Following code is working. but few things bothering me.
1. when I run the code, gluLookAt command has no effect.
2. z axis into the screen seems to be the positive.

please help to solve these two dilemmas

Code :
#include <GL/glut.h>
#include<GL/gl.h>
#include<GL/glu.h>
 
double rotate_y=0;
double rotate_x=0;
 
void reshape(int w, int h)
{
	glViewport(0,0,w,h);
 
	glMatrixMode(GL_PROJECTION);
		glLoadIdentity();
		glOrtho(-5,5,-5,5,-5,5);
 
		glLoadIdentity();
		gluLookAt(0.2,0,-2,0,-0.5,0,0,1,0);
}
 
void display(void)
{
	glClearColor(0,0,0,0);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
		glLoadIdentity();
		glRotatef( rotate_x, 1.0, 0.0, 0.0 );
		glRotatef( rotate_y, 0.0, 1.0, 0.0 );
 
 
	glColor3f(0,1,0);
	glBegin(GL_POLYGON);
		glVertex3f(0.5,-0.5,-1);
		glVertex3f(0.5,0.5,-1);
		glVertex3f(-0.5,0.5,-1);
		glVertex3f(-0.5,-0.5,-1);
	glEnd();
 
	glColor3f(1,0,0);
	glBegin(GL_POLYGON);
		glVertex3f(0.5,-0.5,-0.8);
		glVertex3f(0.5,0.5,-0.8);
		glVertex3f(-0.5,0.5,-0.8);
		glVertex3f(-0.5,-0.5,-0.8);
	glEnd();
 
	glColor3f(0,0,1);
	glBegin(GL_POLYGON);
		glVertex3f(0.5,-0.5,-0.2);
		glVertex3f(0.5,0.5,-0.2);
		glVertex3f(-0.5,0.5,-0.2);
		glVertex3f(-0.5,-0.5,-0.2);
	glEnd();
 
	glutSwapBuffers();
 
 
}
 
void specialKeys( int key, int x, int y ) {
 
  //  Right arrow - increase rotation by 5 degree
  if (key == GLUT_KEY_RIGHT)
    rotate_y += 5;
 
  //  Left arrow - decrease rotation by 5 degree
  else if (key == GLUT_KEY_LEFT)
    rotate_y -= 5;
 
  else if (key == GLUT_KEY_UP)
    rotate_x += 5;
 
  else if (key == GLUT_KEY_DOWN)
    rotate_x -= 5;
 
  //  Request display update
  glutPostRedisplay();
 
}
 
int main (int argc, char *argv[])
{
	glutInit(&argc, argv);
	glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowPosition(100,100);
	glutInitWindowSize(500,500);
	glutCreateWindow ("animating triangles");
	glEnable(GL_DEPTH_TEST);
	glutDisplayFunc(display);
	glutReshapeFunc(reshape);
	glutSpecialFunc(specialKeys);
	glutMainLoop ();
	return 0;
}