directedline.cc

Mesa is an open-source implementation of the OpenGL specification - a system for rendering interacti

/*
** 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.
**
*/
/*
*/

#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include "glimports.h"
#include "zlassert.h"

#include "quicksort.h"
#include "directedLine.h"
#include "polyDBG.h"

#ifdef __WATCOMC__
#pragma warning 726 10
#endif

//we must return the newLine
directedLine* directedLine::deleteChain(directedLine* begin, directedLine* end)
{
  if(begin->head()[0] ==  end->tail()[0] &&
     begin->head()[1] ==  end->tail()[1]
     )
    {
      directedLine *ret = begin->prev;
      begin->prev->next = end->next;
      end->next->prev = begin->prev;
      delete begin->sline;
      delete end->sline;
      delete begin;
      delete end;

      return ret;
    }

  directedLine* newLine;
  sampledLine* sline = new sampledLine(begin->head(), end->tail());
  newLine =  new directedLine(INCREASING, sline);
  directedLine *p = begin->prev;
  directedLine *n = end->next;
  p->next = newLine;
  n->prev = newLine;
  newLine->prev = p;
  newLine->next = n;

  delete begin->sline;
  delete end->sline;
  delete begin;
  delete end;
  return newLine;
}


void directedLine::deleteSingleLine(directedLine* dline)
{
  //make sure that dline->prev->tail is the same as
  //dline->next->head. This is for numerical erros.
  //for example, if we delete a line which is almost degeneate
  //within (epsilon), then we want to make that the polygon after deletion
  //is still a valid polygon

  dline->next->head()[0] =  dline->prev->tail()[0];
  dline->next->head()[1] =  dline->prev->tail()[1];

  dline->prev->next = dline->next;
  dline->next->prev = dline->prev;

  delete dline;

}

static Int myequal(Real a[2], Real b[2])
{
  /*
  if(a[0]==b[0] && a[1] == b[1])
    return 1;
  else
    return 0;
    */


  if(fabs(a[0]-b[0]) < 0.00001 &&
     fabs(a[1]-b[1]) < 0.00001)
    return 1;
  else
    return 0;

}

directedLine* directedLine::deleteDegenerateLines()
{
  //if there is only one edge or two edges, don't do anything
  if(this->next == this)
    return this;
  if(this->next == this->prev)
    return this;

  //find a nondegenerate line
  directedLine* temp;
  directedLine* first = NULL;
  if(! myequal(head(), tail()))
    /*
  if(head()[0] != tail()[0] ||
  head()[1] != tail()[1])
  */
    first = this;
  else
    {
      for(temp = this->next; temp != this; temp = temp->next)
	{
	  /*
	  if(temp->head()[0] != temp->tail()[0] ||
	     temp->head()[1] != temp->tail()[1])
	     */
	  if(! myequal(temp->head(), temp->tail()))
	    {
	      first = temp;
	      break;
	    }
        
	}
    }

  //if there are no non-degenerate lines, then we simply return NULL.
  if(first == NULL)
    {
      deleteSinglePolygonWithSline();
      return NULL;
    }

  directedLine* tempNext = NULL;
  for(temp =first->next; temp != first; temp = tempNext)
    {
      tempNext = temp->getNext();
/*
      if(temp->head()[0] == temp->tail()[0] &&
	 temp->head()[1] == temp->tail()[1])
*/      

      if(myequal(temp->head(), temp->tail()))
	deleteSingleLine(temp);
    }   
  return first;
}

directedLine* directedLine::deleteDegenerateLinesAllPolygons()
{
  directedLine* temp;
  directedLine *tempNext = NULL;
  directedLine* ret= NULL;
  directedLine* retEnd = NULL;
  for(temp=this; temp != NULL; temp = tempNext)
    {
      tempNext = temp->nextPolygon;
      temp->nextPolygon = NULL;
      if(ret == NULL)
	{
	  ret = retEnd = temp->deleteDegenerateLines();
        
	}
      else
	{
	  directedLine *newPolygon = temp->deleteDegenerateLines();
	  if(newPolygon != NULL)
	    {
	  retEnd->nextPolygon = temp->deleteDegenerateLines();
	  retEnd = retEnd->nextPolygon;
	}
    }
    }
  return ret;
}

directedLine* directedLine::cutIntersectionAllPoly(int &cutOccur)
{
  directedLine* temp;
  directedLine *tempNext = NULL;
  directedLine* ret= NULL;
  directedLine* retEnd = NULL;
  cutOccur = 0;
  for(temp=this; temp != NULL; temp = tempNext)
    {
      int eachCutOccur=0;
      tempNext = temp->nextPolygon;
      temp->nextPolygon = NULL;
      if(ret == NULL)
	{

	  ret = retEnd = DBG_cutIntersectionPoly(temp, eachCutOccur);
	  if(eachCutOccur)
	    cutOccur = 1;
	}
      else
	{

	  retEnd->nextPolygon = DBG_cutIntersectionPoly(temp, eachCutOccur);
	  retEnd = retEnd->nextPolygon;
	  if(eachCutOccur)
	    cutOccur = 1;
	}
    }
  return ret;
}


void directedLine::deleteSinglePolygonWithSline()
{
  directedLine *temp, *tempNext;
  prev->next = NULL;
  for(temp=this; temp != NULL; temp = tempNext)
    {
      tempNext = temp->next;
      delete temp->sline;
      delete temp;
    }
}

void directedLine::deletePolygonListWithSline()
{
  directedLine *temp, *tempNext;
  for(temp=this; temp != NULL; temp=tempNext)
    {
      tempNext = temp->nextPolygon;
      temp->deleteSinglePolygonWithSline();
    }
}

void directedLine::deleteSinglePolygon()
{
  directedLine *temp, *tempNext;
  prev->next = NULL;
  for(temp=this; temp != NULL; temp = tempNext)
    {
      tempNext = temp->next;
      delete temp;
    }
}

void directedLine::deletePolygonList()
{
  directedLine *temp, *tempNext;
  for(temp=this; temp != NULL; temp=tempNext)
    {
      tempNext = temp->nextPolygon;
      temp->deleteSinglePolygon();
    }
}


/*a loop by itself*/
directedLine::directedLine(short dir, sampledLine* sl)
{
  direction = dir;
  sline = sl;
  next = this;
  prev = this;
  nextPolygon = NULL;
//  prevPolygon = NULL;
  rootBit = 0;/*important to initilzae to 0 meaning not root yet*/

  rootLink = NULL;

}

void directedLine::init(short dir, sampledLine* sl)
{
  direction = dir;
  sline = sl;
}

directedLine::directedLine()
{
  next = this;
  prev = this;
  nextPolygon = NULL;
  rootBit = 0;/*important to initilzae to 0 meaning not root yet*/
  rootLink = NULL;
}

directedLine::~directedLine()
{
}

Real* directedLine::head()
{

  return (direction==INCREASING)? (sline->get_points())[0] : (sline->get_points())[sline->get_npoints()-1];
}

/*inline*/ Real* directedLine::getVertex(Int i)
{
  return (direction==INCREASING)? (sline->get_points())[i] : (sline->get_points())[sline->get_npoints() - 1 -i];
}

Real* directedLine::tail()
{
  return (direction==DECREASING)? (sline->get_points())[0] : (sline->get_points())[sline->get_npoints()-1];
}

 /*insert a new line between prev and this*/
void directedLine::insert(directedLine* nl)
{
  nl->next = this;
  nl->prev = prev;
  prev->next = nl;
  prev = nl;
  nl->rootLink = this; /*assuming that 'this' is the root!!!*/
}

Int directedLine::numEdges()
{
  Int ret=0;
  directedLine* temp;
  if(next == this) return 1;

  ret = 1;
  for(temp = next; temp != this; temp = temp->next)
    ret++;
  return ret;
}

Int directedLine::numEdgesAllPolygons()
{
  Int ret=0;
  directedLine* temp;
  for(temp=this; temp!= NULL; temp=temp->nextPolygon)
    {
      ret += temp->numEdges();
    }
  return ret;
}

/*return 1 if the double linked list forms a polygon.
 */
short directedLine::isPolygon()
{
  directedLine* temp;

  /*a polygon contains at least 3 edges*/
  if(numEdges() <=2) return 0;

  /*check this edge*/
  if(! isConnected()) return 0;

  /*check all other edges*/
  for(temp=next; temp != this; temp = temp->next){
    if(!isConnected()) return 0;
  }
  return 1;
}

/*check if the head of this edge is connected to
 *the tail of the prev
 */
short directedLine::isConnected()
{
  if( (head()[0] == prev->tail()[0]) && (head()[1] == prev->tail()[1]))
    return 1;
  else
    return 0;
}

Int compV2InY(Real A[2], Real B[2])
{
  if(A[1] < B[1]) return -1;
  if(A[1] == B[1] && A[0] < B[0]) return -1;
  if(A[1] == B[1] && A[0] == B[0]) return 0;
  return 1;
}

Int compV2InX(Real A[2], Real B[2])
{
  if(A[0] < B[0]) return -1;
  if(A[0] == B[0] && A[1] < B[1]) return -1;
  if(A[0] == B[0] && A[1] == B[1]) return 0;
  return 1;
}

/*compare two vertices NOT lines!
 *A vertex is the head of a directed line.
 *(x_1, y_1) <= (x_2, y_2) if
 *either y_1 < y_2
 *or	 y_1 == y_2 && x_1 < x_2.
 *return -1 if this->head() <= nl->head(),
 *return  1 otherwise
 */
Int directedLine::compInY(directedLine* nl)
{
  if(head()[1] < nl->head()[1]) return -1;
  if(head()[1] == nl->head()[1] && head()[0] < nl->head()[0]) return -1;
  return 1;