Infinite feedback loops can be created through subcompositions with internal trigger ports

Bug Reports
1

Steps causing the bug to occur

  1. Set up some layers and an “is point within layer” node and some way to react on it.
  2. Publish the “Rendered Layers” input port(s).
  3. Connect layers to “Combine Layers With Transform” node.
  4. Publish layer output from “Combine Layers With Transform”.
  5. Store to node library
  6. Create a new composition
  7. Use the newly created node from the library, and connect it to a “Render Layers to Window” node.
  8. Observe high resource usage through the activity monitor.

How did the result differ from what you expected?

High resource usage.

Have you found a workaround?

Connect “Rendered Layers” output port from “Render Layers to Window” to a “Hold” node before connecting to desired input port in custom node.

Other notes

  • Vuo version: 1.2.0
  • macOS version: OS X 10.10

Publishing layers directly without the use of a “Combine Layers With Transform” node will warn about a feedback loop, and prevent connection without the hold node.

RenderedLayersBug.vuo (1.37 KB)

RenderedLayersWorkaround.vuo (1.66 KB)

2

Could you attach your Check Layers subcomposition? (You can find it in Tools > Open User Modules Folder.)

3

Yep

MartinusMagneson.checkLayers.vuo (7.3 KB)

4

Thanks. I see the problem, though I’m not yet sure what the solution should be. I’ve marked this bug report accepted, and I’ll discuss with the team.

In the meantime, using Hold Value outside the subcomposition is a good workaround.

5

In the meantime, using Hold Value outside the subcomposition is a good workaround.

Or, better yet, use Receive Mouse Moves instead of Check Mouse Status, like in the attached composition.

MartinusMagneson.checkLayers.vuo (7.36 KB)

6

Thanks, is there also a difference in using “receive mouse buttons” to the “check mouse status” one? With this loop in place Vuo crashed quite frequently.

7

This issue, where infinite feedback loops could be created through subcompositions with internal trigger ports, has been fixed in Vuo 2.0 beta.