text: /*
   * Copyright 1994-1997 Mark Kilgard, All rights reserved.
   * Distributed under the terms of the MIT License.
   *
   * GPL licensing not permitted.
   *
   * Authors:
   *      Mark Kilgard
   */
  
  /**
  (c) Copyright 1993, 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  Unpublished-- rights reserved under the copyright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(TM) is a trademark of Silicon Graphics, Inc.
  */
  
  #include <math.h>
  #include "glutint.h"
  
  /* Some <math.h> files do not define M_PI... */
  #ifndef M_PI
  #define M_PI 3.14159265358979323846
  #endif
  
  static GLUquadricObj *quadObj;
  
  #define QUAD_OBJ_INIT() { if(!quadObj) initQuadObj(); }
  
  static void
  initQuadObj(void)
  {
    quadObj = gluNewQuadric();
    if (!quadObj)
      __glutFatalError("out of memory.");
  }
  
  /* CENTRY */
  void APIENTRY
  glutWireSphere(GLdouble radius, GLint slices, GLint stacks)
  {
    QUAD_OBJ_INIT();
    gluQuadricDrawStyle(quadObj, GLU_LINE);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    /* If we ever changed/used the texture or orientation state
       of quadObj, we'd need to change it to the defaults here
       with gluQuadricTexture and/or gluQuadricOrientation. */
    gluSphere(quadObj, radius, slices, stacks);
  }
  
  void APIENTRY
  glutSolidSphere(GLdouble radius, GLint slices, GLint stacks)
  {
    QUAD_OBJ_INIT();
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    /* If we ever changed/used the texture or orientation state
       of quadObj, we'd need to change it to the defaults here
       with gluQuadricTexture and/or gluQuadricOrientation. */
    gluSphere(quadObj, radius, slices, stacks);
  }
  
  void APIENTRY
  glutWireCone(GLdouble base, GLdouble height,
    GLint slices, GLint stacks)
  {
    QUAD_OBJ_INIT();
    gluQuadricDrawStyle(quadObj, GLU_LINE);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    /* If we ever changed/used the texture or orientation state
       of quadObj, we'd need to change it to the defaults here
       with gluQuadricTexture and/or gluQuadricOrientation. */
    gluCylinder(quadObj, base, 0.0, height, slices, stacks);
  }
  
  void APIENTRY
  glutSolidCone(GLdouble base, GLdouble height,
    GLint slices, GLint stacks)
  {
    QUAD_OBJ_INIT();
    gluQuadricDrawStyle(quadObj, GLU_FILL);
    gluQuadricNormals(quadObj, GLU_SMOOTH);
    /* If we ever changed/used the texture or orientation state
       of quadObj, we'd need to change it to the defaults here
       with gluQuadricTexture and/or gluQuadricOrientation. */
    gluCylinder(quadObj, base, 0.0, height, slices, stacks);
  }
  
  /* ENDCENTRY */
  
  static void
  drawBox(GLfloat size, GLenum type)
  {
    static GLfloat n[6][3] =
    {
      {-1.0, 0.0, 0.0},
      {0.0, 1.0, 0.0},
      {1.0, 0.0, 0.0},
      {0.0, -1.0, 0.0},
      {0.0, 0.0, 1.0},
      {0.0, 0.0, -1.0}
    };
    static GLint faces[6][4] =
    {
      {0, 1, 2, 3},
      {3, 2, 6, 7},
      {7, 6, 5, 4},
      {4, 5, 1, 0},
      {5, 6, 2, 1},
      {7, 4, 0, 3}
    };
    GLfloat v[8][3];
    GLint i;
  
    v[0][0] = v[1][0] = v[2][0] = v[3][0] = -size / 2;
    v[4][0] = v[5][0] = v[6][0] = v[7][0] = size / 2;
    v[0][1] = v[1][1] = v[4][1] = v[5][1] = -size / 2;
    v[2][1] = v[3][1] = v[6][1] = v[7][1] = size / 2;
    v[0][2] = v[3][2] = v[4][2] = v[7][2] = -size / 2;
    v[1][2] = v[2][2] = v[5][2] = v[6][2] = size / 2;
  
    for (i = 5; i >= 0; i--) {
      glBegin(type);
      glNormal3fv(&n[i][0]);
      glVertex3fv(&v[faces[i][0]][0]);
      glVertex3fv(&v[faces[i][1]][0]);
      glVertex3fv(&v[faces[i][2]][0]);
      glVertex3fv(&v[faces[i][3]][0]);
      glEnd();
    }
  }
  
  /* CENTRY */
  void APIENTRY
  glutWireCube(GLdouble size)
  {
    drawBox(size, GL_LINE_LOOP);
  }
  
  void APIENTRY
  glutSolidCube(GLdouble size)
  {
    drawBox(size, GL_QUADS);
  }
  
  /* ENDCENTRY */
  
  static void
  doughnut(GLfloat r, GLfloat R, GLint nsides, GLint rings)
  {
    int i, j;
    GLfloat theta, phi, theta1;
    GLfloat cosTheta, sinTheta;
    GLfloat cosTheta1, sinTheta1;
    GLfloat ringDelta, sideDelta;
  
    ringDelta = 2.0 * M_PI / rings;
    sideDelta = 2.0 * M_PI / nsides;
  
    theta = 0.0;
    cosTheta = 1.0;
    sinTheta = 0.0;
    for (i = rings - 1; i >= 0; i--) {
      theta1 = theta + ringDelta;
      cosTheta1 = cos(theta1);
      sinTheta1 = sin(theta1);
      glBegin(GL_QUAD_STRIP);
      phi = 0.0;
      for (j = nsides; j >= 0; j--) {
        GLfloat cosPhi, sinPhi, dist;
  
        phi += sideDelta;
        cosPhi = cos(phi);
        sinPhi = sin(phi);
        dist = R + r * cosPhi;
  
        glNormal3f(cosTheta1 * cosPhi, -sinTheta1 * cosPhi, sinPhi);
        glVertex3f(cosTheta1 * dist, -sinTheta1 * dist, r * sinPhi);
        glNormal3f(cosTheta * cosPhi, -sinTheta * cosPhi, sinPhi);
        glVertex3f(cosTheta * dist, -sinTheta * dist,  r * sinPhi);
      }
      glEnd();
      theta = theta1;
      cosTheta = cosTheta1;
      sinTheta = sinTheta1;
    }
  }
  
  /* CENTRY */
  void APIENTRY
  glutWireTorus(GLdouble innerRadius, GLdouble outerRadius,
    GLint nsides, GLint rings)
  {
    glPushAttrib(GL_POLYGON_BIT);
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
    doughnut(innerRadius, outerRadius, nsides, rings);
    glPopAttrib();
  }
  
  void APIENTRY
  glutSolidTorus(GLdouble innerRadius, GLdouble outerRadius,
    GLint nsides, GLint rings)
  {
    doughnut(innerRadius, outerRadius, nsides, rings);
  }
  
  /* ENDCENTRY */
  
  static GLfloat dodec[20][3];
  
  static void
  initDodecahedron(void)
  {
    GLfloat alpha, beta;
  
    alpha = sqrt(2.0 / (3.0 + sqrt(5.0)));
    beta = 1.0 + sqrt(6.0 / (3.0 + sqrt(5.0)) -
      2.0 + 2.0 * sqrt(2.0 / (3.0 + sqrt(5.0))));
    /* *INDENT-OFF* */
    dodec[0][0] = -alpha; dodec[0][1] = 0; dodec[0][2] = beta;
    dodec[1][0] = alpha; dodec[1][1] = 0; dodec[1][2] = beta;
    dodec[2][0] = -1; dodec[2][1] = -1; dodec[2][2] = -1;
    dodec[3][0] = -1; dodec[3][1] = -1; dodec[3][2] = 1;
    dodec[4][0] = -1; dodec[4][1] = 1; dodec[4][2] = -1;
    dodec[5][0] = -1; dodec[5][1] = 1; dodec[5][2] = 1;
    dodec[6][0] = 1; dodec[6][1] = -1; dodec[6][2] = -1;
    dodec[7][0] = 1; dodec[7][1] = -1; dodec[7][2] = 1;
    dodec[8][0] = 1; dodec[8][1] = 1; dodec[8][2] = -1;
    dodec[9][0] = 1; dodec[9][1] = 1; dodec[9][2] = 1;
    dodec[10][0] = beta; dodec[10][1] = alpha; dodec[10][2] = 0;
    dodec[11][0] = beta; dodec[11][1] = -alpha; dodec[11][2] = 0;
    dodec[12][0] = -beta; dodec[12][1] = alpha; dodec[12][2] = 0;
    dodec[13][0] = -beta; dodec[13][1] = -alpha; dodec[13][2] = 0;
    dodec[14][0] = -alpha; dodec[14][1] = 0; dodec[14][2] = -beta;
    dodec[15][0] = alpha; dodec[15][1] = 0; dodec[15][2] = -beta;
    dodec[16][0] = 0; dodec[16][1] = beta; dodec[16][2] = alpha;
    dodec[17][0] = 0; dodec[17][1] = beta; dodec[17][2] = -alpha;
    dodec[18][0] = 0; dodec[18][1] = -beta; dodec[18][2] = alpha;
    dodec[19][0] = 0; dodec[19][1] = -beta; dodec[19][2] = -alpha;
    /* *INDENT-ON* */
  
  }
  
  #define DIFF3(_a,_b,_c) { \
      (_c)[0] = (_a)[0] - (_b)[0]; \
      (_c)[1] = (_a)[1] - (_b)[1]; \
      (_c)[2] = (_a)[2] - (_b)[2]; \
  }
  
  static void
  crossprod(GLfloat v1[3], GLfloat v2[3], GLfloat prod[3])
  {
    GLfloat p[3];         /* in case prod == v1 or v2 */
  
    p[0] = v1[1] * v2[2] - v2[1] * v1[2];
    p[1] = v1[2] * v2[0] - v2[2] * v1[0];
    p[2] = v1[0] * v2[1] - v2[0] * v1[1];
    prod[0] = p[0];
    prod[1] = p[1];
    prod[2] = p[2];
  }
  
  static void
  normalize(GLfloat v[3])
  {
    GLfloat d;
  
    d = sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
    if (d == 0.0) {
      __glutWarning("normalize: zero length vector");
      v[0] = d = 1.0;
    }
    d = 1 / d;
    v[0] *= d;
    v[1] *= d;
    v[2] *= d;
  }
  
  static void
  pentagon(int a, int b, int c, int d, int e, GLenum shadeType)
  {
    GLfloat n0[3], d1[3], d2[3];
  
    DIFF3(dodec[a], dodec[b], d1);
    DIFF3(dodec[b], dodec[c], d2);
    crossprod(d1, d2, n0);
    normalize(n0);
  
    glBegin(shadeType);
    glNormal3fv(n0);
    glVertex3fv(&dodec[a][0]);
    glVertex3fv(&dodec[b][0]);
    glVertex3fv(&dodec[c][0]);
    glVertex3fv(&dodec[d][0]);
    glVertex3fv(&dodec[e][0]);
    glEnd();
  }
  
  static void
  dodecahedron(GLenum type)
  {
    static int inited = 0;
  
    if (inited == 0) {
      inited = 1;
      initDodecahedron();
    }
    pentagon(0, 1, 9, 16, 5, type);
    pentagon(1, 0, 3, 18, 7, type);
    pentagon(1, 7, 11, 10, 9, type);
    pentagon(11, 7, 18, 19, 6, type);
    pentagon(8, 17, 16, 9, 10, type);
    pentagon(2, 14, 15, 6, 19, type);
    pentagon(2, 13, 12, 4, 14, type);
    pentagon(2, 19, 18, 3, 13, type);
    pentagon(3, 0, 5, 12, 13, type);
    pentagon(6, 15, 8, 10, 11, type);
    pentagon(4, 17, 8, 15, 14, type);
    pentagon(4, 12, 5, 16, 17, type);
  }
  
  /* CENTRY */
  void APIENTRY
  glutWireDodecahedron(void)
  {
    dodecahedron(GL_LINE_LOOP);
  }
  
  void APIENTRY
  glutSolidDodecahedron(void)
  {
    dodecahedron(GL_TRIANGLE_FAN);
  }
  
  /* ENDCENTRY */
  
  static void
  recorditem(GLfloat * n1, GLfloat * n2, GLfloat * n3,
    GLenum shadeType)
  {
    GLfloat q0[3], q1[3];
  
    DIFF3(n1, n2, q0);
    DIFF3(n2, n3, q1);
    crossprod(q0, q1, q1);
    normalize(q1);
  
    glBegin(shadeType);
    glNormal3fv(q1);
    glVertex3fv(n1);
    glVertex3fv(n2);
    glVertex3fv(n3);
    glEnd();
  }
  
  static void
  subdivide(GLfloat * v0, GLfloat * v1, GLfloat * v2,
    GLenum shadeType)
  {
    int depth;
    GLfloat w0[3], w1[3], w2[3];
    GLfloat l;
    int i, j, k, n;
  
    depth = 1;
    for (i = 0; i < depth; i++) {
      for (j = 0; i + j < depth; j++) {
        k = depth - i - j;
        for (n = 0; n < 3; n++) {
          w0[n] = (i * v0[n] + j * v1[n] + k * v2[n]) / depth;
          w1[n] = ((i + 1) * v0[n] + j * v1[n] + (k - 1) * v2[n])
            / depth;
          w2[n] = (i * v0[n] + (j + 1) * v1[n] + (k - 1) * v2[n])
            / depth;
        }
        l = sqrt(w0[0] * w0[0] + w0[1] * w0[1] + w0[2] * w0[2]);
        w0[0] /= l;
        w0[1] /= l;
        w0[2] /= l;
        l = sqrt(w1[0] * w1[0] + w1[1] * w1[1] + w1[2] * w1[2]);
        w1[0] /= l;
        w1[1] /= l;
        w1[2] /= l;
        l = sqrt(w2[0] * w2[0] + w2[1] * w2[1] + w2[2] * w2[2]);
        w2[0] /= l;
        w2[1] /= l;
        w2[2] /= l;
        recorditem(w1, w0, w2, shadeType);
      }
    }
  }
  
  static void
  drawtriangle(int i, GLfloat data[][3], int ndx[][3],
    GLenum shadeType)
  {
    GLfloat *x0, *x1, *x2;
  
    x0 = data[ndx[i][0]];
    x1 = data[ndx[i][1]];
    x2 = data[ndx[i][2]];
    subdivide(x0, x1, x2, shadeType);
  }
  
  /* octahedron data: The octahedron produced is centered at the
     origin and has radius 1.0 */
  static GLfloat odata[6][3] =
  {
    {1.0, 0.0, 0.0},
    {-1.0, 0.0, 0.0},
    {0.0, 1.0, 0.0},
    {0.0, -1.0, 0.0},
    {0.0, 0.0, 1.0},
    {0.0, 0.0, -1.0}
  };
  
  static int ondex[8][3] =
  {
    {0, 4, 2},
    {1, 2, 4},
    {0, 3, 4},
    {1, 4, 3},
    {0, 2, 5},
    {1, 5, 2},
    {0, 5, 3},
    {1, 3, 5}
  };
  
  static void
  octahedron(GLenum shadeType)
  {
    int i;
  
    for (i = 7; i >= 0; i--) {
      drawtriangle(i, odata, ondex, shadeType);
    }
  }
  
  /* CENTRY */
  void APIENTRY
  glutWireOctahedron(void)
  {
    octahedron(GL_LINE_LOOP);
  }
  
  void APIENTRY
  glutSolidOctahedron(void)
  {
    octahedron(GL_TRIANGLES);
  }
  
  /* ENDCENTRY */
  
  /* icosahedron data: These numbers are rigged to make an
     icosahedron of radius 1.0 */
  
  #define X .525731112119133606
  #define Z .850650808352039932
  
  static GLfloat idata[12][3] =
  {
    {-X, 0, Z},
    {X, 0, Z},
    {-X, 0, -Z},
    {X, 0, -Z},
    {0, Z, X},
    {0, Z, -X},
    {0, -Z, X},
    {0, -Z, -X},
    {Z, X, 0},
    {-Z, X, 0},
    {Z, -X, 0},
    {-Z, -X, 0}
  };
  
  static int iIndex[20][3] =
  {
    {0, 4, 1},
    {0, 9, 4},
    {9, 5, 4},
    {4, 5, 8},
    {4, 8, 1},
    {8, 10, 1},
    {8, 3, 10},
    {5, 3, 8},
    {5, 2, 3},
    {2, 7, 3},
    {7, 10, 3},
    {7, 6, 10},
    {7, 11, 6},
    {11, 0, 6},
    {0, 1, 6},
    {6, 1, 10},
    {9, 0, 11},
    {9, 11, 2},
    {9, 2, 5},
    {7, 2, 11},
  };
  
  static void
  icosahedron(GLenum shadeType)
  {
    int i;
  
    for (i = 19; i >= 0; i--) {
      drawtriangle(i, idata, iIndex, shadeType);
    }
  }
  
  /* CENTRY */
  void APIENTRY
  glutWireIcosahedron(void)
  {
    icosahedron(GL_LINE_LOOP);
  }
  
  void APIENTRY
  glutSolidIcosahedron(void)
  {
    icosahedron(GL_TRIANGLES);
  }
  
  /* ENDCENTRY */
  
  /* tetrahedron data: */
  
  #define T       1.73205080756887729
  
  static GLfloat tdata[4][3] =
  {
    {T, T, T},
    {T, -T, -T},
    {-T, T, -T},
    {-T, -T, T}
  };
  
  static int tndex[4][3] =
  {
    {0, 1, 3},
    {2, 1, 0},
    {3, 2, 0},
    {1, 2, 3}
  };
  
  static void
  tetrahedron(GLenum shadeType)
  {
    int i;
  
    for (i = 3; i >= 0; i--)
      drawtriangle(i, tdata, tndex, shadeType);
  }
  
  /* CENTRY */
  void APIENTRY
  glutWireTetrahedron(void)
  {
    tetrahedron(GL_LINE_LOOP);
  }
  
  void APIENTRY
  glutSolidTetrahedron(void)
  {
    tetrahedron(GL_TRIANGLES);
  }
  
  /* ENDCENTRY */
  