Rendering

Can anyone tell me the advantages and disadvantages of either

Rendering in a perpetual loop calling a Do Events to check for other events in a program or…

calling the render procedure only when a scene needs updating.

I am wondering how to design my scene builder program.

Hope you can help

kind regards

Alc

Render on input. Games on the other hand check for input then they render the frame whether there was any input or not. The reason is that there are other things in the world that move and need to be rerendered irrespective whether player moved or not.