uniform float ElapsedTime;

void main()
{
    vec4 v = vec4(gl_Vertex);

    //v.y = 0.0;
    v.y = sin(5.0 * v.x + ElapsedTime*0.01)*0.25;

    gl_Position   = gl_ModelViewProjectionMatrix * v;
    gl_FrontColor = gl_Color;
}