/**
 * Compute visibility of each resource bounds for a given view.
 */
/* TODO(fclem): This could be augmented by a 2 pass occlusion culling system. */

#pragma BLENDER_REQUIRE(common_view_lib.glsl)
#pragma BLENDER_REQUIRE(common_math_lib.glsl)
#pragma BLENDER_REQUIRE(common_intersect_lib.glsl)

shared uint shared_result;

void mask_visibility_bit(uint view_id)
{
  if (view_len > 1) {
    uint index = gl_GlobalInvocationID.x * uint(visibility_word_per_draw) + (view_id / 32u);
    visibility_buf[index] &= ~(1u << view_id);
  }
  else {
    atomicAnd(visibility_buf[gl_WorkGroupID.x], ~(1u << gl_LocalInvocationID.x));
  }
}

void main()
{
  if (gl_GlobalInvocationID.x >= resource_len) {
    return;
  }

  ObjectBounds bounds = bounds_buf[gl_GlobalInvocationID.x];

  if (bounds.bounding_sphere.w != -1.0) {
    IsectBox box = isect_data_setup(bounds.bounding_corners[0].xyz,
                                    bounds.bounding_corners[1].xyz,
                                    bounds.bounding_corners[2].xyz,
                                    bounds.bounding_corners[3].xyz);
    Sphere bounding_sphere = Sphere(bounds.bounding_sphere.xyz, bounds.bounding_sphere.w);
    Sphere inscribed_sphere = Sphere(bounds.bounding_sphere.xyz, bounds._inner_sphere_radius);

    for (drw_view_id = 0; drw_view_id < view_len; drw_view_id++) {
      if (drw_view_culling.bound_sphere.w == -1.0) {
        /* View disabled. */
        mask_visibility_bit(drw_view_id);
      }
      else if (intersect_view(inscribed_sphere) == true) {
        /* Visible. */
      }
      else if (intersect_view(bounding_sphere) == false) {
        /* Not visible. */
        mask_visibility_bit(drw_view_id);
      }
      else if (intersect_view(box) == false) {
        /* Not visible. */
        mask_visibility_bit(drw_view_id);
      }
    }
  }
}