Envmap position

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dag
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Envmap position

Post by dag » Tue Oct 11, 2011 8:30 am

Looks like the envmap is mapped around the 0,0,0 coordinates?
That means you need the camera at 0 to avoid distortions.
Shouldn't the envmap map around the camera to get correct spherical mapping and lightingings?
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camera at 0
under.jpg
camera under 0
over.jpg
camera over 0

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galinette
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Re: Envmap position

Post by galinette » Tue Nov 15, 2011 12:37 am

That's very strange... Envmap is supposed to be at infinity, the projection should not depend on camera position...

Are you talking about camera z position or pitch?

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dag
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Re: Envmap position

Post by dag » Tue Nov 15, 2011 1:04 am

Camera Z pos.
The more it's moved up or down the more the env gets distorted, just like if you map it to the inside of a sphere in your modeling app and move the camera up or down.

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CTZn
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Re: Envmap position

Post by CTZn » Tue Nov 15, 2011 4:48 am

Since the environment is a finite sphere indeed, moving it with the camera would affect the lighting of the scene.

Its size may be relative to the scene bounding box, so one should not notice this under a normal usage.
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Re: Envmap position

Post by galinette » Tue Nov 15, 2011 4:55 am

OK

This is a strange way of describing envmap : an infinite sphere should be used.
If finite, it should be centered on the camera.

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CTZn
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Re: Envmap position

Post by CTZn » Tue Nov 15, 2011 5:48 am

galinette wrote:If finite, it should be centered on the camera.
Then lighting would change along with the camera position.

I am not sure that Indigo has always used a finite sphere for environments. A real infinite source sounds more elegant indeed, any technical consideration disregarded. I'm not educated enough :)
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galinette
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Re: Envmap position

Post by galinette » Tue Nov 15, 2011 7:08 am

CTZn wrote:
galinette wrote:If finite, it should be centered on the camera.
Then lighting would change along with the camera position.
Sure... this would be a mess for animations
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CTZn
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Re: Envmap position

Post by CTZn » Thu Nov 17, 2011 12:27 pm

If finite, it should be centered on the camera.
However the issue I am running into currently is with aligning the Indigo and env map suns, one more argument in favor of a fixed world position.

Either as a permanent option, or forced if the sum material involves the sunsky material.

As a permanent centering option, could be among: "camera", "world" (pos either origin), "bounding box".

A true infinite source is still ideally prefered.
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