IDs Buffer

kitjmv · December 14, 2022, 2:00pm

Hello,
I would like to know if there is a way to get an Ids buffer/visibility buffer.
I see for example that in the API there is the possibility to get the z buffer Rhino.Display.ZBufferCapture.
jmv

kitjmv · December 14, 2022, 2:20pm

Or, how can I create my own buffer with different objects?
My knowledge stops at the use of DisplayPipeline and ViewCapture.CaptureToBitmap.

dale · December 15, 2022, 12:31am

Hi @kitjmv,

Perhaps you can step back and describe what problem you are trying to solve?

Thanks,

– Dale

nathanletwory · December 15, 2022, 5:14am

No doubt this is to get a selection map to make it faster to determine what object was clicked on in the viewport. See the custom rotation plug-in @kitjmv has been working on. It would eliminate the need to use GetRenderMeshes and do expensive ray hitting he has been asking a lot about recently.

And some of the related posts RhinoObject.GetRenderMeshes, bug? , Render mesh topology , How do I always switch to wireframe when moving the view? . I thought there were more, but can’t find them now (at least a post with a huge amount of objects in and trying to get render meshes and do fast ray intersection and determining overlapping objects).

kitjmv · December 15, 2022, 8:07am

Hello @dale,

Thank you @nathanletwory, you saved me many minutes of English translation!
That’s right, my goal is to quickly retrieve the object under the mouse cursor.
I don’t need a lot of precision, but it has to be fast, very fast.

Yesterday I found a solution with an “empty” display mode (DisplayModeDescription). No shadow, light and others:

And using a DisplayConduit + RhinoView.CaptureToBitmap

github.com

corbane/Libx.Fix.AutoCameraTarget/blob/master/Main.cs#L543


      
                  case IntersectionStatus.OnVisibleBBox:
                      e.Display.DrawBox (Main.g_intersector.VisibleBBox, SD.Color.FromArgb (125, 255, 0, 0));
                      break;
                  }
              }
          }
          
          

          
#if USE_BITMAP
          
          
class IdConduit : DisplayConduit
          {
              static IdConduit? g_instance;
              static DisplayModeDescription? g_viewmode;
          
          
    public static void Dispose ()
              {
                  if (g_instance == null) return;
                  g_instance.Enabled = false;
                  g_instance = null;
                  g_viewmode = null;

But the performance improvement started to show when 30 objects were under the mouse, producing (when meshed) over a million faces.

To avoid overloading the IdConduit, this technique requires me to keep calculating if the objects are visible in the view and extracting the meshes with RhinoObject.GetRenderMeshes.
It’s a shame because Rhino has the full vertex buffer to display objects on the screen.

So I want to know if there is a way as easy as Rhino.Display.ZBufferCapture to get map Ids (or visibility buffer).

With a depth map and identifiers, it would be easy to calculate an intersection. not precise, but fast.

In the end I wrote my long blabla in English… /

farouk.serragedine · December 15, 2022, 1:53pm

Separate library edit