Unable to display a vertex in the world - c++

Question

I am not able to plot the vertex glVertex2f( 10.0, 0.0 ) in the window, but when I use points like 0.8 it shows up.
Height = 640
Width = 480
So, I might be able to plot points in this range I guess. Can anyone point out the mistake and correct it?
Code:
#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif
#include <cstdlib>
//defining constants
#define MAX_WIDTH 640
#define MAX_HEIGHT 480
//display callback function
void display(){
glClear( GL_COLOR_BUFFER_BIT );
glPointSize( 5 );
glLoadIdentity();
gluLookAt( 0.0, 0.0, 0.0, 0.0, 0.0, 5.0, 0.0, 1.0, 0.0 );
glBegin( GL_POINTS );
//setting the pointer color
glColor3f( 1.0, 1.0, 1.0 );
glVertex2f( 0.0, 0.0 );
glVertex2f( 10.0, 0.0 );
glEnd();
glFlush();
}
//catching keyboard events
void keyboardEvent( unsigned char c, int x, int y ){
if( c == 27 ){
exit(0);
}
}
//catching mouse click events
void mouseEvent( int button, int state, int x, int y ){
//checking if the mouse button is clicked or not using state para.
if( state == GLUT_DOWN ){
if( button == GLUT_LEFT_BUTTON ){
}
else if( button == GLUT_RIGHT_BUTTON ){
}
}
}
//adjusting window when it is moved or resized
void reshape( int w, int h ){
glViewport( 0, 0, w, h );
}
//initialising the window at startup
void initialise(){
glClearColor( 0.0, 0.0, 0.0, 1.0 );
gluOrtho2D( 0, MAX_WIDTH, 0, MAX_HEIGHT );
}
int main( int argc, char **argv ){
//initialising the glut library
glutInit( &argc, argv );
glutInitDisplayMode( GLUT_SINGLE | GLUT_RGB );
glutInitWindowSize( MAX_WIDTH, MAX_HEIGHT );
glutInitWindowPosition( 100, 100 );
glutCreateWindow("DDA Assignment");
//calling normal functions
initialise();
//registering callback functions
glutDisplayFunc( display );
glutKeyboardFunc( keyboardEvent );
glutMouseFunc( mouseEvent );
glutReshapeFunc( reshape );
glutMainLoop();
return 0;
}

Answer 1

The glLoadIdentity() in display() is wiping out the matrix set by gluOrtho2D() in initialise().