/*
 * Copyright (c) 1993-1997, Silicon Graphics, Inc.
 * ALL RIGHTS RESERVED 
 * Permission to use, copy, modify, and distribute this software for 
 * any purpose and without fee is hereby granted, provided that the above
 * copyright notice appear in all copies and that both the copyright notice
 * and this permission notice appear in supporting documentation, and that 
 * the name of Silicon Graphics, Inc. not be used in advertising
 * or publicity pertaining to distribution of the software without specific,
 * written prior permission. 
 *
 * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
 * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
 * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
 * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
 * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
 * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
 * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
 * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
 * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
 * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
 * 
 * US Government Users Restricted Rights 
 * Use, duplication, or disclosure by the Government is subject to
 * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
 * (c)(1)(ii) of the Rights in Technical Data and Computer Software
 * clause at DFARS 252.227-7013 and/or in similar or successor
 * clauses in the FAR or the DOD or NASA FAR Supplement.
 * Unpublished-- rights reserved under the copyright laws of the
 * United States.  Contractor/manufacturer is Silicon Graphics,
 * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
 *
 * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
 */

/*
 * select.c
 * This is an illustration of the selection mode and 
 * name stack, which detects whether objects which collide 
 * with a viewing volume.  First, four triangles and a 
 * rectangular box representing a viewing volume are drawn 
 * (drawScene routine).  The green triangle and yellow 
 * triangles appear to lie within the viewing volume, but 
 * the red triangle appears to lie outside it.  Then the 
 * selection mode is entered (selectObjects routine).  
 * Drawing to the screen ceases.  To see if any collisions 
 * occur, the four triangles are called.  In this example, 
 * the green triangle causes one hit with the name 1, and 
 * the yellow triangles cause one hit with the name 3.
 */

#include <windows.h>

#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glaux.h>

#include <stdio.h>

#define BUFSIZE 512 
  
void drawTriangle(GLfloat x1,GLfloat y1,GLfloat x2,GLfloat y2,GLfloat x3,GLfloat y3,GLfloat z) { 
  glBegin(GL_TRIANGLES); 
  glVertex3f(x1,y1,z); 
  glVertex3f(x2,y2,z); 
  glVertex3f(x3,y3,z); 
  glEnd(); 
} 
  
void drawViewVol(GLfloat x1,GLfloat x2,GLfloat y1,GLfloat y2,GLfloat z1,GLfloat z2) { 
  glColor3f(1.0,1.0,1.0); 
  glBegin(GL_LINE_LOOP); 
  glVertex3f(x1,y1,-z1); 
  glVertex3f(x2,y1,-z1); 
  glVertex3f(x2,y2,-z1); 
  glVertex3f(x1,y2,-z1); 
  glEnd(); 
  glBegin(GL_LINE_LOOP); 
  glVertex3f(x1,y1,-z2); 
  glVertex3f(x2,y1,-z2); 
  glVertex3f(x2,y2,-z2); 
  glVertex3f(x1,y2,-z2); 
  glEnd(); 
  glBegin(GL_LINES); 
  glVertex3f(x1,y1,-z1); 
  glVertex3f(x1,y1,-z2); 
  glVertex3f(x1,y2,-z1); 
  glVertex3f(x1,y2,-z2); 
  glVertex3f(x2,y1,-z1); 
  glVertex3f(x2,y1,-z2); 
  glVertex3f(x2,y2,-z1); 
  glVertex3f(x2,y2,-z2); 
  glEnd(); 
} 
  
void drawScene(void) { 
  glMatrixMode(GL_PROJECTION); 
  glLoadIdentity(); 
  gluPerspective(40.0,1.333,0.01,100.0); 
  glMatrixMode(GL_MODELVIEW); 
  glLoadIdentity(); 
  gluLookAt(7.5,7.5,12.5,2.5,2.5,-5.0,0.0,1.0,0.0); 
  glColor3f(0.0,1.0,0.0); 
  drawTriangle(2.0,2.0,3.0,2.0,2.5,3.0,-5.0); 
  glColor3f(1.0,0.0,0.0); 
  drawTriangle(2.0,7.0,3.0,7.0,2.5,8.0,-5.0); 
  glColor3f(1.0,1.0,0.0); 
  drawTriangle(2.0,2.0,3.0,2.0,2.5,3.0,0.0); 
  drawTriangle(2.0,2.0,3.0,2.0,2.5,3.0,-10.); 
  drawViewVol(0.0,5.0,0.0,5.0,0.0,10.0); 
} 
  
void processHits(GLint hits,GLuint buffer[]) { 
  int i,j; 
  GLuint names,*ptr; 
  printf("hits = %d\n",hits); 
  ptr =(GLuint *) buffer; 
  for ( i = 0 ; i < hits ; i++ ) { 
    names = *ptr; 
    printf("number of names=%d\n",names); 
    ptr++; 
    printf(" z1 is %u;",*ptr); 
    ptr++; 
    printf(" z2 is %u\n",*ptr); 
    ptr++; 
    printf(" the name is "); 
    for( j = 0 ; j < (int) names ; j++ ) 
      printf("%d ",*ptr); 
    ptr++; 
    printf("\n"); } 
} 
  
void myinit(void) { 
  glDepthFunc(GL_LESS); 
  glEnable(GL_DEPTH_TEST); 
  glShadeModel(GL_FLAT); 
} 
  
void selectObjects(void) { 
  GLuint selectBuf[BUFSIZE]; 
  GLint hits; 
  glSelectBuffer(BUFSIZE,selectBuf); 
  glRenderMode(GL_SELECT); 
  glInitNames(); 
  glPushName(-1); 
  glPushMatrix(); 
  glMatrixMode(GL_PROJECTION); 
  glLoadIdentity(); 
  glOrtho(0.0,5.0,0.0,5.0,0.0,10.0); 
  glMatrixMode(GL_MODELVIEW); 
  glLoadIdentity(); 
  glLoadName(1); 
  drawTriangle(2.0,2.0,3.0,2.0,2.5,3.0,-5.0); 
  glLoadName(2); 
  drawTriangle(2.0,7.0,3.0,7.0,2.5,8.0,-5.0); 
  glLoadName(3); 
  drawTriangle(2.0,2.0,3.0,2.0,2.5,3.0,0.0); 
  drawTriangle(2.0,2.0,3.0,2.0,2.5,3.0,-10.); 
  glPopMatrix(); 
  glFlush(); 
  hits = glRenderMode(GL_RENDER); 
  processHits(hits,selectBuf); 
} 
  
void CALLBACK display(void) { 
  glClearColor(0.0,0.0,0.0,0.0); 
  glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT); 
  drawScene(); 
  selectObjects(); 
  glFlush(); 
} 
  
void main(void) { 
  auxInitDisplayMode(AUX_SINGLE|AUX_RGB|AUX_DEPTH); 
  auxInitPosition(0,0,200,200); 
  auxInitWindow("Sélection d'objets"); 
  myinit(); 
  auxMainLoop(display); 
}