Edge Scroll Problem

So I threw together a quick script to use the mouse as a way to navigate my game. It is somewhat simple, but it won't work. Not just straight out though. The far right of the screen (4th if statement?) works fine with no issues.

var zspeed = 10.0; //ignore var xspeed = 10.0; //ignore var yscale = Screen.height / 2.0; var xscale = Screen.width / 2.0; function Update () { var ypos = Screen.height / 2.0 - Input.mousePosition.y; var xpos = Screen.width / 2.0 - Input.mousePosition.x; if(Input.mousePosition.y == 0) { transform.position.z -= Time.deltaTime * zspeed; transform.position.x -= xpos / xscale * Time.deltaTime * xspeed; } if(Input.mousePosition.y == Screen.height) { transform.position.z += Time.deltaTime * zspeed; transform.position.x -= xpos / xscale * Time.deltaTime * xspeed; } if(Input.mousePosition.x == 0) { transform.position.z -= ypos / yscale * Time.deltaTime * xspeed; transform.position.x -= Time.deltaTime * zspeed; } if(Input.mousePosition.x == Screen.width) { transform.position.z -= ypos / yscale * Time.deltaTime * xspeed; transform.position.x += Time.deltaTime * zspeed; } }

The script moves a camera. When the mouse is at one side of the screen, the camera moves in that general direction, but there is also a formula to see exactly where the mouse is along the edge of the screen to move the camera in that direction too. I'm bad at explaining things, but if you have questions please ask. I really want this solved so thanks to anybody who leaves a response