Create Launcher snapshots automatically

[thrust26]

It should be possible to create the snapshot collection (mostly) automatically using e.g. the following procedure:

• iterate over all ROMs of a given directory
• start each ROM
• wait a few seconds (to skip input blocks e.g. for title screen or game start tunes)
• simulate RESET
• wait a few seconds
• press FIRE (joystick, paddles...)
• wait a few seconds
• save snapshot
• exit ROM

Not all screenshots will be good enough, but I figure we could reach >90%.

We could also create multiple screenshots (ROM start, after RESET, after FIRE) this way and then sort out (almost) duplicate ones (I think there are tools for this).

Maybe this could be done in combination with #509?

[thrust26]

After adding the swchb command, we are almost there. We can use -debug and autoexec.script to create the necessary snapshots.

Here is an example for autoexec.script which creates four snapshots/game:

frame 10
savesnap

swchb fd
frame 1
swchb ff
frame 60
savesnap

joy0fire 0
frame 1
joy0fire 1
frame 60
savesnap

joy0fire 0
frame 1
joy0fire 1
frame 60
savesnap

frame 1
exitRom

It creates a SELECT and two joystick FIRE button events. These are meant to skip potential title screens and menus. This way the last snapshot should (in most cases) display the game screen.

Now it takes a batch file to process all files of a folder. And a tool, which helps eliminating double snapshots. Alternatively taking the first three snapshots could be removed from the script.

[thrust26]

Batch file:

set scriptpath=%~dp0
for %%f in (*.bin) do stella.exe -debug "%scriptpath%%%f"

Identifiying similar images works well, e.g. with Awesome Duplicate Photo Finder

Remaining issues:

• the debugger snapshots have a variable height (should be no problem)
• the filenames of debugger snapshots have special names (should be an easy fix).