var KERNEL_SIZE=2;
var KERNEL_LOOP=KERNEL_SIZE/2-0.5;
var KERNEL_CONTRIBUTIONS=KERNEL_SIZE*KERNEL_SIZE;

//#GLSLSource
pub.buildShader=function(features) {
    var shadowMapSampler = "\n"+
    "const float shadowTexelSize=1.0/2048.0;\n"+
    //When dot-producted with the packed values in the shadow map will produce a Z value in the range 0-1
    "const vec4 bitShifts=vec4(1.0/(256.0*256.0*256.0),1.0/(256.0*256.0),1.0/256.0,1.0);\n"+
    "float rand(vec2 co){\n"+
    "    return fract(sin(dot(co.xy,vec2(12.9898,78.233)))*43758.5453);\n"+
    "}\n"+
    "float ShadowMapSamplerStochastic(vec4 sunShadowMapPosition, sampler2D sunShadowMap, float shadowStrength) {\n"+
    "   float shadowEffect;\n"+
    "   vec3 shadowMapTexel=sunShadowMapPosition.xyz/sunShadowMapPosition.w;\n"+
    "   shadowMapTexel.z-=shadowMapTexel.z*0.003;\n"+
    "   if (shadowMapTexel.x<0.0 || shadowMapTexel.x>1.0 || shadowMapTexel.y<0.0 || shadowMapTexel.y>1.0 || shadowMapTexel.z<0.0 || shadowMapTexel.z>0.45) shadowEffect=1.0;\n"+
    "   else {\n"+
    "       float shadowTotal=0.0, shadowMapDepth=0.0;\n"+
    "       vec2 lookupTexel;\n";
    for (var pixelX=-KERNEL_LOOP; pixelX<=KERNEL_LOOP; pixelX+=1.0) {
        for (var pixelY=-KERNEL_LOOP; pixelY<=KERNEL_LOOP; pixelY+=1.0) {
            shadowMapSampler +=
    "       lookupTexel=shadowMapTexel.xy+shadowTexelSize*( vec2(cos(rand(sunShadowMapPosition.xy))+("+pixelX+"),sin(rand(sunShadowMapPosition.yx))+("+pixelY+")) );\n"+
    "       shadowMapDepth=dot(texture2D(sunShadowMap,lookupTexel),bitShifts);\n"+
    "       shadowTotal+=step(shadowMapDepth,shadowMapTexel.z)*shadowStrength;\n";
        }
    }
    shadowMapSampler +=
    "       shadowEffect=max(1.0-(shadowTotal/"+KERNEL_CONTRIBUTIONS+".0),0.0);\n"+
    "   }\n"+
    "   return shadowEffect;\n"+
    "}\n"+
};