ico.c

   1 /**
   2  * @file ico.c
   3  * @brief The icosahedron 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 "ico.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 #include <string.h>
  32
  33 #define X .525731112119133606f
  34 #define Z .850650808352039932f
  35
  36 static GLfloat vdata [12][3] = {
  37 {-X, 0.0, Z}, {X, 0.0, Z}, {-X, 0.0, -Z},
  38 {X, 0.0, -Z}, {0.0, Z, X}, {0.0, Z, -X},
  39 {0.0, -Z, X}, {0.0, -Z, -X}, {Z, X, 0.0},
  40 {-Z, X, 0.0}, {Z, -X, 0.0}, {-Z, -X, 0.0}
  41 };
  42
  43 static GLuint tindices [20][3] = {
  44  {1, 4, 0}, {4, 9, 0},
  45  {4, 5, 9}, {8, 5, 4},
  46  {1, 8, 4}, {1, 10, 8},
  47  {10, 3, 8}, {8, 3, 5},
  48  {3, 2, 5}, {3, 7, 2},
  49  {3, 10, 7}, {10, 6, 7},
  50  {6, 11, 7}, {6, 0, 11},
  51  {6, 1, 0}, {10, 1, 6},
  52  {11, 0, 9}, {2, 11, 9},
  53  {5, 2, 9}, {11, 2, 7}
  54 };
  55
  56 void dup3(float *a,float *b)
  57 {
  58         *a++=*b++;
  59         *a++=*b++;
  60         *a=*b;
  61 }
  62
  63 void mid(float *a,float *b,float *c)
  64 {
  65 float d;
  66         a[0]=(*b++ + *c++)/2.0f;
  67         a[1]=(*b++ + *c++)/2.0f;
  68         a[2]=(*b + *c)/2.0f;
  69         d=1.0f/sqrtf(a[0]*a[0]+a[1]*a[1]+a[2]*a[2]);
  70         a[0]*=d;
  71         a[1]*=d;
  72         a[2]*=d;
  73
  74 }
  75
  76
  77 void makeicosahedron(int sub,float scale)
  78 {
  79 float tris[65536][3];
  80 int i,j,p,q;
  81 int numt;
  82         numt=0;
  83         j=0;
  84         for(i=0;i<20;++i)
  85         {
  86                 p=tindices[i][0];
  87                 tris[j][0]=vdata[p][0];
  88                 tris[j][1]=vdata[p][1];
  89                 tris[j][2]=vdata[p][2];
  90                 ++j;
  91                 p=tindices[i][1];
  92                 tris[j][0]=vdata[p][0];
  93                 tris[j][1]=vdata[p][1];
  94                 tris[j][2]=vdata[p][2];
  95                 ++j;
  96                 p=tindices[i][2];
  97                 tris[j][0]=vdata[p][0];
  98                 tris[j][1]=vdata[p][1];
  99                 tris[j][2]=vdata[p][2];
 100                 ++j;
 101                 ++numt;
 102         }
 103         while(sub--)
 104         {
 105                 j=numt;
 106                 numt<<=2;
 107                 while(--j>=0)
 108                 {
 109                         float ttt[3][3];
 110                         p=j*3;
 111                         q=p*4;
 112                         memcpy(ttt,tris[p],sizeof(ttt));
 113
 114                         mid(tris[q++],ttt[0],ttt[1]);
 115                         dup3(tris[q++],ttt[1]);
 116                         mid(tris[q++],ttt[1],ttt[2]);
 117
 118                         dup3(tris[q++],ttt[0]);
 119                         mid(tris[q++],ttt[0],ttt[1]);
 120                         mid(tris[q++],ttt[0],ttt[2]);
 121
 122                         mid(tris[q++],ttt[1],ttt[2]);
 123                         dup3(tris[q++],ttt[2]);
 124                         mid(tris[q++],ttt[0],ttt[2]);
 125
 126                         mid(tris[q++],ttt[0],ttt[1]);
 127                         mid(tris[q++],ttt[1],ttt[2]);
 128                         mid(tris[q++],ttt[0],ttt[2]);
 129
 130                 }
 131         }
 132         glEnable(GL_NORMALIZE);
 133         p=0;
 134         glBegin(GL_TRIANGLES);
 135         for(i=0;i<numt;++i)
 136         {
 137                 norm2(tris[p],tris[p+1],tris[p+2]);
 138                 glVertex3f(tris[p][0]*scale,tris[p][1]*scale,tris[p][2]*scale);
 139                 ++p;
 140                 glVertex3f(tris[p][0]*scale,tris[p][1]*scale,tris[p][2]*scale);
 141                 ++p;
 142                 glVertex3f(tris[p][0]*scale,tris[p][1]*scale,tris[p][2]*scale);
 143                 ++p;
 144         }
 145         glEnd();
 146 }
 147