#version 300 es
precision highp float;

in vec2 v_texcoord;
uniform sampler2D tex;
out vec4 fragColor;

void main() {
    float o = 0.003;

    vec4 c = vec4(0.0);
    c += texture(tex, v_texcoord + vec2(-o, -o)) * 0.0625;
    c += texture(tex, v_texcoord + vec2( 0, -o)) * 0.125;
    c += texture(tex, v_texcoord + vec2( o, -o)) * 0.0625;
    c += texture(tex, v_texcoord + vec2(-o,  0)) * 0.125;
    c += texture(tex, v_texcoord              ) * 0.25;
    c += texture(tex, v_texcoord + vec2( o,  0)) * 0.125;
    c += texture(tex, v_texcoord + vec2(-o,  o)) * 0.0625;
    c += texture(tex, v_texcoord + vec2( 0,  o)) * 0.125;
    c += texture(tex, v_texcoord + vec2( o,  o)) * 0.0625;

    fragColor = c;
}