Re: [Openexr-devel] Saving EXR file one channel at time

[Pavel Ledin]

Hello Pavel,


Many people what have such functionality.
But it's not possible in OpenEXR.
It's lack of exr format.


Thursday, August 19, 2010, 4:23:19 PM, you wrote:

>   Hi!

> I need to save an EXR file with several channels (for example 
> RGBA+Depth+AmbientOcclusion) in a kind of strange way. I'd like to save
> the RGBA channels first and then, after some time, add a Depth channel
> and then the other channel (layer, whatever) into the same file. I tried
> this by first setting the header to have all necessary channel (names)
> and then filling a framebuffer first with RGBA channels only, writing 
> pixels, then creating another framebuffer with depth channel (and same
> header), writing pixels and so on. This is obviously not the right 
> approach, since I ended up with a file containing only the last channel
> :-) (I first tried R, then GBA for example).

> The reason for wanting to create the single file in several passes is 
> memory constraints (the images will be rather big, generated in Direct3D
> and I don't want to hold all of them in memory at once). Is it even 
> possible?

> I'm using Imf::OutputFile (scan-lines).

> Many thanks! (my first post, hopefully correctly sent)




-- 
Best regards,
 Pavel Ledin aka Puppet                            mailto:address@hidden
 Lighting & Shading TD, Animaccord
 Moscow, Russia