#ifdef GL_ES
precision mediump float;
#endif
varying vec4 v_color;
varying vec2 v_texCoords;

uniform sampler2D u_texture;
uniform float u_time;

float round(float f, float v){
    return float(int(f / v)) * v;
}

void main(){
    vec2 r = v_texCoords.xy;
    vec4 c = v_color * texture2D(u_texture, v_texCoords.xy);
    gl_FragColor = c * vec4(vec3(round(1.0 + sin((r.x + r.y) * 404.0 + u_time / 20.0) / 10.0, 0.05)), 1.0);
}