회전 3D 가스켓을 향한 시점의 이동

이번 소스는 잘 몰라서 원 소스를 보고 보충수업 해야겠다 -_-


#include <stdlib.h>
#include <GL/glut.h>
#include <time.h>

GLfloat v[4][3]={{0.0, 0.0, 1.0}, {0.0, 0.942809, -0.33333},
      {-0.816497, -0.471405, -0.333333}, {0.816497, -0.471405, -0.333333}};

GLfloat colors[4][3] = {{1.0, 0.0, 0.0}, {0.0, 1.0, 0.0},
                        {0.0, 0.0, 1.0}, {0.0, 0.0, 0.0}};
GLfloat eye[3], at[3];
GLfloat eye_start[3] = {1.0, 1.0, 1.0};
GLfloat eye_end[3] = {0.0, 0.0, 0.0};
GLfloat alpha=0.0, delta=0.003;

int n;
static GLfloat theta[] = {0.0,0.0,0.0};
static GLint axis = 2;

void triangle(GLfloat *va, GLfloat *vb, GLfloat *vc)
{
       glVertex3fv(va);
       glVertex3fv(vb);
       glVertex3fv(vc);
}

void tetra(GLfloat *a, GLfloat *b, GLfloat *c, GLfloat *d)
{
    glColor3fv(colors[0]);
    triangle(a, b, c);
    glColor3fv(colors[1]);
    triangle(a, c, d);
    glColor3fv(colors[2]);
    triangle(a, d, b);
    glColor3fv(colors[3]);
    triangle(b, d, c);
}

void divide_tetra(GLfloat *a, GLfloat *b, GLfloat *c, GLfloat *d, int m)
{

    GLfloat mid[6][3];
    int j;
   
 glBegin(GL_TRIANGLES);
 if(m>0)
    {
        /* compute six midpoints */

        for(j=0; j<3; j++) mid[0][j]=(a[j]+b[j])/2;
        for(j=0; j<3; j++) mid[1][j]=(a[j]+c[j])/2;
        for(j=0; j<3; j++) mid[2][j]=(a[j]+d[j])/2;
        for(j=0; j<3; j++) mid[3][j]=(b[j]+c[j])/2;
        for(j=0; j<3; j++) mid[4][j]=(c[j]+d[j])/2;
        for(j=0; j<3; j++) mid[5][j]=(b[j]+d[j])/2;

        /* create 4 tetrahedrons by subdivision */

        divide_tetra(a, mid[0], mid[1], mid[2], m-1);
        divide_tetra(mid[0], b, mid[3], mid[5], m-1);
        divide_tetra(mid[1], mid[3], c, mid[4], m-1);
        divide_tetra(mid[2], mid[4], d, mid[5], m-1);

    }
    else(tetra(a,b,c,d)); /* draw tetrahedron at end of recursion */
 glEnd();
}

void display()
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   
 glLoadIdentity();
    gluLookAt(1.0,1.0,1.0,
  0.0,0.0,0.0,
  0.0,1.0,0.0);

 

 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);
   
 divide_tetra(v[0], v[1], v[2], v[3], n);
   
    glFlush();
 glutSwapBuffers();
}

void mouse(int btn, int state, int x, int y)
{

/* 회전 중심축을 선택 */

 if(btn==GLUT_LEFT_BUTTON && state == GLUT_DOWN) axis = 0;
 if(btn==GLUT_MIDDLE_BUTTON && state == GLUT_DOWN) axis = 1;
 if(btn==GLUT_RIGHT_BUTTON && state == GLUT_DOWN) axis = 2;
}

void myReshape(int w, int h)
{
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60.0, (GLfloat)w/h, 0.1, 1000.0);
    glMatrixMode(GL_MODELVIEW);
}

void spinCube(void)
{

/* 선택된 축을 중심으로 회전 */
 theta[axis] += 2.0;
 if( theta[axis] > 360.0 ) theta[axis] -= 360.0;
 
 for(int i=0; i<=300000;i++)
 //delay();
 glutPostRedisplay();

 
}

void approach(int value)
{
 int i;
 alpha=alpha+delta;
 for(i=0;i<3;i++)eye[i]=(1.0-alpha)*eye_start[i]+alpha*eye_end[i];
    glutTimerFunc(50, approach, 1);
}

 

int main(int argc, char **argv)
{

   n=2;
 glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(400, 400);
    glutCreateWindow("3D Gasket");
    glutReshapeFunc(myReshape);
    glutDisplayFunc(display);
 glutIdleFunc(spinCube);
    glEnable(GL_DEPTH_TEST);
 glutMouseFunc(mouse);
    glClearColor (1.0, 1.0, 1.0, 1.0);
    glutMainLoop();
}