shader_type canvas_item;
render_mode unshaded;

uniform sampler2D screen_texture : hint_screen_texture, repeat_disable, filter_nearest;
uniform vec4 add_color : source_color = vec4(1.0);
uniform sampler2D fringe_color;
uniform float fringe_threshold;
uniform float threshold;
varying vec4 global_center;
varying vec4 screen_center;
void vertex() {
	 vec4 local_center = vec4(0.0, 0.0, 0.0, 1.0); 

    // Transform local center to global coordinates
    global_center = CANVAS_MATRIX * local_center;
	// Called for every vertex the material is visible on.
}

void fragment() {
	// Called for every pixel the material is visible on.
	vec4 color = texture(screen_texture, SCREEN_UV);
	vec4 acol = add_color;
	acol.a = min(acol.a, color.a);
	//COLOR = mix(color, add_color, acol.a);
	vec2 ucrd = vec2(UV.x - 0.5, UV.y - 0.5) * 2.0;
	float d = ucrd.x * ucrd.x + ucrd.y * ucrd.y;
	if(d < threshold * threshold){
		float ft = threshold - fringe_threshold;
		if(d < ft *  ft){
			COLOR = vec4(mix(color.rgb, add_color.rgb, acol.a), color.a);
		}else{
			vec4 f_col = texture(fringe_color, vec2((pow(d, .5) - ft)/fringe_threshold));
			COLOR = vec4(mix(color.rgb, f_col.rgb, acol.a), color.a);
		}
	}else{
		COLOR = vec4(UV, 0, 0);	
	}
	
}

//void light() {
//	// Called for every pixel for every light affecting the CanvasItem.
//	// Uncomment to replace the default light processing function with this one.
//}