Re: 16 bit color buffer

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Christophe Bernardi (gorbalou++at++oktal.fr)
Wed, 30 Jun 1999 11:58:19 +0200

Angus Dorbie wrote:
>
> Using a luminance alpha visual is the right choice (r & a bits only).
>
> There was a bug with the selection of visuals in performer, so you may
> be running into that. It's slightly worrying because you say you appear
> to get rgba12 which is not the fastest visual, rgb10 would be
> prefferable for speed unrelated to your problem but generally relevant
> for other readers.
>
> Try using attributes to choose the visual.

I think I got the good visual. See the output:

with 10b:
pfPipeWindow Framebuffer Configuration: IRIS Performer [pipe 0]
        RGB_BITS: 10
        ALPHA_BITS: 0
        CI_BITS: 24
        DEPTH_BITS: 16
        MIN_DEPTH_VAL: 0
        MAX_DEPTH_VAL: 2147483647
        MS_SAMPLES: 8
        STENCIL_BITS: 8
        DOUBLEBUFFER: 1
        STEREO: 0
...
0-11=0.000000 first and last line with the same value in the FB
12-24=0.000977 = 1/2^10
25-37=0.001953
38-49=0.002930
...

with 12b:
pfPipeWindow Framebuffer Configuration: IRIS Performer [pipe 0]
        RGB_BITS: 12
        ALPHA_BITS: 12
        CI_BITS: 24
        DEPTH_BITS: 23
        MIN_DEPTH_VAL: 0
        MAX_DEPTH_VAL: 2147483647
        MS_SAMPLES: 0
        STENCIL_BITS: 8
        DOUBLEBUFFER: 1
        STEREO: 0
...
0-1=0.000000
2-4=0.000244 = 1/2^12
5-7=0.000488
8-10=0.000732
...

with 16b:
pfPipeWindow Framebuffer Configuration: IRIS Performer [pipe 0]
        RGB_BITS: 16
        ALPHA_BITS: 16
        CI_BITS: 64
        DEPTH_BITS: 23
        MIN_DEPTH_VAL: 0
        MAX_DEPTH_VAL: 2147483647
        MS_SAMPLES: 0
        STENCIL_BITS: 8
        DOUBLEBUFFER: 1
        STEREO: 0
...
0-1=0.000000
2-4=0.000244 != 1/2^16
5-7=0.000488
8-10=0.000732
...

> >
> > 14
> > # visualClass level rgb {R,G,B,A}Bits accum{R,G,B,A}Bits double stereo
> > indexBits depthBits stencilBits aux msamples mbuffers
> > #
> > # overlay
> > 4 1 1 5 5 5 1 0 0 0 0 0 0 15 0 0 0 0 0
> > # multisample
> > 4 0 3 16 0 0 16 25 0 0 25 0 0 12 23 8 0 0 0
> > 4 0 1 16 0 0 16 0 0 0 0 0 0 24 23 8 0 8 1
> > 4 0 1 10 10 10 0 32 32 32 0 1 0 24 16 8 0 8 1
> > 4 0 1 8 8 8 8 32 32 32 32 1 0 24 16 8 0 4 1
> > 4 0 1 8 8 8 8 0 0 0 0 1 0 24 15 1 0 4 1
> > 4 0 1 12 12 12 12 32 32 32 32 0 0 24 16 8 0 4 1
> > 4 0 1 10 10 10 0 0 0 0 0 1 0 24 23 1 0 4 1
> > 4 0 1 10 10 10 0 25 25 25 0 0 1 30 0 0 0 8 1
> > 4 0 1 5 5 5 1 0 0 0 0 1 0 24 15 8 0 4 1
> > # truecolor visuals
> > 4 0 1 12 12 12 12 32 32 32 32 0 0 24 23 8 0 0 0
> > 4 0 1 12 12 12 12 32 32 32 32 1 0 24 23 8 0 0 0
> > # pseudocolor visuals
> > 3 0 0 0 0 0 0 0 0 0 0 0 0 12 23 8 0 0 0
> > 3 0 0 0 0 0 0 0 0 0 0 1 0 12 23 8 0 0 0
> >

Is this file correct ?
 I need more information/doc on the format of this file and the relation
 with the output of glxinfo -fbcinfo.

2. with pbuffer but I don't know how to make the p bit in the drawable
type for glxinfo -fbcinfo

Remark: on O2 I have these visuals but they don't have Xid
0xffffffff -1 ?? . 8 . r . . 8 . . . . . . . . . . . .
p|P 0x5c
0xffffffff -1 ?? . 16 . r . . 16 . . . . . . . . . . . .
p|P 0x5d
0xffffffff -1 ?? . 64 . r . . 16 16 16 16 . . . . . . . . .
p|P 0x5e

 Thanks,

-- 
  ---------------------------------
  Christophe Bernardi
  Oktal
  2, Impasse de Boudeville 31100 Toulouse
  Tel: 05 62 11 93 50
  Fax: 05 62 11 50 29
  mailto:gorbalou++at++oktal.fr
  ----------------------------------

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