Add Custom Render Plugin Example

[JShep1]

The last piece to getting the custom render engine issue (#100) resolved.

This example simply adds a mock render engine plugin that the user can load with --render-engine HelloWorldPlugin, it won't display anything to the scene as there is actually no implementation, this just serves as a template for any future user desiring to write their own render engine plugin.

Signed-off-by: John Shepherd john@openrobotics.org

Depends on gazebosim/gz-sim#373

[iche033]

The changes here allows the plugin to load in the ign-rendering side. It's now just failing in RenderUtil on the in-gazebo side since there are several places that assume a non-null scene..

[JShep1]

The changes here allows the plugin to load in the ign-rendering side. It's now just failing in RenderUtil on the in-gazebo side since there are several places that assume a non-null scene..

Can you make the PR? Mainly so I can approve. Also, I made an additional PR for ign-gazebo here adding additional null checks. I'm still getting a seg fault when attempting to run the mock render engine plugin, and gdb actually isn't helpful at all so I'm trying to figure out where exactly is occurring.

I found where the seg faults were occurring in Scene3D, I'm getting a successfully loaded plugin displaying a blank screen now. I also accidentally added to your branch thinking this one was currently checked out 😅

[iche033]

created pull request #156 containing the null checks, and your changes :)

[JShep1]

This is ready for a review whenever you have time. @iche033

[iche033]

Nice it's working for me! I am able load the hello world plugin following the instructions in the README.md. Just some minor style and doc comments

[codecov]

Codecov Report

Merging #154 into ign-rendering3 will increase coverage by 0.03%.
The diff coverage is 75.00%.

@@                Coverage Diff                 @@
##           ign-rendering3     #154      +/-   ##
==================================================
+ Coverage           50.44%   50.48%   +0.03%     
==================================================
  Files                 129      129              
  Lines               11709    11740      +31     
==================================================
+ Hits                 5907     5927      +20     
- Misses               5802     5813      +11     

Impacted Files	Coverage Δ
src/base/BaseRenderEngine.cc	73.80% <75.00%> (-4.09%)	⬇️
...e/ignition/rendering/base/BaseGaussianNoisePass.hh	100.00% <0.00%> (+3.33%)	⬆️

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[chapulina]

👍