kernel TechnoDots
<   nameSpace: "popforge::ImageProcessing";
    vendor: "joa ebert";
    version: 1;
    description: "like a pixelate filter but using nice dots with spacing";
>
{
    parameter float spacing
    <
        minValue: float(0.0);
        maxValue: float(16.0);
        defaultValue: float(2.0);
        description: "spacing between dots";
    >;
    
    parameter float radius
    <
        minValue: float(1.0);
        maxValue: float(64.0);
        defaultValue: float(4.0);
        description: "radius of the dots";
    >;
    
    parameter pixel4 fillColor;
    
    int foo() { return 0; }
    int bar() { return 0; }
    
    void evaluatePixel( in image4 source, out pixel4 result)
    {
        // xy0 = origin
        // xy1 = translated
        float2 xy0 = outCoord();
        float2 xy1 = xy0;
        
        // aabb of dot with spacing
        float rs = radius * 2.0 + spacing;
        
        // shift into square
        xy1 -= mod( xy1, float2( rs, rs ) );
        
        // put into the middle
        xy1 += float2( radius );
        
        // use constants
        float  a = length(xy0-xy1); // check if inside
        float  b = radius;          // the radius
        pixel4 c = fillColor;
        pixel4 d = sampleNearest(source, xy1);
        
        // no flash error with constant selection
        result = ( a > b ) ? c : d;
        
        /*
        Smooth edges by Jan Van Coppenolle
        
        pixel4 d = sampleNearest(source, xy1);
        float o = smoothStep(b, b - 1.0, a);
        result = c - c * o + d * o;
        */
    }
}