[vlc-devel] [PATCH] blend: Handle alpha when blending in RGBA?buffers

Martin Storsjö martin at martin.st
Thu Jan 16 18:21:05 CET 2014


On Thu, 16 Jan 2014, Steinar H. Gunderson wrote:

> On Thu, Jan 16, 2014 at 10:43:06PM +0800, Rémi Denis-Courmont wrote:
>> Is this patch not preventing unrolling? If so, performance will be rather
>> badly affected? (Yes, obviously this depends on the compiler)
>
> Well, obviously you won't know without testing, but ifs in general don't
> prevent unrolling. (Of course, the ideal case here is that the if is hoisted
> out of the loop.)

In this case, has_alpha is actually a template parameter so the ifs should 
(didn't check but I'd hope so) be stripped out by the compiler altogether.

// Martin


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