Hi, recently I'm trying to make a perspective projection matrix for OpenGL. I've been successful so far, the perspectivity itself is working. My problem is with the aspect ratio: when I render a cube, it is stretched when the aspect ratio isn't 1. I've found a similar question in the forum that was marked as solved but that didn't help me. The aspect ratio is correct, it's printed out when resized.

One weird behaviour I encountered is that when the aspect ratio is between 2 and 3, the projection works as expected, so when I toggle between 1.9 and 2 the cube on the screen scales immediately in one direction.

Here is my matrix (I know that it's row major):

float b,t,l,r,n,f,an;
n = 0.1;
f = 100;
an = 3.14/2;
	
t = tan(an/2) * n;
b = -t;
r = t*ar;
l = -r;

float p[] = {
	2*n/(r-l),	0,			(r+l)/(r-l),	0,
	0,			2*n/(t-b),	(t+b)/(t-b),	0,
	0,			0,			-(f+n)/(f-n),	-2*f*n/(f-n),
	0,			0,				-1,				0
};

In my own projects, I use this one (column-major):

• a is the aspect ratio.
• angle is the field of view

getPerspectiveProjection(angle, a, zMin, zMax) {
        var ang = Math.tan(angle * Math.PI / 360);
        return [
            0.5 / ang, 0, 0, 0,
            0, 0.5 * a / ang, 0, 0,
            0, 0, -(zMax + zMin) / (zMax - zMin), -1,
            0, 0, (-2 * zMax * zMin) / (zMax - zMin), 0
        ];
    }

If you copy & pasted your code, please tell me what ar is, and if right is just negative left then two of the terms in your matrix are equal to zero. (I wager that the perspective projection matrix you googled is flat-out wrong!)