OpenCL gegl:weighted-blend blends full transparencies differently than non OpenCL
On my laptop running:
$ GEGL_USE_OPENCL=no gegl -o tmp.png -- rectangle color=#0f00 weighted-blend aux=[ gegl:rectangle color=#0f00 ]
produces a different output than:
$ GEGL_USE_OPENCL=yes gegl -o tmp.png -- rectangle color=#0f00 weighted-blend aux=[ gegl:rectangle color=#0f00 ]
the problem is that the cl version, in case total_alpha == 0
, assigns 1 to the output alpha, whereas the C version outputs transparent black.