Not yet. Still trying to scour the internet.

You are correct. There shouldn't be a restriction. Providing your code may help in diagnosing what could be happening. Do you have something that you can post?

!! SOLVED !! It turns out that preparing an application for speech recognition using live audio from the microphone is a two step process. The first step is well documented and involves adding a key to the app's info.plist document. The following screenshot shows the entry that is needed in the app's project file. To add a key via the UI, mouse-over any key, and click the plus icon that shows to the right of that key. You can then choose the needed key from the drop-down list that appears next. After choosing the key, you will need to add some descriptive text that will show in the permissions request window when the app is first launched on the computer/device. The second step in this process is not well documented. I stumbled upon it accidentally while researching something for a different matter. Evidently, MacOS apps run in a sandbox and need to register which capabilities they want to use. The following screenshot is found in the Signing & Capabilities tab of the app's project file. Look for the section labelled 'App Sandbox'. If it isn't there, you may need to add it via the +Capability button found just below the tabs. Look for Audio Input in the 'Hardware' group and ensure that the checkbox is checked.

Is this for MacOS or iOS?

Generally speaking, your shapeNode conversion should work. It's possible that you are experiencing either a layering problem (triangles are behind the main background color - check the zPosition on your spriteNodes), or the conversion of the shapeNode to a texture isn't working as you would expect. I ran into similar problems with shapeNodes in my game. One thing you could do to troubleshoot is to use Playgrounds to build and convert a shapeNode to a texture, then add it to a scene in the Playground. If that doesn't work (just like in your app), then you have a nice laboratory where you can try different things to figure out what is causing the problem. If I recall correctly, one of the problems that I ran into had to do with positioning of a shapeNode and/or its converted texture. There might be other valid reasons why your triangles aren't showing, but the Playground approach should help you explore various possibilities.

Even if you could prevent the device from making a screenshot, how would you prevent someone from using a regular camera, or other mobile device with a camera, from taking a picture of what is showing in your app? Perhaps some insights into why you need to prevent users from making screenshots would help generate ideas for how to address it.