/* File SOMBRERO.C: Sombrero - HGC/EGA version */
#include <conio.h>
#include <graphics.h> //-+-±×·¡ÇÈ ÇÔ¼ö¿Í ¼öÇÐ ÇÔ¼öÀ2Ç ¼±¾ðÀÌ µé¾îÀÖÀ½
#include <math.h>     //-+
		      // +-----ºÒ¸°ÇüÀ» Á¤ÀÇ
typedef enum {false, true} boolean;

void graph(double y, double z, int *plotted);     //-+
void rotate3d(double xr, double yr, double zr,    // | ÇÔ¼ö ¼±¾ð
	      double *px, double *py, double *pz);//-+

			      /*      |z        *///  ÀÌ ¿¹Á¦¿¡¼­
#define SIZE 2.               /*      |         *///  ¾²ÀÎ 3Â÷¿ø ÁÂÇ¥°è
#define ZROTATE 11.           /*      |         */// 2 ±×·¡ÇÈ È­¸éÀº
#define YROTATE 40.           /*      +------ y *///  yzÆò¸é¿¡ ÇØ´çÇÔ
#define XROTATE 0.            /*     /          */
			      /*    /           */
			      /*   x            */

double function(double x, double y)//     ¸ß½ÃÄÚ ¸ðÀÚ¸¦ ³ªÅ¸³»´Â
{                                  //       3Â÷¿ø Æò¸éÀÇ ½Ä
    double f;

    f = hypot(x, y) / 35.;
    if (fabs(f) < 1.e-5) return (40. * M_PI);
    else return (40. * sin(f * M_PI) / f);
}

void main(void)
{ //                      ÀÚµ¿º¯¼ö¸¦ ¼±¾ð(Á¤ÀÇ)
    int graphdrive = DETECT, graphmode;
    int plotted = false; //---- °î¼±ÀÇ ½ÃÀÛÁ¡ÀÎÁöÀÇ ¿©ºÎ¸¦ °¡¸²
    double x, y, z, x2, y2, z2; //---- 3Â÷¿ø ÁÂÇ¥
    double zr, yr, xr; //---- °¢°¢ zÃà, yÃà, xÃàÀ» Áß½ÉÀ¸·Î Çϴ ȸÀü°¢

    initgraph(&graphdrive, &graphmode, "");

    zr = ZROTATE * M_PI / 180.; //-+
    yr = YROTATE * M_PI / 180.; // | ¶óµð¾È °ªÀ¸·Î ȯ»ê
    xr = XROTATE * M_PI / 180.; //-+

    for (x = -115.2; x <= 115.; x += 5.) {
	for (y = -115.; y <= 115.; y += 5.) {
	    z = function(x, y);
	    x2 = x * SIZE; //-+-- ÁÂÇ¥¸¦ SIZE¹è¸¸Å­ È®´ë
	    y2 = y * SIZE; // |          zÃà, yÃà, xÃàÀ» Áß½ÉÀ¸·Î °¢°¢
	    z2 = z * SIZE; //-+                    |  ȸÀü
	    rotate3d(xr, yr, zr, &x2, &y2, &z2);//-+
	    graph(y2, z2, &plotted); //---+
	}                    //        3Â÷¿ø °î¼±À»
	plotted = false;     // yzÆò¸é¿¡ Åõ¿µÇÑ Á¤»ç¿µÀ» È­¸é¿¡2 ±×¸²
    }          //    |
	       //	   +-»õ·Î¿î °î¼±À» ±×¸²
    getch();
    closegraph(); //---- ±×·¡ÇÈ ½Ã½ºÅÛÀ» Á¾·á
}

/* Rotation order :  z axis -> y axis -> x axis */

void rotate3d(double xr, double yr, double zr, double *px, double *py, double *pz)
{
    double x = *px, y = *py, z = *pz;
    double x1, y1, z1, x2, y2, z2, x3, y3, z3;

    x1 = x * cos(zr) - y * sin(zr); //  -+
    y1 = x * sin(zr) + y * cos(zr); //   | zÃàÀ» Áß½ÉÀ¸·Î zr¸¸Å­ ȸÀü
    z1 = z;                        //   -+

    x2 = x1 * cos(yr) - z1 * sin(yr); //-+
    y2 = y1;                          // | yÃàÀ» Áß½ÉÀ¸·Î yr¸¸Å­ ȸÀü
    z2 = x1 * sin(yr) + z1 * cos(yr); //-+

    x3 = x2;                          //-+
    y3 = y2 * cos(xr) - z2 * sin(xr); // | xÃàÀ» Áß½ÉÀ¸·Î xr¸¸Å­ ȸÀü
    z3 = y2 * sin(xr) + z2 * cos(xr); //-+

    *px = x3; //-+
    *py = y3; // | ½Ç¸Å°³º¯¼ö x2, y2, z2¿¡ °ªÀ» ´ëÀÔ
    *pz = z3; //-+ (actual parameter)
}

void graph(double y, double z, int *plotted)
{
    int xx, yy, xasp, yasp;

    getaspectratio(&xasp, &yasp); //---- È­¸éÀÇ Á¾È¾ºñ¸¦ ±¸ÇÔ
    xx = getmaxx() / 2 + (int)y;
    yy = getmaxy() / 2 - (int)(z * xasp / yasp);
    if (*plotted == false) moveto(xx, yy); //--- CP¸¸ À̵¿
    else lineto(xx, yy); //---- °î¼±ÀÇ ½ÃÀÛÀÌ ¾Æ´Ï¸é ¼±À» ±×¸²
    *plotted = true;
}