[Mesa-dev] [PATCH 2/2] mesa: Speedup the xrgb -> argb special case in fast_read_rgba_pixels_memcpy

[Patrick Baggett]

On Mon, Mar 11, 2013 at 9:56 AM, Jose Fonseca <jfonseca at vmware.com> wrote:

> I'm surprised this is is faster.
>
> In particular, for big things we'll be touching memory twice.
>
> Did you measure the speed up?
>
> Jose
>

I'm sorry to be dull, but is there a SSE2 implementation of this somewhere
for x86 / x64 CPUs?

Patrick


>
> ----- Original Message -----
> > ---
> >  src/mesa/main/readpix.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/mesa/main/readpix.c b/src/mesa/main/readpix.c
> > index 349b0bc..0f5c84c 100644
> > --- a/src/mesa/main/readpix.c
> > +++ b/src/mesa/main/readpix.c
> > @@ -285,11 +285,12 @@ fast_read_rgba_pixels_memcpy( struct gl_context
> *ctx,
> >        }
> >     } else if (copy_xrgb) {
> >        /* convert xrgb -> argb */
> > +      int alphaOffset = texelBytes - 1;
> >        for (j = 0; j < height; j++) {
> > -         GLuint *dst4 = (GLuint *) dst, *map4 = (GLuint *) map;
> > +         memcpy(dst, map, width * texelBytes);
> >           int i;
> >           for (i = 0; i < width; i++) {
> > -            dst4[i] = map4[i] | 0xff000000;  /* set A=0xff */
> > +            dst[i * texelBytes + alphaOffset] = 0xff;  /* set A=0xff */
> >           }
> >           dst += dstStride;
> >           map += stride;
> > --
> > 1.8.1.5
> >
> > _______________________________________________
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> > mesa-dev at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
> >
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