shader_type canvas_item;

uniform float shift_strength : hint_range(0.0, 1.0);
uniform float blur_strength : hint_range(0.0, 1.0);
uniform float vignette_alpha : hint_range(0.0, 1.0);
uniform float vignette_inner : hint_range(0.0, 1.0) = 0.5;
uniform float vignette_outer : hint_range(0.0, 2.0) = 1.0;

void fragment() {
	vec3 color = vec3(0);

	//模糊+色移
	float shift = 0.01 * shift_strength;
	float blur = 0.01 * blur_strength;
	vec2 direction = UV - vec2(0.5);
	float f = 0.1;
	color *= f;
	for(int i=1; i < 10; i++) {
		vec2 target_uv = UV - blur * direction * float(i);
		vec3 target_color = vec3(0);
		target_color.r = texture(TEXTURE, vec2(target_uv.x + shift, target_uv.y)).r;
		target_color.g = texture(TEXTURE, target_uv).g;
		target_color.b = texture(TEXTURE, vec2(target_uv.x - shift, target_uv.y)).b;
		color += target_color * f;
	}

	//暗角
	float x = abs(UV.r-.5)*2.0;
	float y = abs(UV.g-.5)*2.0;
	float q = 1.0-(1.0-sqrt(x*x+y*y)/vignette_outer)/(1.0-vignette_inner);
	q = clamp(q*vignette_alpha,0.0,1.1);
	color *= (1.0-q);

	COLOR.rgb = color;
}