How can I add in my XY axis?

I have been at this project for weeks…and it finally works!! yay!!! But now I have a new problem…I want to be able to just show the X and Y axis throughout my entire animation. I have tried plugging in this code snippet but I can’t figure out where the correct placement would be. I have tried pushing and popping, and putting it in different locations within my display function, but I have yet to see any lines drawn…any suggestions?

Code Snippet:

	glColor3f(1.0, 1.0, 1.0);
	
	glBegin(GL_LINE);
		glVertex2f(400, 0);
		glVertex2f(400, 800);
	glEnd();
	
	glBegin(GL_LINE);
		glVertex2f(0, 400);
		glVertex2f(800, 400);
	glEnd();

And here is my amazing program in all of it’s glory! It’ s a very simple animation showing how rotation is done in openGL.

#include <stdlib.h>
#include <stdio.h>
#include <GLUT/glut.h>




float yPosition = 0;
float zPosition = 0;
float topLeftX = 0.5;
float topLeftY = 0.75;
float topRightX = 0.75;
float topRightY = 0.75;
float bottomRightX = 0.75;
float bottomRightY = 0.5;
float bottomLeftX = 0.5;
float bottomLeftY = 0.5;
float xPos = 0.75;
float yPos = 0.75;
float zPos = 0;
float startXPos = 0.75;
float startYPos = 0.75;
int yDirection = 0; //1-up, 0-down
int xDirection = 0; //1-stopped, 0-left, 2- right
int yRotate = 0;	//0- rotate, 1- stop rotating
int zRotate = 0;	//0- rotate, 1- stop rotating
int count;

//the init function is used to initialize things that only need to be execute once
void init()
{
	glClearColor(1.0,1.0,1.0,0.0);
	glEnable(GL_DEPTH_TEST);
}

void setWindow(double left, double right, double bottom, double top)
{
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-1.0, 1.0, -1.0, 1.0, -1.0, 1.0);
}

void setViewport(int left, int right, int bottom, int top)
{
	glViewport(left, bottom, right-left, top-bottom);
}

//function for drawing, called whenever there needs to be a redraw
void display(void)
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);	
	

	glColor3f(1,0,0);
	
	glPushMatrix();
	
	glTranslated(xPos, yPos, 0);
	
	glRotatef(yPosition, 0, 1, 0);
	glRotatef(zPosition, 0, 0, 1);

		if (xDirection==0){			//if moving left
			xPos-=0.0005;			//move in a negative direction along the xaxis	
			yPos = (startYPos*xPos/startXPos);
			
			glutPostRedisplay();
		}
	
		if (xDirection==1) {
			xPos==0.0;
			yPos==0.0;
			
			yPosition+=0.05;
			zPosition+=0.05;
			
			glutPostRedisplay();
		}
		
		if (xDirection==2){		
			xPos+=0.0005;			//move in a negative direction along the xaxis	
			yPos = (startYPos*xPos/startXPos);
			glutPostRedisplay();
		}
	
		if (xDirection==3) {
			xPos==0.0;
			yPos==0.0;
			glutPostRedisplay();
		}
	
		
		if (xDirection==0 && xPos > 0.0) {
			xDirection=0;
		}
		if (xDirection==0 && xPos < 0.0) {
			xDirection=1;			//stop at origin
		}
		if (xDirection==1 && yPosition > 45.0) {
			xDirection=2;
		}
		if (xDirection==2 && xPos==startXPos) {
			xDirection=3;
		}
	
	//glutWireCube(.25);
	
	glBegin(GL_POLYGON);
		glVertex2f(-0.1, -0.1);	//bottom left
		glVertex2f(-0.1,0.1);	//top left
		glVertex2f(0.1, 0.1);	//top right
		glVertex2f(0.1, -0.1);	//bottom right
	glEnd();
	
	glPopMatrix();

	glutSwapBuffers();
}

void reshape (int w, int h)
{
	glViewport (0, 0, (GLsizei) w, (GLsizei) h);
	glMatrixMode (GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(60.0, (GLfloat) w/ (GLfloat) h, 1.0, 20.0);
	glMatrixMode (GL_MODELVIEW);
	glLoadIdentity();
	gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
}

void keyboard(unsigned char key, int x, int y)
{
	switch (key) {
			
		case 27: 
			exit(0);
			break;			
		case 'y':
			yPosition=yPosition+5;
			if (yPosition>360)
				yPosition=0;
			glutPostRedisplay();
			break;		
		case 'z':
			zPosition=zPosition+5;
			if (zPosition>360)
				zPosition=0;
			glutPostRedisplay();
			break;	
	}
}

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode (GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);  //double pixel buffer that holds RGB 
	glutInitWindowSize(800, 800);
	glutInitWindowPosition(0,0);
	
	glutCreateWindow(argv[0]);

	init();
	
	glutDisplayFunc(display);
	glutReshapeFunc(reshape);
	//glutKeyboardFunc(keyboard);
	glutMainLoop();
	return 0;
}


I would expect to do it after the popMatrix in the display function. But you vertex values look wrong if you are using that glOrtho function since it says
your x values will range from -1 -> 1 and y from -1 -> 1 but your axis draw code is in screen coordinates.

Thank you for your reply, I actually never call the setWindow function where the glOrtho function is so I thought that using the screen coordinates would work?

Found the problem! I needed insert the code snippet where tonyo_au suggested, but I needed a push and a pop surrounding the snippet.

Thank you!!!