Blur-texture sampling has been changed to `CLAMP_TO_EDGE` in commit
4b0ff37b36 and to using the buffer
textures at screen position instead of texture origin in commit
89c18afac6.
When using the above approach, expanding the buffer textures by the same
amount as the damage region is not needed anymore, as we cannot render
more than the screen region anyways. Having larger-than-screen buffer
textures might lead to a slight darkening at the upper and right edges
since we don't necessarily trigger the `CLAMP_TO_EDGE` condition in the
intermediate steps. This becomes apparent when using dual-kawase at large
blur-strengths with light backgrounds.
These changes do not affect the general approach of rendering a
larger-than-window region with the blur to accommodate the necessary
increase in damage region.
Related: 6d646b543f
1dbffec3ae