OpenGL

#include <GL/glut.h>
#define Height 512
#define Width 512


void displayRectangleWithLinesAndPoints(void)
{
   glClear(GL_COLOR_BUFFER_BIT);


   // Define the size of the rectangle
   GLfloat height = 0.5;
   GLfloat width = 1.0;


   // Calculate the coordinates to center the rectangle
   GLfloat xLeft = -width / 2.0;
   GLfloat xRight = width / 2.0;
   GLfloat yBottom = -height / 2.0;
   GLfloat yTop = height / 2.0;


   // Draw the rectangle
   glBegin(GL_LINES);
   glColor3f(0.0, 0.0, 1.0); // Set color to blue


   // Bottom side
   glVertex3f(xLeft, yBottom, 0.0);
   glVertex3f(xRight, yBottom, 0.0);


   // Right side
   glVertex3f(xRight, yBottom, 0.0);
   glVertex3f(xRight, yTop, 0.0);


   // Top side
   glVertex3f(xRight, yTop, 0.0);
   glVertex3f(xLeft, yTop, 0.0);


   // Left side
   glVertex3f(xLeft, yTop, 0.0);
   glVertex3f(xLeft, yBottom, 0.0);
   glEnd();


   // Draw the mid vertical line
   glBegin(GL_LINES);
   glColor3f(1.0, 0.0, 0.0); // Set color to red
   glVertex3f(0.0, yBottom, 0.0); // Start point of the line
   glVertex3f(0.0, yTop, 0.0);    // End point of the line
   glEnd();


   // Draw the mid horizontal line
   glBegin(GL_LINES);
   glColor3f(1.0, 0.0, 0.0); // Set color to red
   glVertex3f(xLeft, 0.0, 0.0); // Start point of the line
   glVertex3f(xRight, 0.0, 0.0); // End point of the line
   glEnd();


   // Calculate midpoints
   GLfloat xMidVertical = 0.0;
   GLfloat yMidHorizontal = 0.0;


   // Draw points at the midpoints and four points at each side
   glBegin(GL_POINTS);
   glColor3f(0.0, 1.0, 0.0); // Set color to green


   // Midpoint of the vertical line
   glVertex3f(xMidVertical, (yBottom + yTop) / 2.0, 0.0);


   // Midpoint of the horizontal line
   glVertex3f((xLeft + xRight) / 2.0, yMidHorizontal, 0.0);


   // Center of the rectangle
   glVertex3f((xLeft + xRight) / 2.0, (yBottom + yTop) / 2.0, 0.0);


   // Midpoint of the diagonal line from bottom-left to top-right
   glVertex3f((xLeft + xRight) / 2.0, (yBottom + yTop) / 2.0, 0.0);


   // Four points at each side
   glVertex3f(xLeft/2, 0.1, 0.0);
   glVertex3f(xLeft + (xRight) / 2.0, yBottom/2, 0.0);
   glVertex3f(xRight/2, 0.1, 0.0);
   glVertex3f(( xRight) / 2.0, yBottom+yTop/2, 0.0);


   glEnd();


   glFlush();
}


int main(int argc, char **argv)
{
   glutInit(&argc, argv);
   glutInitWindowSize(Width, Height);
   glutInitWindowPosition(10, 10);
   glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE); // Removed GLUT_DEPTH, using GLUT_SINGLE for simplicity


   glutCreateWindow("Rectangle Example with Midpoints and Points on Sides");
   glutDisplayFunc(displayRectangleWithLinesAndPoints);
   glutMainLoop();


   return 0;
}