Preparing an orthographic projection matrix

Orthographic projection is another type of operation that transforms vertices from their local coordinate system to a clip space. But opposed to a perspective projection, it doesn't take a perspective division into account (doesn't simulate the way we perceive our surroundings). But similarly to a perspective projection, it is also represented by a 4x4 matrix, which we need to create in order to use this type of projection.

How to do it...

1. Create two variables of type float named left_plane and right_plane, and initialize them with the positions (on the x axis) of left and right clipping planes, respectively.
2. Prepare two variables of type float named bottom_plane and top_plane. Initialize them with positions of (on the y axis) of the bottom and top clipping planes, respectively.
3. Create two variables of type float named near_plane and far_plane. Use them to hold distances from the camera to the near and far clipping planes, respectively.
4. Create a variable...