Can't get my FPS Camera working. WebGL demo and code included.

I’m trying to figure out how to make a fps camera but unfortunately stuck. I’ll briefly explain what I’m doing but I’ll also share my webgl code so you can see for yourself.

        // First I get the difference between the current mouse coords and the last. The html lock cursor api returns it and I store it in Game.Input.

	this.yaw += Game.Input.x * this.sensitivity;
	this.pitch += Game.Input.y * this.sensitivity;

        // I cap the pitch and yaw

	if (this.yaw < 0.0) this.yaw += 360.0;

	if (this.pitch > 89.0) {
		this.pitch = 89.0;
	if (this.pitch <  -89.0) {
		this.pitch = -89.0;

        // This is where I calculate the view matrix and use the pitch and yaw (by the way these are all matrices, JS doesn't really help specifying that)

        var view = Mathf.Mat4();

        var rotX = Mathf.rotateX(cam.pitch),
             rotY = Mathf.rotateY(-cam.yaw),
             rot  = Mathf.mul(rotX, rotY),
             pos  = Mathf.translate(cam.x, cam.y, cam.z),

             cam  = Mathf.Mat4();
            cam  = Mathf.mul(rot, pos);
            view = Mathf.inverse(cam);

        return view;

        // ... and in my game object draw function, I use the view matrix

	model 		= Mathf.mul(model, scale);
	normMat		= Mathf.transpose(Mathf.inverse(model));
	modelView 	= Mathf.mul(model, view);
	mvp 		         = Mathf.mul(modelView, projection);

Everything works fine, I see the world, I could translate left, right, forward and back if I coded those instructions. But I can’t seem to get the mouse look working, I clearly don’t understand the fps camera concept properly. I also understand that in order to walk towards the correct direction I’m looking at, I need a few more steps using the cross product, but at the moment I just want to look around and can’t seem to get it.

Hope this all makes sense :S Thanks!

WebGL Live Demo:,output

Oh by the way, I wrote my own Math lib, I’m aware that I could have used any popular one out there, but I wanted to learn. If you want to take a look at it (just in case I did something, wrong) it’s here:

I’ll go ahead and copy the rotateX and rotateY functions for your convenience since those are crucial in making the cam rotate.

    Mathf.rotateX = function (degree) {
        var r       = Mathf.Mat4(),
            angle   = Mathf.degToRad(degree),
            cos     = Math.cos(angle),
            sin     = Math.sin(angle);

        r[5] =  cos; r[6] = -sin;
        r[9] =  sin; r[10] = cos;

        return r;

    Mathf.rotateY = function (degree) {
        var r       = Mathf.identity(r),
            angle   = Mathf.degToRad(degree),
            cos     = Math.cos(angle),
            sin     = Math.sin(angle);

        r[0] = cos; r[2]  = -sin;
        r[8] = sin; r[10] =  cos; 

        return r;

One thing you could try: If you’re using the default OpenGL coordinates (x at right, y at top and z going out of the screen), you can try to rotate around x first. Then using the resulted matrix rotate around its y axis vector.

Thanks Silence, I’ll give it a try, although I’m going to probably end up re-writing this function again. I want to make sure I understand this concept. I’ll definitely share my function here on this thread once I have it ready.