test4.cpp

《分形算法与程序设计VC版》<9_04>：内含基于IFS算法的Sierpinski金字塔源代码。双击test4.exe文件

#include <windows.h>
#include <gl/glut.h>
#include <math.h>

const double PI=3.1415926;
const float MIN_LEN = 0.001;
const float LEN = 0.6;
const float g_ax = 0, g_ay = LEN, g_az = 0;
const float g_bx = -LEN, g_by = -LEN, g_bz = LEN;
const float g_cx = LEN, g_cy = -LEN, g_cz = LEN;
const float g_dx = 0, g_dy = -LEN, g_dz = -LEN;

/// 窗口宽度
int g_width=400;

/// 窗口高度
int g_height=300;

///鼠标器左键是否按下
bool mouse_button_pressed=false;    

///记录鼠标器位置
int mouse_x;                        

///记录鼠标器位置
int mouse_y;                        

///旋转的纬度
float theta=0;                     

///旋转的经度
float phi=0;                       


/**
鼠标按钮回调函数
*/
void mouse(int button, int state, int x, int y)
{
    if(button == GLUT_LEFT_BUTTON)
    {
        if(state == GLUT_DOWN)
            //如果鼠标器左键按下，mouse_button_pressed置位
            //并记录光标位置
        {
            mouse_button_pressed = true;
            mouse_x = x;
            mouse_y = y;
        }
        else
        {
            mouse_button_pressed = false;
        }
    }
}

/**
鼠标运动处理函数
*/
void motion(int x, int y)
{
    if(mouse_button_pressed)
    {
        theta -= y-mouse_y;     //根据鼠标器的移动改变旋转的纬度
        if(theta<0) theta += 360;  //限制纬度在0到180度之间
        if(theta> 360) theta -= 360;

        phi += x-mouse_x;       //根据鼠标器的移动改变旋转的经度
        if(phi<0) phi+=360;     //限制经度在0到360度之间
        if(phi>360) phi-=360;

        mouse_x = x;    //更新记录的鼠标器位置
        mouse_y = y;

        glutPostRedisplay();
            //通知系统：窗口需要刷新
    }
}



/**
点类
*/
class point3d {

public:
	float x;
	float y;
	float z;
public:
	point3d(float _x, float _y, float _z)  {x=_x;y=_y;z=_z;}
	point3d(point3d & p)  {x=p.x; y=p.y; z=p.z;}
	point3d middle(point3d & p2) {return point3d((x+p2.x)/2, (y+p2.y)/2, (z+p2.z)/2);}
        float between(point3d & p2) {return (x-p2.x)*(x-p2.x)+(y-p2.y)*(y-p2.y)+(z-p2.z)*(z-p2.z);}
};


/**
绘制Seripinski锥体
三点坐标为a(x1,y1,z1), b(x2,y2,z2), c(x3,y3,z3)
*/

void seripinski(point3d & a, point3d & b, point3d & c, point3d& d)
{
   if (a.between(b) < MIN_LEN ) return;

   //绘制锥体
   glBegin(GL_LINES);
   glVertex3f(a.x, a.y, a.z);
   glVertex3f(b.x, b.y, b.z);
   glVertex3f(a.x, a.y, a.z);
   glVertex3f(c.x, c.y, c.z);
   glVertex3f(a.x, a.y, a.z);
   glVertex3f(d.x, d.y, d.z);
   glEnd();

   glBegin(GL_LINE_LOOP);
   glVertex3f(b.x, b.y, b.z);
   glVertex3f(c.x, c.y, c.z);
   glVertex3f(d.x, d.y, d.z);
   glEnd();
   
   //递归绘制四个锥
   seripinski(a.middle(b), b, b.middle(c), b.middle(d));
   seripinski(a, a.middle(b), a.middle(c), a.middle(d));
   seripinski(a.middle(c), b.middle(c), c, c.middle(d));
   seripinski(a.middle(d), b.middle(d), c.middle(d), d);
}

/**
\b 主处理回调函数,每当需要重画时由OpenGL库调用
\b 该函数功能是调用seripinski,绘制seripinski锥体
*/
void main_display_loop(void)
{
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); //刷新背景 

  glMatrixMode (GL_PROJECTION);   //设置矩阵模式为投影矩阵
  glLoadIdentity();               //初始化投影矩阵
  glOrtho(-1,1,-1,1,-1,1);        //设置平行投影的投影矩阵


  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glRotatef(phi,0,1,0);       //绕y轴旋转OCS，旋转的角度为phi
  glRotatef(theta,1,0,0);     //绕x轴旋转OCS，旋转的角度为theta


  seripinski(point3d(g_ax, g_ay, g_az), point3d(g_bx, g_by, g_bz), point3d(g_cx, g_cy, g_cz), point3d(g_dx, g_dy, g_dz));
  
  glFlush(); 	  //更新窗口 

  //glutSwapBuffers();
}

/**
OPENGL 特性初始化函数
*/
init()
{
  glEnable(GL_DEPTH_TEST);
  glDepthFunc(GL_LESS);

  glClearColor(0,0,0,1); 
  glClearDepth(1);
  glColor3b(0, 90, 85);
}

/// 主函数
int main(int argc, char* argv[])
{
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_SINGLE| GLUT_RGBA);
  glutInitWindowSize(g_width, g_height);
  glutCreateWindow("OpenGL");
  init();
  glutMouseFunc(mouse);
  glutMotionFunc(motion);
  glutDisplayFunc(main_display_loop);
  glutMainLoop();
  return 0;
}