modo-ray-hit-test-three-ways

modo-ray-hit-test-three-ways.txt

//
// This is not a complete implementation, but rather code snippets.
// Tool packet offsets are defined elsewhere.
//

CLxUser_VectorStack	vector_stack (tool_vector);
if (! vector_stack.test ())
{
    return LXe_FALSE;
}

//
// 1. Using CLxUser_Raycast
//
CLxUser_RaycastPacket raycast_packet {};
if (! vector_stack.ReadObject (raycast_packet_offset_, raycast_packet))
{
    return LXe_FALSE;
}

auto screen_event = static_cast<LXpToolScreenEvent*>(vector_stack.Read (screen_event_packet_offset_));
if (! screen_event)
{
    return LXe_FALSE;
}

LXtHitPolygon hit_polygon {};
raycast_packet.HitPolygon (vector_stack, LXf_LAYER_ACTIVE, screen_event->fcx, screen_event->fcy, &hit_polygon);

//
// 2. Using LXpToolHitEvent
//
auto hit_event = static_cast<LXpToolHitEvent*>(vector_stack.Read (hitevent_packet_offset_));
if (! hit_event)
{
    return LXe_FALSE;
}
if (! hit_event->hit.pol)
{
    return LXe_FALSE;
}

//
// 3. Using CLxUser_View3D and CLxUser_Surface(not shown; must account for item transforms)
//    I don't use modo's macro maths in practice.
//
CLxUser_View3DportService view_service {};
const int view_index_current = view_service.Current ();

CLxUser_View3D view {};
view_service.View (view_index_current, view);
if (! view.test ())
{
    return LXe_FALSE;
}

auto screen_event = static_cast<LXpToolScreenEvent*>(vector_stack.Read (screen_event_packet_offset_));
if (! screen_event)
{
    return LXe_FALSE;
}

const int pos_flags {0}; // alternatives: LXi_VPTO3D_SNAP; LXi_VPTO3D_WORK
LXtVector point_from_screen {};
if (LXx_FAIL (view.To3D (screen_event->fcx, screen_event->fcy, point_from_screen, pos_flags)))
{
    return LXe_FALSE;
}

LXtVector ray_direction {};
const double dist_to_point_from_ray_origin = view.EyeVector (point_from_screen, ray_direction);

LXtVector ray_origin {};
LXx_VCPY  (ray_origin, point_from_screen);
LXx_VADDS (ray_origin, ray_direction, dist_to_point_from_ray_origin * -1.0);

// pass ray to function that uses CLxUser_Surface::RayCast