Luna Display update adds 5K resolution option and PC to Mac mode

Has anyone seem a reliable solution like this that will use all the resources of the old Mac for the connected device?

Seem to me an old Mac would be a great dock for a laptop user if a USB-c cable could delivery screen space of the old Mac, networks sharing, use the internal drive as local time machine (back up to something else as well), speakers and webcam for video conference. 2 Mac's as a unified Mac.

Seems all the parts are there but not a neat way to pull them together. 

It seems to always say '2nd display'. Anyone know if this (or some other product) could use it as the primary display? Like, if a hardware device could plug into a PC's HDMI port, or a PS4 (game console), etc. and display it on a Mac, like the M1 iMac or upcoming Pro/Max iMacs? That would work around the missing 'video input' on the iMacs and make them much more useful as a primary display.

cgWerks said:

It seems to always say '2nd display'. Anyone know if this (or some other product) could use it as the primary display? Like, if a hardware device could plug into a PC's HDMI port, or a PS4 (game console), etc. and display it on a Mac, like the M1 iMac or upcoming Pro/Max iMacs? That would work around the missing 'video input' on the iMacs and make them much more useful as a primary display.

It looks like Luna offers this option. In the following video, an iPad is controlling the Mac (0:54):

https://www.youtube.com/watch?v=8OPi2kIFMaQ

An alternative is to use video capture products, here's one connecting a Switch to an iMac:

https://www.youtube.com/watch?v=zm57OzWfSsQ

https://www.amazon.com/Capture-1080P60-Streaming-Recorder-Compatible/dp/B08Z3XDYQ7

Elgato makes products like this and they say they can do 4k60 passthrough:

https://www.amazon.com/Corsair-Zero-lag-passthrough-Ultra-Low-Technology/dp/B07XB6VNLJ

https://www.youtube.com/watch?v=uTGFDTzhdYY

I don't know why Apple stopped supporting target display mode in Macs, it's a nice feature to be able to use Apple's high quality displays with other hardware. Even if they had some kind of USB-C input processing, Apple Silicon should be able to do this efficiently. 3rd parties could take care of the input so Apple could have an API that captures the display input over USB-C and allows it to be displayed in a window/fullscreen and this input can be optionally processed by the hardware encoders for storing and 3rd parties can capture the Mac's keyboard/mouse input when the window is focused and send them over bluetooth or other connection to the external hardware.

If they make a more affordable XDR standalone display, it won't matter so much to do this but target display mode would still useful to have an an option again.

Marvin said:
An alternative is to use video capture products, here's one connecting a Switch to an iMac:

...
Elgato makes products like this and they say they can do 4k60 passthrough:

Interesting, that makes sense. Thanks! I wonder if lag would be a factor if trying to do more intensive gaming (like FPS). I'll have to do some research.