I know that when rendering text from an app, the string must be in RAM because bcall PutS and vPutS would not work right if hl points to a location in the app. Am I correct on that? But am I understanding right that sprite data can be copied from the app directly to the display?

As far as I'm aware, that logic is correct. Why do you ask? Is it giving odd errors or do you just want to know before you write any code involving it?

The latter.

You could try some quick tests, to make sure Axe isn't using the OS's PutSprite routine (bcall), but it should use its own.

Yeah, I believe it has [many] of it's own, no OS calls involved with that whatsoever

Small Update

A slight revision to the text rendering routines. I will prepend each string with a two byte location. When I load the string into hl, I will load 'hl' into (penCol) and 'hl+1' into (penRow). Then, I will 'inc' twice and 'hl' should now point to the start of the string. Means I don't have to manually code the setting of penCol and penRow each time I display text.

Ok, I got a question. This game, as you likely know, will be released as an app. It is very likely that this app will be two pages long (possibly more, but i'll try not to). The question: will I need to do something extra to specify different pages within the app coding? Or will the compiler handle the paging. Compiler is the dcs_sdk compile.sh.

Also, to Kerm directly: I would really like to use your DCS GUI functions, particularly the Text Buttons and and the mouse for those text buttons. Unfortunately I cannot call them from within my game, as this is an app. This leaves me with two options...to swap flash pages to get the routines, copying the data for them into RAM, or to place the routine itself into my app. I'll leave that up to your professional opinion as to which is the best route, but either way I'll need help with swapping flash pages or I'll need those routines, if you would permit that.

Why are you making an app when you can use a program instead? I'd imagine the majority of your program is going to be data, so you could move that to an external appvar and only have executable code inside your main program.

I am not the type of programmer to do that. I dislike sending multiple files and/or relying on them for functionality. An app is more of an inconvenience to me, but it's easier for the user.