GPRM-based button with Start at Loop Point Troubles

Question

First of all, I'm running DVD Studio Pro 4.2.1 on OS X 10.4.11
I'm trying to finish a project where when a video ends, it jumps back to the menu directly to the next button in order. This menu also has a loop point set in order to skip an opening animation. So I wrote the following script to accomplish this:
1: mov GPRM 0, SPRM 8
2: div GPRM0, 1024
3: add GPRM0, 1
4: jump "menu name"(Loop) [GPRM 0]
When I simulate the disc, everything works fine. However, a burned disc fails to return to the loop point. It will start on the next button when the highlights appear at the loop point, but the menu will begin from the beginning animation, not at the loop point.
Is there some conflict between the GPRM based button command and the start at loop point command? I did perform a test with the GPRM based button commands left out and the start at loop point function worked perfectly.
Edit: The "GPRM 0" at the end of the script shouldn't be a link but in brackets instead... the forum changed it to a link by default.
Message was edited by: brazzamHD

Answer 1

Given lines 1, 2 and 3, it is very unlikely that GPRM0 will ever be zero...
What your lines are saying, roughly, is:
"find the value of the last button that was pressed on a menu, and reduce it to a simple integer we can work with. Add '1' to the button number and then jump to the loop point on the menu IF the value in GPRM0 is '1'"
The problem is that it will never be '1' because of line 3. The lowest value it could be is '2' when you keep that line in there.
Also, you don't specify which GPRM you are evaluating in either version of line 4 - I assume GPRM0, as that is the one you are working with in lines 1, 2 and 3.
If you want to return to the loop point of a menu depending on the button the user previously selected being the first button then the code is this:
mov GPRM0, SPRM8
div GPRM0, 1024
Jump MenuName (Loop) If (GPRM0 = 1)
However, you might want to simply start at the loop point of the menu but make sure that the user is on the same button they were on previoulsy, in which case the code would be:
mov GPRM0, SPRM8
div GPRM0, 1024
Jump MenuName (Loop) \[GPRM0\]
To do this you \must make sure that you have checked the GPRM based button checkbox in the property inspector.
If you want to go to the next logical button after the one the user was on previoulsy, then you would need to add a '1' to it. The code looks like this:
mov GPRM0, SPRM8
div GPRM0, 1024
add GPRM0, 1
Jump MenuName (Loop) \[GPRM0\]
Note that the bracket shapes are important... a GPRM based button jump means that you will go to a button which has a value the same as that in the specified GPRM. The square brackets signify it is this kind of move, and not a simple evaluation of true or false.