뿌오오~ 나라

glViewport(start, end, width, height);               // window 상의 뷰포트 위치 및 크기
glMatrixModel(GL_PROJECTION);                  // projection matrix
glLoadIdentity();                                           // matrix identity

glOrtho(left, right, bottom, top, near, far);         // ottho projection
                                                                  // glPerspective projection(...)

glMatrixModel(GL_MODELVIEW);                   // model matrix
glLoadIdentity();                                           // matrix identity