Godot 4 Shader Functions

//#define TAU 6.283185307179586
float circle(vec2 uv, float radius, float feather)
{
    return smoothstep(radius, radius + feather, length(uv - vec2(0.5)));
}

float rectangle (vec2 uv, float width, float height){
    vec2 uv_cartesian = uv * 2.0 - 1.0;
    vec2 uv_reflected = abs(uv_cartesian);
    float dfx = step(width,uv_reflected.x);
    float dfy = step(height, uv_reflected.y);
    return max(dfx,dfy);
}
float polygon(vec2 uv, float width, int sides)
{
    uv = uv * 2.0 - 1.0;
    float angle = atan(uv.x, uv.y);
    float radius = TAU / float(sides);
    float dist = cos(floor(0.5 + angle / radius) * radius - angle)* length(uv) ;
    float poly = step(width, dist);
    return poly;
}
vec2 polar_coordinates(vec2 uv, vec2 center)
{
    vec2 dir = uv - center;
    float radius = length(dir) * 2.0;
    float angle = atan(dir.y, dir.x) / TAU;
    return (vec2(radius, angle));
}
vec2 rotation ( vec2 uv, vec2 center, float angle){
    mat2 rotation = mat2(
                    vec2(cos(angle), -sin(angle)),
                    vec2(sin(angle), cos(angle))
                    );
    uv -= center;
    uv *= rotation;
    uv += center;
    return uv;
}
vec2 scale(vec2 uv, float x, float y)
{
    mat2 scale = mat2(
                vec2(x, 0.0),
                vec2(0.0, y)
                );

    uv -= 0.5;
    uv = uv * scale;
    uv += 0.5;
    return uv;
}
float angleVectors(vec3 v1, vec3 v2){
    return acos(dot(normalize(v1),normalize(v2)));
}