[Mesa-dev] [PATCH v2] dri/i965: fix incorrect rgbFormat in intelCreateBuffer().

[Ilia Mirkin]

Sounds right. That's glEnable/glDisable(GL_FRAMEBUFFER_SRGB). It
defaults to off for desktop GL, and on for GL ES (why? no clue.)

On Tue, Apr 5, 2016 at 8:11 PM, Haixia Shi <hshi at chromium.org> wrote:
> Are you referring to the following check
>
> mesa_format
> _mesa_get_render_format(const struct gl_context *ctx, mesa_format format)
> {
>    if (ctx->Color.sRGBEnabled)
>       return format;
>    else
>       return _mesa_get_srgb_format_linear(format);
> }
>
> So if the platform sets ctx->Color.sRGBEnabled = false then I should not
> have this problem? Thanks
>
> On Tue, Apr 5, 2016 at 2:04 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>>
>> On Tue, Apr 5, 2016 at 4:57 PM, Haixia Shi <hshi at chromium.org> wrote:
>> > CC Stephane
>> >
>> > In my opinion we should not assume sRGB-capable when alpha is requested,
>> > because UNORM is the more common use case. I actually have a use case
>> > where
>> > alpha is requested but not sRGBCapable, and if we assume SRGB by default
>> > then we will get really white-washed faded color.
>>
>> That most likely means that your application is buggy. Even though the
>> SRGB format is returned internally, that doesn't mean that SRGB
>> encoding/decoding is actually enabled. Just provides the option for it
>> to be used.
>>
>> >
>> > On Tue, Apr 5, 2016 at 1:52 PM, Ilia Mirkin <imirkin at alum.mit.edu>
>> > wrote:
>> >>
>> >> On Tue, Apr 5, 2016 at 4:33 PM, Haixia Shi <hshi at chromium.org> wrote:
>> >> > It is incorrect to assume that pixel format is always in BGR byte
>> >> > order.
>> >> > We need to check bitmask parameters (such as |redMask|) to determine
>> >> > whether
>> >> > the RGB or BGR byte order is requested.
>> >> >
>> >> > Furthermore when parameter |sRGBCapable| is set to false, we should
>> >> > be
>> >> > using
>> >> > UNORM format by default.
>> >>
>> >> Unfortunately none of the visuals are exported with that flag, so it
>> >> will always be false in practice. The current logic is also very
>> >> fragile -- you only get a sRGB-capable fb if you happen to request
>> >> alpha.
>> >>
>> >> >
>> >> > v2: reformat code to stay within 80 character per line limit.
>> >> >
>> >> > Signed-off-by: Haixia Shi <hshi at chromium.org>
>> >> > Reviewed-by: Stéphane Marchesin <marcheu at chromium.org>
>> >> > Cc: kenneth.w.graunke at intel.com
>> >> >
>> >> > Change-Id: Ib75087aef1fbfb51baa72517207fed410dcd7b1e
>> >> > ---
>> >> >  src/mesa/drivers/dri/i965/intel_screen.c | 20 ++++++++++++--------
>> >> >  1 file changed, 12 insertions(+), 8 deletions(-)
>> >> >
>> >> > diff --git a/src/mesa/drivers/dri/i965/intel_screen.c
>> >> > b/src/mesa/drivers/dri/i965/intel_screen.c
>> >> > index c6eb50a..a27d7ee 100644
>> >> > --- a/src/mesa/drivers/dri/i965/intel_screen.c
>> >> > +++ b/src/mesa/drivers/dri/i965/intel_screen.c
>> >> > @@ -1000,15 +1000,19 @@ intelCreateBuffer(__DRIscreen * driScrnPriv,
>> >> >        fb->Visual.samples = num_samples;
>> >> >     }
>> >> >
>> >> > -   if (mesaVis->redBits == 5)
>> >> > -      rgbFormat = MESA_FORMAT_B5G6R5_UNORM;
>> >> > -   else if (mesaVis->sRGBCapable)
>> >> > -      rgbFormat = MESA_FORMAT_B8G8R8A8_SRGB;
>> >> > -   else if (mesaVis->alphaBits == 0)
>> >> > -      rgbFormat = MESA_FORMAT_B8G8R8X8_UNORM;
>> >> > -   else {
>> >> > -      rgbFormat = MESA_FORMAT_B8G8R8A8_SRGB;
>> >> > +   if (mesaVis->redBits == 5) {
>> >> > +      rgbFormat = mesaVis->redMask == 0x1f ?
>> >> > MESA_FORMAT_R5G6B5_UNORM
>> >> > +                                           :
>> >> > MESA_FORMAT_B5G6R5_UNORM;
>> >> > +   } else if (mesaVis->alphaBits == 0) {
>> >> > +      rgbFormat = mesaVis->redMask == 0xff ?
>> >> > MESA_FORMAT_R8G8B8X8_UNORM
>> >> > +                                           :
>> >> > MESA_FORMAT_B8G8R8X8_UNORM;
>> >> > +   } else if (mesaVis->sRGBCapable) {
>> >> > +      rgbFormat = mesaVis->redMask == 0xff ?
>> >> > MESA_FORMAT_R8G8B8A8_SRGB
>> >> > +                                           :
>> >> > MESA_FORMAT_B8G8R8A8_SRGB;
>> >> >        fb->Visual.sRGBCapable = true;
>> >> > +   } else {
>> >> > +      rgbFormat = mesaVis->redMask == 0xff ?
>> >> > MESA_FORMAT_R8G8B8A8_UNORM
>> >> > +                                           :
>> >> > MESA_FORMAT_B8G8R8A8_UNORM;
>> >> >     }
>> >> >
>> >> >     /* setup the hardware-based renderbuffers */
>> >> > --
>> >> > 2.8.0.rc3.226.g39d4020
>> >> >
>> >> > _______________________________________________
>> >> > mesa-dev mailing list
>> >> > mesa-dev at lists.freedesktop.org
>> >> > https://lists.freedesktop.org/mailman/listinfo/mesa-dev
>> >
>> >
>
>