shader_type canvas_item;

uniform vec2 uv0;
uniform vec2 uv1;
uniform vec2 uv2;
uniform vec2 uv3;
uniform vec2 uv4;
uniform vec2 uv5;
uniform vec2 uv6;

uniform float smoothness = 2.0;

uniform float offset = 1.0; //move from border
uniform float thick = -0.02; //border thickness
uniform float blur = 8.0;

uniform float uv_scale = 1;

void fragment() {
    vec2 p = UV.xy;
    const int num = 7;
    vec2 v[7];
    v[0] = uv0;
    v[1] = uv1;
    v[2] = uv2;
    v[3] = uv3;
    v[4] = uv4;
    v[5] = uv5;
    v[6] = uv6;

    float d = dot(p-v[0],p-v[0]);
    int j = num-1;
    for( int i=0; i<num; i++)
    {
        vec2 e = v[j] - v[i];
        vec2 w =    p - v[i];
        vec2 b = w - e*clamp( dot(w,e)/dot(e,e), 0.0, 1.0 );
        d = min( d, dot(b,b) );

        j=i;
    }

    d = blur*sqrt(d - thick) - offset;
    float alpha  = 1.0 - exp(-smoothness*abs(d));

    vec2 scale = vec2(1.0, 1.0)*uv_scale;
    COLOR = vec4( texture(TEXTURE, modf(UV/scale, scale)).rgb, alpha);
}