/* aya8.c - Don Yang (uguu.org)

   10/07/06
                                                                           */

#include<sys/time.h>
#include<math.h>
#include<stdio.h>
#include<stdlib.h>
#include<GL/glut.h>

#define z(u,n) gl ## n ## u

typedef double x;
typedef int _;
x
   BUN[] =
   {
      .9, .98,
      1, 0,
      -1
   },
   KA[] =
   {
      .32, .98,
      .36, .12,
      .54, .12,
      .58, .98,
      .9, .98,
      1, 0,
      -1
   },
   CHOU[] =
   {
      .56, .99,
      .58, .7,
      .9, 0,
      -1
   },
   c, d, r, s, t, u, v, i, j, k, l, m, n;

_ A, y, a, _w, w;
unsigned char b[16384], *p;

x X(x O)
{
   return O * (rand() & 0x3fff) / 8191. - O;
}

Z()
{
   struct timeval U;
   gettimeofday(&U, NULL);
   u = U.tv_sec + U.tv_usec / 1e6;
}

I()
{
   Z();
   srand(u);

   glDrawBuffer(GL_BACK);
   glClear(GL_COLOR_BUFFER_BIT);

   glViewport(0, 0,
              a = glutGet(GLUT_WINDOW_WIDTH), y = glutGet(GLUT_WINDOW_HEIGHT));
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   if( a > y )
      gluOrtho2D(-a / (x)y, a / (x)y, -1, 1);
   else
      gluOrtho2D(-1, 1, -y / (x)a, y / (x)a);

   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();

   s = (u - l) / 1.5;

   for(a = 0; a < 23; a++)
   {
      if( (j = s - a / 23.) >= 0 )
      {
         r = j * 2.1;
         for(y = 0; y < 32; y++)
         {
            m = i + y * d / 16.;
            k = j * ((c + y * d / 16.) - m) + m;
            if( a & 1 )
               k += d / 32;
            glPushMatrix();
            glTranslated(r * cos(k) + n,
                         r * sin(k) + t, 0);
            glCallList(w);
            glPopMatrix();
         }
      }
   }

   if( s > 2.2 )
   {
      l = u;
      c = i = X(d);
      if( !(rand() & 3) )
         c += X(d / 3);
      n = X(.5);
      t = X(.5);
   }

   glutSwapBuffers();
   glFlush();
}

F()
{
   Z();

   glGenTextures(1, &_w);
   glBindTexture(GL_TEXTURE_2D, _w);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64, 0,
                GL_RGBA, GL_UNSIGNED_BYTE, b);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

   glEnable(GL_BLEND);
   glEnable(GL_TEXTURE_2D);
   glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

   glNewList(w = glGenLists(1), GL_COMPILE);
   glBegin(GL_TRIANGLE_FAN);
      glTexCoord2d(0, 0); glVertex2d(-.07, -.07);
      glTexCoord2d(1, 0); glVertex2d( .07, -.07);
      glTexCoord2d(1, 1); glVertex2d( .07,  .07);
      glTexCoord2d(0, 1); glVertex2d(-.07,  .07);
   glEnd();
   glEndList();

   l = u; n = a = t = i = c;

   glutDisplayFunc(I);
   I();
}

N()
{
   glutPostRedisplay();
}

M(_ Y, _ O)
{
   N();
}

f(unsigned char Z, _ U, _ N)
{
   glFlush();
   glDeleteLists(w, 1);
   glDeleteTextures(1, &_w);
   exit(0);
}

x o(x *q)
{
   s = *q++;
   v = *q++;
   if( r > s )
   {
      for(; (j = *q++) > s;)
      {
         k = *q++;
         if( r < j )
         {
            v = (k - v) * (r - s) / (j - s) + v;
            break;
         }
         s = j;
         v = k;
      }
   }
   return 255 * v;
}

main(_ argc, char **argv)
{
   glutInit(&argc, argv);

   d = atan2(c = 0, -1);

   for(a = 0; a < 16384; b[a++] = 0);
   p = b;
   for(a = 0; a < 64; a++)
   {
      m = a / 32. - 1;
      for(y = 0; y < 64; y++)
      {
         r = y / 32. - 1;
         r = sqrt(m * m + r * r);

         if( (A = o(BUN)) > 255 ) A = 255;
         *p++ = A;

         if( (A = o(KA)) > 255 ) A = 255;
         *p++ = A;
         *p++ = A;

         if( (A = o(CHOU)) > 255 ) A = 255;
         *p++ = A;
      }
   }

   glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);
   glutSetWindow(glutCreateWindow("Aya"));

   glutDisplayFunc(F);
   glutIdleFunc(N);
   glutReshapeFunc(M);
   glutKeyboardFunc(f);

   glutMainLoop();
}