Previously we were using this workaround when using framebuffer fetch
to emulate dual source blending, but it seems like we also need to use
it when using framebuffer fetch to emulate logic ops, otherwise some
Adreno devices get a crash when compiling OpenGL ES ubershaders.
Using the workaround in specialized shaders doesn't seem to be
necessary, but I've made the same change there for consistency.
This gets us closer to fixing https://bugs.dolphin-emu.org/issues/12791
but doesn't actually fix it.
On devices which have hardware support for dual source blending
but not logic ops, this lets us skip performing the framebuffer
fetch in situations where the game isn't actually using logic ops.
It doesn't make sense for alpha to add the bias ONLY when dividing by 2, while color doesn't apply the bias for divide by 2 only; hardware testing indicates that alpha should have the bias.
This fixes the menus in Mario Kart Wii (https://bugs.dolphin-emu.org/issues/11909) but reintroduces the white rectangle in Fortune Street.
This reverts commit 5aaa5141ed (and several other matching changes elsewhere).
This syntax is allowed by GLSL, but HLSL doesn't allow it. This meant that games using R8 comparisons in equal mode would produce shaders that failed to compile. Super Mario Galaxy's water levels were affected by this.
To do this, I had to decouple framebuffer fetch from shader blending. We need to be able to access framebuffer fetch input when using shader logic ops.
Specifically, when using Manual Texture Sampling, if textures sizes don't match the size the game specifies, things previously broke. That can happen with custom textures, and also with scaled EFB copies at non-native IRs. It breaks most obviously by not scaling the texture coordinates (so only part of the texture shows up), but the hardware wrapping functionality also assumes texture sizes are a power of 2 (or else it will behave weirdly in a way that matches how hardware behaves weirdly). The fix is to provide alternative texture wrapping logic when custom texture sizes are possible.
Note that both GLSL and HLSL provide a fwidth (fragment width) function defined as `fwidth(p) = abs(dFdx(p)) + abs(dFdy(p))`. However, it's easy enough to implement this ourselves (and it makes the code a bit more obvious).
The benefit to exposing this over the raw BP state is that adjustments Dolphin makes, such as LOD biases from arbitrary mipmap detection, will work properly.
