This could cause glReadPixels() calls which assume no buffer is bound
(e.g. CPU EFB access) to fail. The problem was limited to devices which
don't support persistent mapping, as the map path is not otherwise.
Both libusbhid (system library) and libhidapi (3rd party library)
provide a function called hid_init. Dolphin was being linked to both.
The WiimoteScannerHidapi constructor was calling hid_init without
arguments. libusbhid's hid_init expects one argument (a file path).
It was being called as if it was defined without arguments, which
resulted in a garbage path being passed in, and because of that,
the Qt GUI was failing to launch with the following error:
'dolphin-emu-qt2: @ : No such file or directory'
The console appears to behave against standard IEEE754 specification
here, in particular around how NaNs are handled. NaNs appear to have no
effect on the result, and are treated the same as positive or negative
infinity, based on the sign bit.
However, when the result would be NaN (inf - inf, or (-inf) - (-inf)),
this results in a completely fogged color, or unfogged color
respectively. We handle this by returning a constant zero for the A
varaible, and positive or negative infinity for C depending on the sign
bits of the A and C registers. This ensures that no NaN value is passed
to the GPU in the first place, and that the result of the fog
calculation cannot be NaN.
It seems it doesn't like modifying inout variables in place - so instead
use a temporary for ocol0/ocol1 and only write them once at the end of
the shader
This will generate one shader per copy format. For now, it is the same
shader with the colmat hard coded. So it should already improve the GPU
performance a bit, but a rewrite of the shader generator is suggested.
Half of the patch is done by linkmauve1:
VideoCommon: Reorganise the shader writes.
Also skips swapping the window system buffers in headless mode, as there
may not be a surface which can be swapped in the first place. Instead,
we call glFlush() at the end of a frame in this case.
