1 precision mediump float;

     2 

     3 uniform vec3 blob1;

     4 uniform vec3 blob2;

     5 uniform vec3 blob3;

     6 

     7 

     8 uniform float offset;

     9 uniform float threshold;

    10 varying vec2  texCoord;

    11 

    12 void main()

    13     {

    14     vec2  fp = texCoord;//vec2(gl_FragCoord[0], gl_FragCoord[1]);

    15 

    16     vec2  p1 = vec2(blob1[0], blob1[1]);

    17     float d1 = distance(fp,p1);

    18     float acc = blob1[2]/(d1*d1);

    19 

    20     vec2  p2 = vec2(blob2[0], blob2[1]);

    21     float d2 = distance(fp,p2);

    22     acc += blob2[2]/(d2*d2);

    23 

    24     vec2  p3 = vec2(blob3[0], blob3[1]);

    25     float d3 = distance(fp,p3);

    26     acc += blob3[2]/(d3*d3);

    27 

    28     float col = 1.0-((acc/threshold)-offset);

    29     if (col < 0.35)

    30        {

    31        col = 0.35;

    32        }

    33 

    34     gl_FragColor = vec4(col*0.6,col*0.72,col*0.77,1.0);

    35     }