Investigate real time clock, does it pause when text boxes are shown.

[sonneveld]

Double check if NAGI should pause real time clock when text boxes are shown, or if it's handled per game.

The clock_state normally affects the behaviour of the timer but it is not modified in many places. Was the original interpreter relying on disabling interrupts to pause the timer?

[AGKorson]

For MSDOS interpreter - In the timer interrupt function (it's a custom INT set up when AGI starts that runs 20 times per second), AGI updates a running 'tick count', using two 16bit values. This tick counter is used to manage checks for input (keyboard/joystick timing), counting cycles for the shake.screen command and the print window delay (when using v21).

The clock_state value is also checked in each clock interrupt cycle. If it is false (0) then the game's internal clock (v11 - v14) is updated; every 20 ticks it increments v11 (seconds), adjusting others as needed. clock_state is set to true (1) in the pause(), restore.game() and save.game() commands. Those are the only places where the internal clock is paused.

The timer interrupt ALWAYS runs; it is never disabled. It's the clock_state value that determines when to advance the game clock.

You can't really 'pause' the internal clock in logics code; v11-v14 will always update automatically (unless pause/restore/save commands are active). You can create the effect of a pause by watching for changes, then forcing them back to whatever time you want them to be.