Affects per-pixel transparency
The current method renders to the screen by copying the GLES output to a
DIB for transparency using the CPU instead of rendering directly to the
window via the GPU. This is slower and also forces the window to be borderless
as WS_EX_LAYERED affects the non-client region as well.
This change uses DWMEnableBlurBehindWindow which allows using the standard
glClearColor() background alpha and is also performed through the GPU,
eliminating CPU bottlenecks
9584f24be5