#ifndef UNITSPHERE_H

#define UNITSPHERE_H

//*** File this one under the catagory of Stupid Code Tricks.
//*** All I wanted to do was just display a bounding sphere in my
//*** engine as a debugging and visualization aid.  Then I found out
//*** how much code is required just to tesselate a sphere.  Here
//*** is a quick and dirty class which will allow you to produce
//*** a tesselated sphere at some point in world space and with some
//*** radius.  The output tesselated sphere is a always a hard-coded
//*** 224 polygon mesh.
//***
//*** To use in your application simply inherte UnitSphereCallback and
//*** provide the virtual method SphereTriangle
//***
//*** To to produce the tesselated sphere simply invoke the static
//*** method:
//***
//*** UnitSphere::Tesselate(*this,center,radius);
//***
//*** You can replace SpherePoint with whatever your own 3d point
//*** representation might be.
//***
//*** Submitted to FlipCode.com Code of the day on October 10, 2000
//*** by John W. Ratcliff jratcliff@verant.com and is released into
//*** the public domain, for what it's worth.  If somebody knows of
//*** a lean mean high speed sphere tesselator please, feel free to
//*** modify this code snippet and replace it with the new implementation.

class SpherePoint
{
public:
  float x;
  float y;
  float z;
};


class UnitSphereCallback
{
public:
  virtual void SphereTriangle(const SpherePoint &p1,
                              const SpherePoint &p2,
                              const SpherePoint &p3) = 0;
};

class UnitSphere
{
public:

  static void Tesselate(UnitSphereCallback &callback,
                 const SpherePoint ¢er,
                 float radius);
private:
};

#endif
 

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include "unitsphere.h"

static float gVertices[] =
{
 0.0000f,0.0000f,1.0000f,  0.0000f,0.3827f,0.9239f,  -0.1464f,0.3536f,0.9239f,
 -0.2706f,0.2706f,0.9239f,  -0.3536f,0.1464f,0.9239f,  -0.3827f,0.0000f,0.9239f,
 -0.3536f,-0.1464f,0.9239f,  -0.2706f,-0.2706f,0.9239f,  -0.1464f,-0.3536f,0.9239f,
 0.0000f,-0.3827f,0.9239f,  0.1464f,-0.3536f,0.9239f,  0.2706f,-0.2706f,0.9239f,
 0.3536f,-0.1464f,0.9239f,  0.3827f,0.0000f,0.9239f,  0.3536f,0.1464f,0.9239f,
 0.2706f,0.2706f,0.9239f,  0.1464f,0.3536f,0.9239f,  0.0000f,0.7071f,0.7071f,
 -0.2706f,0.6533f,0.7071f,  -0.5000f,0.5000f,0.7071f,  -0.6533f,0.2706f,0.7071f,
 -0.7071f,0.0000f,0.7071f,  -0.6533f,-0.2706f,0.7071f,  -0.5000f,-0.5000f,0.7071f,
 -0.2706f,-0.6533f,0.7071f,  0.0000f,-0.7071f,0.7071f,  0.2706f,-0.6533f,0.7071f,
 0.5000f,-0.5000f,0.7071f,  0.6533f,-0.2706f,0.7071f,  0.7071f,0.0000f,0.7071f,
 0.6533f,0.2706f,0.7071f,  0.5000f,0.5000f,0.7071f,  0.2706f,0.6533f,0.7071f,
 0.0000f,0.9239f,0.3827f,  -0.3536f,0.8536f,0.3827f,  -0.6533f,0.6533f,0.3827f,
 -0.8536f,0.3536f,0.3827f,  -0.9239f,0.0000f,0.3827f,  -0.8536f,-0.3536f,0.3827f,
 -0.6533f,-0.6533f,0.3827f,  -0.3536f,-0.8536f,0.3827f,  0.0000f,-0.9239f,0.3827f,
 0.3536f,-0.8536f,0.3827f,  0.6533f,-0.6533f,0.3827f,  0.8536f,-0.3536f,0.3827f,
 0.9239f,0.0000f,0.3827f,  0.8536f,0.3536f,0.3827f,  0.6533f,0.6533f,0.3827f,
 0.3536f,0.8536f,0.3827f,  0.0000f,1.0000f,0.0000f,  -0.3827f,0.9239f,0.0000f,
 -0.7071f,0.7071f,0.0000f,  -0.9239f,0.3827f,0.0000f,  -1.0000f,0.0000f,0.0000f,
 -0.9239f,-0.3827f,0.0000f,  -0.7071f,-0.7071f,0.0000f,  -0.3827f,-0.9239f,0.0000f,
 0.0000f,-1.0000f,0.0000f,  0.3827f,-0.9239f,0.0000f,  0.7071f,-0.7071f,0.0000f,
 0.9239f,-0.3827f,0.0000f,  1.0000f,0.0000f,0.0000f,  0.9239f,0.3827f,0.0000f,
 0.7071f,0.7071f,0.0000f,  0.3827f,0.9239f,0.0000f,  0.0000f,0.9239f,-0.3827f,
 -0.3536f,0.8536f,-0.3827f,  -0.6533f,0.6533f,-0.3827f,  -0.8536f,0.3536f,-0.3827f,
 -0.9239f,0.0000f,-0.3827f,  -0.8536f,-0.3536f,-0.3827f,  -0.6533f,-0.6533f,-0.3827f,
 -0.3536f,-0.8536f,-0.3827f,  0.0000f,-0.9239f,-0.3827f,  0.3536f,-0.8536f,-0.3827f,
 0.6533f,-0.6533f,-0.3827f,  0.8536f,-0.3536f,-0.3827f,  0.9239f,0.0000f,-0.3827f,
 0.8536f,0.3536f,-0.3827f,  0.6533f,0.6533f,-0.3827f,  0.3536f,0.8536f,-0.3827f,
 0.0000f,0.7071f,-0.7071f,  -0.2706f,0.6533f,-0.7071f,  -0.5000f,0.5000f,-0.7071f,
 -0.6533f,0.2706f,-0.7071f,  -0.7071f,0.0000f,-0.7071f,  -0.6533f,-0.2706f,-0.7071f,
 -0.5000f,-0.5000f,-0.7071f,  -0.2706f,-0.6533f,-0.7071f,  0.0000f,-0.7071f,-0.7071f,
 0.2706f,-0.6533f,-0.7071f,  0.5000f,-0.5000f,-0.7071f,  0.6533f,-0.2706f,-0.7071f,
 0.7071f,0.0000f,-0.7071f,  0.6533f,0.2706f,-0.7071f,  0.5000f,0.5000f,-0.7071f,
 0.2706f,0.6533f,-0.7071f,  0.0000f,0.3827f,-0.9239f,  -0.1464f,0.3536f,-0.9239f,
 -0.2706f,0.2706f,-0.9239f,  -0.3536f,0.1464f,-0.9239f,  -0.3827f,0.0000f,-0.9239f,
 -0.3536f,-0.1464f,-0.9239f,  -0.2706f,-0.2706f,-0.9239f,  -0.1464f,-0.3536f,-0.9239f,
 0.0000f,-0.3827f,-0.9239f,  0.1464f,-0.3536f,-0.9239f,  0.2706f,-0.2706f,-0.9239f,
 0.3536f,-0.1464f,-0.9239f,  0.3827f,0.0000f,-0.9239f,  0.3536f,0.1464f,-0.9239f,
 0.2706f,0.2706f,-0.9239f,  0.1464f,0.3536f,-0.9239f,  0.0000f,0.0000f,-1.0000f
};


static int gFaces[224*3] =
{
 0,1,2, 0,2,3, 0,3,4, 0,4,5, 0,5,6, 0,6,7, 0,7,8, 0,8,9, 0,9,10,
 0,10,11, 0,11,12, 0,12,13, 0,13,14, 0,14,15, 0,15,16, 0,16,1, 1,17,18, 1,18,2,
 2,18,19, 2,19,3, 3,19,20, 3,20,4, 4,20,21, 4,21,5, 5,21,22, 5,22,6, 6,22,23,
 6,23,7, 7,23,24, 7,24,8, 8,24,25, 8,25,9, 9,25,26, 9,26,10, 10,26,27, 10,27,11,
 11,27,28, 11,28,12, 12,28,29, 12,29,13, 13,29,30, 13,30,14, 14,30,31, 14,31,15, 15,31,32,
 15,32,16, 16,32,17, 16,17,1, 17,33,34, 17,34,18, 18,34,35, 18,35,19, 19,35,36, 19,36,20,
 20,36,37, 20,37,21, 21,37,38, 21,38,22, 22,38,39, 22,39,23, 23,39,40, 23,40,24, 24,40,41,
 24,41,25, 25,41,42, 25,42,26, 26,42,43, 26,43,27, 27,43,44, 27,44,28, 28,44,45, 28,45,29,
 29,45,46, 29,46,30, 30,46,47, 30,47,31, 31,47,48, 31,48,32, 32,48,33, 32,33,17, 33,49,50,
 33,50,34, 34,50,51, 34,51,35, 35,51,52, 35,52,36, 36,52,53, 36,53,37, 37,53,54, 37,54,38,
 38,54,55, 38,55,39, 39,55,56, 39,56,40, 40,56,57, 40,57,41, 41,57,58, 41,58,42, 42,58,59,
 42,59,43, 43,59,60, 43,60,44, 44,60,61, 44,61,45, 45,61,62, 45,62,46, 46,62,63, 46,63,47,
 47,63,64, 47,64,48, 48,64,49, 48,49,33, 49,65,66, 49,66,50, 50,66,67, 50,67,51, 51,67,68,
 51,68,52, 52,68,69, 52,69,53, 53,69,70, 53,70,54, 54,70,71, 54,71,55, 55,71,72, 55,72,56,
 56,72,73, 56,73,57, 57,73,74, 57,74,58, 58,74,75, 58,75,59, 59,75,76, 59,76,60, 60,76,77,
 60,77,61, 61,77,78, 61,78,62, 62,78,79, 62,79,63, 63,79,80, 63,80,64, 64,80,65, 64,65,49,
 65,81,82, 65,82,66, 66,82,83, 66,83,67, 67,83,84, 67,84,68, 68,84,85, 68,85,69, 69,85,86,
 69,86,70, 70,86,87, 70,87,71, 71,87,88, 71,88,72, 72,88,89, 72,89,73, 73,89,90, 73,90,74,
 74,90,91, 74,91,75, 75,91,92, 75,92,76, 76,92,93, 76,93,77, 77,93,94, 77,94,78, 78,94,95,
 78,95,79, 79,95,96, 79,96,80, 80,96,81, 80,81,65, 81,97,98, 81,98,82, 82,98,99, 82,99,83,
 83,99,100, 83,100,84, 84,100,101, 84,101,85, 85,101,102, 85,102,86, 86,102,103, 86,103,87, 87,103,104,
 87,104,88, 88,104,105, 88,105,89, 89,105,106, 89,106,90, 90,106,107, 90,107,91, 91,107,108, 91,108,92,
 92,108,109, 92,109,93, 93,109,110, 93,110,94, 94,110,111, 94,111,95, 95,111,112, 95,112,96, 96,112,97,
 96,97,81, 113,98,97, 113,99,98, 113,100,99, 113,101,100, 113,102,101, 113,103,102, 113,104,103, 113,105,104,
 113,106,105, 113,107,106, 113,108,107, 113,109,108, 113,110,109, 113,111,110, 113,112,111, 113,97,112
};


void UnitSphere::Tesselate(UnitSphereCallback &callback,
                 const SpherePoint ¢er,
                 float radius)
{
  int *source = gFaces;

  for (int i=0; i<224; i++)
  {
    int i1 = (*source++)*3;
    int i2 = (*source++)*3;
    int i3 = (*source++)*3;

    SpherePoint p1,p2,p3;

    p1.x = gVertices[i1+0] * radius + center.x;
    p1.y = gVertices[i1+1] * radius + center.y;
    p1.z = gVertices[i1+2] * radius + center.z;

    p2.x = gVertices[i2+0] * radius + center.x;
    p2.y = gVertices[i2+1] * radius + center.y;
    p2.z = gVertices[i2+2] * radius + center.z;

    p3.x = gVertices[i3+0] * radius + center.x;
    p3.y = gVertices[i3+1] * radius + center.y;
    p3.z = gVertices[i3+2] * radius + center.z;

    callback.SphereTriangle(p1,p2,p3);

  }

}