RenderOrder is in different scale in Reverse Z

[darksylinc]

I could not find info online about this problem, so i had to write a
test myself.

The obvious solution is to multiply the depth bias by 100 or so; but I
was wondering what would be the side effects on other geometry.

I.e. what would happen to geometry that is meant to be in front of the
plane? We know a depth bias of 300 works at close range at reverse Z
(where at normal Z a depth bias of 3 was enough), but would the plane
get on top of everything as you move the camera away?

So I made a test: https://www.youtube.com/watch?v=s2XdH3fYUac

We can safely multiply by something like 100 or so, and we will get
better results with reverse Z than we could with normal Z + the usual
depth bias constant scale.

With Normal Z, wven with a depth bias of 3 will eventually be on top of
everything, but with Reverse Z + depth bias of 300, that never happens.

Apparently multiplying the constant bias by 100.0f is the right thing
to do.

Fixes #427

Signed-off-by: Matias N. Goldberg [email protected]

🦟 Bug fix

Fixes #427

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[codecov]

Codecov Report

Merging #514 (5bc9e4b) into ign-rendering6 (93a5307) will increase coverage by 0.00%.
The diff coverage is 80.00%.

@@               Coverage Diff               @@
##           ign-rendering6     #514   +/-   ##
===============================================
  Coverage           55.42%   55.42%           
===============================================
  Files                 195      195           
  Lines               19758    19762    +4     
===============================================
+ Hits                10951    10954    +3     
- Misses               8807     8808    +1     

Impacted Files	Coverage Δ
ogre2/src/Ogre2Material.cc	84.21% <80.00%> (-0.10%)	⬇️

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[iche033]

oh interesting, I didn't expect the fix to be a straightforward multiplication factor. The results look good, thanks for testing!

[osrf-triage]

This pull request has been mentioned on Gazebo Community. There might be relevant details there:

https://community.gazebosim.org/t/new-ignition-releases-2022-03-01-citadel-edifice-fortress/1313/1