const GL = require("gl-react");
const React = require("react");

const shaders = GL.Shaders.create({
  blur1D: {
    frag: `
precision highp float;
varying vec2 uv;
uniform sampler2D t;
uniform vec2 direction;
uniform vec2 resolution;

// from https://github.com/Jam3/glsl-fast-gaussian-blur
vec4 blur9(sampler2D image, vec2 uv, vec2 resolution, vec2 direction) {
  vec4 color = vec4(0.0);
  vec2 off1 = vec2(1.3846153846) * direction;
  vec2 off2 = vec2(3.2307692308) * direction;
  color += texture2D(image, uv) * 0.2270270270;
  color += texture2D(image, uv + (off1 / resolution)) * 0.3162162162;
  color += texture2D(image, uv - (off1 / resolution)) * 0.3162162162;
  color += texture2D(image, uv + (off2 / resolution)) * 0.0702702703;
  color += texture2D(image, uv - (off2 / resolution)) * 0.0702702703;
  return color;
}

void main () {
  gl_FragColor = blur9(t, uv, resolution, direction);
}
    `
  }
});

module.exports = GL.createComponent(
  ({ width, height, direction, children }) =>
    <GL.Node
      shader={shaders.blur1D}
      width={width}
      height={height}
      uniforms={{
        direction,
        resolution: [ width, height ]
      }}>
      <GL.Uniform name="t">{children}</GL.Uniform>
    </GL.Node>
, {
  displayName: "Blur1D"
});