---

dsp.c

Go to the documentation of this file.

/*
** ---------------------------------------------------------------
** dsp.c -  Display module.
**
** ---------------------------------------------------------------
*/

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

#include "iup.h"   /* IupGetAttribute */
#include "cd.h"

#include "prj.h"   /* Odatascreen */
#include "prm.h"
#include "dsp.h"
#include "t3d.h"
#include "zbf.h"

/*
** ---------------------------------------------------------------
** Local variables and symbols:
*/

#ifndef ABS
#define ABS(x) (((x) < 0.0)? -(x): (x))
#endif

static Vec3d view_vector;

#define get_red(_)   ((double)(((_) >> 16) & 0xff) / 255.0)

#define get_green(_) ((double)(((_) >>  8) & 0xff) / 255.0)

#define get_blue(_)  ((double)(((_) >>  0) & 0xff) / 255.0)

#define MIN_COLOR_INTENS  0.50

static char *help_cmd[] =
  {
   "Tecle:",
   "H (de Help)",
   "Ctrl+Q (de Quit)",
   "Ctrl+I (de Info)",
   "Ctrl+O (de Open)",
   "Ctrl+S (de Snap shot)",
   "R (de Reset view)",
   "F (de Fit)" ,
   "P (de Perspec.)",
   "O (de Ortogr.)",
   "X (de Proj. X)",
   "Y (de Proj. Y)",
   "Z (de Proj. Z)",
   "Ctrl+M (de Manip.)",
   "Ctrl+N (de Naveg.)",
   "Ctrl+Z (de Zoom)"
  };

static char *help_msg[] =
  { 
   " ",
   "==> Exibe este help",
   "==> Sai do programa",
   "==> Informacoes sobre o programa",
   "==> Abre modelo de arquivo",
   "==> Desenha o modelo usando CD",
   "==> Inicializa projecao",
   "==> Ajusta modelo na janela" ,
   "==> Projecao conica",
   "==> Projecao cilindrica",
   "==> Projecao ortografica no plano X",
   "==> Projecao ortografica no plano Y",
   "==> Projecao ortografica no plano Z",
   "==> Mouse manipula modelo",
   "==> Mouse controla navegacao",
   "==> Mouse controla zoom"
  };

static int font_list_base;

/*
** ---------------------------------------------------------------
** Private functions:
*/

/*=========================  dspVecUnit  =========================*/
static void dspVecUnit( Vec3d *a, Vec3d *b )
{
 double len = sqrt(a->x*a->x + a->y*a->y + a->z*a->z);

 if( len != 0.0 )
 {
  b->x = a->x / len; 
  b->y = a->y / len;
  b->z = a->z / len;
 }
}
 
/*=========================  zbfVecDot  ==========================*/
static double dspVecDot( Vec3d *a, Vec3d *b )
{ 
 return( a->x*b->x + a->y*b->y + a->z*b->z );
}

/*=======================  dspDecodeColor  =======================*/
static void dspDecodeColor( long int color, unsigned char *red,
                                            unsigned char *green, 
                                            unsigned char *blue )
{
 *red   = (unsigned char)(((color) >> 16) & 0xff);
 *green = (unsigned char)(((color) >>  8) & 0xff);
 *blue  = (unsigned char)(((color) >>  0) & 0xff);
}

/*=======================  dspEncodeColor  =======================*/
static long int dspEncodeColor( unsigned char red, 
                                unsigned char green,
                                unsigned char blue )
{
 return( ((unsigned long)(red)   << 16) |
         ((unsigned long)(green) <<  8) |
         ((unsigned long)(blue)  <<  0) );
}

/*=======================  dspShadeColor  ========================*/
static long int dspShadeColor( Vec3d *normal, Vec3d *view, long int color )
{
 unsigned char red;
 unsigned char green;
 unsigned char blue;
 double        fac;    /* intensity factor */

 dspDecodeColor( color, &red, &green, &blue );

 fac = dspVecDot( normal, view );
 fac = ABS( fac );

 fac = MIN_COLOR_INTENS + (1.0 - MIN_COLOR_INTENS) * fac;

 if( fac < 0.0 )
  fac = 0.0;
 else if( fac > 1.0 )
  fac = 1.0;

 red   = (unsigned char)(fac * (double)red);
 green = (unsigned char)(fac * (double)green);
 blue  = (unsigned char)(fac * (double)blue);

 return( dspEncodeColor( red, green, blue ) );
}

/*=======================  dspInvertMatrix  ======================*/
static void dspInvertMatrix( double mt[4][4], double imt[4][4] )
{
 double det;

 det =
  mt[0][3]*mt[1][2]*mt[2][1]*mt[3][0] - mt[0][2]*mt[1][3]*mt[2][1]*mt[3][0] -
  mt[0][3]*mt[1][1]*mt[2][2]*mt[3][0] + mt[0][1]*mt[1][3]*mt[2][2]*mt[3][0] +
  mt[0][2]*mt[1][1]*mt[2][3]*mt[3][0] - mt[0][1]*mt[1][2]*mt[2][3]*mt[3][0] -
  mt[0][3]*mt[1][2]*mt[2][0]*mt[3][1] + mt[0][2]*mt[1][3]*mt[2][0]*mt[3][1] +
  mt[0][3]*mt[1][0]*mt[2][2]*mt[3][1] - mt[0][0]*mt[1][3]*mt[2][2]*mt[3][1] -
  mt[0][2]*mt[1][0]*mt[2][3]*mt[3][1] + mt[0][0]*mt[1][2]*mt[2][3]*mt[3][1] +
  mt[0][3]*mt[1][1]*mt[2][0]*mt[3][2] - mt[0][1]*mt[1][3]*mt[2][0]*mt[3][2] -
  mt[0][3]*mt[1][0]*mt[2][1]*mt[3][2] + mt[0][0]*mt[1][3]*mt[2][1]*mt[3][2] +
  mt[0][1]*mt[1][0]*mt[2][3]*mt[3][2] - mt[0][0]*mt[1][1]*mt[2][3]*mt[3][2] -
  mt[0][2]*mt[1][1]*mt[2][0]*mt[3][3] + mt[0][1]*mt[1][2]*mt[2][0]*mt[3][3] +
  mt[0][2]*mt[1][0]*mt[2][1]*mt[3][3] - mt[0][0]*mt[1][2]*mt[2][1]*mt[3][3] -
  mt[0][1]*mt[1][0]*mt[2][2]*mt[3][3] + mt[0][0]*mt[1][1]*mt[2][2]*mt[3][3];


 imt[0][0] = (-mt[1][3]*mt[2][2]*mt[3][1] + mt[1][2]*mt[2][3]*mt[3][1] +
               mt[1][3]*mt[2][1]*mt[3][2] - mt[1][1]*mt[2][3]*mt[3][2] -
               mt[1][2]*mt[2][1]*mt[3][3] + mt[1][1]*mt[2][2]*mt[3][3] )
            / det;

 imt[0][1] = ( mt[0][3]*mt[2][2]*mt[3][1] - mt[0][2]*mt[2][3]*mt[3][1] -
               mt[0][3]*mt[2][1]*mt[3][2] + mt[0][1]*mt[2][3]*mt[3][2] +
               mt[0][2]*mt[2][1]*mt[3][3] - mt[0][1]*mt[2][2]*mt[3][3] )
            / det;

 imt[0][2] = (-mt[0][3]*mt[1][2]*mt[3][1] + mt[0][2]*mt[1][3]*mt[3][1] +
               mt[0][3]*mt[1][1]*mt[3][2] - mt[0][1]*mt[1][3]*mt[3][2] -
               mt[0][2]*mt[1][1]*mt[3][3] + mt[0][1]*mt[1][2]*mt[3][3] )
            / det;

 imt[0][3] = ( mt[0][3]*mt[1][2]*mt[2][1] - mt[0][2]*mt[1][3]*mt[2][1] -
               mt[0][3]*mt[1][1]*mt[2][2] + mt[0][1]*mt[1][3]*mt[2][2] +
               mt[0][2]*mt[1][1]*mt[2][3] - mt[0][1]*mt[1][2]*mt[2][3] )
            / det;

 imt[1][0] = ( mt[1][3]*mt[2][2]*mt[3][0] - mt[1][2]*mt[2][3]*mt[3][0] -
               mt[1][3]*mt[2][0]*mt[3][2] + mt[1][0]*mt[2][3]*mt[3][2] +
               mt[1][2]*mt[2][0]*mt[3][3] - mt[1][0]*mt[2][2]*mt[3][3] )
            / det;

 imt[1][1] = (-mt[0][3]*mt[2][2]*mt[3][0] + mt[0][2]*mt[2][3]*mt[3][0] +
               mt[0][3]*mt[2][0]*mt[3][2] - mt[0][0]*mt[2][3]*mt[3][2] -
               mt[0][2]*mt[2][0]*mt[3][3] + mt[0][0]*mt[2][2]*mt[3][3] )
            / det;

 imt[1][2] = ( mt[0][3]*mt[1][2]*mt[3][0] - mt[0][2]*mt[1][3]*mt[3][0] -
               mt[0][3]*mt[1][0]*mt[3][2] + mt[0][0]*mt[1][3]*mt[3][2] +
               mt[0][2]*mt[1][0]*mt[3][3] - mt[0][0]*mt[1][2]*mt[3][3] )
            / det;

 imt[1][3] = (-mt[0][3]*mt[1][2]*mt[2][0] + mt[0][2]*mt[1][3]*mt[2][0] +
               mt[0][3]*mt[1][0]*mt[2][2] - mt[0][0]*mt[1][3]*mt[2][2] -
               mt[0][2]*mt[1][0]*mt[2][3] + mt[0][0]*mt[1][2]*mt[2][3] )
            / det;

 imt[2][0] = (-mt[1][3]*mt[2][1]*mt[3][0] + mt[1][1]*mt[2][3]*mt[3][0] +
               mt[1][3]*mt[2][0]*mt[3][1] - mt[1][0]*mt[2][3]*mt[3][1] -
               mt[1][1]*mt[2][0]*mt[3][3] + mt[1][0]*mt[2][1]*mt[3][3] )
            / det;

 imt[2][1] = ( mt[0][3]*mt[2][1]*mt[3][0] - mt[0][1]*mt[2][3]*mt[3][0] -
               mt[0][3]*mt[2][0]*mt[3][1] + mt[0][0]*mt[2][3]*mt[3][1] +
               mt[0][1]*mt[2][0]*mt[3][3] - mt[0][0]*mt[2][1]*mt[3][3] )
            / det;

 imt[2][2] = (-mt[0][3]*mt[1][1]*mt[3][0] + mt[0][1]*mt[1][3]*mt[3][0] +
               mt[0][3]*mt[1][0]*mt[3][1] - mt[0][0]*mt[1][3]*mt[3][1] -
               mt[0][1]*mt[1][0]*mt[3][3] + mt[0][0]*mt[1][1]*mt[3][3] )
            / det;

 imt[2][3] = ( mt[0][3]*mt[1][1]*mt[2][0] - mt[0][1]*mt[1][3]*mt[2][0] -
               mt[0][3]*mt[1][0]*mt[2][1] + mt[0][0]*mt[1][3]*mt[2][1] +
               mt[0][1]*mt[1][0]*mt[2][3] - mt[0][0]*mt[1][1]*mt[2][3] )
            / det;

 imt[3][0] = ( mt[1][2]*mt[2][1]*mt[3][0] - mt[1][1]*mt[2][2]*mt[3][0] -
               mt[1][2]*mt[2][0]*mt[3][1] + mt[1][0]*mt[2][2]*mt[3][1] +
               mt[1][1]*mt[2][0]*mt[3][2] - mt[1][0]*mt[2][1]*mt[3][2] )
            / det;

 imt[3][1] = (-mt[0][2]*mt[2][1]*mt[3][0] + mt[0][1]*mt[2][2]*mt[3][0] +
               mt[0][2]*mt[2][0]*mt[3][1] - mt[0][0]*mt[2][2]*mt[3][1] -
               mt[0][1]*mt[2][0]*mt[3][2] + mt[0][0]*mt[2][1]*mt[3][2] )
            / det;

 imt[3][2] = ( mt[0][2]*mt[1][1]*mt[3][0] - mt[0][1]*mt[1][2]*mt[3][0] -
               mt[0][2]*mt[1][0]*mt[3][1] + mt[0][0]*mt[1][2]*mt[3][1] +
               mt[0][1]*mt[1][0]*mt[3][2] - mt[0][0]*mt[1][1]*mt[3][2] )
            / det;

 imt[3][3] = (-mt[0][2]*mt[1][1]*mt[2][0] + mt[0][1]*mt[1][2]*mt[2][0] +
               mt[0][2]*mt[1][0]*mt[2][1] - mt[0][0]*mt[1][2]*mt[2][1] -
               mt[0][1]*mt[1][0]*mt[2][2] + mt[0][0]*mt[1][1]*mt[2][2] )
            / det;
}

/*========================  dspGetCamera  ========================*/
static void dspGetCamera( double *eyex, double *eyey, double *eyez,
                          double *refx, double *refy, double *refz,
                          double *vupx, double *vupy, double *vupz )
{
 double mt[4][4];           /* model view matrix */
 double im[4][4];           /* inverse model view matrix */
 double zex, zey, zez;      /* eye normalized z vector */

 glGetDoublev( GL_MODELVIEW_MATRIX, (double *)mt );

/* Get eye z and y normalized vectors (consider vup equal to eye y).
 * Note that OpenGL stores the model view matrix in column major order.
 */
 zex   = mt[0][2]; zey   = mt[1][2]; zez   = mt[2][2];
 *vupx = mt[0][1]; *vupy = mt[1][1]; *vupz = mt[2][1];

/* Invert model view matrix and compute eye location.
 */
 dspInvertMatrix( mt, im );
 *eyex = im[3][0] / im[3][3];
 *eyey = im[3][1] / im[3][3];
 *eyez = im[3][2] / im[3][3];

/* Compute a reference point at a unit distance from eye 
 * along view direction at the negative z side.
 */
 *refx = *eyex - zex;
 *refy = *eyey - zey;
 *refz = *eyez - zez;
}

/*======================  dspGetViewVolume  ======================*/
static int dspGetViewVolume( double *left,   double *right,
                             double *bottom, double *top,
                             double *front,  double *back )
{
 double projmt[4][4];       /* projection matrix */
 int    persp;              /* if true (1), doing perspective projection */

 glGetDoublev( GL_PROJECTION_MATRIX, (double *)projmt );

 if( projmt[2][3] != 0.0 )
  persp = 1;
 else
  persp = 0;

/* Get view volume according to type of projection.
 * Note that OpenGL stores the projection matrix in column-major order.
 */
 if( persp )      /* perspective projection */
 {
  *front  = projmt[3][2] / (projmt[2][2]-1.0);
  *back   = projmt[3][2] / (projmt[2][2]+1.0);
  *left   = (*front * (projmt[2][0]-1.0)) / projmt[0][0];
  *right  = (*front * (projmt[2][0]+1.0)) / projmt[0][0];
  *bottom = (*front * (projmt[2][1]-1.0)) / projmt[1][1];
  *top    = (*front * (projmt[2][1]+1.0)) / projmt[1][1];
 }
 else             /* orthographic projection */
 {
  *front  =  (projmt[3][2]+1.0) / projmt[2][2];
  *back   =  (projmt[3][2]-1.0) / projmt[2][2];
  *left   = -(1.0+projmt[3][0]) / projmt[0][0];
  *right  =  (1.0-projmt[3][0]) / projmt[0][0];
  *bottom = -(1.0+projmt[3][1]) / projmt[1][1];
  *top    =  (1.0-projmt[3][1]) / projmt[1][1];
 }

 return( persp );
}

/*============================  dspPrm  ==========================*/
static void dspPrm( Prm *prm )
{
 glColor3d( get_red( prmGetColor( prm) ),
            get_green( prmGetColor( prm) ),
            get_blue( prmGetColor( prm) ) );

/*** COMPLETE HERE: 43 ***/
}

/*========================  dspHighltPrm  ========================*/
static void dspHighltPrm( Prm *prm )
{
 glColor3d( 1.0, 0.0, 0.0 );   /* red color */

 glDisable( GL_LIGHTING );
/*** COMPLETE HERE: 44 ***/
 glEnable( GL_LIGHTING );
}


/*
** ---------------------------------------------------------------
** Public functions:
*/

/*===========================  dspInit  ==========================*/

void dspInit( void )
{
 GLfloat ambienteLight[] = { 0.35f, 0.35f, 0.35f, 1.0f };
 GLfloat diffuseLight[] = { 0.3f, 0.3f, 0.3f, 1.0f };
 HWND hwnd;
 HDC  hdc;

/* Initialize some OpenGL parameters.
 */
 glLightModeli( GL_LIGHT_MODEL_TWO_SIDE, GL_TRUE );
 glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambienteLight );
 glLightfv( GL_LIGHT0, GL_AMBIENT, ambienteLight );
 glLightfv( GL_LIGHT0, GL_DIFFUSE, diffuseLight );
 glEnable( GL_LIGHT0 );
 glEnable( GL_LIGHTING );
 glEnable( GL_COLOR_MATERIAL );
 glEnable( GL_DEPTH_TEST );
 glPointSize( 4.0 );

/* This is stuff for displaying help text on the data canvas.
 */
 hwnd = (HWND)IupGetAttribute( Odatascreen, IUP_WID );
 hdc  = GetDC( hwnd );
 if(hdc == 0)
   return;
 font_list_base = glGenLists( 256 );
 if( font_list_base == 0 )
  return;
 if( !wglUseFontBitmaps( hdc, 0, 255, font_list_base ) )
  return;
}

/*===========================  dspHelp  ===========================*/

void dspHelp( void )
{
 double win_xmin_help, win_xmax_help, win_ymin_help, win_ymax_help;

 win_xmin_help =  0.0;
 win_xmax_help = 10.0;
 win_ymin_help = -0.5;
 win_ymax_help = 10.0;

 glClearColor( 0.0, 0.0, 0.0, 1.0 );
 glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
 glMatrixMode( GL_PROJECTION );
 glLoadIdentity( );

 glOrtho( (GLdouble)win_xmin_help, (GLdouble)win_xmax_help,
          (GLdouble)win_ymin_help, (GLdouble)win_ymax_help,   0.0, 1.0 );
 glMatrixMode( GL_MODELVIEW );
 glLoadIdentity( );

 glDisable( GL_LIGHTING );
 glDisable( GL_LIGHT0);

 glColor3d( 0.0, 1.0, 0.0 );
 glListBase( font_list_base );

 glRasterPos2d( 0.5,  9.0 );
 glCallLists( (GLsizei)strlen( help_cmd[ 0] ), GL_UNSIGNED_BYTE, help_cmd[ 0] );
 glRasterPos2d( 0.5,  8.0 );
 glCallLists( (GLsizei)strlen( help_cmd[ 1] ), GL_UNSIGNED_BYTE, help_cmd[ 1] );
 glRasterPos2d( 0.5,  7.5 );
 glCallLists( (GLsizei)strlen( help_cmd[ 2] ), GL_UNSIGNED_BYTE, help_cmd[ 2] );
 glRasterPos2d( 0.5,  7.0 );
 glCallLists( (GLsizei)strlen( help_cmd[ 3] ), GL_UNSIGNED_BYTE, help_cmd[ 3] );
 glRasterPos2d( 0.5,  6.5 );
 glCallLists( (GLsizei)strlen( help_cmd[ 4] ), GL_UNSIGNED_BYTE, help_cmd[ 4] );
 glRasterPos2d( 0.5,  6.0 );
 glCallLists( (GLsizei)strlen( help_cmd[ 5] ), GL_UNSIGNED_BYTE, help_cmd[ 5] );
 glRasterPos2d( 0.5,  5.0 );
 glCallLists( (GLsizei)strlen( help_cmd[ 6] ), GL_UNSIGNED_BYTE, help_cmd[ 6] );
 glRasterPos2d( 0.5,  4.5 );
 glCallLists( (GLsizei)strlen( help_cmd[ 7] ), GL_UNSIGNED_BYTE, help_cmd[ 7] );
 glRasterPos2d( 0.5,  4.0 );
 glCallLists( (GLsizei)strlen( help_cmd[ 8] ), GL_UNSIGNED_BYTE, help_cmd[ 8] );
 glRasterPos2d( 0.5,  3.5 );
 glCallLists( (GLsizei)strlen( help_cmd[ 9] ), GL_UNSIGNED_BYTE, help_cmd[ 9] );
 glRasterPos2d( 0.5,  3.0 );
 glCallLists( (GLsizei)strlen( help_cmd[10] ), GL_UNSIGNED_BYTE, help_cmd[10] );
 glRasterPos2d( 0.5,  2.5 );
 glCallLists( (GLsizei)strlen( help_cmd[11] ), GL_UNSIGNED_BYTE, help_cmd[11] );
 glRasterPos2d( 0.5,  2.0 );
 glCallLists( (GLsizei)strlen( help_cmd[12] ), GL_UNSIGNED_BYTE, help_cmd[12] );
 glRasterPos2d( 0.5,  1.0 );
 glCallLists( (GLsizei)strlen( help_cmd[13] ), GL_UNSIGNED_BYTE, help_cmd[13] );
 glRasterPos2d( 0.5,  0.5 );
 glCallLists( (GLsizei)strlen( help_cmd[14] ), GL_UNSIGNED_BYTE, help_cmd[14] );
 glRasterPos2d( 0.5,  0.0 );
 glCallLists( (GLsizei)strlen( help_cmd[15] ), GL_UNSIGNED_BYTE, help_cmd[15] );

 glRasterPos2d( 4.0,  9.0 );
 glCallLists( (GLsizei)strlen( help_msg[ 0] ), GL_UNSIGNED_BYTE, help_msg[ 0] );
 glRasterPos2d( 4.0,  8.0 );
 glCallLists( (GLsizei)strlen( help_msg[ 1] ), GL_UNSIGNED_BYTE, help_msg[ 1] );
 glRasterPos2d( 4.0,  7.5 );
 glCallLists( (GLsizei)strlen( help_msg[ 2] ), GL_UNSIGNED_BYTE, help_msg[ 2] );
 glRasterPos2d( 4.0,  7.0 );
 glCallLists( (GLsizei)strlen( help_msg[ 3] ), GL_UNSIGNED_BYTE, help_msg[ 3] );
 glRasterPos2d( 4.0,  6.5 );
 glCallLists( (GLsizei)strlen( help_msg[ 4] ), GL_UNSIGNED_BYTE, help_msg[ 4] );
 glRasterPos2d( 4.0,  6.0 );
 glCallLists( (GLsizei)strlen( help_msg[ 5] ), GL_UNSIGNED_BYTE, help_msg[ 5] );
 glRasterPos2d( 4.0,  5.0 );
 glCallLists( (GLsizei)strlen( help_msg[ 6] ), GL_UNSIGNED_BYTE, help_msg[ 6] );
 glRasterPos2d( 4.0,  4.5 );
 glCallLists( (GLsizei)strlen( help_msg[ 7] ), GL_UNSIGNED_BYTE, help_msg[ 7] );
 glRasterPos2d( 4.0,  4.0 );
 glCallLists( (GLsizei)strlen( help_msg[ 8] ), GL_UNSIGNED_BYTE, help_msg[ 8] );
 glRasterPos2d( 4.0,  3.5 );
 glCallLists( (GLsizei)strlen( help_msg[ 9] ), GL_UNSIGNED_BYTE, help_msg[ 9] );
 glRasterPos2d( 4.0,  3.0 );
 glCallLists( (GLsizei)strlen( help_msg[10] ), GL_UNSIGNED_BYTE, help_msg[10] );
 glRasterPos2d( 4.0,  2.5 );
 glCallLists( (GLsizei)strlen( help_msg[11] ), GL_UNSIGNED_BYTE, help_msg[11] );
 glRasterPos2d( 4.0,  2.0 );
 glCallLists( (GLsizei)strlen( help_msg[12] ), GL_UNSIGNED_BYTE, help_msg[12] );
 glRasterPos2d( 4.0,  1.0 );
 glCallLists( (GLsizei)strlen( help_msg[13] ), GL_UNSIGNED_BYTE, help_msg[13] );
 glRasterPos2d( 4.0,  0.5 );
 glCallLists( (GLsizei)strlen( help_msg[14] ), GL_UNSIGNED_BYTE, help_msg[14] );
 glRasterPos2d( 4.0,  0.0 );
 glCallLists( (GLsizei)strlen( help_msg[15] ), GL_UNSIGNED_BYTE, help_msg[15] );

 glEnable( GL_LIGHTING );
}

/*==========================  dspModel  ==========================*/

void dspModel( void ) 
{
 Prm *prm;

 for( prm = prmFirst( ); prm != NULL; prm = prmNext( prm ) )
 {
  if( prmCheckSelected( prm ) )
  {
   glEnable( GL_POLYGON_OFFSET_FILL );
   glPolygonOffset( 1.0, 1.0 );
   dspPrm( prm );
   glDisable( GL_POLYGON_OFFSET_FILL );
   dspHighltPrm( prm );
  }
  else
  {
   dspPrm( prm );
  }
 }
}

/*=========================  dspZbfModel  ========================*/

int dspZbfModel( void *Gzbuffercanvas )
{
 int    width, height;      /* zbuffer sizes */
 double eyex, eyey, eyez;   /* camera parameters */
 double refx, refy, refz;
 double vupx, vupy, vupz;
 double left, right;        /* view volume parameters */
 double bottom, top;
 double front, back;
 int    persp;              /* if true (1), doing perspective projection */
 Prm    *prm;
 unsigned char gray_intensity;

 cdActivate( Gzbuffercanvas );
 cdGetCanvasSize( &width, &height, 0L, 0L );

/* Set gray background color and clear canvas.
 */
 gray_intensity = (unsigned char)(0.75 * 255.0);
 cdBackground( dspEncodeColor(gray_intensity, gray_intensity, gray_intensity) );
 cdClear( );

/* Get camera and view volume parameters.
 */
 dspGetCamera( &eyex, &eyey, &eyez, &refx, &refy, &refz, &vupx, &vupy, &vupz );
 persp = dspGetViewVolume( &left, &right, &bottom, &top, &front, &back );

/* Compute normalized view vector.
 */
 view_vector.x = refx - eyex;
 view_vector.y = refy - eyey;
 view_vector.z = refz - eyez;
 dspVecUnit( &view_vector, &view_vector );

/* Build a 3D transformation that transforms from world (object)
 * coordinates to normalized screen coordinates (the view frustum
 * is transformed into a cube of size 2 and center at origin).
 * For perspective projection, place the projection plane at
 * the front view volume plane (OpenGL does this way).
 */
/*** COMPLETE HERE: 45 ***/

/* Display the model in the zbuffer canvas.
 */
/*** COMPLETE HERE: 46 ***/

 return( 1 );
}

/*=======================  dspZbfBeginPoly  ======================*/

void dspZbfBeginPoly( long int color, double nx, double ny, double nz )
{
 Vec3d normal;          /* face normal vector */
 long int shaded_color; /* face color with modified intensity */

 normal.x = nx;
 normal.y = ny;
 normal.z = nz;
 shaded_color = dspShadeColor( &normal, &view_vector, color );
 zbfBeginPoly( shaded_color );
}

/*=========================  dspZbfVertex  =======================*/

void dspZbfVertex( double x, double y, double z )
{
 t3dTransform( &x, &y, &z );
 zbfVertex( x, y, z );
}

/*========================  dspZbfEndPoly  =======================*/

void dspZbfEndPoly( void )
{
 zbfEndPoly( );
}

/*=======================  dspGetPickRay  ========================*/

void dspGetPickRay( int x, int y,
                    double *frontx, double *fronty, double *frontz,
                    double *backx,  double *backy,  double *backz )
{
 double modelMatrix[16];
 double projMatrix[16];
 int    viewport[4];
 int    h;
 double winx, winy, winz;

 glGetDoublev( GL_MODELVIEW_MATRIX, modelMatrix );
 glGetDoublev( GL_PROJECTION_MATRIX, projMatrix );
 glGetIntegerv( GL_VIEWPORT, viewport );

/* Transform from mouse raster position in canvas to 
 * GL viewport position.  It is assumed that the GL 
 * viewport takes the entire canvas.
 */
 h = viewport[3];
 winx = (double)x;
 winy = (double)y;

/* Find ray point in object space at front (near) plane.
 */
 winz = 0.0;
 gluUnProject( winx, winy, winz, modelMatrix, projMatrix,
               viewport, frontx, fronty, frontz );

/* Find ray point in object space at back (far) plane.
 */
 winz = 1.0;
 gluUnProject( winx, winy, winz, modelMatrix, projMatrix,
               viewport, backx, backy, backz );
}

 double winx, winy, winz;

 glGetDoublev( GL_MODELVIEW_MATRIX, modelMatrix );
 glGetDoublev( GL_PROJECTION_MATRIX, projMatrix );
 glGetIntegerv( GL_VIEWPORT, viewport );

/* Transform from mouse raster position in canvas to 
 * GL viewport position.  It is assumed that the GL 
 * viewport takes the entire canvas.
 */
 h = viewport[3];
 winx = (double)x;
 winy = (double)y;

/* Find ray point in object space at front (near) plane.
 */
 winz = 0.0;
 gluUnProject( winx, winy, winz, modelMatrix, projMatrix,
               viewport, frontx, fronty, frontz );

/* Find ray point in object space at back (far) plane.
 */
 winz = 1.0;
 gluUnProject( winx, winy, winz, modelMatrix, projMatrix,
               viewport, backx, backy, backz );
}

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