Sonic and Sega Retro Message Board: evilhamwizard - Viewing Profile - Sonic and Sega Retro Message Board

Judging by this, that's Craig Sitt. ICEKnight did a interview with him years a go.

The game sets njRendererSetFpsLock to 0 for a split moment when the screen begins to fade and then sets it back to 1 again sometime while game is loading the next area.

I recorded a video of what it looks like when njRendererSetFpsLock is set to 0 for the actual gameplay (video might still be rendering):



If you want to achieve this effect yourself, open your copy of jetsetradio.exe in your favorite hex editor and look for the bytes 6A01E86FB9F4FF6A. Change the 6A01 part to 6A00 and save the .exe.

I still haven't figured out how to get the game to properly run as it should with this enabled. :\

I had the same thought as well about the lack of variable frame rate. I'm wondering if the amount of frames produced in game is a hard coded value (41F00000 is 30.0 in single precision, but I think the game actually runs at 31.0 so maybe 41F80000). But then again, I don't know if the game could be passing this value directly within a subroutine or if that float is stored somewhere in the .data segment. It couldn't be something weird like 29.97 right?

Now that I think about it, does anyone know if the Android/iOS port runs at a variable frame rate or if it runs at any other framerate other than 30/31 during game play? I know the iOS version isn't supported with iOS 8, but maybe perhaps the Android port will yield a similar result?

Hm, njRendererSetFpsLock doesn't appear to be it. It unlocks the framerate so it runs at 60, but it causes the game to run at double the framerate (so everything is running too fast). You can tell that this isn't the way it's supposed to run because the in game timer runs at twice the speed. 0 disables the lock, 1 enables it. The game will disable the lock at the initial loading screen, the Heritage logo, and the loading screen in game.

The function that actually sets the njRendererSetFpsLock function to 1 for the gameplay is deProgress(). In my .exe, it's this:

.text:003386F0 ; =============== S U B R O U T I N E =======================================
.text:003386F0
.text:003386F0
.text:003386F0 deProgress      proc near               ; DATA XREF: sub_338740+1Fo
.text:003386F0                 push    1
.text:003386F2                 call    j_njRendererSetFpsLock
.text:003386F7                 push    62h
.text:003386F9                 mov     isBusyLoading, 0
.text:00338703                 call    j_jtActionGet
.text:00338708                 add     esp, 8
.text:0033870B                 test    eax, eax
.text:0033870D                 jnz     short locret_338726
.text:0033870F                 push    0FF000000h
.text:00338714                 push    0FF000000h
.text:00338719                 push    0FF000000h      ; struct CFrameWnd *
.text:0033871E                 call    j_?AFXSetTopLevelFrame@@YAXPAVCFrameWnd@@@Z_33 ; AFXSetTopLevelFrame(CFrameWnd *)
.text:00338723                 add     esp, 0Ch
.text:00338726
.text:00338726 locret_338726:                          ; CODE XREF: deProgress+1Dj
.text:00338726                 retn
.text:00338726 deProgress      endp
.text:00338726
.text:00338726 ; ---------------------------------------------------------------------------

Pseudo code:

void deProgress()
{
  j_njRendererSetFpsLock(1);
  isBusyLoading = 0;
  if ( !j_jtActionGet(98) )
    AFXSetTopLevelFrame((struct CFrameWnd *)0xFF000000);
}

The game is very picky some times when you load it up. Sometimes the game runs at a choppy frame rate if your computer's been on for a while, so that explains why I didn't see the effects of changing the parameter from 1 to 0 initially. I restarted my computer and tried again and this time I got results. But again, this isn't exactly the 60fps I had in mind. I think we'll need to disable the lock as well as change one more thing to allow the game to actually render 60 new frames in one second.

ICEknight, on 30 May 2015 - 09:07 PM, said:

From the Sonic CD symbol names list I found a few years a go.

The two games have a lot of similarities with one another, so it's understandable they share the same symbol names too.