uniform float time;
uniform vec2 resolution;
uniform vec2 mouse;
uniform sampler2D backBuffer;

void main(void)
{

    vec2 uv = gl_FragCoord.xy/resolution.xy;
	vec4 c0 = texture2D(backBuffer,uv).rgba;
             uv = (gl_FragCoord.xy + vec2(5.0,5.0)) /resolution.xy;
             vec4 c1 = texture2D(backBuffer,uv).rgba;

  float y = (0.222 * c1.r) + (0.707 * c1.g) + (0.071 * c1.b);
  float y2 = ((0.222 * c0.r) + (0.707 * c0.g) + (0.071 * c0.b)) / 3.0;
  float red   = c0.r;
  float green = c0.g;
  float blue  = c0.b;
  float alpha = c0.a;
  
  red   = y2 + (1 - y);
  green = y2 + (1 - y);
  blue  = y2 + (1 - y);

    gl_FragColor = vec4(red,green,blue,alpha);
}