new.sksl

float2 inScale = float2(1.0, 1.0);
float inTime = 0.0;
float inGreyscaleSeed = 0.0;

float4 inCellColor = float4(1.0, 1.0, 1.0, 1.0);
float4 inEdgeColor = float4(0.0, 0.0, 0.0, 1.0);
float inRoundness = 0.5;
float inEquidistantEdges = 0.0;
float inLevelsDetail = 1.0;
float inEdgeFeather = 0.1;
float inType = 0.0;
float inDistortionAmount = 0.5;
float inRotation = 0.0;
float inSeed = 0.0;
float inEdgeWidth = 0.1;
float2 inOffset = float2(0.0, 0.0);
float inStyle = 0.0;
float inLevels = 3.0;
float inAlpha = 1.0;

float4 inLevel0Color = float4(1.0, 0.0, 0.0, 1.0);
float4 inLevel1Color = float4(0.0, 1.0, 0.0, 1.0);
float4 inLevel2Color = float4(0.0, 0.0, 1.0, 1.0);
float4 inLevel3Color = float4(1.0, 1.0, 0.0, 1.0);
float4 inLevel4Color = float4(1.0, 0.0, 1.0, 1.0);

float PI = 3.141592653589;

float2 random2(float2 p){
    float3 a = fract(p.xyx * float3(123.34, 234.34, 345.65) + float3(tan(inSeed),sin(-inSeed), cos(-inSeed)));
    a += dot(a, a + 0.45);
    return fract(vec2(a.x * a.y, a.y * a.z));
}

float random(float2 uv){
    return fract(sin(dot(uv, float2(12.9898, 78.233))) * 43758.5453);
}

mat2 rotation(float r)
{
	float cr = cos(r);
	float sr = sin(r);
	return mat2(
		cr,-sr,
		sr,cr
	);
}

///IQ's Polynomial-based smooth minimum.
float smin( float a, float b, float k )
{
    float h = clamp( 0.5+0.5*(b-a)/k, 0.0, 1.0 );
    return mix( b, a, h ) - k*h*(1.0-h);
}

float3 regVoronoi(float2 uv){
    float2 f = floor(uv);
    float2 u = fract(uv);
    float2 dist2, grid2;
    float shade = 0.0;

    float minDist = 10.0;
    for( int x=-1; x<=1; x++ ){
         for( int y=-1; y<=1; y++ )
         {
            float dist;
            float2 grid = float2(float(y),float(x));
            float2 offset = random2(f + grid);

            offset = 0.5 + 0.5 * sin(inTime + 6.2831 * offset * inDistortionAmount) * inDistortionAmount;

            float2 r = grid + offset - u;
            dist = length(r);

            if(dist<minDist)
            {
                minDist = dist;
                dist2 = r;
                grid2 = grid;
                shade = random((f + grid) + sin(inGreyscaleSeed));
            }
         }
    }


    ///Calculate lines and Equidistance mode
    float lineDist = 20.0;
    float EELineDist = 20.0;
    float lineMDist = 20.0;
    for( int j=-3; j<=3; j++ ){
        for( int i=-3; i<=3; i++ ){
            float2 grid = grid2 + float2(float(i),float(j));
            float2 offset = random2(f + grid);

            offset = 0.5 + 0.5 * sin(inTime + 6.2831 * offset * inDistortionAmount) * inDistortionAmount;

            float2 r = grid + offset - u;

            if(dot(dist2-r,dist2-r)>0.00001 ){
                EELineDist = min(EELineDist, dot(0.5 * (dist2 + r), normalize(r - dist2)));
                lineDist =  dot(0.5 * (dist2 + r), normalize(r - dist2));
                lineMDist = smin(lineMDist, lineDist, inRoundness);
            }
        }
    }


    lineMDist = max(lineMDist, 0.00001);
    minDist = max(minDist, 0.0);

    if(inStyle == 3){
        minDist = abs(dist2.x) + abs(dist2.y);
    } else if(inEquidistantEdges == 1){
        minDist = EELineDist;
    }

    return float3(minDist, lineMDist, shade);
}

float4 calcVoronoi(float2 uv, float x, float y, float i, float2 lastId, float minDist, in float oldShade, out float newShade, in float oldLevel, out float newLevel){
    //returning float4 as float4(minDist, float2(lastId), hasChild);
    //shade and level as pointer

    float percentage = inLevelsDetail ;
    float2 f = fract(uv);
    float2 u = floor(uv);
    float2 r = float2(0.0);
    float2 id = float2(0.0);
    float hasChild = 0.0;
    if(i == 0.0){
        id = float2(x,y);
        percentage = percentage / 3.0;
    } else{
        percentage = (percentage / pow(i+2.0,2));
        id = lastId + float2(x,y) / pow(2.0,i);
    }
    float2 offset = random2(id + u);
    offset = 0.5 + 0.5 * sin(inTime + 6.2831 * offset * inDistortionAmount) * inDistortionAmount;
    if(i == 0.0){
        r = id + offset - f;
    } else{
        r = id + (offset / pow(2.0,i)) - f;
    }
    float d;
    if(inStyle == 3){
        d  = abs(r.x) + abs(r.y);
    } else{
        d  =  length(r);
    }
    float rand = random(id + u  + sin(inSeed)) + 0.001;
    if(i >= inLevels){
        rand = 0.0;
    }
    if(rand <= 1.0 - percentage ){
        if(d < minDist){

            minDist = d;
            newLevel = i;
            newShade = random((id + u) + sin(inGreyscaleSeed));

        } else{
            newShade = oldShade;
            newLevel = oldLevel;
        }
    } else{
        newShade = oldShade;
        newLevel = oldLevel;
        hasChild = 1.0;
    }
    return float4(minDist, float2(id), hasChild);
}

float3 hierVoronoi(float2 uv){

    float minDist = 10.0;
    float shade = 0.0;
    float oldShade = 0.0;
    float2 id = float2(0.0);
    float level = 0.;
    float oldLevel = 0.;
    float4 voronoiData = float4(10.0, 0.,0.,0.);
    for(float y=-1.; y<=1.; y++){
        for(float x=-1.; x<=1.; x++){
            voronoiData = calcVoronoi(uv, x, y, 0.0, float2(0.0), voronoiData.x, oldShade, shade, oldLevel, level);
            oldShade = shade;
            oldLevel = level;
            if(voronoiData.a == 1.0){
                float2 id0 = voronoiData.yz;
                for(float l=0.; l<=1.; l++){
                    for(float k=0.; k<=1.; k++){
                        voronoiData = calcVoronoi(uv, k, l, 1.0, id0, voronoiData.x, oldShade,shade, oldLevel, level);
                        oldShade = shade;
                        oldLevel = level;
                        if(voronoiData.a == 1.0){
                            float2 id1 = voronoiData.yz;
                            for(float q=0.; q<=1.; q++){
                                for(float w=0.; w<=1.; w++){
                                    voronoiData = calcVoronoi(uv, w, q, 2.0, id1, voronoiData.x, oldShade,shade, oldLevel, level);
                                    oldShade = shade;
                                    oldLevel = level;
                                    if(voronoiData.a == 1.0){
                                        float2 id2 = voronoiData.yz;
                                        for(float a=0.; a<=1.; a++){
                                            for(float b=0.; b<=1.; b++){
                                                voronoiData = calcVoronoi(uv, b, a, 3.0, id2, voronoiData.x, oldShade,shade, oldLevel, level);
                                                oldShade = shade;
                                                oldLevel = level;
                                                if(voronoiData.a == 1.0){
                                                    float2 id3 = voronoiData.yz;
                                                    for(float c=0.; c<=1.; c++){
                                                        for(float d=0.; d<=1.; d++){
                                                            voronoiData = calcVoronoi(uv, c, d, 4.0, id3, voronoiData.x, oldShade,shade, oldLevel, level);
                                                            oldShade = shade;
                                                            oldLevel = level;
                                                        }
                                                    }
                                                }
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }

    return float3(voronoiData.x, level, shade);

}



half4 main(float2 fragCoord){

    half4 edgeColor = half4(inEdgeColor.rgb/255.0 * (inEdgeColor.a/255.0), inEdgeColor.a/255.0);
    half4 cellColor = half4(inCellColor.rgb/255.0 * (inCellColor.a/255.0), inCellColor.a/255.0);


    half4 level0Color = half4(inLevel0Color.rgb/255.0 * (inLevel0Color.a/255.0), inLevel0Color.a/255.0);
    half4 level1Color = half4(inLevel1Color.rgb/255.0 * (inLevel1Color.a/255.0), inLevel1Color.a/255.0);
    half4 level2Color = half4(inLevel2Color.rgb/255.0 * (inLevel2Color.a/255.0), inLevel2Color.a/255.0);
    half4 level3Color = half4(inLevel3Color.rgb/255.0 * (inLevel3Color.a/255.0), inLevel3Color.a/255.0);
    half4 level4Color = half4(inLevel4Color.rgb/255.0 * (inLevel4Color.a/255.0), inLevel4Color.a/255.0);

    float4 col = float4(1.0);
    float2 uv = fragCoord.xy * rotation(-inRotation);
    uv -= inOffset * rotation(-inRotation);
    uv /= inScale;

    if(inType == 0){
        col.rgb = regVoronoi(uv);

        ///Flat
        if(inStyle == 0){

            col = mix(edgeColor, cellColor,  smoothstep(inEdgeWidth, inEdgeWidth + inEdgeFeather , col.y));
        }
        else if(inStyle == 1){
            col.z = max(col.z, 0.02);
            col = mix(edgeColor, half4(float3(col.z), 1.0),  smoothstep(inEdgeWidth, inEdgeWidth + inEdgeFeather , col.y));
        }
        ///Other styles
        else{
             col = mix(edgeColor, half4(float3(col.x), 1.0), smoothstep(inEdgeWidth, inEdgeWidth + inEdgeFeather, col.y));
        }
    }
    if(inType == 1){
        col.rgb = hierVoronoi(uv);

    ///Flat
    if(inStyle == 0){
        cellColor = mix(level0Color, col, col.y);
        cellColor = mix(cellColor, level1Color, col.y);
        cellColor = mix(cellColor, level2Color, max(col.y - 1.0,0.0));
        cellColor = mix(cellColor, level3Color, max(col.y - 2.0,0.0));
        col = mix(cellColor, level4Color, max(col.y - 3.0,0.0));

      }
    else if(inStyle == 1){
        col = half4(float3(col.z), 1.0);
    }
    ///Euclidean and Manhattan
    else{
       col = half4(float3(col.x),1.0);
        }
    }

    return half4(col * inAlpha);
}