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/*
** License Applicability. Except to the extent portions of this file are
** made subject to an alternative license as permitted in the SGI Free
** Software License B, Version 1.1 (the "License"), the contents of this
** file are subject only to the provisions of the License. You may not use
** this file except in compliance with the License. You may obtain a copy
** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
**
** http://oss.sgi.com/projects/FreeB
**
** Note that, as provided in the License, the Software is distributed on an
** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
**
** Original Code. The Original Code is: OpenGL Sample Implementation,
** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
** Copyright in any portions created by third parties is as indicated
** elsewhere herein. All Rights Reserved.
**
** Additional Notice Provisions: The application programming interfaces
** established by SGI in conjunction with the Original Code are The
** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
** Window System(R) (Version 1.3), released October 19, 1998. This software
** was created using the OpenGL(R) version 1.2.1 Sample Implementation
** published by SGI, but has not been independently verified as being
** compliant with the OpenGL(R) version 1.2.1 Specification.
**
** $Date: 2001/03/17 00:25:41 $ $Revision: 1.1 $
*/
/*
** $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/nurbtess/partitionX.cc,v 1.1 2001/03/17 00:25:41 brianp Exp $
*/
#include <stdlib.h>
#include <stdio.h>
#include "partitionX.h"
#define CONCAVITY_ZERO 1.0e-6 //this number is used to test whether a vertex is concave (refelx)
//or not. The test needs to compute the area of the three adjacent
//vertices to see if the are is positive or negative.
Int isCuspX(directedLine *v)
{
//if v->prev <= v && v->next <= v
//|| v->prev >= v && v->next >= v
Real* T = v->head();
Real* P = v->getPrev()->head();
Real* N = v->getNext()->head();
if(
(compV2InX(T,P) != -1 &&
compV2InX(T,N) != -1
) ||
(compV2InX(T,P) != 1 &&
compV2InX(T,N) != 1
)
)
return 1;
else
return 0;
}
Int isReflexX(directedLine* v)
{
Real* A = v->getPrev()->head();
Real* B = v->head();
Real* C = v->tail();
Real Bx,By, Cx, Cy;
//scale them in case they are too small
Bx = 10*(B[0] - A[0]);
By = 10*(B[1] - A[1]);
Cx = 10*(C[0] - A[0]);
Cy = 10*(C[1] - A[1]);
if(Bx*Cy - Cx*By < -CONCAVITY_ZERO) return 1;
else return 0;
}
/*return
*0: not-cusp
*1: interior cusp
*2: exterior cusp
*/
Int cuspTypeX(directedLine *v)
{
if(! isCuspX(v)) return 0;
else
{
//printf("isCusp,%f,%f\n", v->head()[0], v->head()[1]);
if(isReflexX(v))
{
// printf("isReflex\n");
return 1;
}
else
{
// printf("not isReflex\n");
return 2;
}
}
}
Int numInteriorCuspsX(directedLine *polygon)
{
directedLine *temp;
int ret = 0;
if(cuspTypeX(polygon) == 1)
ret++;
for(temp = polygon->getNext(); temp != polygon; temp = temp->getNext())
if(cuspTypeX(temp) == 1)
ret++;
return ret;
}
void findInteriorCuspsX(directedLine *polygon, Int& ret_n_interior_cusps,
directedLine** ret_interior_cusps)
{
directedLine *temp;
ret_n_interior_cusps = 0;
if(cuspTypeX(polygon) == 1)
{
ret_interior_cusps[ret_n_interior_cusps++] = polygon;
}
for(temp = polygon->getNext(); temp != polygon; temp = temp->getNext())
if(cuspTypeX(temp) == 1)
{
ret_interior_cusps[ret_n_interior_cusps++] = temp;
}
}
directedLine* findDiagonal_singleCuspX(directedLine* cusp)
{
directedLine* temp;
Int is_minimal = ((compV2InX(cusp->head(), cusp->tail()) == -1)? 1:0);
if(is_minimal)
for(temp = cusp->getNext(); temp != cusp; temp = temp->getNext())
{
if(compV2InX(cusp->head(), temp->head()) == 1)
{
return temp;
}
}
else //is maxmal
for(temp = cusp->getNext(); temp != cusp; temp = temp->getNext())
{
if(compV2InX(cusp->head(), temp->head()) == -1)
{
return temp;
}
}
return NULL;
}
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