///////////////////////////////////////////////////////////////////////////////
//
//      ##  ######
//       ######  ###
//  ## ###############        Shark 3D Engine (www.shark3d.com)
//   ########## # # #
//    ########                Copyright (c) 1996-2006 Spinor GmbH.
//   ######### # # #          All rights reserved.
//  ##   ##########
//      ##
//
///////////////////////////////////////////////////////////////////////////////

uniform sampler2D tex0;

uniform vec4 passInfo;

varying vec4 baseVec;

void main(void)
{
    vec2 mainTexCoord = gl_TexCoord[0].xy;
    vec2 offsPix0 = baseVec.xy;
    vec2 offsPix1 = baseVec.zw;
    vec2 offsPix2 = offsPix0 + offsPix1;
    vec2 offsPix3 = offsPix0 - offsPix1;

    vec4 val = texture2D(tex0, mainTexCoord);
    vec4 val0 = texture2D(tex0, mainTexCoord.xy + offsPix0);
    vec4 val1 = texture2D(tex0, mainTexCoord.xy + offsPix1);
    vec4 val2 = texture2D(tex0, mainTexCoord.xy + offsPix2);
    vec4 val3 = texture2D(tex0, mainTexCoord.xy + offsPix3);
    vec4 val4 = texture2D(tex0, mainTexCoord.xy - offsPix0);
    vec4 val5 = texture2D(tex0, mainTexCoord.xy - offsPix1);
    vec4 val6 = texture2D(tex0, mainTexCoord.xy - offsPix2);
    vec4 val7 = texture2D(tex0, mainTexCoord.xy - offsPix3);

    vec4 sum
        = (val * val + val0 * val0 + val1 * val1 + val2 * val2 + val3 * val3
        + 0.5 * (val4 * val4 + val5 * val5 + val6 * val6 + val7 * val7))
        * 0.142857; // = approx. 1.0 / 7.0

   gl_FragColor = sqrt(sum);
}

///////////////////////////////////////////////////////////////////////////////