#version 450 core
in vec2 vTexPos;
out vec4 fColor;
const vec2 winSize = vec2 (300.0,300.0);
// note that the above opening bracket should be the first in this file
// this is so that the window size can be extracted and the shader recompiled on
// the fly
layout (binding = 0) uniform sampler2D screenTexture;
// the 1.5 maximises the blend, so to speak
const float hOff = 1.5 / winSize.x;
const float vOff = 1.5 / winSize.y;
//const vec2 off[9] = vec2[]
//    ( vec2( hOff, vOff )
//    , vec2( hOff,  0.0 )
//    , vec2( hOff,-vOff )
//    , vec2(  0.0, vOff )
//    , vec2(  0.0,  0.0 )
//    , vec2(  0.0,-hOff )
//    , vec2(-hOff, vOff )
//    , vec2(-hOff,  0.0 )
//    , vec2(-hOff,-vOff )
//    );
const vec2 fiveOff[5] = vec2[]
    ( vec2( hOff, vOff )
    , vec2( hOff,-vOff )
    , vec2(  0.0,  0.0 )
    , vec2(-hOff, vOff )
    , vec2(-hOff,-vOff )
    );
void main()
{
    vec4 sumFive = vec4 (0.0,0.0,0.0,0.0);
    for (int i=0; i<5; i++)
    {
        sumFive += vec4(texture(screenTexture, vTexPos + fiveOff[i]));
    }
    //sumFive = sumFive * 3 * sin(dot(vTexPos,vTexPos) * 10000);
    //fColor = vec4 ( max( (sumFive / 10) , texture(screenTexture,vTexPos) ) );   
    fColor = vec4 ( max( (sumFive / 10) , texture(screenTexture,vTexPos) ) );   
    //fColor = max(texture(screenTexture,vTexPos), sumFive / 5);   
    //fColor = vec4 ( (sumFive / 5).rgb, max((sumFive/5.0).a,texture(screenTexture,vTexPos).a) );   
//    vec4 sampleTex[9];
//    for(int i=0; i<9; i++)
//    {
//        sampleTex[i] = vec4(texture(screenTexture, vTexPos + off[i]));
//    }
//    vec4 sampleFive[5];
//    for(int i=0; i<5; i++)
//    {
//        sampleFive[i] = vec4(texture(screenTexture, vTexPos + fiveOff[i]));
//    }
//    vec4 col = vec4(0,0,0,0);
//    for (int i = 0; i < 9; i++)
//        col = combinef(col,sampleTex[i]);
//        //col += sampleTex[i] * frac;
//    float alph = 0.0;
//    for (int i = 0; i < 9; i++)
//        //alph += sampleTex[i].a;
//        alph = max(alph, 0.5 * sampleTex[i].a);
//    alph = max(sampleTex[4].a, alph);
//        //
//    //fColor = col;
//    fColor = vec4(col.rgb/col.a,alph);
//    //if (col.a == 0.0)
//    //{ fColor = vec4(0,0,0,0); }
//    //else
//    //{ fColor = vec4( col.r/col.a , col.g/col.a , col.b/col.a, col.a/9.0); }
}