/* This shader is only used for edge selection and OSX workaround for large wires. */

uniform float wireSize;
uniform vec2 viewportSize;
uniform vec2 viewportSizeInv;

layout(lines) in;
layout(triangle_strip, max_vertices = 4) out;

in float facing_g[];
in float edgeSharpness_g[];

#ifndef SELECT_EDGES
out float facing;
flat out float edgeSharpness;
#endif

void do_vertex(const int i, float coord, vec2 offset)
{
#ifndef SELECT_EDGES
  edgeSharpness = edgeSharpness_g[i];
  facing = facing_g[i];
#endif
  gl_Position = gl_in[i].gl_Position;
  /* Multiply offset by 2 because gl_Position range is [-1..1]. */
  gl_Position.xy += offset * 2.0 * gl_Position.w;
#ifdef USE_WORLD_CLIP_PLANES
  world_clip_planes_set_clip_distance(gl_in[i].gl_ClipDistance);
#endif
  EmitVertex();
}

void main()
{
  vec2 ss_pos[2];
  ss_pos[0] = gl_in[0].gl_Position.xy / gl_in[0].gl_Position.w;
  ss_pos[1] = gl_in[1].gl_Position.xy / gl_in[1].gl_Position.w;

  vec2 line = ss_pos[0] - ss_pos[1];
  line = abs(line) * viewportSize;

  float half_size = wireSize;

  vec3 edge_ofs = half_size * viewportSizeInv.xyy * vec3(1.0, 1.0, 0.0);

  bool horizontal = line.x > line.y;
  edge_ofs = (horizontal) ? edge_ofs.zyz : edge_ofs.xzz;

  if (edgeSharpness_g[0] < 0.0) {
    return;
  }

  do_vertex(0, half_size, edge_ofs.xy);
  do_vertex(0, -half_size, -edge_ofs.xy);
  do_vertex(1, half_size, edge_ofs.xy);
  do_vertex(1, -half_size, -edge_ofs.xy);

  EndPrimitive();
}