Josh English <Jos### [at] joshuarenglishcom> wrote:

> And this created a proof of concept below (completely wrong angles,
> because I have no idea how to make one, and I don't know what it takes
> to get a POV-Ray scene to even make one colorized version.

Paul Bourke has an impressive collection of detailed POV-Ray articles, an I
recall stumbling over his stereogram article several times over the years.


http://paulbourke.net/stereographics/vpac/povray.html

- BE

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"Bald Eagle" <cre### [at] netscapenet> wrote:
> Josh English <Jos### [at] joshuarenglishcom> wrote:
>
> > And this created a proof of concept below (completely wrong angles,
> > because I have no idea how to make one, and I don't know what it takes
> > to get a POV-Ray scene to even make one colorized version.
>
> Paul Bourke has an impressive collection of detailed POV-Ray articles, an I
> recall stumbling over his stereogram article several times over the years.
>
>
> http://paulbourke.net/stereographics/vpac/povray.html
>

That's a very interesting method and description; I had not seen it before.
Thanks. From a quick glance, I can't yet tell if his method creates a complete
stereogram in only *one* render (like using the meshcam), or if it requires two
renders. I'll have to come back to it to absorb it in detail.

Meanwhile, I'm still doing some hard thinking about my red/cyan trials...

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"Kenneth" <kdw### [at] gmailcom> wrote:
>
> Meanwhile, I'm still doing some hard thinking about my red/cyan trials...
>

SO...after *MANY* experiments and failed attempts, here is my first successful
meshcam color anaglyph-- rendered in a single pass with the 'meshcam_persp_demo'
file, only slightly modified. It was a hard learning curve, ha.

I added a few objects to the scene (and in 'demo_common.inc') just to test
various things.

I was pleasantly surprised at the good color separation between the two camera
views, with very little 'ghosting' or cross-talk. Of course, that depends on the
colors matching those of the anaglyph glasses.

The first thing you might notice is that all of the objects pop *out* of the
screen, not into it; I have not yet worked out the proper code changes to fix
that (without messing up something else.) Just getting to this point was a
workout.

I had to abandon the idea of using colored instantiated meshes or spheres to
create the two-color stereo effect; they caused too many odd and un-fixable
problems. Instead, I used very small colored cylinders, placed *just so*, in
combination with changed values in the code's  'location' vector  (location
<0,0,-1.4>). The mesh camera's two views essentially look 'through' the
cylinders. At least, I think so! For this test, I used rgbf <1,0,0,1> and
likewise green (or blue/cyan). There may be better combinations of filter +
transmit colors.

Several of the code's values and settings interact with each other, so it has
been difficult to 'tease out' the best combination. So far, changing the camera
angle (c_angle) and the render resolution both work OK with my set-up, without
having to make other changes. I even made a short anaglyph animation, moving the
camera around.

Prior to this successful demo, I tried all sorts of crazy and unworkable
schemes. Some are worth posting about later, because they show some interesting
behavior of the meshcam and its meshes.

--to be continued!--

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Attachments:
Download 'meshcam_anaglyph_1_kw.jpg' (212 KB)

Preview of image 'meshcam_anaglyph_1_kw.jpg'

Well done, sir!

-- 
Thomas

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"Kenneth" <kdw### [at] gmailcom> wrote:
> "Kenneth" <kdw### [at] gmailcom> wrote:
>
> SO...after *MANY* experiments and failed attempts, here is my first successful
> meshcam color anaglyph-- rendered in a single pass with the 'meshcam_persp_demo'
> file, only slightly modified.
>
> The first thing you might notice is that all of the objects pop *out* of the
> screen, not into it...

I solved the 3-D depth problem of the objects appearing solely in front of the
'screen plane', and I'm generally happy with the single-render effect--
although the method I used is not ideal. (The only post-processing I did was to
add the text.)

Essentially, there is a basic horizontal translation of the 2nd camera mesh to
*get* the 3-D, then I rotated that mesh horizontally (about it's 'spherical
center point') to correct the in/out depth effect. But rotating the camera mesh
introduces subtle 'lens distortion' when that view is combined with the 1st
camera mesh; it's most pronounced near the diagonal edges of the frame, as
slight vertical color offsets . The mesh-camera's 'angle' setting (c_angle)
affects the amount of this distortion; I used 65 for this view, which is rather
wide-angle. With, say, 45, there is less offset.

Ideally, the objects in the two colored views should appear to have only strict
horizontal displacement; without the needed rotation, that IS so. To correct the
3-D depth appearance, I tried other strict translations instead-- but they
caused depth-REVERSAL problems (or wiped out the 3-D altogether.)

I think I understand why the rotated mesh causes the slight offset, but I don't
know how to correct for it.  It looks kind of like lens 'barrel distortion', but
not quite. So I tried invoking that feature in the demo scene, in a 'reverse'
way, but it affects BOTH meshes (since a single created mesh is used for both
views.) Of course, it's possible that there are other code changes or tricks
that might work instead of a simple rotation, but no luck so far.

As was suggested earlier, the *best* way to get such a stereogram would be to
use two separate mesh CAMERAS, rather than two meshes in a single camera. I
tried that-- but multiple 'camera' statements in a scene are not allowed, with
the usual error message, "More than one camera in scene, ignoring previous
camera(s)".

Meanwhile, I continue to learn new things!

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Attachments:
Download 'meshcam_anaglyph_2_kw.jpg' (194 KB)

Preview of image 'meshcam_anaglyph_2_kw.jpg'

26/05/2023 18:53, Kenneth wrote:
> I solved the 3-D depth problem of the objects appearing solely in front of the
> 'screen plane', and I'm generally happy with the single-render effect--
> although the method I used is not ideal. (The only post-processing I did was to
> add the text.)
> 
  A very nice result!

Paolo

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