How did Toni fix PP Hammer and Spindizzy Worlds flicker?

[rsn8887]

I am trying to wrap my head around the old UAE codebase of UAE4All2, since I have it running on Vita with lots of nice options such as custom controls, shaders, touch controls, and fast. Naturally, all the old UAE bugs are present from fifteen years ago. How has it been that long?

I would like to fix one bug, the "flicker in PP Hammer and Spindizzy Worlds." It was fixed by Toni Wilen in 0.9.91.

WinUAE 0.9.91 (19.08.2004) "WinUAE 1.0 public beta #2" 
====================================================== 

Bugs in 0.9.90 fixed: 

- Multiple directory filesystem emulation bugs (files getting truncated 
to zero if opened in rw-mode, read-only files failing to open and some 
operations returning incorrect AmigaDOS error codes) 
- AGA horizontal scrolling bug in some games. 
- Stereo separation setting was not always set properly. 
- Another task-switching Direct3D/OpenGL-mode problem. 

Other fixes and updates: 

- Picasso96 black screen after CTRL-ALT-DEL. 
- bsdsocket update, fixes ~2 second pause on some systems and 
added internet connection off-line check (Stephen Riedelbeck) 
- CPU idle calculation update. CPU Idle-setting may need re-adjusting. 
- PP Hammer and Spindizzy Worlds graphics flicker fixed in non-cycle 
exact mode (again..) 

New features: 

- "uae-configuration" Amiga side program that can list current configuration, 
change all configuration parameters and send any inputevent on the fly. 
- Both right alt and ctrl are mapped to firebutton in keyboard layout B 
(some laptops don´t have right ctrl key). 
- disable quickstart-mode if using -f or -config= -command 
line parameters

It does not require cycle exact, which is good. Is there any way I can see the code changes that fixed the bug. Or, Toni, do you remember how you fixed this 15 years ago

Also, I would love to implement 4 player adapter into this old codebase, but I cannot even find where the support for it is in the modern code, and I have no clue how to transplant that into the old code. The old code has very simple joy0, joy1, and mousehack functions only.

[Galahad/FLT]

more compatible blitter speed in non cycle-exact mode (Spindizzy Worlds, PP Hammer..)

[rsn8887]

Thanks I wish I could see the changed lines of code that made this work. It might be easy to back port into UAE4All2, if I could only see the changes. I don't think GitHub existed back then, otherwise I could just look at the commit.

[dalek]

you could compare source tarballs here: https://sourceforge.net/projects/winuae/files/WinUAE/

but sounds like you would be better of backporting the UAE4All2 changes to a newer WinUAE core.

[Toni Wilen]

One possible change: blitter approximate timing also included number of bitplanes active, increasing time before blitter is finished. (blitter_slowdown())

[Toni Wilen]

Originally Posted by rsn8887

Thanks I wish I could see the changed lines of code that made this work. It might be easy to back port into UAE4All2, if I could only see the changes. I don't think GitHub existed back then, otherwise I could just look at the commit.

It didn't exist but nearly everything is there since 0.8.26-something. When I started using github, I commited every winuae source version I had, one by one.

[rsn8887]

Originally Posted by Toni Wilen

It didn't exist but nearly everything is there since 0.8.26-something. When I started using github, I commited every winuae source version I had, one by one.

Thank you Toni, I found it. I don't understand much of it, but it turns out blitter_slowdown() was completely disabled in UAE4All2. According to a comment in the code, it was disabled because it caused graphical glitches in Shadow Of the Beast.

I am learning. I know that UAE4All2 has three blitter modes: immediate, normal, and improved.

From my own experience with the emulator, immediate blitter mode seems to work the best (no flicker in Rick Dangerous, less flicker in Lionheart etc.).

But none of the three modes ever had blitter_slowdown() enabled. It was completely commented out in the source. I am thinking of enabling it again, maybe only in normal mode.

Should blit_slowdown() be active even if currprefs.immediate_blits is set to true? Or should blit_slowdown be bypassed in this case to make blitting truly immediate?

EDIT: I enabled blit_slowdown() (in normal mode only for now), and it works! The flicker in PP Hammer and Spindizzy Worlds is gone. Thanks for your help!

EDIT2: And in newer versions of WinUAE, blit_slowdown seems to be ignored if immediate_blits is true, as I thought it should. That's how it is now in UAE4All2 Vita, too.

EDIT3: Fixed version of UAE4All2 Vita is here: https://github.com/rsn8887/uae4all2/releases