//go:build ignore
//kage:unit pixels

package main

const THRESHOLD = .9
const DIRECTIONS = 30.0  // BLUR DIRECTIONS (Default 16.0 - More is better but slower)
const QUALITY = 12.0      // BLUR QUALITY (Default 4.0 - More is better but slower)
const SIZE = 5.0         // BLUR SIZE (Radius)
const PI = 6.28318530718 // Pi*2
const OPACITY = 0.21


var Time float
var NoiseOffset float

func Fragment(dstPos vec4, srcPos vec2, color vec4) vec4 {
    uv := srcPos
    
    average := vec3(0.0)
    radius := SIZE / 2
    
    amount := 0.0
    for d:=0.0; d<PI; d+=PI/DIRECTIONS{
		for i:=1.0/QUALITY; i<=1.0; i+=1.0/QUALITY{
            t := imageSrc0UnsafeAt(uv + vec2(cos(d),sin(d))*radius*log(i)).rgb

            brightness := dot(t.rgb, vec3(0.2126, 0.7152, 0.0722))
            if brightness > THRESHOLD {
                average += t
                amount += 1.0
            }
        }
    } 
    
    col :=  imageSrc0UnsafeAt(uv).rgb
    if amount > 0 {
        col += (average / amount) * OPACITY
    }
    
    return vec4(col,1.0)
}