Function lookAt

docs/app/js/sanddance-app.js:73912–73976

(out, eye, center, up)

    return out;
}
function lookAt(out, eye, center, up) {
    var x0, x1, x2, y0, y1, y2, z0, z1, z2, len;
    var eyex = eye[0];
    var eyey = eye[1];
    var eyez = eye[2];
    var upx = up[0];
    var upy = up[1];
    var upz = up[2];
    var centerx = center[0];
    var centery = center[1];
    var centerz = center[2];
    if (Math.abs(eyex - centerx) < _commonJs.EPSILON && Math.abs(eyey - centery) < _commonJs.EPSILON && Math.abs(eyez - centerz) < _commonJs.EPSILON) return identity(out);
    z0 = eyex - centerx;
    z1 = eyey - centery;
    z2 = eyez - centerz;
    len = 1 / Math.hypot(z0, z1, z2);
    z0 *= len;
    z1 *= len;
    z2 *= len;
    x0 = upy * z2 - upz * z1;
    x1 = upz * z0 - upx * z2;
    x2 = upx * z1 - upy * z0;
    len = Math.hypot(x0, x1, x2);
    if (!len) {
        x0 = 0;
        x1 = 0;
        x2 = 0;
    } else {
        len = 1 / len;
        x0 *= len;
        x1 *= len;
        x2 *= len;
    }
    y0 = z1 * x2 - z2 * x1;
    y1 = z2 * x0 - z0 * x2;
    y2 = z0 * x1 - z1 * x0;
    len = Math.hypot(y0, y1, y2);
    if (!len) {
        y0 = 0;
        y1 = 0;
        y2 = 0;
    } else {
        len = 1 / len;
        y0 *= len;
        y1 *= len;
        y2 *= len;
    }
    out[0] = x0;
    out[1] = y0;
    out[2] = z0;
    out[3] = 0;
    out[4] = x1;
    out[5] = y1;
    out[6] = z1;
    out[7] = 0;
    out[8] = x2;
    out[9] = y2;
    out[10] = z2;