Cocktail Shader Rotation

[caver01]

@caver01 Oh, I see, you want mirrored gameplay.

[caver01]

@caver01 What emulator are you using? With MAME, you can usually configure the ROM's DIP switch for Cocktail Mode so it will actually FLIP the image for player 2. Using this, I don't ever need to use any mirroring. Of course, this is exclusive to arcade games.

[chirpy]

I have looked at this option using mame2010. But i've been searching for a more 'universal' option for not just arcade games.
It'd be great for the function to go mirrored on everything from metal slug to nes games. :-)

[caver01]

@chirpy Understood. What about deploying your shader (I assume via retroarch.cfg files), but then adding a line in the config to rotate it back? The configs could be per-rom, so you aren't changing it on the fly, but a custom config per game.

[chirpy]

Sounds interesting. What would the correct 'line in the config' be?

[caver01]

@chirpy

# Forces a certain rotation of the screen.
# The rotation is added to rotations which the libretro core sets (see video_allow_rotate).
# The angle is <value> * 90 degrees counter-clockwise.

video_rotation = 0

So, basically you set the value of this line to 1, 2 or 3, and with a little trial and error, you can get the rotation the way you need.

[chirpy]

It didnt work. The rotation command did work. but it rotated both shaders, meaning 1 of them were always pointing to the side.
Is there any command to refer directly to a shader?

[caver01]

@chirpy probably within the shader. Sorry. You will have to learn OpenGL shader code I think. There are resources online (I searched for them once) but it is beyond my abilities. It may be worth asking on retroarch/libretro forums. It's not really a RetroPie thing.

[chirpy]

Fair enough, i'll give that a try. If i get any solutions i'll be sure to post back here anyway.
Thanks for your time.

[Thought]

Any luck? Also, (I'm new to RetroPie) what are the steps you took to get the cocktail shader? I've been looking around, but have yet to figure out how to find it, let alone get it running. Help?