bool GraphicsUtil::linesCross(b2Vec2 v0, b2Vec2 v1, b2Vec2 t0, b2Vec2 t1, b2Vec2 &intersectionPoint){    if ( areVecsEqual(v1,t0) ||        areVecsEqual(v0,t0) ||        areVecsEqual(v1,t1) ||        areVecsEqual(v0,t1) )        return false;    b2Vec2 vnormal = v1 - v0;    vnormal = b2Cross(1.0f, vnormal);    float v0d = b2Dot(vnormal, v0);    float t0d = b2Dot(vnormal, t0);    float t1d = b2Dot(vnormal, t1);    if ( t0d > v0d && t1d > v0d )        return false;    if ( t0d < v0d && t1d < v0d )        return false;    b2Vec2 tnormal = t1 - t0;    tnormal = b2Cross(1.0f, tnormal);    t0d = b2Dot(tnormal, t0);    v0d = b2Dot(tnormal, v0);    float v1d = b2Dot(tnormal, v1);    if ( v0d > t0d && v1d > t0d )        return false;    if ( v0d < t0d && v1d < t0d )        return false;    intersectionPoint = v0 + ((t0d-v0d)/(v1d-v0d)) * (v1-v0);    return true;}