src/ball.c

   1 /*
   2  *   Copyright (C) 2003 Robert Kooima
   3  *
   4  *   SUPER EMPTY BALL is free software; you can redistribute it and/or modify
   5  *   it under the terms of the GNU General Public License as published by the
   6  *   Free Software Foundation;  either version 2 of the  License, or (at your
   7  *   option) any later version.
   8  *
   9  *   This program  is distributed  in the  hope that it  will be  useful, but
  10  *   WITHOUT   ANY   WARRANTY;  without   even   the   implied  warranty   of
  11  *   MERCHANTABILITY  or  FITNESS FOR  A  PARTICULAR  PURPOSE.   See the  GNU
  12  *   General Public License for more details.
  13  */
  14
  15 #include "gl.h"
  16 #include "vec3.h"
  17
  18 /*---------------------------------------------------------------------------*/
  19
  20 static void section(int d,
  21                     const double p0[3], const double c0[4],
  22                     const double p1[3], const double c1[4],
  23                     const double p2[3], const double c2[4])
  24 {
  25     if (d == 0)
  26     {
  27         glColor4dv(c0);
  28         glNormal3dv(p0);
  29         glVertex3dv(p0);
  30
  31         glColor4dv(c1);
  32         glNormal3dv(p1);
  33         glVertex3dv(p1);
  34
  35         glColor4dv(c2);
  36         glNormal3dv(p2);
  37         glVertex3dv(p2);
  38     }
  39     else
  40     {
  41         double p01[3], p12[3], p20[3];
  42         double c01[4], c12[4], c20[4];
  43
  44         v_mid(p01, p0, p1);
  45         v_mid(p12, p1, p2);
  46         v_mid(p20, p2, p0);
  47
  48         v_nrm(p01, p01);
  49         v_nrm(p12, p12);
  50         v_nrm(p20, p20);
  51
  52         c01[0] = (c0[0] + c1[0]) / 2.0;
  53         c01[1] = (c0[1] + c1[1]) / 2.0;
  54         c01[2] = (c0[2] + c1[2]) / 2.0;
  55         c01[3] = (c0[3] + c1[3]) / 2.0;
  56
  57         c12[0] = (c1[0] + c2[0]) / 2.0;
  58         c12[1] = (c1[1] + c2[1]) / 2.0;
  59         c12[2] = (c1[2] + c2[2]) / 2.0;
  60         c12[3] = (c1[3] + c2[3]) / 2.0;
  61
  62         c20[0] = (c2[0] + c0[0]) / 2.0;
  63         c20[1] = (c2[1] + c0[1]) / 2.0;
  64         c20[2] = (c2[2] + c0[2]) / 2.0;
  65         c20[3] = (c2[3] + c0[3]) / 2.0;
  66
  67         section(d - 1, p0,  c0,  p01, c01, p20, c20);
  68         section(d - 1, p01, c01, p1,  c1,  p12, c12);
  69         section(d - 1, p20, c20, p12, c12, p2,  c2);
  70         section(d - 1, p01, c01, p12, c12, p20, c20);
  71     }
  72 }
  73
  74 GLuint ball_init(int d)
  75 {
  76     static const float s[3] = { 1.0f, 1.0f, 1.0f };
  77
  78     static const double p[6][3] = {
  79         { +1.0,  0.0,  0.0 },
  80         { -1.0,  0.0,  0.0 },
  81         {  0.0, +1.0,  0.0 },
  82         {  0.0, -1.0,  0.0 },
  83         {  0.0,  0.0, +1.0 },
  84         {  0.0,  0.0, -1.0 },
  85     };
  86     static const double c[2][4] = {
  87         { 0.0, 0.0, 0.0, 0.5 },
  88         { 1.0, 1.0, 1.0, 0.5 },
  89     };
  90
  91     GLuint list = glGenLists(1);
  92
  93     glNewList(list, GL_COMPILE);
  94     glPushAttrib(GL_LIGHTING_BIT);
  95     {
  96         glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR,  s);
  97         glMaterialf (GL_FRONT_AND_BACK, GL_SHININESS, 64.0f);
  98
  99         glEnable(GL_COLOR_MATERIAL);
 100
 101         glBegin(GL_TRIANGLES);
 102         {
 103             section(d, p[4], c[0], p[0], c[0], p[2], c[0]);
 104             section(d, p[0], c[1], p[5], c[1], p[2], c[1]);
 105             section(d, p[5], c[0], p[1], c[0], p[2], c[0]);
 106             section(d, p[1], c[1], p[4], c[1], p[2], c[1]);
 107
 108             section(d, p[0], c[1], p[4], c[1], p[3], c[1]);
 109             section(d, p[5], c[0], p[0], c[0], p[3], c[0]);
 110             section(d, p[1], c[1], p[5], c[1], p[3], c[1]);
 111             section(d, p[4], c[0], p[1], c[0], p[3], c[0]);
 112         }
 113         glEnd();
 114     }
 115     glPopAttrib();
 116     glEndList();
 117
 118     return list;
 119 }
 120
 121 void ball_draw(GLuint list, double r,
 122                const double p[3],
 123                const double e[3][3])
 124 {
 125     double M[16];
 126
 127     m_basis(M, e[0], e[1], e[2]);
 128
 129     glPushAttrib(GL_DEPTH_BUFFER_BIT);
 130     {
 131         glDepthMask(GL_FALSE);
 132
 133         glDisable(GL_TEXTURE_2D);
 134         glPushMatrix();
 135         {
 136             glTranslated(p[0], p[1], p[2]);
 137             glMultMatrixd(M);
 138             glScaled(r, r, r);
 139
 140             glCullFace(GL_FRONT);
 141             glCallList(list);
 142             glCullFace(GL_BACK);
 143             glCallList(list);
 144         }
 145         glPopMatrix();
 146         glEnable(GL_TEXTURE_2D);
 147     }
 148     glPopAttrib();
 149 }
 150
 151 /*---------------------------------------------------------------------------*/
 152