmoothTextureCoords, IsFoldFree, MarkFolds (see descriptions)
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Revision 1.4 2007/02/02 01:23:47 tarini
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added a few general comments on AreaPreserving optimizer, recapping optimizer features.
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Revision 1.3 2007/02/02 01:18:15 tarini
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First version: general virtual class for texture optimizers. A subclass for area preservation.
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****************************************************************************/
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#ifndef __VCGLIB__TEXTCOOORD_OPTIMIZATION
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#define __VCGLIB__TEXTCOOORD_OPTIMIZATION
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#include <vcg/container/simple_temporary_data.h>
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/*
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SINGLE PATCH TEXTURE OPTIMIZATIONS
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A set of classes to perform optimizations of disk->disk parametrization.
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Requires texture coords to be defined per vertex (replicate seams).
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*/
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namespace vcg
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{
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namespace tri
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{
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/* Base class for all Texture Optimizers*/
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template<class MESH_TYPE>
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class TextureOptimizer{
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protected:
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MESH_TYPE &m;
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SimpleTempData<typename MESH_TYPE::VertContainer, int > isFixed;
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public:
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/* Tpyes */
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typedef MESH_TYPE MeshType;
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typedef typename MESH_TYPE::VertexIterator VertexIterator;
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typedef typename MESH_TYPE::FaceIterator FaceIterator;
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typedef typename MESH_TYPE::VertexType VertexType;
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typedef typename MESH_TYPE::FaceType FaceType;
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typedef typename MESH_TYPE::ScalarType ScalarType;
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/* Access functions */
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const MeshType & Mesh() const {return m;}
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MeshType & Mesh() {return m;}
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/* Constructior */
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TextureOptimizer(MeshType &_m):m(_m),isFixed(_m.vert){
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assert(m.HasPerVertexTexture());
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}
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// initializes on current geometry
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virtual void TargetCurrentGeometry()=0;
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// performs an interation. Returns largest movement.
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virtual ScalarType Iterate()=0;
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// performs an iteration (faster, but it does not tell how close it is to stopping)
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virtual void IterateBlind()=0;
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// performs <steps> iteration
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virtual ScalarType IterateN(int step){
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for (int i=0; i<step-1; i++) {
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this->IterateBlind();
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}
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if (step>1) return this->Iterate(); else return 0;
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}
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// performs iterations until convergence.
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bool IterateUntilConvergence(ScalarType threshold=0.0001, int maxite=5000){
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int i;
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while (Iterate()>threshold) {
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if (i++>maxite) return false;
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}
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return true;
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}
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// desctuctor: free temporary field
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~TextureOptimizer(){
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isFixed.Stop();
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};
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// set the current border as fixed (forced to stay in position during text optimization)
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void SetBorderAsFixed(){
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isFixed.Start();
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for (VertexIterator v=m.vert.begin(); v!=m.vert.end(); v++) {
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isFixed[v]=(v->IsB())?1:0;
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}
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}
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// everything moves, no vertex must fixed during texture optimization)
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void SetNothingAsFixed(){
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isFixed.Start();
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for (VertexIterator v=m.vert.begin(); v!=m.vert.end(); v++) {
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isFixed[v]=0;
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}
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}
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// fix a given vertex
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void FixVertex(const VertexType *v, bool fix=true){
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isFixed[v]=(fix)?1:0;
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}
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};
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/*
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AREA PRESERVING TEXTURE OPTIMIZATION
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as in: Degener, P., Meseth, J., Klein, R.
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"An adaptable surface parameterization method."
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Proc. of the 12th International Meshing oundtable, 201<30>213 [2003].
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Features:
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:) - Balances angle and area distortions (best results!).
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:) - Can choose how to balance area and angle preservation (see SetTheta)
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theta=0 -> pure conformal (use MIPS instead!)
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theta=3 -> good balance between area and angle preservation
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theta>3 -> care more about area than about angles
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:( - Slowest method.
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:( - Requires a fixed boundary, else expands forever in texture space (unless theta=0).
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:( - Diverges in presence of flipped faces (unless theta=0).
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:( - Requires a speed parameter to be set.
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Speed too large => when close, bounces back and forth around minimum, w/o getting any closer.
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Lower speed => longer convercence times
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*/
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template<class MESH_TYPE>
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class AreaPreservingTextureOptimizer:public TextureOptimizer<MESH_TYPE>{
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public:
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/* Types */
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typedef MESH_TYPE MeshType;
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typedef typename MESH_TYPE::VertexIterator VertexIterator;
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typedef typename MESH_TYPE::FaceIterator FaceIterator;
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typedef typename MESH_TYPE::VertexType VertexType;
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typedef typename MESH_TYPE::FaceType FaceType;
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typedef typename MESH_TYPE::ScalarType ScalarType;
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private:
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typedef TextureOptimizer<MESH_TYPE> Super; // superclass (commodity)
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// extra data per face: [0..3] -> cotangents. [4] -> area*2
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SimpleTempData<typename MESH_TYPE::FaceContainer, Point4<ScalarType> > data;
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SimpleTempData<typename MESH_TYPE::VertContainer, Point2<ScalarType> > sum;
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ScalarType totArea;
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ScalarType speed;
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int theta;
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public:
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// constructor and destructor
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AreaPreservingTextureOptimizer(MeshType &_m):Super(_m),data(_m.face),sum(_m.vert){
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speed=0.001;
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theta=3;
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}
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~AreaPreservingTextureOptimizer(){
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data.Stop();
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sum.Stop();
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Super::isFixed.Stop();
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}
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void SetSpeed(ScalarType _speed){
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speed=_speed;
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}
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ScalarType GetSpeed(){
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return speed;
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}
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// sets the parameter theta:
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// good parameters are in 1..3
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// 0 = converge to pure conformal, ignore area preservation
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// 3 = good balance between area and conformal
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// >3 = area more important, angle preservation less important
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void SetTheta(int _theta){
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theta=_theta;
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}
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int GetTheta(){
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return theta;
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}
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void IterateBlind(){
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/* todo: do as iterate, but without */
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Iterate();
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}
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ScalarType Iterate(){
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ScalarType max; // max displacement
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#define v0 (f->V0(i)->T().P())
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#define v1 (f->V1(i)->T().P())
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#define v2 (f->V2(i)->T().P())
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for (VertexIterator v=Super::m.vert.begin(); v!=Super::m.vert.end(); v++) {
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sum[v].SetZero();
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}
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ScalarType tot_proj_area=0;
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for (FaceIterator f=Super::m.face.begin(); f!=Super::m.face.end(); f++) {
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int i=0;
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double area2 = ((v1-v0) ^ (v2-v0));
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tot_proj_area+=area2;
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}
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double scale= 1.0; //tot_proj_area / tot_area ;
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for (FaceIterator f=Super::m.face.begin(); f!=Super::m.face.end(); f++) {
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int i=0; ScalarType area2 = ((v1-v0) ^ (v2-v0));
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for (i=0; i<3; i++){
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ScalarType
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a = (v1-v0).Norm(),
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b = ((v1-v0) * (v2-v0))/a,
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c = area2 / a,
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m0= data[f][i] / area2,
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m1= data[f][(i+1)%3] / area2,
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m2= data[f][(i+2)%3] / area2,
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mx= (b-a)/area2,
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my= c/area2, // 1.0/a
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mA= data[f][3]/area2 * scale,
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e = m0*((b-a)*(b-a)+c*c) + m1*(b*b+c*c) + m2*a*a, // as obvious
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M1= mA + 1.0/mA,
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M2= mA - 1.0/mA,
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px= e*my,
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py=-e*mx,
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qx= m1*b+ m2*a,
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qy= m1*c,
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/* linear weightings
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dx= (OMEGA) * (my * M2) +
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(1-OMEGA) * ( px - 2.0*qx),
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dy= (OMEGA) * (-mx * M2) +
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(1-OMEGA) * ( py - 2.0*qy),*/
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// exponential weighting
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// 2d gradient
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dx=// M1
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//*M1 // ^ theta-1
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pow(M1,theta-1)
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*(px*(M1+ theta*M2) - 2.0*qx*M1),
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dy=// M1
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//*M1 // ^ theta-1
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pow(M1,theta-1)
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*(py*(M1+ theta*M2) - 2.0*qy*M1),
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gy= dy/c,
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gx= (dx - gy*b) / a;
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// 3d gradient
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sum[f->V(i)]+= ( (v1-v0) * gx + (v2-v0) * gy ) * data[f][3];
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}
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}
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max=0; // max displacement
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speed=0.001;
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for (VertexIterator v=Super::m.vert.begin(); v!=Super::m.vert.end(); v++)
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if ( !Super::isFixed[v] ) //if (!v->IsB())
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{
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ScalarType n=sum[v].Norm();
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if ( n > 1 ) { sum[v]/=n; n=1.0;}
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if ( n*speed<=0.1 ); {
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v->T().P()-=(sum[v] * speed ) /** scale*/;
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if (max<n) max=n;
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}
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//else rejected++;
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}
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return max;
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#undef v0
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#undef v1
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#undef v2
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//printf("rejected %d\n",rejected);
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}
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void TargetCurrentGeometry(){
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Super::isFixed.Start();
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data.Start();
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sum.Start();
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totArea=0;
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for (FaceIterator f=Super::m.face.begin(); f!=Super::m.face.end(); f++) {
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double area2 = ((f->V(1)->P() - f->V(0)->P() )^(f->V(2)->P() - f->V(0)->P() )).Norm();
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totArea+=area2;
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//if ( Super::isFixed[f->V1(0)] )
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for (int i=0; i<3; i++){
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data[f][i]=(
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(f->V1(i)->P() - f->V0(i)->P() )*(f->V2(i)->P() - f->V0(i)->P() )
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)/area2;
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data[f][3]=area2;
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}
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}
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}
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};
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/* texture coords general utility functions */
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/*++++++++++++++++++++++++++++++++++++++++++*/
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// returns false if any fold is present (faster than MarkFolds)
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template<class MESH_TYPE>
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bool IsFoldFree(MESH_TYPE &m){
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assert(m.HasPerVertexTexture());
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typedef typename MESH_TYPE::VertexType::TextureType::PointType PointType;
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typedef typename MESH_TYPE::VertexType::TextureType::PointType::ScalarType ScalarType;
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ScalarType lastsign=0;
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for (typename MESH_TYPE::FaceIterator f=m.face.begin(); f!=m.face.end(); f++){
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ScalarType sign=((f->V(1)->T().P()-f->V(0)->T().P()) ^ (f->V(2)->T().P()-f->V(0)->T().P()));
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if (sign!=0) {
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if (sign*lastsign<0) return false;
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lastsign=sign;
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}
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}
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return true;
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}
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// detects and marks folded faces, by setting their quality to 0 (or 1 otherwise)
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// returns number of folded faces
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template<class MESH_TYPE>
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int MarkFolds(MESH_TYPE &m){
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assert(m.HasPerVertexTexture());
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assert(m.HasPerFaceQuality());
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typedef typename MESH_TYPE::VertexType::TextureType::PointType PointType;
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typedef typename MESH_TYPE::VertexType::TextureType::PointType::ScalarType ScalarType;
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SimpleTempData<typename MESH_TYPE::FaceContainer, short> sign(m.face);
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sign.Start(0);
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// first pass, determine predominant sign
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int npos=0, nneg=0;
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ScalarType lastsign=0;
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for (typename MESH_TYPE::FaceIterator f=m.face.begin(); f!=m.face.end(); f++){
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ScalarType fsign=((f->V(1)->T().P()-f->V(0)->T().P()) ^ (f->V(2)->T().P()-f->V(0)->T().P()));
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if (fsign<0) { sign[f]=-1; nneg++; }
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if (fsign>0) { sign[f]=+1; npos++; }
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}
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// second pass, detect folded faces
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int res=0;
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short gsign= (nneg>npos)?-1:+1;
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for (typename MESH_TYPE::FaceIterator f=m.face.begin(); f!=m.face.end(); f++){
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if (sign[f]*gsign<0){
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res++;
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f->Q()=0;
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} else f->Q()=1;
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}
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sign.Stop();
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return res;
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}
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// Smooths texture coords.
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// (can be useful to remove folds,
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// e.g. these created when obtaining tecture coordinates after projections)
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template<class MESH_TYPE>
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void SmoothTextureCoords(MESH_TYPE &m){
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assert(m.HasPerVertexTexture());
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typedef typename MESH_TYPE::VertexType::TextureType::PointType PointType;
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SimpleTempData<typename MESH_TYPE::VertContainer, int> div(m.vert);
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SimpleTempData<typename MESH_TYPE::VertContainer, PointType > sum(m.vert);
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div.Start();
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sum.Start();
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for (typename MESH_TYPE::VertexIterator v=m.vert.begin(); v!=m.vert.end(); v++) {
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sum[v].SetZero();
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div[v]=0;
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}
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for (typename MESH_TYPE::FaceIterator f=m.face.begin(); f!=m.face.end(); f++){
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div[f->V(0)] +=2; sum[f->V(0)] += f->V(2)->T().P(); sum[f->V(0)] += f->V(1)->T().P();
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div[f->V(1)] +=2; sum[f->V(1)] += f->V(0)->T().P(); sum[f->V(1)] += f->V(2)->T().P();
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div[f->V(2)] +=2; sum[f->V(2)] += f->V(1)->T().P(); sum[f->V(2)] += f->V(0)->T().P();
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}
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for (typename MESH_TYPE::VertexIterator v=m.vert.begin(); v!=m.vert.end(); v++) // if (!v->IsB())
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{
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if (v->div>0) {
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v->T().P() = sum[v]/div[v];
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}
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}
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div.Stop();
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sum.Stop();
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}
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} } // End namespace vcg::tri
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#endif // __VCGLIB__TEXTCOOORD_OPTIMIZATION
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