C-Play “on-top” of other apps
C-Play nodes can run above other local applications. This is useful when another program should remain open and interactive behind the C-Play output, while C-Play can still reveal, hide, mask, or layer content in front of it.
Common examples are:
- A PowerPoint, browser, game engine, simulation, or control UI running behind the C-Play node window.
- C-Play fading its node window opacity down to reveal the application behind it.
- C-Play staying on top for mapped media, subtitles, masks, or overlays while another application continues to render locally.
- A local Windows application sending frames to C-Play through Spout instead of going through the network.
Always on top
The window on-top action keeps the node display window above other operating-system windows. Toggle it from the C-Play header using the window on-top action described in Views.
You can also make this active at startup with Node windows always on top at startup in Window & UI settings.
When this is enabled, you can keep another application running behind C-Play while C-Play remains the visible projection surface. For example, a browser or PowerPoint can sit behind the node window, and C-Play can show mapped media, foreground images, or presentation layers above it.
Reveal the application behind C-Play
C-Play can fade node window opacity between fully visible and hidden. This makes it possible to reveal the local application behind C-Play without changing focus or closing the C-Play node window.
Use the window opacity action in the header, or trigger it from a presentation Control layer using SetNodeWindowsOpacity. The fade duration is configured in Window & UI settings.
Typical workflow:
- Start the background application on the node machine.
- Place the application window on the same display area as the C-Play node window.
- Start C-Play and enable window on-top.
- Fade C-Play opacity down when the background application should be visible.
- Fade C-Play opacity back up when C-Play content should take over again.
This is a local-compositing technique. The application behind C-Play is not captured as a C-Play texture; it is simply visible because the C-Play node window is transparent or hidden.
Use C-Play layers above another app
Presentation layers can be used as overlays while the background application keeps running. For example, a master-slide layer can act as a persistent background or mask, while a normal slide layer can show titles, logos, timers, or mapped media above the live application.
Layer ordering still follows the normal presentation rules described in Presentation (Slides & Layers): master layers are behind normal media, slide layers are in front of media, and foreground images are on top.
Spout for local app sharing
Spout is a Windows-only way for one application to share live GPU frames with another application on the same machine. When another application can send Spout, C-Play can receive it as a Spout layer.
This is different from the on-top/opacity workflow:
| Workflow | Best for | What C-Play receives |
|---|---|---|
| On-top + opacity | Revealing a full local app behind the C-Play node window | No texture; the app is visible through the OS window stack |
| Spout layer | Bringing a local app’s rendered output into C-Play as content | A live video texture that can be mapped, faded, masked, and layered |
To use Spout:
- Start the sending application and enable its Spout output.
- In C-Play, add a Spout layer.
- Select the sender from the Spout sender list.
- Configure the layer like other live video layers.
Spout is often the cleaner option when the external application should become part of the C-Play composition. On-top/opacity is often simpler when the external application should stay as a separate local program that is only revealed at certain moments.