anchor.diff:  
   void main()
   {
  -	outputColor = imageFilter(fragCoords);
  +	outputColor = vec4(fragColor, 1.0) + imageFilter(UV);
   }
positive.code: #version 330
  
  im vec3 viewPortResolution; //viewport resoltuion
  in float textureResolution; //texture resolution
  in sampler2D texture; // 2D texture
  in vec2 fragCoords; // Coordinates of the pixel
  
  out vec4 outputColor; // Final color
  
  vec4 imageFilter(in vec2 fragCoord)
  {
  	vec2 p = fragCoord.xy / viewPortResolution.xy;
  	vec2 uv = p * 1.0; // This is to scale the texture (1.0 being original size)
  
  	uv = uv * textureResolution + 0.5;
  
  	vec2 iuv = floor(uv);
  	vec2 fuv = fract(uv);
  
negative.code: 
  	uv = (uv - 0.5) / textureResolution;
  
  	vec3 color = texture(textureSampler, uv).xyz;
  	
  	vec4 fragColor = vec4(color, 1.0);
  
  	return fragColor;
  