layout (location=0) in vec2 a_co;

uniform vec4 uOffset;

void main()
{
   float fbarx = (a_co.x+uOffset.x) * uOffset.z;
   float fbary = a_co.y*uOffset.w + uOffset.y;

   vec2 vpos = vec2( fbarx, fbary );
   gl_Position = vec4(vpos,0.0,1.0);
}