mouse move

gistfile1.js

function mouseMove(e) {
    var cw = c.width;
    var ch = c.height;
    var wh = 1 / Math.sqrt(cw * cw + ch * ch);
    var x = e.clientX - c.offsetLeft - cw * 0.5;
    var y = e.clientY - c.offsetTop - ch * 0.5;
    var sq = Math.sqrt(x * x + y * y);
    var r = sq * 2.0 * Math.PI * wh;
    if (sq != 1) {
        sq = 1 / sq;
        x *= sq;
        y *= sq;
    }
    q.rotate(r, [y, x, 0.0], qt);
}