Pastel Soften

#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif

uniform vec2 resolution;
uniform vec2 cameraAddent;
uniform mat2 cameraOrientation;
uniform samplerExternalOES cameraBack;
uniform sampler2D backbuffer;
uniform int pointerCount;
uniform vec2 touch;

vec3 at_cam(vec2 offset)
{
    vec2 uv = (gl_FragCoord.xy + offset) / resolution.xy;
    vec2 st = cameraAddent + uv * cameraOrientation;
    return texture2D(cameraBack, st).rgb;
}

vec3 at_back(vec2 offset)
{
    vec2 uv = (gl_FragCoord.xy + offset) / resolution.xy;
    return texture2D(backbuffer, uv).rgb;
}

void main(void) {

  const int layers = 8;
  const int range = 5;

  float lyf = float(layers-1);
    const int hlist_size = layers;
    vec2 tuv = touch / resolution.xy;

    float final;
  if (pointerCount == 0) {
    final = at_back(vec2(0)).r;
  } else if (tuv.y > 0.3) {
    float hlist[hlist_size];
    for (int i = 0; i < hlist_size; i++)
      hlist[i] = 0.0;
    final = at_back(vec2(0)).r;
    int greatest = int(final*lyf);
    for (int dx = -range; dx <= range; dx++) {
        for(int dy = -range; dy <= range; dy++) {
            vec2 delta = vec2(dx, dy);
            if (delta == vec2(0))
              continue;
            float value = at_back(delta).r;
            int hash = int(value*lyf);
            hlist[hash] += exp(1.0-length(delta));
            if(hlist[hash] > hlist[greatest]) {
                greatest = hash;
                final = value;
            }
        }
    }
  } else {
    vec3 cam = at_cam(vec2(0));
    float lum = (cam.r + cam.g + cam.b) / 3.0;
    final = floor(lum*(lyf-1.0))/(lyf-1.0);
  }

    gl_FragColor = vec4(vec3(final), 1);
}