Re: [info-performer] problem with reading color values back on Linux

From: Guillaume Millet (millet++at++oktal.fr)
Date: 07/12/2002 01:19:14

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pfHi,

Is your X server configured in 24 or 32 bpp? Because if your are in 16
bpp mode there is a dithering effect and you cant read the same value in
the frame buffer.
For configuring this it's in the XF86Config file in the Screen section:
DefaultDepth 24
and you must have video mode define for Depth 24.

Bye

Quincy wrote:

>Hi,
>
>I'm using linux version of performer to draw objects with certain color,
>but when I use glReadPixels to read the color values back, the rounding
>error is quite strange, for example, a set of black pixels may read back
>with rgb values to be:
>0.000000 0.000000 0.000000
>0.000000 0.015873 0.000000
>0.000000 0.000000 0.000000
>0.000000 0.015873 0.000000
>
>and a set of pixels all with color values: 0, 0.5, 0.98 will be read back
>like:
>0.000000 0.523810 1.000000
>0.000000 0.507937 1.000000
>0.000000 0.523810 1.000000
>0.000000 0.507937 1.000000
>etc.
>
>Does anybody know what might have caused this and how to resolve
>it? Thanks in advance.
>
>Best regards,
>
>Quincy Yu
>
>
>
>

• Next message: Kejian: "[info-performer] Question about Geometry on the scene graph"
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• In reply to: Quincy: "[info-performer] problem with reading color values back on Linux"

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