
	  
	    t:
	    dt:
	    fps:
	    avg fps:

	    frames per phys:
	    
	    
	    

	    phys dt:
	    
	    use measured dt
	    * 
	  
let dir = keys_down.has("ArrowRight") - keys_down.has("ArrowLeft");
let h_hat = r90ccw(gravity); h_hat.mag = 1;
if (h_hat[0] < 0 || h_hat[1] < 0 || mousedown) h_hat = minus(h_hat);
const current_speed = vel.dot(h_hat);
const desired_speed = movement_speed * dir;
const friction = onGround? movement_accel : (keys_down.has("ArrowLeft") || keys_down.has("ArrowRight"))?air_accel:air_hdrag;
accel = plus(accel,times(h_hat,friction*(desired_speed-current_speed)));
ok
collision state: