[GEM-dev] framebuffer and pix_data

[cyrille henry]

ok,
thanks for the answer.
i still don't understand all of this, i need to have a deeper look.

now, i know where to look.

thanks
cyrille


Wesley Smith a écrit :
>>> What exactly do you mean by 16/32 bits color?  Do you mean per-channel
>>> or combined RGBA values?
>> i mean per channel.
>>
>>
>>>  glReadPixels works with any format that I've
>>> come across.  What makes you think it won't work for your situation?
>> the doc i find there :
>> http://www.opengl.org/sdk/docs/man/xhtml/glReadPixels.xml
>> does not specify a format with 16/32 bit per channel.
>> unless i'm misunderstand something...
>>
>> did your really used glReadPixels with 16 or 32 bit per channel?
>> and if yes, with what type and format?
> 
> The OpenGL docs like this one don't cross-reference other uses/abuses
> of the function.  glReadPixels as documented in your link refers to
> its use on the standard OpenGL drawing buffers but does not mention
> anything about extensions like FBOs.  Typical OpenGL draw buffers can
> only have integer types, so you don't see the higher bpp type enums in
> the docs.  However, when an FBO is active, you can set the read buffer
> to the FBO as in glReadBuffer(GL_COLOR_ATTACHMENT0_EXT).  Then when
> you call glReadPixels, it will read the pixels in the FBO and if the
> FBO happens to have a float texture target attached to it, you will be
> able to read floating point values via glReadPixels.
> 
> HTH,
> wes
> 
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