uniform mat4 ViewProjectionMatrix;
#ifdef USE_WORLD_CLIP_PLANES
uniform mat4 ModelMatrix;
#endif

/* ---- Instantiated Attrs ---- */
in float pos;

/* ---- Per instance Attrs ---- */
in vec3 color;
in vec4 corners[2]; /* trouble fetching vec2 */
in float depth;
in vec4 tria;
in mat4 InstanceModelMatrix;

flat out vec4 finalColor;

void main()
{
  vec3 pPos;

  if (pos == 1.0) {
    pPos = vec3(corners[0].xy, depth);
  }
  else if (pos == 2.0) {
    pPos = vec3(corners[0].zw, depth);
  }
  else if (pos == 3.0) {
    pPos = vec3(corners[1].xy, depth);
  }
  else if (pos == 4.0) {
    pPos = vec3(corners[1].zw, depth);
  }
  else if (pos == 5.0) {
    pPos = vec3(tria.xy, depth);
  }
  else if (pos == 6.0) {
    vec2 ofs = tria.xy - corners[0].xy;
    ofs.x = -ofs.x;
    pPos = vec3(corners[1].zw + ofs, depth);
  }
  else if (pos == 7.0) {
    pPos = vec3(tria.zw, depth);
  }
  else {
    pPos = vec3(0.0);
  }

  gl_Position = ViewProjectionMatrix * InstanceModelMatrix * vec4(pPos, 1.0);

  finalColor = vec4(color, 1.0);

#ifdef USE_WORLD_CLIP_PLANES
  world_clip_planes_calc_clip_distance((ModelMatrix * InstanceModelMatrix * vec4(pPos, 1.0)).xyz);
#endif
}