GRAPHICS: Several shaders seem to be buggy

[raziel-]

I did a quick test with all the available shaders and found four that behave strange or are buggy or wrongly interpreted (you tell me) :-)

cel/presets/MMJ_Shader_strong.glslp
-> wobbles from left to right and vice versa in the lower 50% of the screen, other disturbances can be seen in the middle of the screen while it wobbles

handheld/console-border/psp-2x.glslp (all of the sizes are affected)
-> turns the console graphics upside down (see screenshot)

handheld/simpletex_lcd+gba-color.glslp (also "+gbc-" and all "lcd" shaders are affected)
-> turns the whole screen upside down

ntsc/artifact-colos.glslp
-> suddenly turns darker vertically after around 55% of the screen

All of this is with the test pattern and confirmed on both AmigaOS4 and Windows

[tag2015]

I can't reproduce the simpletex issue.
Regarding the PSP shaders, the "border" image is already flipped in the /resources... so not really surprising :D

[tag2015]

Going back to this bug, I noticed that these shaders are not part of the small set that we ship with scummvm, so it's quite likely that some may be misbehaving.