openGL의 미스테리...

카메라 (gluLookAt) 와 중심점의 거리가 1.0 을 넘어서면 시야에서 사라진다 -_-
이 사태를 해결하려면 어떻게 해야할려나?

웃긴건 카메라보다 뒤쪽으로 가는건 괜찮음..
아무튼 X(red) Y(green) Z(blue) 의 좌표는 (1.0) 으로 했기 땜누에 방향에 문제는 없어 보이고
화면 안쪽으로 -Z 축인건 맞은데 도대체 멀까나...
또한 축은 길이가 1 이지만, sin 곡선은 3.6 인데 중심축과 카메라의 거리가 1 이내에 있을때에는
sin 곡선도 잘리지 않음 -_-
(코드 붙여 넣고 보니.. scale을 1/4로 줘서 그렇군 .. 3.6 길이가 그러면 0.9가 되니 1 안에 들어옴)

gluLookAt(0.10, 0.0, 0.2, 0.0, 0.0, -2.0, 0.0, 1.0, 0.0)으로 설정했을 경우

gluLookAt(0.10, 0.0, 1.0, 0.0, 0.0, -2.0, 0.0, 1.0, 0.0)으로 설정했을경우

#include "GL/gl.h"
#include "GL/glu.h"
#include "GL/glut.h"
#include "math.h"

static int x_angle = 0, y_angle = 0, z_angle = 0;

void dump_matrix(GLint line)
{
	GLint idx;
	GLdouble mat[16];

	printf("*** LINE : %d\n",line);

	glGetDoublev(GL_MODELVIEW_MATRIX, mat);
	printf("GL_MODELVIEW_MATRIX\n");
		for(idx=0;idx<16;idx++)
		{
			printf("%f ",mat[idx]);
			if(idx % 4 == 3) printf("\n");
		}

	glGetDoublev(GL_PROJECTION_MATRIX, mat);
	printf("GL_PROJECTION_MATRIX\n");
		for(idx=0;idx<16;idx++)
		{
			printf("%f ",mat[idx]);
			if(idx % 4 == 3) printf("\n");
		}
	printf("\n");
}

void draw_sin()
{
	int temp;

	glPushMatrix();
//		glLoadIdentity();
		printf("angle [%d,%d,%d]\n",x_angle,y_angle,z_angle);
		glScalef(0.25,0.25,0.25);
		glRotated(x_angle,1,0,0);
		glRotated(y_angle,0,1,0);
		glRotated(z_angle,0,0,1);

		// X-axis - RED
		glColor3f(1.0, 0.0, 0.0);
		glBegin(GL_LINE);
			glVertex3f(0.0, 0.0, 0.0);
			glVertex3f(1.0, 0.0, 0.0);
		glEnd();

		// Y-axis - GRREN
		glColor3f(0.0, 1.0, 0.0);
		glBegin(GL_LINE);
			glVertex3f(0.0, 0.0, 0.0);
			glVertex3f(0.0, 1.0, 0.0);
		glEnd();

		// Z-axis - BLUE
		glColor3f(0.0, 0.0, 1.0);
		glBegin(GL_LINE);
			glVertex3f(0.0, 0.0, 0.0);
			glVertex3f(0.0, 0.0, 1.0);
		glEnd();

		glColor3f(1.0, 1.0, 1.0);
		glBegin(GL_LINE_STRIP);
			for(temp = 0; temp < 360; temp++)
			{
				glVertex3f(0.01*temp,sin(3.1415927/180*temp),0);
			}
		glEnd();
	glPopMatrix();
}

void display(void)
{
	glClear(GL_COLOR_BUFFER_BIT);

	glMatrixMode(GL_MODELVIEW); //GL_PROJECTION
	glPushMatrix();
		glViewport(0, 0, 250, 250); 
		gluLookAt(0.10, 0.0, 0.2, 0.0, 0.0, -2.0, 0.0, 1.0, 0.0);
		draw_sin();
	glPopMatrix();

	glPushMatrix();
		glViewport(250, 0, 250, 250); 
		gluLookAt(0.2, 0.0, 0.2, 0.0, 0.0, -2.0, 0.0, 1.0, 0.0);
		draw_sin();
	glPopMatrix();

	glutSwapBuffers();
}

void reshape(int w, int h)
{
	glViewport(0, 0, (GLsizei) w, (GLsizei) h); 
#if 0
	glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0);
#endif
#if 0
	glMatrixMode(GL_MODELVIEW); //GL_PROJECTION
		glLoadIdentity();
		gluLookAt(0.0, 0.0, 0.0, 0.0, 0.0, -100.0, 0.0, 1.0, 0.0);
#endif
//	dump_matrix(__LINE__);
}

void keyboard(unsigned char key, int x, int y)
{
	printf("key[%d] x[%d] y[%d]\n",key,x,y);
	switch (key)
	{
	  default:
		  break;
	}
}

void keyboard_spe(int key, int x, int y)
{
	printf("key[%d] x[%d] y[%d]\n",key,x,y);
	switch (key)
	{
		case GLUT_KEY_F1:
		case GLUT_KEY_F2:
		case GLUT_KEY_F3:
		case GLUT_KEY_F4:
		case GLUT_KEY_F5:
		case GLUT_KEY_F6:
		case GLUT_KEY_F7:
		case GLUT_KEY_F8:
		case GLUT_KEY_F9:
		case GLUT_KEY_F10:
		case GLUT_KEY_F11:
		case GLUT_KEY_F12:
			break;
		case GLUT_KEY_LEFT:
			y_angle = (y_angle - 15) % 360;
			glutPostRedisplay();
			break;
		case GLUT_KEY_RIGHT:
			y_angle = (y_angle + 15) % 360;
			glutPostRedisplay();
			break;
		case GLUT_KEY_UP:
			x_angle = (x_angle + 15) % 360;
			glutPostRedisplay();
			break;
		case GLUT_KEY_DOWN:
			x_angle = (x_angle - 15) % 360;
			glutPostRedisplay();
			break;
		case GLUT_KEY_PAGE_UP:
			z_angle = (z_angle + 15) % 360;
			glutPostRedisplay();
			break;
		case GLUT_KEY_PAGE_DOWN:
			z_angle = (z_angle - 15) % 360;
			glutPostRedisplay();
			break;
		case GLUT_KEY_HOME:
		case GLUT_KEY_END:
		case GLUT_KEY_INSERT:
			break;

		default:
			break;
	}
}

void mouse(int button, int state, int x, int y)
{
	printf("button[%d] state[%d] x[%d] y[%d]\n",button,state,x,y);
	switch(button)
	{
		case GLUT_LEFT_BUTTON:
			break;
		case GLUT_MIDDLE_BUTTON:
			break;
		case GLUT_RIGHT_BUTTON:
			break;
	}

	switch(state)
	{
		case GLUT_UP:
			break;
		case GLUT_DOWN:
			break;
	}
}

void mouse_motion(int x, int y)
{
	printf("motion x[%d] y[%d]\n",x,y);
}

void mouse_passive(int x, int y)
{
	printf("passive x[%d] y[%d]\n",x,y);
}

void idlefunc()
{
	glutPostRedisplay();
}

void timerfunc(int value)
{
	glutTimerFunc(1000, timerfunc, 0);
}

void entry(int state)
{
	printf("entry state[%d]\n",state);
	switch(state)
	{
		case GLUT_LEFT:
			break;
		case GLUT_ENTERED:
			break;
	}
}

void visibility(int state)
{
	printf("visibility state[%d]\n",state);
	switch(state)
	{
		case GLUT_NOT_VISIBLE:
			break;
		case GLUT_VISIBLE:
			break;
	}
}

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);

	// GLUT Window
	glutInitWindowSize(500, 500); 
	glutInitWindowPosition(100, 100);
	glutCreateWindow(argv[0]);

	glClearColor(0.0, 0.0, 0.0, 0.0);
//	glShadeModel(GL_FLAT); //GL_SMOOTH

	glutDisplayFunc(display); 				// Draw callback
//	glutReshapeFunc(reshape);				// Draw callback
	glutKeyboardFunc(keyboard);			// Keyboard callback
	glutSpecialFunc(keyboard_spe);			// Keyboard callback
//	glutMouseFunc(mouse);				// Mouse callback
//	glutMotionFunc(mouse_motion);			// Mouse callback
//	glutPassiveMotionFunc(mouse_passive);	// Mouse callback
//	glutIdleFunc(idlefunc);					// Period callback
//	glutTimerFunc(1000, timerfunc, 0);		// Period callback
//	glutEntryFunc(entry);					// Window callback
//	glutVisibilityFunc(visibility);				// Window callback

	glutMainLoop();
	return 0;
}