#ifdef GL_ES
precision mediump float;
precision mediump int;
#endif

uniform sampler2D u_texture;

uniform float u_time;
uniform float u_progress;
uniform vec4 u_color;
uniform vec2 u_uv;
uniform vec2 u_uv2;
uniform vec2 u_texsize;

varying vec4 v_color;
varying vec2 v_texCoord;

float rand(vec2 co){
    return fract(sin(dot(co.xy ,vec2(12.9898,78.233))) * 43758.5453);
}

bool id(vec4 v){
    return v.a > 0.1;
}

void main() {
    vec2 coords = (v_texCoord.xy - u_uv) / (u_uv2 - u_uv);
    vec2 t = v_texCoord.xy;

	vec4 c = texture2D(u_texture, v_texCoord.xy);
	
	vec2 v = vec2(1.0/u_texsize.x, 1.0/u_texsize.y);
	float step = 1.0;
	
	bool outline = texture2D(u_texture, t).a < 0.1 &&
		(id(texture2D(u_texture, t + vec2(0, step) * v)) || id(texture2D(u_texture, t + vec2(0, -step) * v)) ||
		id(texture2D(u_texture, t + vec2(step, 0) * v)) || id(texture2D(u_texture, t + vec2(-step, 0) * v)));
	
    if(1.0-abs(coords.x - 0.5)*2.0 < 1.0-u_progress){
        c = vec4(0.0);
    }

    if(c.a > 0.01 || outline){
        float f = abs(sin(coords.x*2.0 + u_time));
        if(f > 0.9 )
            f = 1.0;
        else
            f = 0.0;
        c = mix(c, u_color, f * u_color.a);
    }

    gl_FragColor = c * v_color;
}