#version 450

layout(location = 0) out vec2 uv;

void main() {
  float x = float((gl_VertexIndex << 1) & 2);
  float y = float(gl_VertexIndex & 2);
  uv = vec2(x, y);
  gl_Position = vec4(uv * 2.0 - 1.0, 0.0, 1.0);
  gl_Position.y *= -1.0;
}