실습3

#include <GL/glut.h>

static GLfloat theta[] = {0.0, 0.0, 0.0};
static GLint axis =1;

static GLfloat theta_degree=0.1;
static GLfloat zoom_factor = 0.0;
static GLfloat transZ = 0.0;

GLfloat vertices[8][3] = {{-1.0, -1.0, 1.0}, {-1.0, 1.0, 1.0}, {1.0, 1.0, 1.0}, {1.0, -1.0, 1.0}, {-1.0, -1.0, -1.0}, {-1.0, 1.0, -1.0}, {1.0, 1.0, -1.0}, {1.0, -1.0, -1.0} };

GLfloat colors[8][3] = {{0.0, 0.0, 0.0}, {1.0, 0.0, 0.0}, {1.0, 1.0, 0.0}, {0.0, 1.0, 0.0}, {0.0, 0.0, 1.0}, {1.0, 0.0, 1.0}, {1.0, 1.0, 1.0}, {0.0, 1.0, 1.0} };

void quad(int a, int b, int c, int d)
{
 glBegin(GL_QUADS);
 glColor3fv(colors[a]);
 glVertex3fv(vertices[a]);
 glColor3fv(colors[b]);
 glVertex3fv(vertices[b]);
 glColor3fv(colors[c]);
 glVertex3fv(vertices[c]);
 glColor3fv(colors[d]);
 glVertex3fv(vertices[d]);
 glEnd();
 glFlush();
}
void cube()
{
 quad(0, 3, 2, 1);  // 앞 면
 quad(2, 3, 7, 6);  // 오른쪽 면
 quad(0, 4, 7, 3);  // 아랫 면
 quad(1, 2, 6, 5);  // 윗 면
 quad(4, 5, 6, 7);  // 뒷 면
 quad(0, 1, 5, 4);  // 왼쪽 면
}

void coodiaxis()
{
 glColor3f(1.0, 0.0, 0.0);  // 각 좌표축을 그림
 glBegin(GL_LINES);
  glVertex3f( 0.0, 0.0, 0.0);  
  glVertex3f( 2.5, 0.0, 0.0);
  glVertex3f( 2.5, 0.0, 0.0);  
  glVertex3f( 2.45, 0.05, 0.0); // 화살표
  glVertex3f( 2.5, 0.0, 0.0);  
  glVertex3f( 2.45,-0.05, 0.0);

  glVertex3f( 0.0, 0.0, 0.0);  
  glVertex3f( 0.0, 2.5, 0.0);
  glVertex3f( 0.0, 2.5, 0.0);  
  glVertex3f( 0.05, 2.45, 0.0); // 화살표
  glVertex3f( 0.0, 2.5, 0.0);  
  glVertex3f( -0.05, 2.45, 0.0);

  glVertex3f( 0.0, 0.0, 0.0);  
  glVertex3f( 0.0, 0.0, 2.5);
  glVertex3f( 0.0, 0.0, 2.5);  
  glVertex3f( 0.0, 0.05, 2.45); // 화살표
  glVertex3f( 0.0, 0.0, 2.5);  
  glVertex3f( 0.0,-0.05, 2.45);
 glEnd();
 glFlush();
 glColor3f(1.0, 0.0, 0.0);
 glRasterPos3f(2.6, 0.0, 0.0);   // X 축 표시
 glutBitmapCharacter(GLUT_BITMAP_9_BY_15, 'X');

 glRasterPos3f(0.0, 2.6, 0.0);   // Y 축 표시
 glutBitmapCharacter(GLUT_BITMAP_9_BY_15, 'Y');

 glRasterPos3f(0.0, 0.0, 2.6);   // Z 축 표시
 glutBitmapCharacter(GLUT_BITMAP_9_BY_15, 'Z');

}

void spinCube(void)
{
 theta[axis] += theta_degree;
 if(theta[axis] > 360)
  theta[axis] -= 360;
 glutPostRedisplay();
}

void key(unsigned char k, int x, int y) {
 theta[0] = theta[1] = theta[2] = 0.0;
 glLoadIdentity();
 switch(k) {
 case 'x' :
  axis=0;
  break;
 case 'y':
  axis=1;
  break;
 case'z':
  axis=2;
  break;
 case '=':
  theta_degree += 0.1;
  break;
 case '-':
  theta_degree -= 0.1;
  break;
 case'[':
  transZ -=0.2;
  break;
 case ']':
  transZ += 0.2;
  break;
 }
}

void special_key(int k, int x, int y)
{
 switch(k){
 case GLUT_KEY_PAGE_UP:
  zoom_factor -= 0.2;
  break;
 case GLUT_KEY_PAGE_DOWN:
  zoom_factor += 0.2;
  break;
 }
}
void display(void)
{
 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 glLoadIdentity();
 gluLookAt(2.5+zoom_factor, 2.5+zoom_factor, 3.0+zoom_factor, -(2.5+zoom_factor), -(2.5+zoom_factor), -(3.0+zoom_factor), 0.0f, 1.0f, 0.0f);
 glTranslatef(0.0f, 0.0f, transZ);
 glRotatef(theta[0], 1.0, 0.0, 0.0);
 glRotatef(theta[1], 0.0, 1.0, 0.0);
 glRotatef(theta[2], 0.0, 0.0, 1.0);
 
 cube();
 coodiaxis();

 glFlush();
 glutSwapBuffers();
}

void reshape(GLsizei w, GLsizei h)
{
   GLfloat fovy = 60.0;
   GLfloat aspect;
   if(h == 0) h = 1;
   aspect = (GLfloat)w / (GLfloat)h;
   glViewport(0, 0, w, h); // 뷰포트를 창의 크기에 맞게 설정
   glMatrixMode(GL_PROJECTION); // 투시변환 행렬의 설정
   glLoadIdentity(); // 현재 행렬의 초기화
   gluPerspective(fovy, aspect, 1.0, 100.0);
   glMatrixMode(GL_MODELVIEW); // 모델뷰 변환 행렬의 설정
   glLoadIdentity();
    glFlush();
}

void init(void)
{
 glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
}

void main(int argc, char**argv)
{
 glutInit(&argc, argv);
 glClearDepth(1.0f);
 glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
 glutInitWindowSize(500,500);
 glutInitWindowPosition(0,0);
 glutCreateWindow("spin cube");

 glutReshapeFunc(reshape);
 glutDisplayFunc(display);
 glutIdleFunc(spinCube);
 glutKeyboardFunc(key);
 
 glutSpecialFunc(special_key);
 init();
 glEnable(GL_DEPTH_TEST);
 glutMainLoop();
}