[OpenGL]간단한 나무 만들기 함수

void tree(GLfloat x, GLfloat y, GLfloat z, GLfloat width, GLfloat height, GLfloat theight)
{
    /* function tree()
    중심 x, y, z 좌표를 받아 사각뿔의 밑면 길이가 width이고 사각뿔 높이가 height이고 줄기 부분 높이가 theight인 나무 생성
    x : x 좌표
    y : y 좌표
    z : z 좌표
    width : 나무 잎 부분 사각뿔 밑면 길이
    eight : 나무 잎 부분 사각뿔 높이 길이
    theight : 나무 줄기 부분 원기둥 높이
    */
    float v[3][3];
    float out[3];

    v[0][0]= x; v[0][1]=y; v[0][2]=z;
    v[1][0] = x-width; v[1][1] = y-height; v[1][2] = z-width;
    v[2][0] = x-width; v[2][1] = y-height; v[2][2] = z+width;

    glPushMatrix();
    glTranslated(x, y+height+theight, z);
    glColor3ub(34, 139, 34);

    glBegin(GL_TRIANGLE_FAN);   //나무 윗부분 사각뿔
    calcNormal(v, out);
    glNormal3f(0.0f, 1.0f, 0.0f);
    glVertex3f(x, y, z);
    glNormal3fv(out);
    glVertex3f(x-width, y-height, z-width);
    glNormal3fv(out);
    glVertex3f(x-width, y-height, z+width);
    v[1][0] = x-width; v[1][1] = y-height; v[1][2] = z+width;
    v[2][0] = x+width; v[2][1] = y-height; v[2][2] = z-width;
    calcNormal(v, out);

    glNormal3fv(out);
    glVertex3f(x+width, y-height, z+width);
    v[1][0] = x+width; v[1][1] = y-height; v[1][2] = z+width;
    v[2][0] = x+width; v[2][1] = y-height; v[2][2] = z-width;
    calcNormal(v, out);

    glNormal3fv(out);
    glVertex3f(x+width, y-height, z-width);
    v[1][0] = x+width; v[1][1] = y-height; v[1][2] = z-width;
    v[2][0] = x-width; v[2][1] = y-height; v[2][2] = z-width;
    calcNormal(v, out);

    glNormal3fv(out);
    glVertex3f(x-width, y-height, z-width);
    glEnd();

    glBegin(GL_QUADS);       //사각뿔 밑면
    glNormal3f(0.0f, -1.0f, 0.0f);
    glVertex3f(x-width, y-height, z-width);
    glVertex3f(x+width, y-height, z-width);
    glVertex3f(x+width, y-height, z+width);
    glVertex3f(x-width, y-height, z+width);
    glEnd();
 
    glTranslatef(x, y-height, z);
    glRotated(90.0f, 1.0f, 0.0f, 0.0f);
    treebottom(0.0f, 0.0f, 0.0f, 10.0f, theight);  //나무 원기둥 함수
    glPopMatrix();
}