circ.cpp

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/*
** ----------------------------------------------------------------
** circ.cpp  -  Circle primitive class.
**
** ----------------------------------------------------------------
*/

/*
** ---------------------------------------------------------------
** Global variables and symbols:
*/
#ifdef _WIN32
#include <windows.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <GL/gl.h>
#include <GL/glu.h>

#include "prm.h"
#include "circ.h"
#include "cd.h"
#include "wd.h"
#include "dsp.h"

/*
** ---------------------------------------------------------------
** Initialization of class variables:
*/
const int Circ::CIRC_SEGS = 32;

const double Circ::M_PI = 3.141592654;

/*
** ---------------------------------------------------------------
** Public constructor and destructor functions:
**
*/
/*==========================  Circ::Circ  =========================*/

Circ::Circ( )
{
/* Set primitive type.
 */
 this->type = PRM_CIRC;

/* Set default values for new primitive.
 */
 c.x = 0.0;
 c.y = 0.0;
 r = 1.0;
}

/*==========================  Circ::Circ  =========================*/

Circ::Circ(int back) : Prm( back )
{
/* Set primitive type.
 */
 this->type = PRM_CIRC;

/* Set default values for new primitive.
 */
 c.x = 0.0;
 c.y = 0.0;
 r = 1.0;
}

/*==========================  Circ::~Circ  ========================*/

Circ::~Circ( )
{
}

/*
** ---------------------------------------------------------------
** Protected instance (object) functions
**
*/
/*====================  Circ::GetLateralNormal  ===================*/

void Circ::GetLateralNormal( Coord* p, Coord* normal )
{
 double len; 
 normal->x = p->x - c.x;
 normal->y = p->y - c.y;
 len = sqrt( normal->x*normal->x + normal->y*normal->y );
 normal->x /= len;
 normal->y /= len;
}

/*
** ---------------------------------------------------------------
** Public instance (object) functions
** (implemented in the derived class):
**
*/
/*==========================  Circ::Read  =========================*/

void Circ::Read( FILE* fd )
{
 fscanf( fd, "%lg %lg %lg", &c.x, &c.y, &r );
}

/*=========================  Circ::Write  =========================*/

void Circ::Write( FILE* fd )
{
 fprintf( fd, "%g %g %g\n", c.x, c.y, r );
}

/*========================  Circ::GetNPts  ========================*/

int Circ::GetNPts( )
{
 return( 4 );
}

/*=======================  Circ::SetCoords  =======================*/

void Circ::SetCoords( int id, double x, double y )
{
 r = sqrt( (x - c.x) * (x - c.x) + (y - c.y) * (y - c.y) );
}

/*=======================  Circ::GetCoords  =======================*/

void Circ::GetCoords( int id, double* x, double* y )
{
 *x = c.x + r;
 *y = c.y;
}

/*=======================  Circ::Set1stPt  ========================*/

void Circ::Set1stPt( double x, double y )
{
 c.x = x;
 c.y = y;
}

/*=======================  Circ::Set2ndPt  ========================*/

void Circ::Set2ndPt( double x, double y )
{
 r = sqrt( (x - c.x) * (x - c.x) + (y - c.y) * (y - c.y) );
}

/*=======================  Circ::PickArea  ========================*/

int Circ::PickArea( double x, double y )
{
 double dist;         /* distance from point to center */

 dist = sqrt( (x - c.x) * (x - c.x) + 
              (y - c.y) * (y - c.y) );

 if( dist <= r )
 {
  return( 1 );
 }

 return( 0 );
}

/*======================  Circ::PickVertex  =======================*/

int Circ::PickVertex( double x, double y, double tol, int* id )
{
 if(      (ABS( (c.x + r) - x ) <= tol ) && 
          (ABS(  c.y      - y ) <= tol ) )
 {
  *id = 0;
  return( 1 );
 }
 else if( (ABS(  c.x      - x ) <= tol ) && 
          (ABS( (c.y + r) - y ) <= tol ) )
 {
  *id = 1;
  return( 1 );
 }
 else if( (ABS( (c.x - r) - x ) <= tol ) && 
          (ABS(  c.y      - y ) <= tol ) )
 {
  *id = 2;
  return( 1 );
 }
 else if( (ABS(  c.x      - x ) <= tol ) && 
          (ABS( (c.y - r) - y ) <= tol ) )
 {
  *id = 3;
  return( 1 );
 }

 return( 0 );
}

/*=======================  Circ::PickSide  ========================*/

int Circ::PickSide( double x, double y, double tol, int* id )
{
 return( 0 );
}

/*=======================  Circ::Translate  =======================*/

void Circ::Translate( double dx, double dy )
{
 c.x += dx;
 c.y += dy;
}

/*====================  Circ::TranslateVertex  ====================*/

void Circ::TranslateVertex( int id, double dx, double dy )
{
 double x;
 double y;

 if( id == 0 )
 {
  x = c.x + r + dx;
  y = c.y;
  if( x < (c.x + COORD_TOL) )
   return;
 }
 else if( id == 1 )
 {
  x = c.x;
  y = c.y + r + dy;
  if( y < (c.y + COORD_TOL) )
   return;
 }
 else if( id == 2 )
 {
  x = c.x - r + dx;
  y = c.y;
  if( x > (c.x - COORD_TOL) )
   return;
 }
 else if( id == 3 )
 {
  x = c.x;
  y = c.y - r + dy;
  if( y > (c.y - COORD_TOL) )
   return;
 }
 else
 {
  return;
 }

 r = sqrt( (x - c.x) * (x - c.x) + (y - c.y) * (y - c.y) );
}

/*=====================  Circ::TranslateSide  =====================*/

void Circ::TranslateSide( int id, double dx, double dy )
{
}

/*=========================  Circ::GetBox  ========================*/

void Circ::GetBox( double* xmin, double* xmax, double* ymin, double* ymax )
{
 *xmin = c.x - r;
 *xmax = c.x + r;
 *ymin = c.y - r;
 *ymax = c.y + r;
}

/*====================  Circ::DisplayBoundary  ====================*/

void Circ::DisplayBoundary( )
{
 double d = 2.0 * r;

 wdArc( c.x, c.y, d, d, 0.0, 360.0 ); 
 wdMark( c.x + r, c.y ); 
 wdMark( c.x, c.y + r ); 
 wdMark( c.x - r, c.y ); 
 wdMark( c.x, c.y - r ); 
}

/*====================  Circ::DisplayInterior  ====================*/

void Circ::DisplayInterior( )
{
 double d = 2.0 * r;

 wdSector( c.x, c.y, d, d, 0.0, 360.0 ); 
}

/*=====================  Circ::DisplaySolid  ======================*/

void Circ::DisplaySolid( )
{
 Coord p[32];                     /* circle points */
 Coord normal;                    /* face normal vector */
 double alpha;                    /* circle angle */
 double delta = 2*M_PI/CIRC_SEGS; /* increment of circle angle */
 int i;

/* Build circle points.
 */
 alpha = 0.0;
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  p[i].x = c.x + r * cos( alpha );
  p[i].y = c.y + r * sin( alpha );
  alpha += delta;
 }

/* Display base circle.
 */
 glBegin( GL_TRIANGLE_FAN );
 glNormal3d( 0.0, 0.0, -1.0 );
 for( i = 0; i <= CIRC_SEGS; i++ )
 {
  glVertex3d( p[i%CIRC_SEGS].x, p[i%CIRC_SEGS].y, 0.0 );
 }
 glEnd( );

/* If the height of the primitive is null, return;
 */
 if( height == 0.0 )
 {
  return;
 }

/* Display top circle.
 */
 glBegin( GL_TRIANGLE_FAN );
 glNormal3d( 0.0, 0.0,  1.0 );
 for( i = 0; i <= CIRC_SEGS; i++ )
 {
  glVertex3d( p[i%CIRC_SEGS].x, p[i%CIRC_SEGS].y, height );
 }
 glEnd( );

/* Display lateral faces.
 */
 glBegin( GL_QUADS );
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  GetLateralNormal( &p[i], &normal );
  glNormal3d( normal.x, normal.y, 0.0 );
  glVertex3d( p[i].x, p[i].y, height );
  glVertex3d( p[i].x, p[i].y, 0.0 );
  GetLateralNormal( &p[(i+1)%CIRC_SEGS], &normal );
  glNormal3d( normal.x, normal.y, 0.0 );
  glVertex3d( p[(i+1)%CIRC_SEGS].x, p[(i+1)%CIRC_SEGS].y, 0.0 );
  glVertex3d( p[(i+1)%CIRC_SEGS].x, p[(i+1)%CIRC_SEGS].y, height );
 }
 glEnd( );
}

/*======================  Circ::HighltSolid  ======================*/
  
void Circ::HighltSolid( )
{
 Coord p[32];                     /* circle points */
 double alpha;                    /* circle angle */
 double delta = 2*M_PI/CIRC_SEGS; /* increment of circle angle */
 int i;
 
/* Build circle points.
 */
 alpha = 0.0;
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  p[i].x = c.x + r * cos( alpha );
  p[i].y = c.y + r * sin( alpha );
  alpha += delta;
 }

/* Display base circle.
 */
 glBegin( GL_LINE_LOOP );
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  glVertex3d( p[i].x, p[i].y, 0.0 );
 }
 glEnd( );

 glBegin( GL_POINTS );
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  glVertex3d( p[i].x, p[i].y, 0.0 );
 }
 glEnd( );

/* If the height of the primitive is null, return;
 */
 if( height == 0.0 )
 {
  return;
 }

/* Display top circle.
 */
 glBegin( GL_LINE_LOOP );
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  glVertex3d( p[i].x, p[i].y, height );
 }
 glEnd( );

 glBegin( GL_POINTS );
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  glVertex3d( p[i].x, p[i].y, height );
 }
 glEnd( );

/* Display lateral edges.
 */
 glBegin( GL_LINES );
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  glVertex3d( p[i].x, p[i].y, height );
  glVertex3d( p[i].x, p[i].y, 0.0 );
 }
 glEnd( );
}

/*====================  Circ::DisplayZbuffer  =====================*/

void Circ::DisplayZbuffer( )
{
 Coord p[32];                     /* circle points */
 Coord normal;                    /* face normal vector */
 double alpha;                    /* circle angle */
 double delta = 2*M_PI/CIRC_SEGS; /* increment of circle angle */
 Coord  midpt;                    /* auxiliar lateral face mid point */
 int i;

/* Build circle points.
 */
 alpha = 0.0;
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  p[i].x = c.x + r * cos( alpha );
  p[i].y = c.y + r * sin( alpha );
  alpha += delta;
 }

/* Display base circle.
 * To display means to project the face and send it to the zbuffer module.
 */
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  Dsp::ZbfBeginPoly( color, 0.0, 0.0, -1.0 );
  Dsp::ZbfVertex( c.x, c.y, 0.0 );
  Dsp::ZbfVertex( p[(i+1)%CIRC_SEGS].x, p[(i+1)%CIRC_SEGS].y, 0.0 );
  Dsp::ZbfVertex( p[i].x, p[i].y, 0.0 );
  Dsp::ZbfEndPoly( );
 }

/* If the height of the primitive is null, return;
 */
 if( height == 0.0 )
 {
  return;
 }

/* Display top circle (send to zbuffer module).
 */
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  Dsp::ZbfBeginPoly( color, 0.0, 0.0, 1.0 );
  Dsp::ZbfVertex( c.x, c.y, height );
  Dsp::ZbfVertex( p[(i+1)%CIRC_SEGS].x, p[(i+1)%CIRC_SEGS].y, height );
  Dsp::ZbfVertex( p[i].x, p[i].y, height );
  Dsp::ZbfEndPoly( );
 }

/* Display lateral faces (send to zbuffer module).
 */
 for( i = 0; i < CIRC_SEGS; i++ )
 {
  midpt.x = (p[i].x + p[(i+1)%CIRC_SEGS].x) * 0.5;
  midpt.y = (p[i].y + p[(i+1)%CIRC_SEGS].y) * 0.5;
  GetLateralNormal( &midpt, &normal );
  Dsp::ZbfBeginPoly( color, normal.x, normal.y, 0.0 );
  Dsp::ZbfVertex( p[i].x, p[i].y, height );
  Dsp::ZbfVertex( p[i].x, p[i].y, 0.0 );
  Dsp::ZbfVertex( p[(i+1)%CIRC_SEGS].x, p[(i+1)%CIRC_SEGS].y, 0.0 );
  Dsp::ZbfVertex( p[(i+1)%CIRC_SEGS].x, p[(i+1)%CIRC_SEGS].y, height );
  Dsp::ZbfEndPoly( );
 }
}

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