double lerp(double y1,double y2,double mu){
   return(y1*(1-mu)+y2*mu);
}

sf::Color lerpColor(const sf::Color& from,const sf::Color& to,float pos, float size){
    sf::Color result;
    double mu = double(pos / size);
    result.r   = (sf::Uint8)lerp(from.r, to.r,mu);
    result.g   = (sf::Uint8)lerp(from.g, to.g,mu);
    result.b   = (sf::Uint8)lerp(from.b, to.b,mu);
    result.a   = (sf::Uint8)lerp(from.a, to.a,mu);
    return result;
}


sf::VertexArray createFilledRoundedRectangle(const sf::Vector2f& pos, const sf::Vector2f& size, float radius, const sf::Color& top, const sf::Color& bottom, int points){

    sf::VertexArray vertex(sf::TrianglesFan, (points*4)+6);

    // open shape at center
    vertex[0].position = sf::Vector2f(pos.x+(size.x/2),pos.y+(size.y/2));
    vertex[0].color    = lerpColor(top,bottom,size.y/2,size.y);

    int indice = 1;

    // top left
    float angle = 180.0f;
    for(int i=0; i<points; ++i){

        float x = (pos.x + radius) + radius * cos(angle * 3.14159265359 / 180.f);
        float y = (pos.y + radius) + radius * sin(angle * 3.14159265359 / 180.f);
        angle += float(90.0f/points);
        vertex[indice].position = sf::Vector2f(x,y);
        vertex[indice].color    = lerpColor(top,bottom,y-pos.y,size.y);

        indice++;
    }

    vertex[indice].position = sf::Vector2f(pos.x+radius,pos.y);
    vertex[indice].color    = lerpColor(top,bottom,0,size.y);
    indice++;

    // top right
    angle = 270.0f;
    for(int i=0; i<points; ++i){
        float x = (pos.x + (size.x - radius)) + radius * cos(angle * 3.14159265359 / 180);
        float y = (pos.y + radius) + radius            * sin(angle * 3.14159265359 / 180);
        angle += float(90/points);
        vertex[indice].position = sf::Vector2f(x,y);
        vertex[indice].color    = lerpColor(top,bottom,y-pos.y,size.y);
        indice++;
    }

    vertex[indice].position = sf::Vector2f(pos.x+size.x,pos.y+radius);
    vertex[indice].color    = lerpColor(top,bottom,radius,size.y);
    indice++;


    // bottom right
    angle = 0.0f;
    for(int i=0; i<points; ++i){
        float x = (pos.x + (size.x - radius)) + radius * cos(angle * 3.14159265359 / 180);
        float y = (pos.y + (size.y - radius)) + radius * sin(angle * 3.14159265359 / 180);
        angle += float(90/points);
        vertex[indice].position = sf::Vector2f(x,y);
        vertex[indice].color    = lerpColor(top,bottom,y-pos.y,size.y);
        indice++;
    }

    vertex[indice].position = sf::Vector2f(pos.x+size.x-radius,pos.y+size.y);
    vertex[indice].color    = lerpColor(top,bottom,size.y,size.y);
    indice++;

    // bottom left
    angle = 90.0f;
    for(int i=0; i<points; ++i){
        float x = (pos.x + radius) + radius              * cos(angle * 3.14159265359 / 180);
        float y = (pos.y + (size.y - radius)) + radius   * sin(angle * 3.14159265359 / 180);
        angle += float(90/points);
        vertex[indice].position = sf::Vector2f(x,y);
        vertex[indice].color    = lerpColor(top,bottom,y-pos.y,size.y);
        indice++;
    }

    vertex[indice].position = sf::Vector2f(pos.x,pos.y+size.y-radius);
    vertex[indice].color    = lerpColor(top,bottom,size.y-radius,size.y);
    indice++;

    // close shape
    vertex[indice].position = sf::Vector2f(pos.x,pos.y+radius);
    vertex[indice].color    = lerpColor(top,bottom,radius,size.y);
    return vertex;
}



sf::VertexArray createHollowRoundedRectangle(const sf::Vector2f& pos, const sf::Vector2f& size, float radius, const sf::Color& color, int points){

    sf::VertexArray vertex(sf::LinesStrip, (points*4)+6);


    // open shape
    vertex[0].position = sf::Vector2f(pos.x,pos.y+radius);
    vertex[0].color    = color;

    int indice = 1;

    // top left
    float angle = 180.0f;
    for(int i=0; i<points; ++i){

        float x = (pos.x+radius) + radius * cos(angle * 3.14159265359 / 180.f);
        float y = (pos.y+radius) + radius * sin(angle * 3.14159265359 / 180.f);
        angle += float(90.0f/points);
        vertex[indice].position = sf::Vector2f(x,y);
        vertex[indice].color    = color;

        indice++;
    }

    vertex[indice].position = sf::Vector2f(pos.x+radius,pos.y);
    vertex[indice].color    = color;
    indice++;

    // top right
    angle = 270.0f;
    for(int i=0; i<points; ++i){
        float x = (pos.x+(size.x - radius)) + radius * cos(angle * 3.14159265359 / 180);
        float y = (pos.y+radius) + radius            * sin(angle * 3.14159265359 / 180);
        angle += float(90/points);
        vertex[indice].position = sf::Vector2f(x,y);
        vertex[indice].color    = color;
        indice++;
    }

    vertex[indice].position = sf::Vector2f(pos.x+size.x,pos.y+radius);
    vertex[indice].color    = color;
    indice++;


    // bottom right
    angle = 0.0f;
    for(int i=0; i<points; ++i){
        float x = (pos.x+(size.x - radius)) + radius * cos(angle * 3.14159265359 / 180);
        float y = (pos.y+(size.y - radius)) + radius * sin(angle * 3.14159265359 / 180);
        angle += float(90/points);
        vertex[indice].position = sf::Vector2f(x,y);
        vertex[indice].color    = color;
        indice++;
    }

    vertex[indice].position = sf::Vector2f(pos.x+size.x-radius,pos.y+size.y);
    vertex[indice].color    = color;
    indice++;

    // bottom left
    angle = 90.0f;
    for(int i=0; i<points; ++i){
        float x = (pos.x+radius) + radius            * cos(angle * 3.14159265359 / 180);
        float y = (pos.y+(size.y - radius)) + radius * sin(angle * 3.14159265359 / 180);
        angle += float(90/points);
        vertex[indice].position = sf::Vector2f(x,y);
        vertex[indice].color    = color;
        indice++;
    }

    vertex[indice].position = sf::Vector2f(pos.x,pos.y+size.y-radius);
    vertex[indice].color    = color;
    indice++;

    // close shape
    vertex[indice].position = sf::Vector2f(pos.x,pos.y+radius);
    vertex[indice].color    = color;
    return vertex;
}


sf::VertexArray createLine(const sf::Vector2f& from, const sf::Vector2f& to, const sf::Color& color){
    sf::VertexArray vertex(sf::Lines, 2);

    vertex[0].position  = from;
    vertex[0].color     = color;

    vertex[1].position  = to;
    vertex[1].color     = color;

    return vertex;
}