uniform float alpha_value;
uniform float time;


void main(void)
{ 
   vec4 color;
   color.x = 1.0;
   color.y = 1.0;
   color.z = 0.0;
   color.w =  alpha_value * ((sin(time * 5.0) + 1.0) / 2.0 );
   gl_FragColor = color;
 
   
}