shader_type spatial;
render_mode unshaded;

uniform sampler2D effect_texture;
uniform sampler2D SCREEN_TEXTURE : hint_screen_texture, filter_linear_mipmap;

uniform float time_elapsed = 0.;
uniform float speed = 0.;

//void vertex() {
	//VERTEX.y += cos(VERTEX.x * TIME *0.05)*3.1 ;
//}

float neighbour_alpha_accumulator(vec2 coord, float input_margin) {
	float acc = 0.;
	float margin = (1.-coord.y) * input_margin;
	for (float i=-margin;i<=margin;i=i+margin) {
		for (float j=-margin;j<=margin;j=j+margin) {
			vec2 new_uv = coord + vec2(i,j);
			float val = 0.;
			if (new_uv.x > 1. || new_uv.x < 0. || new_uv.y > 1. || new_uv.y < 0.) {
				val = 0.;
			} else {
				val = texture(effect_texture, coord + vec2(i,j)).a;
			}
			acc += val;
		}
	}
	
	float final_val = acc/9.;
	if (final_val >= 1.) {
		final_val = 0.;
	} else {
		final_val = texture(effect_texture, coord).a;
	}
	
	return final_val;
}

void fragment() {
	
	vec2 new_uv = UV;
	//if (new_uv.x > 1. || new_uv.x < 0. || new_uv.y > 1. || new_uv.y < 0.) {
		//COLOR.a = 0.;
	//} else {
		//COLOR = texture(TEXTURE, new_uv);
	//}
	ALBEDO = vec3(1.);
	ALPHA = neighbour_alpha_accumulator(UV, 0.1);
}