shader_type canvas_item;

//混合颜色
uniform vec4 blend : source_color = vec4(1.0, 1.0, 1.0, 1.0);
//混合度
uniform float schedule : hint_range(0.0, 1.0) = 0.0;
//透明度
uniform float alpha : hint_range(0.0, 1.0) = 1.0;

//------------------ 轮廓相关 --------------
uniform bool show_outline = true;
//轮廓颜色
uniform vec4 outline_color : source_color = vec4(0.0, 0.0, 0.0, 1.0);
//是否是彩虹轮廓
uniform bool outline_rainbow  = false;
//彩虹轮廓变化周期
const float frequency = 0.25;
const float light_offset = 0.5;

void fragment() {
	//显示轮廓
	if (show_outline) {
		vec2 size = TEXTURE_PIXEL_SIZE;
		float outline;
		outline = texture(TEXTURE, UV + vec2(-size.x, 0)).a;
		outline += texture(TEXTURE, UV + vec2(0, size.y)).a;
		outline += texture(TEXTURE, UV + vec2(size.x, 0)).a;
		outline += texture(TEXTURE, UV + vec2(0, -size.y)).a;
		outline = min(outline, 1.0);
		
		vec4 animated_line_color = vec4(
			light_offset + sin(2.0 * 3.14 * frequency * TIME),
			light_offset + sin(2.0 * 3.14 * frequency * TIME + radians(120.0)),
			light_offset + sin(2.0 * 3.14 * frequency * TIME + radians(240.0)),
			1.0
		);
		
		vec4 color = texture(TEXTURE, UV);
		if (outline_rainbow){
			COLOR = mix(color, animated_line_color, outline - color.a);
		} else {
			COLOR = mix(color, outline_color , outline - color.a);
		}
	}
	
	vec4 col = mix(COLOR, blend, schedule);
	col = mix(vec4(0.0, 0.0, 0.0, 0.0), col, COLOR.a);
	col.a *= alpha;
	COLOR = col;
}