diamond.c

   1 /**
   2  * @file diamond.c
   3  * @brief The blood diamond module.
   4  *
   5  * Copyright 2001, 2008 David Ashley  <dashxdr@gmail.com>
   6  * Copyright 2008 Stephen M. Webb  <stephen.webb@bregmasoft.ca>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of Version 2 of the GNU General Public License as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21 #include "diamond.h"
  22
  23 #if defined(_WIN32) && !defined(__CYGWIN__)
  24 # define WIN32_LEAN_AND_MEAN 1
  25 # include <windows.h>
  26 #endif
  27
  28 #include <GL/gl.h>
  29 #include <math.h>
  30 #include "misc.h"
  31
  32
  33 /** Blood diamonds */
  34 void makediamond(float size)
  35 {
  36 #define DSIDES 9
  37 float x[DSIDES],z[DSIDES];
  38 int i,j,t,o=0;
  39 float a;
  40 float c,s,d,h;
  41 float p2;
  42         for(i=0;i<DSIDES;++i)
  43         {
  44                 a=i*PI*2.0f/DSIDES;
  45                 x[i]=cosf(a)*size;
  46                 z[i]=sinf(a)*size;
  47         }
  48
  49         glEnable(GL_NORMALIZE);
  50
  51         p2=size*0.5f;
  52         for(t=0;t<2;++t)
  53         {
  54                 float p1=(t&1) ? -size : size;
  55
  56                 glBegin(GL_TRIANGLE_FAN);
  57                 glVertex3f(0.0, p1, 0.0);
  58                 d=(!t) ? size-p2 : size+p2;
  59                 h=sqrtf(size*size+d*d);
  60                 c=(!t) ? size/h : -size/h;
  61                 s=d/h;
  62                 for(i=0;i<DSIDES+1;++i)
  63                 {
  64                         j=(i<DSIDES) ? i : i-DSIDES;
  65                         if(!t) j=DSIDES-1-j;
  66                         if(i)
  67                                 glNormal3f((x[j]+x[o])/2.0f*s,size*c,(z[j]+z[o])/2.0f*s);
  68                         glVertex3f(x[j],p2,z[j]);
  69                         o=j;
  70                 }
  71                 glEnd();
  72         }
  73 }
  74
  75