#version 430 core

in VS_OUT {
  vec4 Texture;
} fs_in;

layout (location = 0) out vec4 Color;

layout (rg16i, binding = 0) readonly uniform iimageBuffer Image;

vec2 get_sample(int coordinate)
{
  ivec2 v = imageLoad(Image, coordinate).xy;
  return vec2(float(v.x), float(v.y)) * (1.0 / 32768.0);
}

void main()
{
  vec2 v = get_sample(int(gl_FragCoord.x));

  float y = -(fs_in.Texture.y * 2 - 1);

  float c;
  if (y > 0) {
    c = float(y < v.x);
  } else {
    c = float(y > v.y);
  }

  Color = vec4(c, 0, 0, 1);
}