Resizing window skewes display (OpenGL) - c++

Question

I am making a program that bounces balls of the edge of its window, but I'm having issues with the bounds getting skewed.
If I set the initial resolution to a square window,
int windowWidth = 600;
int windowHeight = 600;
it works fine. As soon as I reshape the window, the bounds on the window get skewed.
When it's square, it looks like this:
When I stretch it by its width, it looks like this:
When I stretch it by its height, it looks like this:
Basically I'm not able to resize the window without skewing the bounds of the window.
This is the code for my reshape function:
void reshape(GLsizei weight, GLsizei height)
{
if (height == 0) height = 1; // To prevent divide by 0
GLfloat aspect = (GLfloat)weight / height; // Get aspect ratio
// Set the viewport to cover the entire window
glViewport(0, 0, weight, height);
// Adjust the aspect ratio of clipping area to match the viewport
glMatrixMode(GL_PROJECTION); // Select the Projection matrix
glLoadIdentity(); // Reset
for (int i = 0; i < numOfBalls; i++)
{
if (weight <= height)
{
balls[i].xLeft = -1.0;
balls[i].xRight = 1.0;
balls[i].yBottom = -1.0 / aspect;
balls[i].yTop = 1.0 / aspect;
}
else
{
balls[i].xLeft = -1.0 * aspect;
balls[i].xRight = 1.0 * aspect;
balls[i]. yBottom = -1.0;
balls[i]. yTop = 1.0;
}
gluOrtho2D(balls[i].xLeft, balls[i].xRight, balls[i].yBottom, balls[i].yTop);
balls[i].xPosMin = balls[i].xLeft + balls[i].ballRadius;
balls[i].xPosMax = balls[i].xRight - balls[i].ballRadius;
balls[i].yPosMin = balls[i].yBottom + balls[i].ballRadius;
balls[i].yPosMax = balls[i].yTop - balls[i].ballRadius;
}
glMatrixMode(GL_MODELVIEW); // Select the model-view matrix
glLoadIdentity(); // Reset
}
*Note: I can post more code if needed...

Answer 1

Try cut this from your loop:
gluOrtho2D(balls[i].xLeft, balls[i].xRight, balls[i].yBottom, balls[i].yTop);
and define your orthographic matrix once.
I think whenever your loop execute, you multiply a new matrix with previously inserted matrix in GL.
The produced orthographic matrix by GL is this:
Now when you set width: 800 and height: 600 your aspect ratio will be 1.33 and matrix for first loop will be:
Now by each loop, GL will multiply new matrix with previous matrix and coordinates will get closer by multiply each by 0.75.
(Also i am not sure)