#ifdef GL_ES

precision mediump float;

#endif

uniform vec4 infiniteRect;

uniform vec4 inputBBox[1];

varying vec4 outputBBox;

uniform vec2  center;

uniform float radius;

uniform float blur;

void addPoint(inout vec4 rect, vec2 p) {

  rect.xy = min(rect.xy, p);

  rect.zw = max(rect.zw, p);

}

void addBlurredPointBox(inout vec4 rect, vec2 p)

{

  vec2 v        = p - center;

  float vLength = length(v);

  float dist    = max(length(v) - radius, 0.0);

  float b       = blur * dist;

  v *= (b / max(vLength, 0.01));

  addPoint(rect, p - v);

  addPoint(rect, p + v);

}

void main( void )

{

  outputBBox = inputBBox[0];

  if(outputBBox != infiniteRect)

  {

    // Add the bounding box of each blurred corner

    addBlurredPointBox(outputBBox, inputBBox[0].xy);

    addBlurredPointBox(outputBBox, inputBBox[0].xw);

    addBlurredPointBox(outputBBox, inputBBox[0].zy);

    addBlurredPointBox(outputBBox, inputBBox[0].zw);

  }

  gl_Position = vec4(0.0);                            // Does not link without

}