shader_type canvas_item;

#include "res://shaders/tools.gdshaderinc"

const vec2 center = vec2(0.125, 0.125);
const float sharpness = 300.0;

uniform float rotation = 0.0;
uniform vec4 color = vec4(1.0, 1.0, 1.0, 1.0);
uniform float width = 1.0;
uniform float speed = 1.0;
uniform bool disabled = false;
uniform vec2 scale = vec2(1.0, 1.0);


void vertex()
{
    rotate_vec2(UV, rotation, center);
}


void fragment()
{
   	COLOR = color;
    if (disabled)
    {
        float ds = 1.0 / sharpness;
        float tx = float(int(TIME * 1000.0 * speed) % 10000) / 1000.0 * center.x + center.x;
        COLOR.a = 0.0;
        vec2 uv = UV;
        rotate_vec2(uv, -rotation, center);
        float v3 = smoothstep(0.0, 1.0, (uv.x - center.x / 2.0 / scale.x) * sharpness);
        float v4 = smoothstep(0.0, 1.0, (uv.y - center.y / 2.0 / scale.y) * sharpness);
        float v5 = smoothstep(0.0, 1.0, (center.x * 2.0 - center.x / 2.0 / scale.x - uv.x) * sharpness);
        float v6 = smoothstep(0.0, 1.0, (center.y * 2.0 - center.y / 2.0 / scale.y - uv.y) * sharpness);

        for (float x = -2.0; x < 2.0; x += 0.03)
        {
            float v0 = smoothstep(0.0, 1.0, (tx - UV.x + x) * sharpness + width);
            float v1 = smoothstep(0.0, 1.0, (UV.x - tx - x) * sharpness + width);
            float v2 = smooth_px(length(UV.x - center.x), center.x * 2.0 - ds, ds);
            COLOR.a += v0 * v1 * v2 * v3 * v4 * v5 * v6;
        }
        COLOR.a *= color.a;
    }
}
