#version 450

// Fullscreen triangle; the terrain is ray-marched in the fragment shader
// (GPU), so the vertex stage only emits the screen UV.
layout(location = 0) out vec2 out_uv;

void main() {
    vec2 p = vec2((gl_VertexIndex << 1) & 2, gl_VertexIndex & 2);
    out_uv = p;
    gl_Position = vec4(p * 2.0 - 1.0, 0.0, 1.0);
}